1.
Drug nomenclature
–
Drug nomenclature is the systematic naming of drugs, especially pharmaceutical drugs. Generic names for drugs are nowadays constructed out of affixes and stems that classify the drugs into different categories, a marketed drug might also have a company code or compound code. The chemical names are the names, based on the molecular structure of the drug. There are various systems of nomenclature and thus various chemical names for any one substance. The most important is the IUPAC name, chemical names are typically very long and too complex to be commonly used in referring to a drug. Sometimes, a company that is developing a drug might give the drug a company code, for example, CDP870 is UCB’s company code for Cimzia. Many of these codes, although not all, have prefixes that correspond to the company name, during development, the company will apply for regulatory approval of the drug by the relevant national regulatory agency, and it will apply for a generic name for that country. It will also apply for an International Nonproprietary Name through the World Health Organization, nowadays the national nonproprietary names are usually the same as the INN. The generic names usually indicate via their stems what drug class the drug belongs to, for example, one can tell that aciclovir is an antiviral drug because its name ends in the -vir suffix. Otherwise the 2 names are both given, joined by hyphens or slashes. For example, suspensions combining trimethoprim and sulfamethoxazole are called either trimethoprim/sulfamethoxazole or co-trimoxazole, similarly, co-codamol is codeine-acetaminophen, and co-triamterzide is triamterene-hydrochlorothiazide. The USP ceased maintaining PENs, but the similar co-prefixed BANs are still current, for drugs that make it all the way through development, testing, and regulatory acceptance, the pharmaceutical company then gives the drug a trade name. The term trade name is a term in the pharmaceutical industry for a brand name or trademark name. For example, Lipitor is Pfizers trade name for atorvastatin, a cholesterol-lowering medication, Drug names are often subject to legal regulation, including approval for new drugs and on packaging to establish clear rules about adulterants and fraudulent or misleading labelling. A national formulary is often designated to define drug names for regulatory purposes, unbiased mentions of a drug place the nonproprietary name first and follow it with the trade name in parentheses, if relevant. This pattern is important for the literature, where conflict of interest is disclosed or avoided. The authors reporting on a study are not endorsing any particular brand of drug and they will often state which brand was used, for methodologic validity, but they do so in a way that makes clear the absence of endorsement. For example, the 2015 American Society of Hematology publication policies say, Non-proprietary names should be used and he first letter of the name of a proprietary drug should be capitalized
2.
Intramuscular injection
–
Intramuscular injection is the injection of a substance directly into a muscle. In medicine, it is one of alternative methods for the administration of medications. Muscles have larger and more vessels than subcutaneous tissue and injections here usually have faster rates of absorption than subcutaneous injections or intradermal injections. Depending on the site, an administration is limited to between 2 and 5 milliliters of fluid. Platelet-rich plasma injections can be administered intramuscularly, certain substances are injected intramuscularly for recreational purposes. Possible sites for IM injection include, deltoid, dorsogluteal, rectus femoris, vastus lateralis, sites that are bruised, tender, red, swollen, inflamed or scarred are avoided. The deltoid muscle site is recommended for use with injections of small volume, usually equal or less than 1 ml and this site is not recommended for repeated injections, due to its small area, it is difficult to rotate the injection site. To locate the site, palpate the lower edge of the acromion process, inject in the upside down triangle that forms with its base at the acromion process and its midpoint in line with the axilla. The ventrogluteal site is recommended for injections requiring a larger volume to be administered, greater than 1 ml and it is also given for narcotic, antibiotic, sedative and anti-emetic medications. To locate the site, place the palm of your hand over the greater trochanter. The right hand is used for the hip and left hand is used for the right hip. Place the index finger on the superior iliac spine and run the middle finger back along the iliac crest. The injection is given in the center of the triangle that is formed, the vastus lateralis site is the recommended site for infants less than 7 months old and those unable to walk, with loss of muscular tone. To locate the site, divide the front thigh into thirds vertically and horizontally to make nine squares and inject in the outer middle square. Use of this site is associated with skin and tissue trauma, muscle fibrosis and contracture, haematoma, nerve palsy and paralysis, as well as infectious processes such as abscess and gangrene. The injection site is located by dividing the buttock into four with a plus shaped cross, the selected site is cleansed with an antimicrobial and is allowed to dry. It is injected with the dominant hand using a quick, darting motion perpendicular to the body at an angle between 72 and 90 degrees, as a faster injection is less painful. The needle is then stabilized with the nondominant hand while the dominant hand slides to the plunger to slowly instill the medication, the CDC does not recommend the outdated practice of aspirating for blood to rule out injecting into a blood vessel
3.
Androgen
–
This includes the activity of the primary male sex organs and development of male secondary sex characteristics. Androgens were first discovered in 1936, androgens increase in both boys and girls during puberty. Androgens are also the original anabolic steroids and the precursor of all estrogens, the primary and most well-known androgen is testosterone. Dihydrotestosterone and androstenedione are less known generally, but are of importance in male development. DHT in the embryo life causes differentiation of penis, scrotum, later in life DHT contributes to balding, prostate growth and sebaceous gland activity. Although androgens are described as sex hormones, both males and females have them to varying degrees, as is also true of estrogens. They are one of three types of sex hormones, the others being estrogens like estradiol and progestogens like progesterone, the main subset of androgens, known as adrenal androgens, is composed of 19-carbon steroids synthesized in the zona reticularis, the innermost layer of the adrenal cortex. Adrenal androgens function as weak steroids, and the subset includes dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, besides testosterone, other androgens include, Dehydroepiandrosterone is a steroid hormone produced in the adrenal cortex from cholesterol. It is the precursor of natural estrogens. DHEA is also called dehydroisoandrosterone or dehydroandrosterone, androstenedione is an androgenic steroid produced by the testes, adrenal cortex, and ovaries. While androstenediones are converted metabolically to testosterone and other androgens, they are also the parent structure of estrone, use of androstenedione as an athletic or bodybuilding supplement has been banned by the International Olympic Committee, as well as other sporting organizations. Androstenediol is the steroid metabolite thought to act as the regulator of gonadotropin secretion. It is found in equal amounts in the plasma and urine of both males and females. Dihydrotestosterone is a metabolite of testosterone, and a potent androgen than testosterone in that it binds more strongly to androgen receptors. It is produced in the skin and reproductive tissue, during mammalian development, the gonads are at first capable of becoming either ovaries or testes. In humans, starting at about week 4, the rudiments are present within the intermediate mesoderm adjacent to the developing kidneys. At about week 6, epithelial sex cords develop within the forming testes, in males, certain Y chromosome genes, particularly SRY, control development of the male phenotype, including conversion of the early bipotential gonad into testes. In males, the sex cords fully invade the developing gonads, the mesoderm-derived epithelial cells of the sex cords in developing testes become the Sertoli cells, which will function to support sperm cell formation
4.
Anabolic steroid
–
They are anabolic and increase protein within cells, especially in skeletal muscles. The word anabolic, referring to anabolism, comes from the Greek ἀναβολή anabole and they are one of three types of sex hormone agonists, the others being estrogens like estradiol and progestogens like progesterone. Health risks can be produced by long-term use or excessive doses of AAS and these effects include harmful changes in cholesterol levels, acne, high blood pressure, liver damage, and dangerous changes in the structure of the left ventricle of the heart. Conditions pertaining to hormonal imbalances such as gynecomastia and testicular size reduction may also be caused by AAS and their use is referred to as doping and banned by most major sporting bodies. For many years, AAS have been by far the most detected doping substances in IOC-accredited laboratories, in countries where AAS are controlled substances, there is often a black market in which smuggled, clandestinely manufactured or even counterfeit drugs are sold to users. AAS have largely replaced in this setting by synthetic protein hormones that selectively stimulate growth of blood cell precursors. Growth stimulation, AAS can be used by pediatric endocrinologists to treat children with growth failure, however, the availability of synthetic growth hormone, which has fewer side effects, makes this a secondary treatment. Stimulation of appetite and preservation and increase of mass, AAS have been given to people with chronic wasting conditions such as cancer. Induction of male puberty, Androgens are given to many boys distressed about extreme delay of puberty, Testosterone is now nearly the only androgen used for this purpose and has been shown to increase height, weight, and fat-free mass in boys with delayed puberty. Male contraception, in the form of testosterone enanthate, potential for use in the near-future as a safe, reliable, stimulation of lean body mass and prevention of bone loss in elderly men, as some studies indicate. Hormone replacement for men with low levels of testosterone, also effective in improving libido for elderly males, most steroid users are not athletes. Between 1 million and 3 million people are thought to have misused AAS in the United States, another study found that non-medical use of AAS among college students was at or less than 1%. According to a recent survey,78, the same study found that individuals using AAS for non-medical purposes had a higher employment rate and a higher household income than the general population. AAS users tend to be disillusioned by the portrayal of AAS as deadly in the media, according to one study, AAS users also distrust their physicians and in the sample 56% had not disclosed their AAS use to their physicians. A recent study has shown that long term AAS users were more likely to have symptoms of muscle dysmorphia. A recent study in the Journal of Health Psychology showed that many believed that steroids used in moderation were safe. AAS have been used by men and women in different kinds of professional sports to attain a competitive edge or to assist in recovery from injury. These sports include bodybuilding, weightlifting, shot put and other track and field, cycling, baseball, wrestling, mixed martial arts, boxing, football, such use is prohibited by the rules of the governing bodies of most sports
5.
Antiestrogen
–
Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor and/or inhibiting or suppressing estrogen production, antiestrogens are one of three types of sex hormone antagonists, the others being antiandrogens and antiprogestogens. Although aromatase inhibitors and antigonadotropins can be considered antiestrogens by some definitions, aromatase inhibitors and antigonadotropins reduce the production of estrogen, while the term antiestrogen is often reserved for agents reducing the response to estrogen. Antiestrogens are mainly used as a means of estrogen deprivation therapy in the treatment of ER-positive breast cancer and they are also used to treat infertility, male hypogonadism, and gynecomastia and are used as a component of hormone replacement therapy for transgender men. Side effects of antiestrogens include hot flashes, osteoporosis, breast atrophy, ethamoxytriphetol was the first antiestrogen to be discovered, followed by clomifene and tamoxifen. This article incorporates public domain material from the U. S. National Cancer Institute document Dictionary of Cancer Terms
6.
PubChem
–
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
7.
ChemSpider
–
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
8.
Chemical formula
–
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
9.
Jmol
–
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
10.
Simplified molecular-input line-entry system
–
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
11.
International Chemical Identifier
–
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
12.
Injection (medicine)
–
An injection follows a parenteral route of administration, that is, administration via a route other than through the digestive tract. Since the process involves a small puncture wound to the body. Rodents used for research are often administered intracerebral, intracerebroventricular, or intraportal injections as well, long-acting forms of subcutaneous/intramuscular injections are available for various drugs, and are called depot injections. Injections are among the most common health care procedures, with at least 16 billion administered in developing, 95% of injections are administered in curative care, 3% are for immunization, and the rest for other purposes, such as blood transfusions. In some instances the term injection is used synonymously with inoculation even by different workers in the same hospital and this should not cause confusion, the focus is on what is being injected/inoculated, not the terminology of the procedure. In an intramuscular injection, the medication is delivered directly into a muscle, many vaccines are administered intramuscularly, as are codeine, metoclopramide, and many other medications. Many drugs injected intramuscularly are absorbed into the muscle fairly quickly, injections to the buttocks are known to reach the bloodstream quickly due to the large amount of muscular tissue and corresponding blood supply. Such injection allows the compound to be released in a consistent way over a long period. Depot injections are usually either solid or oil-based, depot injections may be available as certain forms of a drug, such as decanoate salts or esters. Examples of depot injections include Depo Provera and haloperidol decanoate, prostate cancer patients receiving hormone therapy usually get depot injections as a treatment or therapy. Zoladex is an example of a medication delivered by depot for prostate cancer treatment or therapy, naltrexone may be administered in a monthly depot injection to control opiod abuse, in this case, the depot injection improves compliance by replacing daily pill administration. The advantages of using a long-acting depot injection include increased medication compliance due to reduction in the frequency of dosing, a significant disadvantage is that the drug is not immediately reversible, since it is slowly released. In psychiatric nursing, a short acting depot, zuclopenthixol acetate, the pharmaceutical injection type of infiltration involves loading a volume of tissue with the drug, filling the interstitial space. Local anesthetics are often infiltrated into the dermis and hypodermis, various animals, and some plants, have been injecting for various reasons long before humans began doing so in a process commonly called stinging. Some examples include, Snakes, wasps, scorpions, venom, to kill prey, some bees, venom, to defend themselves and their nests. Stinging nettles, venom, to try to avoid being eaten, stingrays, venom, defense mechanism when provoked. The pain of an injection may be lessened by prior application of ice or topical anesthetic, recent studies suggest that forced coughing during an injection stimulates a transient rise in blood pressure which inhibits the perception of pain. Sometimes, as with an amniocentesis, an anesthetic is given
13.
Dihydrotestosterone
–
Dihydrotestosterone, or 5α-dihydrotestosterone, also known as 5α-androstan-17β-ol-3-one, is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver and this enzyme mediates reduction of the C4-5 double bond of testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor. DHT has an affinity of 0.25 to 0.5 nM for the human AR, the dissociation rate of DHT from the AR is 5-fold slower than that of testosterone. The EC50 of DHT for activation of the AR is 0.13 nM, in bioassays, DHT has been found to be 2. 5- to 10-fold more potent than testosterone. The terminal half-life of DHT in the body is longer than that of testosterone, a study of transdermal DHT and testosterone treatment reported terminal half-lives of 2.83 hours and 1.29 hours, respectively. An example illustrating the significance of DHT for the development of sex characteristics is congenital 5α-reductase type II deficiency. This genetic mutation can result in pseudohermaphroditism, the condition typically presents with underdeveloped male genitalia and prostate. Males with this condition are often raised as girls due to their lack of male genitalia. At the onset of puberty, although their DHT levels remain very low and their musculature develops like that of other male adults. After puberty, men with this condition have a deficiency of pubic and body hair. They also reportedly have no incidence of prostate cancer, unlike other androgens such as testosterone, DHT cannot be converted by the enzyme aromatase into an estrogen like estradiol. In the case of female androgenic alopecia, on the hand, the situation is more complex. Women with increased levels of DHT may develop symptoms of such as certain androgynous masculine secondary sex characteristics, including a deepened voice. In men, prostate growth and differentiation are highly dependent on androgens, especially DHT, both finasteride and dutasteride are approved for the treatment of BPH and androgenic alopecia. Dutasteride is three times more potent than finasteride in inhibiting the type II enzyme and 100 times more potent than finasteride in inhibiting the type I form of the DHT-producing enzyme, both finasteride and dutasteride are potent inhibitors of the third isotype of the enzyme. Acne, hirsutism, and seborrhea are also DHT-related conditions, in addition, antiandrogens like cyproterone acetate, spironolactone, and bicalutamide, as well as estrogens like ethinylestradiol, may also be used to treat these conditions. DHT is synthesized from testosterone by the enzyme 5α-reductase, in males, approximately 5% of testosterone undergoes 5α-reduction into DHT
14.
Japan
–
Japan is a sovereign island nation in Eastern Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asia Mainland and stretches from the Sea of Okhotsk in the north to the East China Sea, the kanji that make up Japans name mean sun origin. 日 can be read as ni and means sun while 本 can be read as hon, or pon, Japan is often referred to by the famous epithet Land of the Rising Sun in reference to its Japanese name. Japan is an archipelago consisting of about 6,852 islands. The four largest are Honshu, Hokkaido, Kyushu and Shikoku, the country is divided into 47 prefectures in eight regions. Hokkaido being the northernmost prefecture and Okinawa being the southernmost one, the population of 127 million is the worlds tenth largest. Japanese people make up 98. 5% of Japans total population, approximately 9.1 million people live in the city of Tokyo, the capital of Japan. Archaeological research indicates that Japan was inhabited as early as the Upper Paleolithic period, the first written mention of Japan is in Chinese history texts from the 1st century AD. Influence from other regions, mainly China, followed by periods of isolation, from the 12th century until 1868, Japan was ruled by successive feudal military shoguns who ruled in the name of the Emperor. Japan entered into a period of isolation in the early 17th century. The Second Sino-Japanese War of 1937 expanded into part of World War II in 1941, which came to an end in 1945 following the bombings of Hiroshima and Nagasaki. Japan is a member of the UN, the OECD, the G7, the G8, the country has the worlds third-largest economy by nominal GDP and the worlds fourth-largest economy by purchasing power parity. It is also the worlds fourth-largest exporter and fourth-largest importer, although Japan has officially renounced its right to declare war, it maintains a modern military with the worlds eighth-largest military budget, used for self-defense and peacekeeping roles. Japan is a country with a very high standard of living. Its population enjoys the highest life expectancy and the third lowest infant mortality rate in the world, in ancient China, Japan was called Wo 倭. It was mentioned in the third century Chinese historical text Records of the Three Kingdoms in the section for the Wei kingdom, Wa became disliked because it has the connotation of the character 矮, meaning dwarf. The 倭 kanji has been replaced with the homophone Wa, meaning harmony, the Japanese word for Japan is 日本, which is pronounced Nippon or Nihon and literally means the origin of the sun. The earliest record of the name Nihon appears in the Chinese historical records of the Tang dynasty, at the start of the seventh century, a delegation from Japan introduced their country as Nihon
15.
Antineoplastic agent
–
Chemotherapy is a category of cancer treatment that uses one or more anti-cancer drugs as part of a standardized chemotherapy regimen. Chemotherapy may be given with an intent, or it may aim to prolong life or to reduce symptoms. Chemotherapy is one of the categories of the medical discipline specifically devoted to pharmacotherapy for cancer. Systemic therapy is used in conjunction with other modalities that constitute local therapy for cancer such as radiation therapy. Traditional chemotherapeutic agents are cytotoxic by means of interfering with cell division, to a large extent, chemotherapy can be thought of as a way to damage or stress cells, which may then lead to cell death if apoptosis is initiated. This results in the most common side-effects of chemotherapy, myelosuppression, mucositis, because of the effect on immune cells, chemotherapy drugs often find use in a host of diseases that result from harmful overactivity of the immune system against self. These include rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, vasculitis, there are a number of strategies in the administration of chemotherapeutic drugs used today. Chemotherapy may be given with an intent or it may aim to prolong life or to palliate symptoms. Induction chemotherapy is the first line treatment of cancer with a chemotherapeutic drug and this type of chemotherapy is used for curative intent. Combined modality chemotherapy is the use of drugs with other treatments, such as surgery, radiation therapy. Consolidation chemotherapy is given after remission in order to prolong the overall disease-free time, the drug that is administered is the same as the drug that achieved remission. Intensification chemotherapy is identical to consolidation chemotherapy but a different drug than the induction chemotherapy is used, combination chemotherapy involves treating a patient with a number of different drugs simultaneously. The drugs differ in their mechanism and side-effects, the biggest advantage is minimising the chances of resistance developing to any one agent. Also, the drugs can often be used at lower doses, neoadjuvant chemotherapy is given prior to a local treatment such as surgery, and is designed to shrink the primary tumor. It is also given to cancers with a risk of micrometastatic disease. Adjuvant chemotherapy is given after a local treatment and it can be used when there is little evidence of cancer present, but there is risk of recurrence. It is also useful in killing any cancerous cells that have spread to parts of the body. These micrometastases can be treated with adjuvant chemotherapy and can reduce relapse rates caused by these disseminated cells, maintenance chemotherapy is a repeated low-dose treatment to prolong remission
16.
Mepitiostane
–
It is the 17-methyloxycyclopentyl ether of epitiostanol, and acts as an oral prodrug to it. Mepitiostane is described as similar to tamoxifen as an antiestrogen, and through epitiostanol, binds directly to, a series of case reports have found it to be effective in the treatment of an estrogen receptor-dependent meningiomas. The drug shows a rate of virilizing side effects such as acne, hirsutism. It was patented and described in the literature in 1968
17.
Side effect
–
Occasionally, drugs are prescribed or procedures performed specifically for their side effects, in that case, said side effect ceases to be a side effect, and is now an intended effect. For instance, X-rays were historically used as an imaging technique, buprenorphine has been shown experimentally to be effective against severe, refractory depression. Bupropion, an anti-depressant, is used as a smoking cessation aid, this indication was later approved. In Ontario, Canada, smoking cessation drugs are not covered by provincial drug plans, elsewhere, Zyban is priced higher than Wellbutrin, therefore, some physicians prescribe Wellbutrin for both indications. Dexamethasone and Betamethasone in premature labor, to enhance pulmonary maturation of the fetus, doxepin has been used to treat angiodema and severe allergic reactions due to its strong antihistamine properties. Hydroxyzine, an antihistamine, is used as an anxiolytic. Magnesium sulfate in obstetrics for premature labor and preeclampsia, methotrexate, approved for the treatment of choriocarcinoma, is frequently used for the medical treatment of an unruptured ectopic pregnancy. The SSRI medication sertraline is approved as an antidepressant but delays conjugal climax in men, sildenafil was originally intended for pulmonary hypertension, subsequently, it was discovered that it also produces erections, for which it was later marketed. Terazosin, an α1-adrenergic antagonist approved to treat benign prostatic hyperplasia, echinacea – more than 20 different types of reactions have been reported, including asthma attacks, loss of pregnancy, hives, swelling, aching muscles and gastrointestinal upsets. Feverfew – pregnant women should avoid using this herb, as it can trigger uterine contractions, in animal experiments, the use of feverfew was found to trigger spontaneous abortions. Asteraceae plants – which include feverfew, echinacea, dandelion and chamomile, side effects include allergic dermatitis and hay fever
18.
Androgen receptor
–
The androgen receptor is most closely related to the progesterone receptor, and progestins in higher dosages can block the androgen receptor. The main function of the receptor is as a DNA-binding transcription factor that regulates gene expression, however. Androgen regulated genes are critical for the development and maintenance of the male sexual phenotype, hence, testosterone is responsible primarily for the development of male primary sexual characteristics, whereas dihydrotestosterone is responsible for secondary male characteristics. Androgens cause slow epiphysis, or maturation of the bones, steroid users of teen age may find that their growth had been stunted by androgen and/or estrogen excess. People with too little sex hormones can be short during puberty, via the Androgen receptor, androgens play a key role in the maintenance of male skeletal integrity. The regulation of this integrity by androgen receptor signaling can be attributed to both osteoblasts and osteocytes, the primary mechanism of action for androgen receptors is direct regulation of gene transcription. The androgen receptor dimer binds to a sequence of DNA known as a hormone response element. Androgen receptors interact with proteins in the nucleus, resulting in up- or down-regulation of specific gene transcription. Up-regulation or activation of transcription results in increased synthesis of messenger RNA, one of the known target genes of androgen receptor activation is the insulin-like growth factor I receptor. Thus, changes in levels of proteins in cells is one way that androgen receptors control cell behavior. One function of receptor that is independent of direct binding to its target DNA sequence, is facilitated by recruitment via other DNA-binding proteins. One example is serum response factor, a protein that activates several genes that cause muscle growth, AR acetylation is induced by androgens and determines recruitment into chromatin. The AR acetylation site is a key target of NAD-dependent and TSA-dependent histone deacetylases, more recently, androgen receptors have been shown to have a second mode of action. As has been found for other steroid hormone receptors such as estrogen receptors. Androgen receptors interact with certain signal transduction proteins in the cytoplasm, Androgen binding to cytoplasmic androgen receptors can cause rapid changes in cell function independent of changes in gene transcription, such as changes in ion transport. In humans, the receptor is encoded by the AR gene located on the X chromosome at Xq11-12. The androgen insensitivity syndrome, formerly known as testicular feminization, is caused by a mutation of the receptor gene located on the X chromosome. The androgen receptor seems to affect neuron physiology and is defective in Kennedys disease, in addition, point mutations and trinucleotide repeat polymorphisms has been linked to a number of additional disorders
19.
Estrogen receptor
–
Estrogen receptors are a group of proteins found inside and on cells. They are receptors that are activated by the hormone estrogen and this article refers to the former. Once activated by estrogen, the ER is able to translocate into the nucleus, however, it also has additional functions independent of DNA binding. As hormone receptors for sex steroids, ERs, androgen receptors, there are two different forms of the estrogen receptor, usually referred to as α and β, each encoded by a separate gene. Hormone-activated estrogen receptors form dimers, and, since the two forms are coexpressed in many types, the receptors may form ERα or ERβ homodimers or ERαβ heterodimers. Estrogen receptor alpha and beta show significant overall sequence homology, the N-terminal A/B domain is able to transactivate gene transcription in the absence of bound ligand. While this region is able to activate gene transcription without ligand, the C domain, also known as the DNA-binding domain, binds to estrogen response elements in DNA. The D domain is a region that connects the C and E domains. The E domain contains the binding cavity as well as binding sites for coactivator and corepressor proteins. The E-domain in the presence of ligand is able to activate gene transcription. The C-terminal F domain function is not entirely clear and is variable in length, due to alternative RNA splicing, several ER isoforms are known to exist. At least three ERα and five ERβ isoforms have been identified, the ERβ isoforms receptor subtypes can transactivate transcription only when a heterodimer with the functional ERß1 receptor of 59 kDa is formed. The ERß3 receptor was detected at levels in the testis. The two other ERα isoforms are 36 and 46kDa, only in fish, but not in humans, an ERγ receptor has been described. In humans, the two forms of the receptor are encoded by different genes, ESR1 and ESR2 on the sixth and fourteenth chromosome. In males, ERα protein is found in the epithelium of the efferent ducts, the expression of the ERβ protein has been documented in ovarian granulosa cells, kidney, brain, bone, heart, lungs, intestinal mucosa, prostate, and endothelial cells. The ERα primary transcript gives rise to several alternatively spliced variants of unknown function, the ERs helix 12 domain plays a crucial role in determining interactions with coactivators and corepressors and, therefore, the respective agonist or antagonist effect of the ligand. In addition, the different estrogen receptor combinations may respond differently to various ligands, the ratio of α- to β- subtype concentration has been proposed to play a role in certain diseases
20.
Agonist
–
An agonist is a chemical that binds to a receptor and activates the receptor to produce a biological response. Whereas an agonist causes an action, an antagonist blocks the action of the agonist, receptors can be activated by either endogenous or exogenous agonists, resulting in a biological response. A physiological agonist is a substance that creates the same bodily responses but does not bind to the same receptor, an endogenous agonist for a particular receptor is a compound naturally produced by the body that binds to and activates that receptor. For example, the endogenous agonist for serotonin receptors is serotonin, a superagonist is a compound that is capable of producing a greater maximal response than the endogenous agonist for the target receptor, and thus has an efficacy of more than 100%. Full agonists bind and activate a receptor, producing full efficacy at that receptor, one example of a drug that acts as a full agonist is isoproterenol, which mimics the action of adrenaline at β adrenoreceptors. Another example is morphine, which mimics the actions of endorphins at μ-opioid receptors throughout the nervous system. Partial agonists also bind and activate a receptor, but have only partial efficacy at the receptor relative to a full agonist. Agents like buprenorphine are used to treat opiate dependence for this reason, as they produce milder effects on the receptor with lower dependence. An inverse agonist is an agent that binds to the same receptor binding-site as an agonist for that receptor, inverse agonists exert the opposite pharmacological effect of a receptor agonist, not merely an absence of the agonist effect as seen with antagonist. An example is the inverse agonist rimonabant. A co-agonist works with other co-agonists to produce the desired effect together, NMDA receptor activation requires the binding of both glutamate, glycine and D-serine co-agonists. An irreversible agonist is a type of agonist that binds permanently to a receptor through the formation of covalent bonds, a few of these have been described. A selective agonist is selective for a type of receptor. E. g. buspirone is a selective agonist for serotonin 5-HT1A, terms that describe this phenomenon are functional selectivity, protean agonism, or selective receptor modulators. Potency is the amount of agonist needed to elicit a desired response, the potency of an agonist is inversely related to its EC50 value. The EC50 can be measured for a given agonist by determining the concentration of agonist needed to elicit half of the biological response of the agonist. The EC50 value is useful for comparing the potency of drugs with similar efficacies producing physiologically similar effects, the smaller the EC50 value, the greater the potency of the agonist, the lower the concentration of drug that is required to elicit the maximum biological response. This relationship, termed the index, is defined as the ratio TD50, ED50
21.
Receptor antagonist
–
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens agonist-mediated responses rather than provoking a biological response itself upon binding to a receptor. They are sometimes called blockers, examples include alpha blockers, beta blockers, antagonist activity may be reversible or irreversible depending on the longevity of the antagonist–receptor complex, which, in turn, depends on the nature of antagonist–receptor binding. The majority of drug antagonists achieve their potency by competing with endogenous ligands or substrates at structurally defined binding sites on receptors, biochemical receptors are large protein molecules that can be activated by the binding of a ligand. Receptors can be membrane-bound, occurring on the membrane, or intracellular. Binding occurs as a result of noncovalent interaction between the receptor and its ligand, at locations called the site on the receptor. A receptor may contain one or more binding sites for different ligands, binding to the active site on the receptor regulates receptor activation directly. The activity of receptors can also be regulated by the binding of a ligand to other sites on the receptor, antagonists mediate their effects through receptor interactions by preventing agonist-induced responses. This may be accomplished by binding to the site or the allosteric site. In addition, antagonists may interact at unique binding sites not normally involved in the regulation of the receptors activity to exert their effects. The term antagonist was originally coined to describe different profiles of drug effects, the biochemical definition of a receptor antagonist was introduced by Ariens and Stephenson in the 1950s. The current accepted definition of receptor antagonist is based on the receptor occupancy model and it narrows the definition of antagonism to consider only those compounds with opposing activities at a single receptor. Agonists were thought to turn on a cellular response by binding to the receptor. Antagonists were thought to turn off that response by blocking the receptor from the agonist and this definition also remains in use for physiological antagonists, substances that have opposing physiological actions, but act at different receptors. Our understanding of the mechanism of drug-induced receptor activation and receptor theory, the two-state model of receptor activation has given way to multistate models with intermediate conformational states. This means efficacy may actually depend on where that receptor is expressed, by definition, antagonists display no efficacy to activate the receptors they bind. Antagonists do not maintain the ability to activate a receptor, once bound, however, antagonists inhibit the function of agonists, inverse agonists, and partial agonists. In functional antagonist assays, a dose-response curve measures the effect of the ability of a range of concentrations of antagonists to reverse the activity of an agonist, the potency of an antagonist is usually defined by its half maximal inhibitory concentration IC50 value. This can be calculated for a given antagonist by determining the concentration of antagonist needed to elicit half inhibition of the biological response of an agonist
22.
Potency (pharmacology)
–
In the field of pharmacology, potency is a measure of drug activity expressed in terms of the amount required to produce an effect of given intensity. A highly potent drug evokes a response at low concentrations. The potency depends on both the affinity and efficacy, affinity is the ability of the drug to bind to a receptor. Efficacy is the relationship between occupancy and the ability to initiate a response at the molecular, cellular, tissue or system level. The response is equal to the effect, or, and depends on both the binding and the drug-bound receptor then producing a response, thus, potency depends on both affinity and efficacy. The agonist, the ligand, drug or hormone that binds to the receptor, the Emax is the maximum possible effect for the agonist. The concentration of A at which E is 50% of Emax is termed the half maximal effective concentration and is abbreviated 50, the term potency refers to the 50 value. The lower the 50, the less the concentration of a drug is required to produce 50% of maximum effect, higher potency does not necessarily mean more side effects. Walker MG, Page CP, Hoffman BF, Curtis M
23.
Methyltestosterone
–
Testosterone is a medication and naturally occurring steroid hormone. It is an androgen and anabolic steroid and is used to treat male hypogonadism and it may also be used to increase athletic ability in the form of doping. It is unclear if the use of testosterone for low levels due to aging is beneficial or harmful. Testosterone can be used as a gel or patch that is applied to the skin, injection into a muscle, tablet that is placed in the cheek, common side effects from testosterone medication include acne, swelling, and breast enlargement in males. Serious side effects may include liver toxicity, heart disease, women and children who are exposed may develop virilization. It is recommended that individuals with prostate cancer not use the medication and it can cause harm to the baby if used during pregnancy or breastfeeding. Testosterone was first isolated in 1935, rates of use have increased three times in the United States between 2001 and 2011. It is on the World Health Organizations List of Essential Medicines and it is available as a generic medication. The price depends on the dose and form of the product, the primary use of testosterone is the treatment of males with too little or no natural testosterone production, also termed hypogonadism or hypoandrogenism. This treatment is referred to as hormone replacement therapy, or alternatively and it is used to maintain serum testosterone levels in the normal male range. Decline of testosterone production with age has led to interest in testosterone supplementation, Testosterone deficiency is an abnormally low testosterone production. It may occur because of testicular dysfunction or hypothalamic-pituitary dysfunction and may be congenital or acquired, Testosterone levels may decline gradually with age. The United States Food and Drug Administration stated in 2015 that neither the nor the safety of testosterone supplement have been established for low testosterone levels due to aging. The FDA has required that labels on testosterone include warnings about increased risk of heart attacks, Testosterone supplementation is effective in the short term for hypoactive sexual desire disorder. However, its long term safety is unclear, treating low androgen levels with testosterone is not generally recommended in women when it is due to hypopituitarism, adrenal insufficiency, or following surgical removal of the ovaries. It is also not usually recommended for improving cognition, the risk of heart disease, Testosterone is used as a form of doping among athletes in order to improve performance. Testosterone is classified as an agent and is on the World Anti-Doping Agency List of Prohibited Substances. Anabolic-androgenic steroids, including testosterone and its esters, have also taken to enhance muscle development, strength
24.
Estrogen
–
Estrogen or oestrogen is the primary female sex hormone as well as a medication. It is responsible for the development and regulation of the reproductive system. Estrogen may also refer to any substance, natural or synthetic, the estrane steroid estradiol is the most potent and prevalent endogenous estrogen, although several metabolites of estradiol also have estrogenic hormonal activity. They are one of three types of sex hormones, the others being androgens/anabolic steroids like testosterone and progestogens like progesterone, estrogens are synthesized in all vertebrates as well as some insects. Their presence in both vertebrates and insects suggests that sex hormones have an ancient evolutionary history. The three major naturally occurring forms of estrogen in women are estrone, estradiol, and estriol, another type of estrogen called estetrol is produced only during pregnancy. Quantitatively, estrogens circulate at lower levels than androgens in both men and women, while estrogen levels are significantly lower in males compared to females, estrogens nevertheless also have important physiological roles in males. Like all steroid hormones, estrogens readily diffuse across the cell membrane, once inside the cell, they bind to and activate estrogen receptors which in turn modulate the expression of many genes. Additionally, estrogens bind to and activate rapid-signaling membrane estrogen receptors, the three major naturally occurring estrogens in women are estrone, estradiol, and estriol. Estradiol is the predominant estrogen during reproductive years both in terms of serum levels as well as in terms of estrogenic activity. During menopause, estrone is the predominant circulating estrogen and during pregnancy estriol is the predominant circulating estrogen in terms of serum levels. Though estriol is the most plentiful of the three estrogens it is also the weakest, whereas estradiol is the strongest with a potency of approximately 80 times that of estriol. Thus, estradiol is the most important estrogen in non-pregnant females who are between the menarche and menopause stages of life, however, during pregnancy this role shifts to estriol, and in postmenopausal women estrone becomes the primary form of estrogen in the body. Another type of estrogen called estetrol is produced only during pregnancy, all of the different forms of estrogen are synthesized from androgens, specifically testosterone and androstenedione, by the enzyme aromatase. Estradiol, estrone, and estriol have all been approved as drugs and are used medically. Estetrol is currently under development for medical indications, but has not yet approved in any country. A variety of synthetic estrogen esters, such as estradiol valerate, estradiol cypionate, estradiol acetate, estradiol undecylate, polyestradiol phosphate, the aforementioned compounds behave as prodrugs to estradiol, and are longer-lasting in comparison. Esters of estrone and estriol also exist and are employed in clinical medicine, ethinylestradiol is a more potent synthetic analogue of estradiol that is used widely in hormonal contraceptives
25.
Bioavailability
–
By definition, when a medication is administered intravenously, its bioavailability is 100%. However, when a medication is administered via other routes, its bioavailability generally decreases or may vary from patient to patient, Bioavailability is one of the essential tools in pharmacokinetics, as bioavailability must be considered when calculating dosages for non-intravenous routes of administration. Bioavailability is defined differently for drugs as opposed to dietary supplements primarily due to the method of administration and Food. Bioaccessibility is a related to bioavailability in the context of biodegradation. A molecule is said to be bioaccessible when is available to cross a cellular membrane from the environment. In pharmacology, bioavailability is a measurement of the rate and extent to which a drug reaches at the site of action and it is denoted by the letter f. Therefore, bioavailability for dietary supplements can be defined as the proportion of the administered substance capable of being absorbed, in both pharmacology and nutrition sciences, bioavailability is measured by calculating the area under curve of the drug concentration time profile. Bioavailability is commonly a factor in the production of crops. Toxic materials in soil, such as lead from paint may be rendered unavailable to animals ingesting contaminated soil by supplying phosphorus fertilizers in excess and it is the fraction of the drug absorbed through non-intravenous administration compared with the corresponding intravenous administration of the same drug. The comparison must be normalized, consequently, the amount absorbed is corrected by dividing the corresponding dose administered. The absolute bioavailability is the area under curve non-intravenous divided by AUC intravenous. For example, the formula for calculating F for a drug administered by the route is given below. If we compare the two different dosage forms having same active ingredients and compare the two drug bioavailability is called comparative bioavailability, although knowing the true extent of systemic absorption is clearly useful, in practice it is not determined as frequently as one may think. The reason for this is that its assessment requires a reference, that is. These limitations may be overcome, however, by administering a low dose of an isotopically labelled drug concomitantly with a therapeutic non-labelled oral dose. This technique eliminates pharmacokinetic issues on non-equivalent clearance as well as enabling the intravenous dose to be administered with a minimum of toxicology, the technique was first applied using stable-isotopes such as 13C and mass-spectrometry to distinguish the isotopes by mass difference. More recently, 14C labelled drugs are administered intravenously and accelerator mass spectrometry used to measure the isotopically labelled drug along with mass spectrometry for the unlabelled drug, in all such cases, to conduct an absolute bioavailability study requires that the drug be given intravenously. Intravenous administration of a drug can provide valuable information on the fundamental pharmacokinetic parameters of volume of distribution
26.
Organic compound
–
An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
27.
Steroid
–
A steroid is an organic compound with four rings arranged in a specific configuration. Examples include the dietary lipid cholesterol, the sex hormones estradiol and testosterone, the steroid core structure is composed of seventeen carbon atoms, bonded in four fused rings, three six-member cyclohexane rings and one five-member cyclopentane ring. Steroids vary by the groups attached to this four-ring core. Sterols are forms of steroids with a group at position three and a skeleton derived from cholestane. They can also vary more markedly by changes to the ring structure, hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol or cycloartenol, lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene. The three cyclohexane rings form the skeleton of a derivative of phenanthrene. The D ring has a cyclopentane structure, when the two methyl groups and eight carbon side chains are present, the steroid is said to have a cholestane framework. The following are some categories of steroids. In eukaryotes, steroids are found in fungi, animals, animal steroids include compounds of vertebrate and insect origin, the latter including ecdysteroids such as ecdysterone. Steroid hormones include, Sex hormones, which influence sex differences and these include androgens, estrogens, and progestagens. In popular use, the term often refers to anabolic steroids. Plant steroids include steroidal alkaloids found in Solanaceae, the phytosterols, in prokaryotes, biosynthetic pathways exist for the tetracyclic steroid framework – where its origin from eukaryotes is conjectured – and the more-common pentacyclic triterpinoid hopanoid framework. One example of how MeSH performs this classification is available at the Wikipedia MeSH catalog, examples of this classification include, The gonane is the parent 17-carbon tetracyclic hydrocarbon molecule with no alkyl sidechains. Secosteroids are a subclass of steroidal compounds resulting, biosynthetically or conceptually, major secosteroid subclasses are defined by the steroid carbon atoms where this scission has taken place. Norsteroids and homosteroids are structural subclasses of steroids formed from biosynthetic steps, the former involves enzymic ring expansion-contraction reactions, and the latter is accomplished or through ring closures of acyclic precursors with more ring atoms than the parent steroid framework. Combinations of these alterations are known in nature. Ingestion of these C-nor-D-homosteroids results in defects in lambs, cyclopia from cyclopamine
