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SN-38
SN-38 is an antineoplastic drug. It is the active metabolite of irinotecan (an analog of camptothecin - a topoisomerase I inhibitor) but has 1000 times more activity than irinotecan itself. In vitro cytotoxicity assays show that the potency of SN-38 relative to irinotecan varies from 2- to 2000-fold.http://labeling.pfizer.com/ShowLabeling.aspx?id=533 SN38 is formed via hydrolysis of irinotecan by carboxylesterases and metabolized via glucuronidation by UGT1A1. The variant of UGT1A1 in ~10% of Caucasians which leads to poor metabolism of SN-38 predicts irinotecan toxicity, as it is then less easily excreted from the body in its SN-38 glucuronide form. SN-38 and its glucuronide are lost into the bile and intestines. It can cause the symptoms of diarrhoea and myelosuppression experienced by ~25% of the patients administered irinotecan. Interactive pathway map See also * NK012, a nanodevice formulation of SN-38 *Sacituzumab govitecan Sacituzumab govitecan, sold under the brand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irinotecan
Irinotecan, sold under the brand name Camptosar among others, is a medication used to treat colon cancer, and small cell lung cancer. For colon cancer it is used either alone or with fluorouracil. For small cell lung cancer it is used with cisplatin. It is given intravenously. Common side effects include diarrhea, vomiting, bone marrow suppression, hair loss, shortness of breath, and fever. Other severe side effects include blood clots, colon inflammation, and allergic reactions. Those with two copies of the UGT1A1*28 gene variant are at higher risk for side effects. Use during pregnancy can result in harm to the baby. Irinotecan is a topoisomerase inhibitor—it blocks the topoisomerase I enzyme, resulting in DNA damage and cell death. Irinotecan was approved for medical use in the United States in 1996. It is on the World Health Organization's List of Essential Medicines. It is made from the natural compound camptothecin which is found in the Chinese ornamental tree ''Campt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacituzumab Govitecan
Sacituzumab govitecan, sold under the brand name Trodelvy, is a Trop-2-directed antibody and topoisomerase inhibitor drug conjugate used for the treatment of metastatic triple-negative breast cancer and metastatic urothelial cancer. The most common side effects include nausea, neutropenia, diarrhea, fatigue, anemia, vomiting, alopecia (hair loss), constipation, decreased appetite, rash and abdominal pain. Sacituzumab govitecan has a boxed warning about the risk of severe neutropenia (abnormally low levels of white blood cells) and severe diarrhea. Sacituzumab govitecan may cause harm to a developing fetus or newborn baby. Women are advised not to breastfeed while on sacituzumab govitecan and one month after the last dose is administered. The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) consider it to be a first-in-class medication. Sacituzumab govitecan was approved for medical use in the European Union in November 2021. Medical uses Sac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NK012
NK012 is a 'nanodevice' formulation of SN-38 (an irinotecan metabolite). NK012 is an SN-38-releasing polymeric micelle constructed by covalently attaching SN-38 to the block copolymer PEG-PGlu, followed by self-assembly of amphiphilic block copolymers in aqueous media. It has completed phase II clinical trials for triple-negative breast cancer and relapsed small cell lung cancer. In 2016, Nippon Kayaku received orphan drug designation for NK012 from the US FDA.Nippon Kayaku Announces FDA Orphan Drug Designation to New Polymeric micelle Anti-Cancer Drug NK012 for Small Cell Lung Cancer. (2016). Evaluategroup.com. Retrieved 24 November 2017, from http://www.evaluategroup.com/Universal/View.aspx?type=Story&id=644017 This means that if it is approved in the United States, Nippon Kayaku will be entitled to 7 years of market exclusivity. This is intended to incentivize future development, but does not mean the drug has been approved. See also * Nanomedicine * Targeted drug delivery Tar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Metabolite
An active metabolite is an active form of a drug after it has been processed by the body. Metabolites of drugs An active metabolite results when a drug is metabolized by the body into a modified form which continues to produce effects in the body. Usually these effects are similar to those of the parent drug but weaker, although they can still be significant (see e.g. 11-hydroxy-THC, morphine-6-glucuronide). Certain drugs such as codeine and tramadol have metabolites (morphine and ''O''-desmethyltramadol respectively) that are stronger than the parent drug and in these cases the metabolite may be responsible for much of the therapeutic action of the parent drug. Sometimes, however, metabolites may produce toxic effects and patients must be monitored carefully to ensure they do not build up in the body. This is an issue with some well-known drugs, such as pethidine (meperidine) and dextropropoxyphene. Prodrugs Sometimes drugs are formulated in an inactive form that is designe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camptothecin
Camptothecin (CPT) is a topoisomerase inhibitor. It was discovered in 1966 by M. E. Wall and M. C. Wani in systematic screening of natural products for anticancer drugs. It was isolated from the bark and stem of ''Camptotheca acuminata'' (Camptotheca, Happy tree), a tree native to China used in traditional Chinese medicine. It has been used clinically more recently in China for the treatment of gastrointestinal tumors. CPT showed anticancer activity in preliminary clinical trials, especially against breast, ovarian, colon, lung, and stomach cancers. However, it has low solubility and adverse effects have been reported when used therapeutically, so synthetic and medicinal chemists have developed numerous syntheses of camptothecin and various derivatives to increase the benefits of the chemical, with good results. Four CPT analogues have been approved and are used in cancer chemotherapy today, topotecan, irinotecan, belotecan, and trastuzumab deruxtecan. Camptothecin has also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topoisomerase I
DNA topoisomerases (or topoisomerases) are enzymes that catalyze changes in the topological state of DNA, interconverting relaxed and supercoiled forms, linked (catenated) and unlinked species, and knotted and unknotted DNA. Topological issues in DNA arise due to the intertwined nature of its double-helical structure, which, for example, can lead to overwinding of the DNA duplex during DNA replication and transcription. If left unchanged, this torsion would eventually stop the DNA or RNA polymerases involved in these processes from continuing along the DNA helix. A second topological challenge results from the linking or tangling of DNA during replication. Left unresolved, links between replicated DNA will impede cell division. The DNA topoisomerases prevent and correct these types of topological problems. They do this by binding to DNA and cutting the sugar-phosphate backbone of either one (type I topoisomerases) or both (type II topoisomerases) of the DNA strands. This transien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylesterase
The enzyme carboxylesterase (or carboxylic-ester hydrolase, EC 3.1.1.1; systematic name carboxylic-ester hydrolase) catalyzes reactions of the following form: :a carboxylic ester + H2O \rightleftharpoons an alcohol + a carboxylate Most enzymes from this group are serine hydrolases belonging to the superfamily of proteins with α/β hydrolase fold. Some exceptions include an esterase with β-lactamase-like structure (). Carboxylesterases are widely distributed in nature, and are common in mammalian liver. Many participate in phase I metabolism of xenobiotics such as toxins or drugs; the resulting carboxylates are then conjugated by other enzymes to increase solubility and eventually excreted. The essential polyunsaturated fatty acid arachidonic acid (AA C20 H32 O2; 20: 4, n-6), formed by the synthesis from dietary linoleic acid (LA: C18H32O2 18:2, n-6), has a role as a human carboxylesterase inhibitor. The carboxylesterase family of evolutionarily related proteins (those w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucuronidation
Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve glycosidic bonds. Mechanism Glucuronidation consists of transfer of the glucuronic acid component of uridine diphosphate glucuronic acid to a substrate by any of several types of UDP-glucuronosyltransferase. UDP-glucuronic acid (glucuronic acid linked via a glycosidic bond to uridine diphosphate) is an intermediate in the process and is formed in the liver. One example is the N-glucuronidation of an aromatic amine, 4-aminobiphenyl, by UGT1A4 or UGT1A9 from human, rat, or mouse liver. : The substances resulting from glucuronidation are known as glucuronides (or glucuronosides) and are typically much more water-soluble than the non-glucuronic acid-containing substances from which they were originally synthesised. The human body uses glucuronidat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UGT1A1
UDP-glucuronosyltransferase 1-1 also known as UGT-1A is an enzyme that in humans is encoded by the ''UGT1A1'' gene. UGT-1A is a uridine diphosphate glucuronosyltransferase (UDP-glucuronosyltransferase, UDPGT), an enzyme of the glucuronidation pathway that transforms small Lipophilicity, lipophilic (fat-soluble) molecules, such as steroids, bilirubin, hormones, and drugs, into water-soluble, excretable metabolites. Gene The UGT1A1 gene is part of a complex locus (genetics), locus that encodes several UDP-glucuronosyltransferases. The locus includes thirteen unique alternative first exons followed by four common exons. Four of the alternate first exons are considered pseudogenes. Each of the remaining nine 5' exons may be spliced to the four common exons, resulting in nine proteins with different N-termini and identical C-termini. Each first exon encodes the substrate binding site, and is regulated by its own promotor (biology), promoter. Over 100 mutation, genetic variants within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxicity
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell ( cytotoxicity) or an organ such as the liver (hepatotoxicity). By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large. Sometimes the word is more or less synonymous with poisoning in everyday usage. A central concept of toxicology is that the effects of a toxicant are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to bypas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diarrhoea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal. The most common cause is an infection of the intestines due to either a virus, bacterium, or parasite—a condition also known as gastroenteritis. These infections are often acquired from food or water that has been contaminated by feces, or directly from another person who is infected. The three types of diarrhea are: short duration watery diarrhea, short duration bloody diarrhea, and persistent diarrhea (lasting more than two weeks, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
