1.
Drugs.com
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Drugs. com is an online pharmaceutical encyclopedia which provides drug information for consumers and healthcare professionals primarily in the USA. The domain Drugs. com was registered by Bonnie Neubeck in 1994. In 1999 at the height of the boom, Eric MacIver purchased an option to buy the domain from Neubeck. com. Venture Frogs sold the drugs. com domain name to an investor in June 2001. The Drugs. com website is owned and operated by the Drugsite Trust, the Drugsite Trust is a privately held Trust administered by two New Zealand pharmacists, Karen Ann and Phillip James Thornton The Drugs. com website was officially launched in September 2001. Stedmans, AHFS, Harvard Health Publications, Mayoclinic, North American Compendiums, in March 2008, Drugs. com announced the release of Mednotes —an online personal medication record application which connected to Google Health. In May 2010, U. S. FDA announced a collaboration with Drugs. com to distribute consumer health updates on the Drugs. com website, Drugs. com is certified by the TRUSTe online privacy certification program and the HONcode Health on the Net Foundation
2.
PubChem
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PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service
3.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses
4.
European Chemicals Agency
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ECHA is the driving force among regulatory authorities in implementing the EUs chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and it is located in Helsinki, Finland. The Agency, headed by Executive Director Geert Dancet, started working on 1 June 2007, the REACH Regulation requires companies to provide information on the hazards, risks and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most commonly used substances have been registered, the information is technical but gives detail on the impact of each chemical on people and the environment. This also gives European consumers the right to ask whether the goods they buy contain dangerous substances. The Classification, Labelling and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU. This worldwide system makes it easier for workers and consumers to know the effects of chemicals, companies need to notify ECHA of the classification and labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100000 substances, the information is freely available on their website. Consumers can check chemicals in the products they use, Biocidal products include, for example, insect repellents and disinfectants used in hospitals. The Biocidal Products Regulation ensures that there is information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation, the law on Prior Informed Consent sets guidelines for the export and import of hazardous chemicals. Through this mechanism, countries due to hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have effects on human health and the environment are identified as Substances of Very High Concern 1. These are mainly substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment, other substances considered as SVHCs include, for example, endocrine disrupting chemicals. Companies manufacturing or importing articles containing these substances in a concentration above 0 and they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy, once a substance has been officially identified in the EU as being of very high concern, it will be added to a list. This list is available on ECHA’s website and shows consumers and industry which chemicals are identified as SVHCs, Substances placed on the Candidate List can then move to another list
5.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
6.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
7.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES
8.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure
9.
Phenylacetic acid
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Phenylacetic acid, also known by various synonyms, is an organic compound containing a phenyl functional group and a carboxylic acid functional group. It is a solid with a disagreeable odor. Endogeneously, it is a catabolite of phenylalanine, as a commercial chemical, because it can be used in the illicit production of phenylacetone, it is subject to controls in countries including the United States and China. Synonyms include α-toluic acid, benzeneacetic acid, alpha tolylic acid, 2-phenylacetic acid, Phenylacetic acid has been found to be an active auxin, found predominantly in fruits. However, its effect is weaker than the effect of the basic auxin molecule indole-3-acetic acid. In addition the molecule is produced by the metapleural gland of most ant species. This compound may be prepared by the hydrolysis of benzyl cyanide, Phenylacetic acid is used in some perfumes and it is also used in penicillin G production and diclofenac production. This compound is then secreted by the patients body and its also used in the illicit production of phenylacetone, which is used in the manufacture of methamphetamine
10.
Bayer
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Bayer AG, German pronunciation, ) is a German multinational chemical, pharmaceutical and life sciences company. It is headquartered in Leverkusen, where its sign is a landmark. Bayers primary areas of business include human and veterinary pharmaceuticals, consumer products, agricultural chemicals and biotechnology products. The company is a component of the Euro Stoxx 50 stock market index, the companys motto is science for a better life. Bayers first and best known product was aspirin, there is a dispute about what scientist at Bayer made the most important contributions to it, Bayer trademarked the name heroin for the drug diacetylmorphine and marketed it as a cough suppressant and non-addictive substitute for morphine from 1898 to 1910. Bayer also introduced phenobarbital, prontosil, the first widely used antibiotic and the subject of the 1939 Nobel Prize in Medicine, the antibiotic Cipro, in 2014 Bayer bought MSDs consumer business, with brands such as Claritin, Coppertone and Dr. Scholls. Its BayerCropscience business develops genetically modified crops and pesticides and its materials science division makes polymers like polyurethanes and polycarbonate. Bayer was founded in Barmen in 1863 and it was part of IG Farben, the worlds largest chemical and pharmaceutical company, from 1925 to 1952, and then again became an independent company. The company played a key role in the Wirtschaftswunder during the early Cold War, Bayer acquired Schering in 2006 and announced its acquisition of Monsanto in 2016, the merger is still pending approval. Bayer AG was founded in Barmen, Germany in 1863 by Friedrich Bayer and his partner, the companys corporate logo, the Bayer cross, was introduced in 1904. It consists of the horizontal word BAYER crossed with the vertical word BAYER, an illuminated version of the logo is a landmark in Leverkusen, the location of Bayer AGs headquarters. Bayers first major product was acetylsalicylic acid, a modification of salicylic acid or salicin and it is now widely used in the US, UK, and France for all brands of the drug. However, it is still a trademark of Bayer in more than 80 other countries, including Canada, Mexico, Germany. As of 2011, approximately 40 thousand tons of aspirin are produced each year and 10 to 20 billion tablets are taken in the U. S. alone each year for prevention of cardiovascular events. It is on the WHO Model List of Essential Medicines, the most important medications needed in a health system. There has been controversy over the roles played by Bayer scientists in the development of aspirin, Arthur Eichengrün, a Bayer chemist, claimed to be the first to discover an aspirin formulation which did not have the unpleasant side effects of nausea and gastric pain. Eichengrün also claimed that he invented the name aspirin and was the first person to use the new formulation to test its safety, Bayer contends that aspirin was discovered by Felix Hoffmann to alleviate the sufferings of his father, who had arthritis. Various sources support the conflicting claims, most mainstream historians attribute the invention of aspirin to Felix Hoffmann and/or Arthur Eichengrün
11.
PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby
12.
Inhalational anaesthetic
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An inhalational anaesthetic is a chemical compound possessing general anaesthetic properties that can be delivered via inhalation. They are administered by anaesthetists through a mask, laryngeal mask airway or tracheal tube connected to an anaesthetic vaporiser. All of these share the property of being quite hydrophobic. The ideal volatile anaesthetic agent offers smooth and reliable induction and maintenance of general anaesthesia with minimal effects on other organ systems. In addition it is odourless or pleasant to inhale, safe for all ages and in pregnancy, not metabolised, rapid in onset and offset, potent, none of the agents currently in use are ideal, although many have some of the desirable characteristics. For example, sevoflurane is pleasant to inhale and is rapid in onset and offset and it is also safe for all ages. However, it is expensive, and approximately half as potent as isoflurane, other gases or vapors which produce general anaesthesia by inhalation include nitrous oxide, cyclopropane and xenon. These are stored in gas cylinders and administered using flowmeters, rather than vaporisers, cyclopropane is explosive and is no longer used for safety reasons, although otherwise it was found to be an excellent anaesthetic. Xenon is odourless and rapid in onset, but is expensive and requires specialized equipment to administer, under hyperbaric conditions, other gases such as nitrogen, and noble gases such as argon, krypton, and xenon become anaesthetics. When inhaled at high pressures, nitrogen begins to act as an anaesthetic agent. However, the minimum alveolar concentration for nitrogen is not achieved until pressures of about 20 to 30 atm are attained, argon is slightly more than twice as anaesthetic as nitrogen per unit of partial pressure. Xenon however is an anaesthetic at 80% concentration and normal atmospheric pressure. The full mechanism of action of volatile anaesthetic agents is unknown and has been the subject of intense debate. Anesthetics have been used for 160 years, and how work is one of the great mysteries of neuroscience, says anaesthesiologist James Sonner of the University of California. Anaesthesia research has been for a time a science of untestable hypotheses, notes Neil L. Harrison of Cornell University. Most of the injectable anesthetics appear to act on a molecular target. It looks like inhaled anesthetics act on multiple molecular targets and that makes it a more difficult problem to pick apart. However, the agent may bind to a receptor with a weak interaction, a physical interaction such as swelling of nerve cell membranes from gas solution in the lipid bilayer may be operative
13.
Chloroethane
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It is a colorless, flammable gas or refrigerated liquid with a faintly sweet odor. Some chloroethane is generated as a byproduct of polyvinyl chloride production, should demand for chloroethane continue to fall to the point where making it for its own sake is not economical, this may become the leading source of the chemical. Beginning in 1922 and continuing through most of the 20th century, the use of chloroethane was to produce tetraethyllead. TEL has been or is being phased out in most of the world. It also reacts with metal to give ethylaluminium sesquichloride, a precursor to polymers. Like other chlorinated hydrocarbons, chloroethane has been used as a refrigerant, an aerosol propellant, an anesthetic. For a time it was used as a chemical in the aluminium chloride catalyzed process to produce ethylbenzene. At present though, it is not widely used in any of these roles, the only remaining industrially important use of chloroethane is in treating cellulose to make ethylcellulose, a thickening agent and binder in paints, cosmetics, and similar products. Chloroethane is supplied as a liquid in a spray bottle propelled by its own vapor pressure and it acts as a mild topical anesthetic by its chilling effect when sprayed on skin, such as when removing splinters in a clinical setting. The heat absorbed by the liquid on tissues produces a deep and rapid chill. The vapor is flammable and narcotic, which requires care, similar to poppers, ethyl chloride is used as an inhalant during sexual activity, primarily by gay men. A small amount of the substance is placed on the tooth using a cotton wad. Chloroethanes low boiling point creates a chilling effect. If the tooth is still alive this should be sensed by the patient as mild discomfort that subsides when the wad is removed, monochloroethane is the least toxic of the chloroethanes. Like other chlorinated hydrocarbons, it is a nervous system depressant. People breathing its vapors at less than 1% concentration in air usually experience no symptoms, at concentrations of 3% to 5%, victims usually exhibit symptoms similar to those of alcohol intoxication. If exposed to higher than 6% to 8% victims often exhibit shallow breathing, loss of consciousnesses. They can be aroused with physical contact or loud noise, at this point removal from the area of exposure is advised to restore consciousness
14.
Chloroform
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Chloroform, or trichloromethane, is an organic compound with formula CHCl3. It is a colorless, sweet-smelling, dense liquid that is produced on a scale as a precursor to PTFE. It is also a precursor to various refrigerants and it is one of the four chloromethanes and a trihalomethane. The molecule adopts tetrahedral molecular geometry with C3v symmetry, the total global flux of chloroform through the environment is approximately 7005660000000000000♠660000 tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil and its half-life in air ranges from 55 to 620 days. Biodegradation in water and soil is slow, chloroform does not significantly bioaccumulate in aquatic organisms. Justus von Liebig carried out the cleavage of chloral. Eugène Soubeiran obtained the compound by the action of chlorine bleach on both ethanol and acetone, in 1834, French chemist Jean-Baptiste Dumas determined chloroforms empirical formula and named it. In 1835, Dumas prepared the substance by the cleavage of trichloroacetic acid. Regnault prepared chloroform by chlorination of chloromethane, in 1842 Dr Robert Mortimer Glover in London discovered the anaesthetic qualities of chloroform on laboratory animals. In 1847, Scottish obstetrician James Y. Simpson was the first to demonstrate the properties of chloroform on humans. By the 1850s, chloroform was being produced on a basis by using the Liebig procedure. Today, chloroform — along with dichloromethane — is prepared exclusively, in industry, chloroform is produced by heating a mixture of chlorine and either chloromethane or methane. CDCl3 is a solvent used in NMR spectroscopy. Deuterochloroform is produced by the reaction, the reaction of acetone with sodium hypochlorite or calcium hypochlorite. The haloform process is now obsolete for the production of ordinary chloroform, deuterochloroform can also be prepared by the reaction of sodium deuteroxide with chloral hydrate, or from ordinary chloroform. The haloform reaction can also occur inadvertently in domestic settings, bleaching with hypochlorite generates halogenated compounds in side reactions, chloroform is the main byproduct. Chlorodifluoromethane is then converted into tetrafluoroethylene, the precursor to Teflon
15.
Cyclopropane
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Cyclopropane and propene have the same molecular formula but have different structures, making them structural isomers. Cyclopropane is an anaesthetic when inhaled, Cyclopropane was discovered in 1881 by August Freund, who also proposed the correct structure for the new substance in his first paper. Freund treated 1, 3-dibromopropane with sodium, causing an intramolecular Wurtz reaction leading directly to cyclopropane, the yield of the reaction was improved by Gustavson in 1887 with the use of zinc instead of sodium. Cyclopropane had no application until Henderson and Lucas discovered its anaesthetic properties in 1929. Cyclopropane was introduced into use by the American anaesthetist Ralph Waters who used a closed system with carbon dioxide absorption to conserve this then-costly agent. Cyclopropane is a potent, non-irritating and sweet smelling agent with a minimum alveolar concentration of 17. 5%. This meant induction of anaesthesia by inhalation of cyclopropane and oxygen was rapid, however at the conclusion of prolonged anaesthesia patients could suffer a sudden decrease in blood pressure, potentially leading to cardiac dysrhythmia, a reaction known as cyclopropane shock. For this reason, as well as its high cost and its nature, it was latterly used only for the induction of anaesthesia. Cylinders and flow meters were coloured orange, Cyclopropane is inactive at the GABAA and glycine receptors, and instead acts as an NMDA receptor antagonist. It also inhibits the AMPA receptor and nicotinic receptors. The triangular structure of cyclopropane requires the bond angles between carbon-carbon bonds to be 60° and this is far less than the thermodynamically most stable angle of 109. 5° and leads to significant ring strain. The molecule also has torsional strain due to the conformation of its hydrogen atoms. As such, the bonds between the atoms are considerably weaker than in a typical alkane, resulting in much higher reactivity. Bonding between the centres is generally described in terms of bent bonds. In this model the carbon-carbon bonds are bent outwards so that the angle is 104°. This reduces the level of strain and is achieved by distorting the sp3 hybridisation of carbon atoms to technically sp5 hybridisation. This stabilization is referred to as σ-aromaticity, cf. the cyclic delocalization of the six π electrons in benzene as the example of aromaticity. Cyclopropane was first produced via a Wurtz coupling, in which 1, the yield of this reaction can be improved by exchanging the metal for zinc
16.
Desflurane
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Desflurane is a highly fluorinated methyl ethyl ether used for maintenance of general anesthesia. Like halothane, enflurane, and isoflurane, it is a mixture of. Together with sevoflurane, it is replacing isoflurane for human use, except in economically undeveloped areas. It has the most rapid onset and offset of the volatile anesthetic drugs used for general anesthesia due to its low solubility in blood, some drawbacks of desflurane are its low potency, its pungency and its high cost. It may cause tachycardia and airway irritability when administered at concentrations greater than 10 vol%, due to this airway irritability, desflurane is infrequently used to induce anesthesia via inhalation techniques. Though it vaporises very readily, it is a liquid at room temperature, anaesthetic machines are fitted with a specialized anaesthetic vaporiser unit that heats liquid desflurane to a constant temperature. The CO2 absorbent Baralyme, when dried, is most culpable for the production of carbon monoxide from desflurane degradation, dry conditions in the carbon dioxide absorbent are conducive to this phenomenon, such as those resulting from high fresh gas flows. In addition to global warming potentials, drug potency and fresh gas flow rates must be considered for meaningful comparisons between anesthetic gases, on a per-MAC-hour basis, the total life cycle GHG impact of desflurane is more than 20 times higher than Isoflurane and Sevoflurane. One paper finds anesthesia gases used globally contribute the equivalent of 1 million cars to global warming and this estimate is commonly cited as a reason to neglect pollution prevention by anesthesiologists, however this is problematic. This estimate is extrapolated from only one U. S. institution’s anesthetic practices, researchers neglected to include nitrous oxide in their calculations, and reported an erroneous average of 17 kg CO2e per anesthetic. However, institutions that utilize some Desflurane and account for nitrous oxide have reported an average of 175-220 kg CO2e per anesthetic, sulbaek-Anderson’s group therefore likely underestimated the total worldwide contribution of inhaled anesthetics, and yet still advocates for inhaled anesthetic emissions prevention. A recent clinical study found that desflurane has lower bispectral index, bochum, Dissertation,2006 Patel SS, Goa KL. A review of its pharmacodynamic and pharmacokinetic properties and its efficacy in general anaesthesia
17.
Diethyl ether
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Diethyl ether or simply ether, is an organic compound in the ether class with the formula 2O. It is a colorless, highly flammable liquid. It is commonly used as a solvent in laboratories and as a fluid for some engines. It was formerly used as an anesthetic, until non-flammable drugs were developed. It has been used as a drug to cause intoxication. The compound may have created by either Jābir ibn Hayyān in the 8th century or Ramon Llull in 1275. At about the time, Paracelsus discovered ethers analgesic properties in chickens. The name ether was given to the substance in 1729 by August Sigmund Frobenius and it is particularly important as a solvent in the production of cellulose plastics such as cellulose acetate. Ether starting fluid is sold and used in countries with cold climates, for the same reason it is also used as a component of the fuel mixture for carbureted compression ignition model engines. In this way diethyl ether is very similar to one of its precursors, diethyl ether is a common laboratory aprotic solvent. It has limited solubility in water and dissolves 1.5 g/100 ml water at 25 °C and this, coupled with its high volatility, makes it ideal for use as the non-polar solvent in liquid-liquid extraction. When used with a solution, the diethyl ether layer is on top due to the fact that it has a lower density than the water. It is also a solvent for the Grignard reaction in addition to other reactions involving organometallic reagents. Morton participated in a demonstration of ether anesthesia on October 16,1846 at the Ether Dome in Boston. British doctors were aware of the properties of ether as early as 1840 where it was widely prescribed in conjunction with opium. Because of its associations with Boston, the use of ether became known as the Yankee Dodge, diethyl ether depresses the myocardium and increases tracheobronchial secretions. Diethyl ether could also be mixed with other agents such as chloroform to make C. E. mixture, or chloroform. In the 2000s, ether is rarely used, the use of flammable ether was displaced by nonflammable fluorinated hydrocarbon anesthetics
18.
Enflurane
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Developed by Ross Terrell in 1963, it was first used clinically in 1966. It was increasingly used for anesthesia during the 1970s and 1980s but is no longer in common use. Enflurane is an isomer of isoflurane. It vaporizes readily, but is a liquid at room temperature, clinically, enflurane produces a dose-related depression of myocardial contractility with an associated decrease in myocardial oxygen consumption. Between 2% and 5% of the dose is oxidised in the liver, producing fluoride ions. This is significantly higher than the metabolism of its structural isomer isoflurane, enflurane also lowers the threshold for seizures, and should especially not be used on people with epilepsy. Like all potent inhalation agents it is a known trigger of malignant hyperthermia. Like the other potent inhalation agents it relaxes the uterus in pregnant women which is associated with blood loss at delivery or other procedures on the gravid uterus. The obsolete agent methoxyflurane had an effect and caused acute renal failure. Enflurane is similarly metabolised but the liberation of fluoride results in a lower plasma level, the exact mechanism of the action of general anaesthetics have not been delineated. In the workplace, people may be exposed to enflurane by breathing it in as a waste gas, swallowing it, eye contact. The National Institute for Occupational Safety and Health has set a recommended limit for exposure to waste anaesthetic gas of 2 ppm over a 60-minute period. Symptoms of occupational exposure to enflurane include eye irritation, central nervous system depression, analgesia, anesthesia, convulsions, and respiratory depression
19.
Ethylene
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Ethylene is a hydrocarbon which has the formula C 2H4 or H2C=CH2. It is a flammable gas with a faint sweet and musky odour when pure. Ethylene is widely used in the industry, and its worldwide production exceeds that of any other organic compound. Much of this production goes toward polyethylene, a used plastic containing polymer chains of ethylene units in various chain lengths. Ethylene is also an important natural plant hormone, used in agriculture to force the ripening of fruits and this hydrocarbon has four hydrogen atoms bound to a pair of carbon atoms that are connected by a double bond. All six atoms that comprise ethylene are coplanar, the H-C-H angle is 117. 4°, close to the 120° for ideal sp² hybridized carbon. The molecule is relatively rigid, rotation about the C-C bond is a high energy process that requires breaking the π-bond. The π-bond in the molecule is responsible for its useful reactivity. The double bond is a region of high density, thus it is susceptible to attack by electrophiles. Many reactions of ethylene are catalyzed by metals, which bind transiently to the ethylene using both the π and π* orbitals. Being a simple molecule, ethylene is spectroscopically simple and its UV-vis spectrum is still used as a test of theoretical methods. In the United States and Europe, approximately 90% of ethylene is used to produce ethylene oxide, ethylene dichloride, most of the reactions with ethylene are electrophilic addition. Polyethylene consumes more than half of the worlds ethylene supply, polyethylene, also called polyethene, is the worlds most widely used plastic. It is primarily used to make films in packaging, carrier bags, linear alpha-olefins, produced by oligomerization are used as precursors, detergents, plasticisers, synthetic lubricants, additives, and also as co-monomers in the production of polyethylenes. Ethylene is oxidized to ethylene oxide, a key raw material in the production of surfactants and detergents by ethoxylation. Ethylene oxide is hydrolyzed to produce ethylene glycol, widely used as an automotive antifreeze as well as higher molecular weight glycols, glycol ethers. Ethylene undergoes oxidation by palladium to give acetaldehyde and this conversion remains a major industrial process. The process proceeds via the initial complexation of ethylene to a Pd center, major intermediates from the halogenation and hydrohalogenation of ethylene include ethylene dichloride, ethyl chloride and ethylene dibromide
20.
Halothane
–
Halothane, sold under the brandname Fluothane among others, is a general anesthetic. It can be used to start or maintain anaesthesia, one of its benefits is that it does not increase the production of saliva which can be particularly useful in those who are difficult to intubate. Side effects include an irregular heartbeat, decreased effort to breathe and it should not be used in people with porphyria or a history of malignant hyperthermia either in themselves or their family members. It is unclear whether use during pregnancy is harmful to the baby, halothane is a chiral molecule that is used as a racemic mixture. It is on the World Health Organizations List of Essential Medicines, as of 2014 the wholesale cost in the developing world is about 22 to 52 USD for a 250 ml bottle. Its use in developed countries has been replaced by newer agents such as sevoflurane. It is no commercially available in the United States. It is a potent anesthetic with a MAC of 0. 74% and its blood/gas partition coefficient of 2.4 makes it an agent with moderate induction and recovery time. It is not a good analgesic and its muscle relaxation effect is moderate, in rare cases, repeated exposure to halothane in adults was noted to result in severe liver injury. This occurred in one in 10,000 exposures. The resulting syndrome was referred to as halothane hepatitis, and is thought to result from the metabolism of halothane to trifluoroacetic acid via oxidative reactions in the liver, about 20% of inhaled halothane is metabolized by the liver and these products are excreted in the urine. The hepatitis syndrome had a mortality rate of 30% to 70%, concern for hepatitis resulted in a dramatic reduction in the use of halothane for adults and it was replaced in the 1980s by enflurane and isoflurane. By 2005, the most common volatile anesthetics used were isoflurane, sevoflurane, however, by 2000, sevoflurane, excellent for inhalation induction, had largely replaced the use of halothane in children. Halothane sensitises the heart to catecholamines, so it is liable to cause cardiac arrhythmias, occasionally fatal and this seems to be especially problematic in dental anaesthesia. Like all the potent inhalational agents, it is a potent trigger for malignant hyperthermia. Similarly, in common with the potent inhalational agents, it relaxes uterine smooth muscle. People can be exposed to halothane in the workplace by breathing it in as waste gas, skin contact, eye contact. The National Institute for Occupational Safety and Health has set a recommended limit of 2 ppm over 60 minutes
21.
Isoflurane
–
Isoflurane, sold under the trade name Forane among others, is a general anesthetic. It can be used to start or maintain anesthesia, often another medication, however, is used to start anesthesia due to airway irritation with isoflurane. Side effects include an effort to breathe, low blood pressure. Serious side effects may include malignant hyperthermia and high blood potassium and it should not be used in people with a history of malignant hyperthermia either in themselves or their family members. It is unknown if use during pregnancy is safe for the baby, however, isoflurane is in the halogenated ether family of medication. Isoflurane was approved for use in the United States in 1979. It is on the World Health Organizations List of Essential Medicines, the wholesale cost in the developing world is about 17.24 to 170.40 USD per 250 ml bottle. Isoflurane is always administered in conjunction with air and/or pure oxygen, often nitrous oxide is also used. It is usually used to maintain a state of anesthesia that has been induced with another drug. Animal studies have raised safety concerns of certain general anesthetics, in particular ketamine and isoflurane in young children, the risk of neurodegeneration was increased in combination of these agents with nitrous oxide and benzodiazepines such as midazolam. Whether these concerns occur in humans is unclear, concerns exist with regard to the relationship between administration of isoflurane and postoperative cognitive dysfunction, for which the elderly are especially vulnerable. This area is important as some of the commonly used inhaled anesthetics may cause damage that accelerates the onset of Alzheimer’s disease. It is a mixture of - and -optical isomers. It vaporizes readily, but is a liquid at room temperature, similar to many general anesthetics, the exact mechanism of the action has not been clearly delineated. Isoflurane reduces pain sensitivity and relaxes muscles, isoflurane likely binds to GABA, glutamate and glycine receptors, but has different effects on each receptor. It potentiates glycine receptor activity, which decreases motor function and it inhibits receptor activity in the NMDA glutamate receptor subtypes. Isoflurane inhibits conduction in activated potassium channels and it activates calcium ATPase by increasing membrane fluidity. It binds to the D subunit of ATP synthase and NADH dehydrogenase, general anaesthesia with isoflurane reduces plasma endocannabinoid AEA concentrations, and this could be a consequence of stress reduction after loss of consciousness
22.
Methoxyflurane
–
It was first synthesized in the late 1940s by William T. Miller and his team of chemists following their involvement in the Manhattan Project. Methoxyflurane is a potent and highly lipid-soluble anesthetic agent, characterized by very slow induction. It is non-flammable, has relatively mild effects, and it does not predispose the heart to rhythm disturbances. It is, however, a significant respiratory depressant, Methoxyflurane has powerful analgesic properties at well below full anesthetic doses. It was utilized in devices for obstetric analgesia, in a manner that foreshadowed the patient-controlled analgesia infusion pumps of today. The biodegradation of methoxyflurane produces inorganic fluoride and dichloroacetic acid, the combined effects of these two compounds may be responsible for the toxicity of methoxyflurane to some of the major organs of the human body. Methoxyflurane was determined to be nephrotoxic in a dose-dependent response and hepatotoxic at anesthetic doses in 1973, the drug is currently only available from one manufacturer. It is self-administered to children and adults using the Penthrox inhaler, a non-opioid alternative to morphine, it is also easier to use than nitrous oxide. The device is referred to as the green whistle, due to its appearance. Each 3 milliliter dose lasts approximately 30 minutes, pain relief begins after 6–8 breaths and continues for several minutes after stopping inhalation. The maximum recommended dose is 6 milliliters per day or 15 milliliters per week because of the risk of cumulative dose-related nephrotoxicity and it is a halogenated ether in form of a clear, colorless liquid, and its vapor has a strong fruity aroma. It is miscible with ethanol, acetone, chloroform, diethyl ether, with a minimum alveolar concentration of 0. 16%, methoxyflurane is an extremely potent anesthetic agent. It is a powerful agent at well below full anesthetic concentrations. Because of its low volatility and very high boiling point, methoxyflurane has a low pressure at ambient temperature. It is therefore difficult to vaporize methoxyflurane using conventional anesthetic vaporizers. The carbon–fluorine bond, a component of all compounds, is the strongest chemical bond in organic chemistry. Furthermore, this bond becomes shorter and stronger as more atoms are added to the same carbon on a given molecule. Because of this, fluoroalkanes are some of the most chemically stable organic compounds, Methoxyflurane has a very high lipid solubility, which gives it very slow pharmacokinetics, this being undesirable for routine application in the clinical setting
23.
Nitrous oxide
–
Nitrous oxide, commonly known as laughing gas or nitrous, is a chemical compound, an oxide of nitrogen with the formula N 2O. At room temperature, it is a colorless, odorless non-flammable gas, at elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen. Nitrous oxide has significant medical uses, especially in surgery and dentistry and its name laughing gas is due to the euphoric effects of inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. It is also used as an oxidizer in rocket propellants, Nitrous oxide occurs in small amounts in the atmosphere, but has been found recently to be a major scavenger of stratospheric ozone, with impact comparable to that of CFCs. It is estimated that 30% of the N 2O in the atmosphere is the result of human activity, Nitrous oxide can be used as an oxidizer in a rocket motor. This has the advantages over other oxidisers in that it is not only non-toxic, as a secondary benefit it can be readily decomposed to form breathing air. Its high density and low storage pressure enable it to be competitive with stored high-pressure gas systems. In a 1914 patent, American rocket pioneer Robert Goddard suggested nitrous oxide, Nitrous oxide has been the oxidiser of choice in several hybrid rocket designs. The combination of nitrous oxide with hydroxyl-terminated polybutadiene fuel has been used by SpaceShipOne and it is also notably used in amateur and high power rocketry with various plastics as the fuel. Nitrous oxide can also be used in a monopropellant rocket, in the presence of a heated catalyst, N 2O will decompose exothermically into nitrogen and oxygen, at a temperature of approximately 1,070 °F. Because of the heat release, the catalytic action rapidly becomes secondary as thermal autodecomposition becomes dominant. In a vacuum thruster, this can provide a monopropellant specific impulse of as much as 180 s, while noticeably less than the Isp available from hydrazine thrusters, the decreased toxicity makes nitrous oxide an option worth investigating. Nitrous oxide is said to deflagrate somewhere around 600 °C at a pressure of 21 atmospheres, at 600 psi for example, the required ignition energy is only 6 joules, whereas N 2O at 130 psi a 2500-joule ignition energy input is insufficient. In vehicle racing, nitrous oxide allows the engine to burn more fuel by providing more oxygen than air alone, the gas itself is not flammable at a low pressure/temperature, but it delivers more oxygen than atmospheric air by breaking down at elevated temperatures. Therefore, it is mixed with another fuel that is easier to deflagrate. Nitrous oxide is a strong oxidant roughly equivalent to hydrogen peroxide, Nitrous oxide is sometimes injected into the intake manifold, whereas other systems directly inject right before the cylinder to increase power. The technique was used during World War II by Luftwaffe aircraft with the GM-1 system to boost the output of aircraft engines. Originally meant to provide the Luftwaffe standard aircraft with superior high-altitude performance, accordingly, it was only used by specialized planes like high-altitude reconnaissance aircraft, high-speed bombers, and high-altitude interceptor aircraft
24.
Sevoflurane
–
Sevoflurane, is a sweet-smelling, nonflammable, highly fluorinated methyl isopropyl ether used as an inhalational anaesthetic for induction and maintenance of general anesthesia. After desflurane, it is the volatile anesthetic with the fastest onset and offset and it is one of the most commonly used volatile anesthetic agents, particularly for outpatient anesthesia, across all ages, as well as in veterinary medicine. Together with desflurane, sevoflurane is replacing isoflurane and halothane in modern anesthesiology and it is often administered in a mixture of nitrous oxide and oxygen. Sevoflurane is the agent for mask induction due to its lesser irritation to mucous membranes. Sevoflurane was discovered by Ross Terrell and independently by Bernard M Regan, a detailed report of its development and properties appeared in 1975 in a paper authored by Richard Wallin, Bernard Regan, Martha Napoli and Ivan Stern. It was introduced into clinical practice initially in Japan in 1990, the rights for sevoflurane worldwide were held by AbbVie. It is now available as a generic drug, Sevoflurane is an inhaled anaesthetic that is often used to put children asleep for surgery. During the process of waking up from the medication, it has known to cause agitation. It is not clear if this can be prevented, Sevoflurane raises intracranial pressure and can cause respiratory depression. Studies examining a current significant health concern, anesthetic-induced neurotoxicity are fraught with confounders, and many are underpowered statistically, to either support or refute the potential connection. The exact mechanism of the action of general anaesthetics have not been delineated, Sevoflurane is thought to potentially act as a positive allosteric modulator of the GABAA receptor. However, it acts as an NMDA receptor antagonist, potentiates glycine receptor currents. A review of its pharmacodynamic and pharmacokinetic properties and its use in general anaesthesia. Wallin, Richard F. Regan, Bernard M. Napoli, Martha D. Stern, Sevoflurane, A New Inhalational Anesthetic Agent. CS1 maint, Multiple names, authors list Propofol and Sevoflurane Anesthesia
25.
Trichloroethylene
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The chemical compound trichloroethylene is a halocarbon commonly used as an industrial solvent. It is a clear liquid with a sweet smell. It should not be confused with the similar 1,1, 1-trichloroethane, industrial abbreviations include TCE, trichlor, Trike, Tricky and tri. It has been sold under a variety of trade names, under the trade names Trimar and Trilene, trichloroethylene was used as a volatile anesthetic and as an inhaled obstetrical analgesic in millions of patients. Pioneered by Imperial Chemical Industries in Britain, its development was hailed as an anesthetic revolution, originally thought to possess less hepatotoxicity than chloroform, and without the unpleasant pungency and flammability of ether, TCE use was nonetheless soon found to have several pitfalls. The introduction of halothane in 1956 greatly diminished the use of TCE as a general anesthetic, TCE was still used as an inhalation analgesic in childbirth given by self-administration. Fetal toxicity and concerns for potential of TCE led to its abandonment in developed countries by the 1980s. Due to concerns about its toxicity, the use of trichloroethylene in the food, legislation has forced the substitution of trichloroethylene in many processes in Europe as the chemical was classified as a carcinogen carrying an R45 risk phrase, May cause cancer. Groundwater contamination by TCE has become an important environmental concern for human exposure, the results of the study have formally characterized the chemical as a human carcinogen and a non-carcinogenic health hazard. A2011 toxicological review performed by the EPA continues to list trichloroethylene as a known carcinogen, prior to the early 1970s, most trichloroethylene was produced in a two-step process from acetylene. First, ethylene is chlorinated over a ferric chloride catalyst to produce 1, the most commonly used catalyst is a mixture of potassium chloride and aluminum chloride. However, various forms of carbon can also be used. This reaction produces tetrachloroethylene as a byproduct, and depending on the amount of chlorine fed to the reaction, typically, trichloroethylene and tetrachloroethylene are collected together and then separated by distillation. Trichloroethylene is a solvent for a variety of organic materials. When it was first widely produced in the 1920s, trichloroethylenes major use was to extract vegetable oils from plant materials such as soy, coconut, other uses in the food industry included coffee decaffeination and the preparation of flavoring extracts from hops and spices. It has also used for drying out the last bit of water for production of 100% ethanol. From the 1930s through the 1970s, both in Europe and in North America, trichloroethylene was used as a volatile anesthetic almost invariably administered with nitrous oxide. Marketed in the UK by ICI under the trade name Trilene it was coloured blue to avoid confusion with the similar smelling chloroform, Trilene was also used as a potent inhaled analgesic, mainly during childbirth
26.
Vinyl ether
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Vinyl ether, also known as divinyl ether, divinyl oxide, Vinethene and ethenoxyethene, is a clear, nearly colorless, volatile liquid which was briefly used as an inhalation anesthetic. It can be cyclopolymerized by itself and serves as a cross-linker in copolymerizations, in practice, vinyl ether proved to have favorable properties that allowed its brief usage as an anesthetic, on the other hand, it left many unimpressed. Aggravated by the issue of potentially toxic degradation over long-term storage and possible hepatic toxicity, today, vinyl ether is a relic in the field of anesthesiology, however, the analytical techniques used to study its pharmacology laid the groundwork for the testing of new anesthetic agents. The first preparation of vinyl ether was reported in 1887 by Semmler and this chemist reported the production of vinyl ether from its sulfur substituted analogue, divinyl sulfide, by reaction with silver oxide. Semmlers product which boiled at 39 °C was found to be sulfur free, in 1899, Knorr and Matthes attempted a synthesis of vinyl ether by exhaustive methylation of morpholine. They attained such a quantity of product that no characterization was possible. Cretcher et al. reported, in 1925, what would become the foundation for one method used to produce vinyl ether. It was stated that the action of heated sodium hydroxide upon β, however, in a subtly modified process Hibbert et al. reported the isolation of a product boiling at 34-35 °C, divinyl ether. Finally, in 1929, a patent issued to Merck & Co reported isolation of vinyl ether boiling ca.28 °C. The currently accepted boiling point of vinyl ether is 28.3 °C, even before its isolation and characterization, the application of an unsaturated ether as an anesthetic interested some pharmacologists. One such pharmacologist, Chauncey Leake, was captivated by the then theoretical vinyl ether. Leake predicted that vinyl ether would combine the properties of two agents, ethyl ether, and ethylene. As an anesthetic ethylene has many properties, although its very low potency often requires hypoxic conditions to achieve full anesthesia. Ethyl Ether on the hand is a fairly potent anesthetic. In comparison to ether, ethylene has a much lower occurrence of post operative nausea, additionally, ethylene has faster induction, solely guided by predictions based upon structure, Leake perused the usage of vinyl ether as an inhalation anesthetic. As vinyl ether was unknown in its form, Leake approached organic chemists at Berkeley asking them to synthesize this novel anesthetic. Leake’s colleagues however, were unable to prepare vinyl ether, later though, using samples received from Princeton, in 1930, Leake and fellow researcher Mei-Yu Chen published a brief study characterizing the anesthetic effects of vinyl ether upon mice. In the conclusion of this study, they cordially invited further research of this drug and this invitation was accepted, in 1933 Samuel Gelfan and Irving Bell of the University of Alberta published the first human trials of vinyl ether
27.
Xenon
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Xenon is a chemical element with symbol Xe and atomic number 54. It is a colorless, dense, odorless gas found in the Earths atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser used a xenon dimer molecule as the lasing medium. Xenon is used to search for hypothetical weakly interacting massive particles, naturally occurring xenon consists of eight stable isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the ratios of xenon are an important tool for studying the early history of the Solar System. Radioactive xenon-135 is produced by beta decay from iodine-135, and is the most significant neutron absorber in nuclear reactors, Xenon was discovered in England by the Scottish chemist William Ramsay and English chemist Morris Travers in September 1898, shortly after their discovery of the elements krypton and neon. They found xenon in the left over from evaporating components of liquid air. Ramsay suggested the name xenon for this gas from the Greek word ξένον, neuter singular form of ξένος, meaning foreign, strange, in 1902, Ramsay estimated the proportion of xenon in the Earths atmosphere to be one part in 20 million. During the 1930s, American engineer Harold Edgerton began exploring strobe light technology for high speed photography and this led him to the invention of the xenon flash lamp in which light is generated by passing brief electric current through a tube filled with xenon gas. In 1934, Edgerton was able to generate flashes as brief as one microsecond with this method, in 1939, American physician Albert R. Behnke Jr. began exploring the causes of drunkenness in deep-sea divers. He tested the effects of varying the breathing mixtures on his subjects, from his results, he deduced that xenon gas could serve as an anesthetic. Xenon was first used as an anesthetic in 1951 by American anesthesiologist Stuart C. Cullen, who used it with two patients. Xenon and the noble gases were for a long time considered to be completely chemically inert. Since O2 and xenon have almost the same first ionization potential, on March 23,1962, he mixed the two gases and produced the first known compound of a noble gas, xenon hexafluoroplatinate. Bartlett thought its composition to be Xe+−, but later revealed that it was probably a mixture of various xenon-containing salts. By 1971, more than 80 xenon compounds were known, in November 1989, IBM scientists demonstrated a technology capable of manipulating individual atoms
28.
Phenols
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In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group bonded directly to an aromatic hydrocarbon group. The simplest of the class is phenol, which is also called carbolic acid C 6H 5OH, phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule. Synonyms are arenols or aryl alcohols, phenolic compounds are synthesized industrially, they also are produced by plants and microorganisms, with variation between and within species. Although similar to alcohols, phenols have unique properties and are not classified as alcohols and they have higher acidities due to the aromatic rings tight coupling with the oxygen and a relatively loose bond between the oxygen and hydrogen. The acidity of the group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids. Phenols can have two or more hydroxy groups bonded to the ring in the same molecule. The simplest examples are the three benzenediols, each having two groups on a benzene ring. Organisms that synthesize phenolic compounds do so in response to pressures such as pathogen and insect attack, UV radiation. As they are present in food consumed in human diets and in used in traditional medicine of several cultures, their role in human health. Some phenols are germicidal and are used in formulating disinfectants, others possess estrogenic or endocrine disrupting activity. They can also be classified on the basis of their number of phenol groups and they can therefore be called simple phenols or monophenols, with only one phenolic group, or di-, tri- and oligophenols, with two, three or several phenolic groups respectively. The phenolic unit can be found dimerized or further polymerized, creating a new class of polyphenol, two natural phenols from two different categories, for instance a flavonoid and a lignan, can combine to form a hybrid class like the flavonolignans. Nomenclature of polymers, Plants in the genus Humulus and Cannabis produce terpenophenolic metabolites, phenolic lipids are long aliphatic chains bonded to a phenolic moiety. The majority of compounds are solubles molecules but the smaller molecules can be volatiles. Many natural phenols present chirality within their molecule, an example of such molecules is catechin. Cavicularin is an unusual macrocycle because it was the first compound isolated from nature displaying optical activity due to the presence of planar chirality, natural phenols chemically interact with many other substances. Stacking, a property of molecules with aromaticity, is seen occurring between phenolic molecules. When studied in mass spectrometry, phenols easily form adduct ions with halogens and they can also interact with the food matrices or with different forms of silica
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Fospropofol
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Fospropofol, often used as the disodium salt is an intravenous sedative-hypnotic agent. It is currently approved for use in sedation of adult patients undergoing diagnostic or therapeutic procedures such as endoscopy, often, fospropofol is administered in conjunction with an opioid such as fentanyl. Fospropofol is a prodrug of propofol, it is metabolized by alkaline phosphatases to an active metabolite, initial trial results on fospropofol pharmacokinetics were retracted by the investigators. As of 2011, new results were not available, Fospropofol is classified as a Schedule IV controlled substance in the United States Controlled Substances Act. Fechner J, Ihmsen H, Hatterscheid D, et al, comparative pharmacokinetics and pharmacodynamics of the new propofol prodrug GPI15715 and propofol emulsion. Gibiansky E, Struys MM, Gibiansky L, et al, AQUAVAN injection, a water-soluble prodrug of propofol, as a bolus injection, a phase I dose-escalation comparison with DIPRIVAN, pharmacokinetics. Struys MM, Vanluchene AL, Gibiansky E, et al, AQUAVAN injection, a water-soluble prodrug of propofol, as a bolus injection, a phase I dose-escalation comparison with DIPRIVAN, pharmacodynamics and safety. Pruitt R, Cohen LB, Gibiansky E, et al, a randomized, open-label, multicenter, dose-ranging study of sedation with Aquavan injection during colonoscopy. Lampotang S, Lizdas D, Gravenstein N, Yavas S, university of Florida Department of Anesthesiology Virtual Anesthesia Machine Web site, Web Simulation of Fospropofol Pharmacokinetics
30.
Propofol
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Propofol, marketed as Diprivan among others, is a short-acting medication that results in a decreased level of consciousness and lack of memory for events. Its uses include the starting and maintenance of anesthesia, sedation for mechanically ventilated adults. It is also used for status epilepticus if other medications have not worked, maximum effect takes about two minutes to occur and it typically lasts five to ten minutes. Common side effects include a heart rate, low blood pressure, burning sensation at the site of injection. Other serious side effects may include seizures, infections with improper use, addiction and it appears to be safe for using during pregnancy but has not been well studied in this group. However, it is not recommended during cesarean section, Propofol is not a pain medication, so opioids such as morphine may also be used. Whether or not they are always needed is unclear, Propofol is believed to work at least partly via the receptor for GABA. It is on the World Health Organizations List of Essential Medicines and it is available as a generic medication. The wholesale price in the world is between 0.61 and 8.50 USD per vial. It has been referred to as milk of amnesia because of the appearance of the intravenous preparation. Propofol is also used in veterinary medicine, Propofol is used for induction and maintenance of anesthesia, having largely replaced sodium thiopental. Propofol is also used to sedate individuals who are receiving mechanical ventilation but are not undergoing surgery, in critically ill patients, propofol has been found to be superior to lorazepam both in effectiveness and overall cost. Propofol is often used instead of sodium thiopental for starting anesthesia because recovery from propofol is more rapid, Propofol is also used for procedural sedation. Its use in these results in a faster recovery compared to midazolam. It can also be combined with opioids or benzodiazepines, because of its fast induction and recovery time, propofol is also widely used for sedation of infants and children undergoing MRI. It is also used in combination with ketamine as the two together have lower rates of side effects. The Missouri Supreme Court decided to allow the use of propofol to execute prisoners condemned to death, the United Kingdom had already banned the export of medicines or veterinary medicines containing propofol to the United States. Recreational use of the drug via self-administration has been reported, but is rare due to its potency
31.
Opioid
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Opioids are substances that act on opioid receptors to produce morphine-like effects. Opioids are most often used medically to relieve pain, and by people addicted to opioids, opioids include opiates, an older term that refers to such drugs derived from opium, including morphine itself. Other opioids are semi-synthetic and synthetic drugs such as hydrocodone, oxycodone and fentanyl, antagonist drugs such as naloxone, the terms opiate and narcotic are sometimes encountered as synonyms for opioid. Opiate is properly limited to the alkaloids found in the resin of the opium poppy although some include semi-synthetic derivatives. In some jurisdictions all controlled drugs are classified as narcotics. The term can have pejorative connotations and its use is discouraged where that is the case. Primarily used for relief, including anesthesia they are also used to suppress cough, suppress diarrhea, treat addiction, reverse opioid overdose. Extremely strong opioids are approved only for use such as immobilizing large mammals. Opioids act by binding to receptors, which are found principally in the central and peripheral nervous system. These receptors mediate both the psychoactive and the effects of opioids. The side effects of opioids may include itchiness, sedation, nausea, respiratory depression, constipation, Tolerance and dependence will develop with continuous use, requiring increasing doses and leading to a withdrawal syndrome upon abrupt discontinuation. The euphoria attracts recreational use, and frequent, escalating recreational use of opioids typically results in addiction, accidental overdose or concurrent use with other depressant drugs commonly results in death from respiratory depression. Because of opioid drugs reputation for addiction and fatal overdose, most are controlled substances, illicit production, smuggling, and addiction to opioids prompted treaties, laws and policing which have realized limited success. In 2013 between 28 and 38 million people used opioids illicitly, in 2011 an estimated 4 million people in the United States used opioids recreationally or were dependent on them. Current increased rates of use and addiction are attributed to over-prescription of opioid medications. Conversely, fears about over-prescribing, exaggerated side effects and addiction from opioids are similarly blamed for under-treatment of pain, the term opioid originated in the 1950s. It combines opium + -oid meaning opiate-like, by the late 1960s, research found that opiate effects are mediated by activation of specific molecular receptors in the nervous system, which were termed opioid receptors. The definition of opioid was later refined to refer to substances that have activities that are mediated by the activation of opioid receptors
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Morphine
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Morphine is a pain medication of the opiate type which is found naturally in a number of plants and animals. It acts directly on the nervous system to decrease the feeling of pain. It can be taken for both pain and chronic pain. Morphine is frequently used for pain from myocardial infarction and during labour and it can be given by mouth, by injection into a muscle, by injecting under the skin, intravenously, into the space around the spinal cord, or rectally. Maximum effect is around 20 min when given intravenously and 60 min when given by mouth while duration of effect is three and seven hours. Potentially serious side effects include a decreased respiratory effort and low blood pressure, morphine has a high potential for addiction and abuse. If the dose is reduced after long-term use, withdrawal may occur, common side effects include drowsiness, vomiting, and constipation. Caution is advised when used during pregnancy or breast feeding, as morphine will affect the baby, morphine was first isolated between 1803 and 1805 by Friedrich Sertürner. This is generally believed to be the first isolation of an ingredient from a plant. Merck began marketing it commercially in 1827, morphine was more widely used after the invention of the hypodermic syringe in 1853–1855. Sertürner originally named the substance morphium after the Greek god of dreams, the primary source of morphine is isolation from poppy straw of the opium poppy. In 2013, an estimated 523,000 kilograms of morphine were produced, about 45,000 kilograms were used directly for pain, an increase over the last twenty years of four times. Most use for this purpose was in the developed world, about 70% of morphine is used to make other opioids such as hydromorphone, oxycodone and heroin. It is a Schedule II drug in the United States, Class A in the United Kingdom and it is on the World Health Organizations List of Essential Medicines, the most effective and safe medicines needed in a health system. Morphine is sold under trade names. Morphine is used primarily to treat both acute and chronic severe pain and it is also used for pain due to myocardial infarction and for labor pains. Its duration of analgesia is about three to seven hours, however, concerns exist that morphine may increase mortality in the setting of non ST elevation myocardial infarction. Morphine has also traditionally used in the treatment of acute pulmonary edema
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. PMID 4148526.
