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Adefovir
Adefovir is a prescription medicine used to treat (chronic) infections with hepatitis B virus. A prodrug form of adefovir was previously called bis-POM PMEA, with trade names Preveon and Hepsera. It is an orally administered nucleotide analog reverse-transcriptase inhibitor (ntRTI). It can be formulated as the pivoxil prodrug adefovir dipivoxil. Uses It is used for treatment of hepatitis B. Trials of adefovir in patients with HIV have not shown any clear benefits. History Adefovir was invented in the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic by Antonín Holý, and the drug was developed by Gilead Sciences for HIV with the brand name Preveon. However, in November 1999, an expert panel advised the U.S. Food and Drug Administration (FDA) not to approve the drug due to concerns about the severity and frequency of kidney toxicity when dosed at 60 or 120 mg. The FDA followed that advice, refusing to approve adefovir as a treatment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adefovir Dipivoxil Structure
Adefovir is a prescription medicine used to treat (chronic) infections with hepatitis B virus. A prodrug form of adefovir was previously called bis-POM PMEA, with trade names Preveon and Hepsera. It is an orally administered nucleotide analog reverse-transcriptase inhibitor (ntRTI). It can be formulated as the pivoxil prodrug adefovir dipivoxil. Uses It is used for treatment of hepatitis B. Trials of adefovir in patients with HIV have not shown any clear benefits. History Adefovir was invented in the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic by Antonín Holý, and the drug was developed by Gilead Sciences for HIV with the brand name Preveon. However, in November 1999, an expert panel advised the U.S. Food and Drug Administration (FDA) not to approve the drug due to concerns about the severity and frequency of kidney toxicity when dosed at 60 or 120 mg. The FDA followed that advice, refusing to approve adefovir as a treatment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonín Holý
Antonín Holý (1 September 1936 – 16 July 2012) was a pioneering Czech scientist. He specialised in the field of chemistry and cooperated on the development of important antiretroviral drugs used in the treatment of HIV and hepatitis B. He was involved in the creation of the most effective drug (as of early 2009) in the treatment of AIDS. Antonín Holý is the author of more than 450 papers, 400 scientific discoveries and holds 60 patents. With more than 400 discoveries to his credit, his work has affected millions of people with viral diseases such as HIV/AIDS and hepatitis B and many other viral diseases. In 2008 he received an Honorary Professorship at the University of Manchester's School of Chemistry. Scientific career Born in Prague, Czechoslovakia, Antonín Holý studied organic chemistry from 1954 to 1959 at the Faculty of Science of Charles University in Prague. From 1960 he trained at the Institute of Organic Chemistry and Biochemistry (IOCB) of the Czechoslovak Acad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse-transcriptase Inhibitor
Reverse-transcriptase inhibitors (RTIs) are a class of antiretroviral drugs used to treat HIV infection or AIDS, and in some cases hepatitis B. RTIs Enzyme inhibition, inhibit activity of reverse transcriptase, a viral DNA polymerase that is required for replication of HIV and other retroviruses. Mechanism of action When HIV infects a cell, reverse transcriptase copies the viral single stranded RNA genome into a double-stranded viral DNA. The viral DNA is then integrated into the host chromosomal DNA, which then allows host cellular processes, such as transcription and translation, to reproduce the virus. RTIs block reverse transcriptase's enzymatic function and prevent completion of synthesis of the double-stranded viral DNA, thus preventing HIV from multiplying. A similar process occurs with other types of viruses. The hepatitis B virus, for example, carries its genetic material in the form of DNA, and employs an RNA-dependent DNA polymerase to replicate. Some of the same compou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Transcriptase Inhibitors
Reverse-transcriptase inhibitors (RTIs) are a class of antiretroviral drugs used to treat HIV infection or AIDS, and in some cases hepatitis B. RTIs inhibit activity of reverse transcriptase, a viral DNA polymerase that is required for replication of HIV and other retroviruses. Mechanism of action When HIV infects a cell, reverse transcriptase copies the viral single stranded RNA genome into a double-stranded viral DNA. The viral DNA is then integrated into the host chromosomal DNA, which then allows host cellular processes, such as transcription and translation, to reproduce the virus. RTIs block reverse transcriptase's enzymatic function and prevent completion of synthesis of the double-stranded viral DNA, thus preventing HIV from multiplying. A similar process occurs with other types of viruses. The hepatitis B virus, for example, carries its genetic material in the form of DNA, and employs an RNA-dependent DNA polymerase to replicate. Some of the same compounds used as RTIs c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pivaloyloxymethyl
Pivaloyloxymethyl (POM, pivoxil, pivoxyl) is a protecting group used in organic synthesis.''Protective Groups in Organic Synthesis'', 3rd Edition, Theodora M. Greene and Peter G. M. Wuts, The POM radical has the formula (CH3)3C-CO-O-CH2. The POM group is also sometimes used to produce prodrugs. For example, the POM group can be attached to a negatively charged organophosphate group(s) of a drug causing a neutralization of the negative charge, which can allow the drug to become more lipid-soluble and thus more able to diffuse passively across cell membranes into cells. Upon entry into cells, the POM portion of the molecule can be removed by cellular processes resulting in release of active drug. Clinically used prodrugs containing pivaloyloxymethyl groups include adefovir dipivoxil, pivampicillin, cefditoren pivoxil, pivmecillinam, and valproate pivoxil. Tenofovir disoproxil contains a very similar prodrug group. See also * Pivalic acid Pivalic acid is a carboxylic acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prodrug
A prodrug is a medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug is absorbed, distributed, metabolized, and excreted (ADME). Prodrugs are often designed to improve bioavailability when a drug itself is poorly absorbed from the gastrointestinal tract. A prodrug may be used to improve how selectively the drug interacts with cells or processes that are not its intended target. This reduces adverse or unintended effects of a drug, especially important in treatments like chemotherapy, which can have severe unintended and undesirable side effects. History Many herbal extracts historically used in medicine contain glycosides (sugar derivatives) of the active agent, which are hydrolyzed in the intestines to release the active and more bioavailable aglycone. For example, salicin is a β-D-glucopyranosid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis B
Hepatitis B is an infectious disease caused by the ''Hepatitis B virus'' (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection. Many people have no symptoms during an initial infection. For others, symptoms may appear 30 to 180 days after becoming infected and can include a rapid onset of sickness with nausea, vomiting, yellowish skin, fatigue, dark urine, and abdominal pain. Symptoms during acute infection typically last for a few weeks, though some people may feel sick for up to six months. Deaths resulting from acute stage HBV infections are rare. An HBV infection lasting longer than six months is usually considered chronic. The likelihood of developing chronic hepatitis B is higher for those who are infected with HBV at a younger age. About 90% of those infected during or shortly after birth develop chronic hepatitis B, while less than 10% of those infected after the age of five develop chronic cases. Most of those wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academy Of Sciences Of The Czech Republic
The Czech Academy of Sciences (abbr. CAS, cs, Akademie věd České republiky, abbr. AV ČR) was established in 1992 by the Czech National Council as the Czech successor of the former Czechoslovak Academy of Sciences and its tradition goes back to the Royal Bohemian Society of Sciences (founded in 1784) and the Emperor Franz Joseph Czech Academy for Sciences, Literature and Arts (founded in 1890). The Academy is the leading non-university public research institution in the Czech Republic. It conducts both fundamental and strategic applied research. It has three scientific divisions, namely the Division of Mathematics, Physics, and Earth Sciences, Division of Chemical and Life Sciences, and Division of Humanities and Social Sciences. The Academy currently manages a network of sixty research institutes and five supporting units staffed by a total of 6,400 employees, over one half of whom are university-trained researchers and Ph.D. scientists. The Head Office of the Academy and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilead Sciences
Gilead Sciences, Inc. () is an American biopharmaceutical company headquartered in Foster City, California, that focuses on researching and developing antiviral drugs used in the treatment of HIV/AIDS, hepatitis B, hepatitis C, influenza, and COVID-19, including ledipasvir/sofosbuvir and sofosbuvir. Gilead is a member of the NASDAQ Biotechnology Index and the S&P 500. Gilead was founded in 1987 under the name Oligogen by Michael L. Riordan. The original name was a reference to oligomers, small strands of DNA used to target genetic sequences. Gilead held its IPO in 1992, and successfully developed drugs like Tamiflu and Vistide that decade. In the 2000s, Gilead received approval for drugs including Viread and Hepsera, among others. It began evolving from a biotechnology company into a pharmaceutical company, acquiring several subsidiaries, though it still relied heavily on contracting to manufacture its drugs. The company continued its growth in the 2010s, but came under heavy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food And Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, caffeine products, dietary supplements, Prescription drug, prescription and Over-the-counter drug, over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), cosmetics, Animal feed, animal foods & feed and Veterinary medicine, veterinary products. The FDA's primary focus is enforcement of the Federal Food, Drug, and Cosmetic Act (FD&C), but the agency also enforces other laws, notably Section 361 of the Public Health Service Act, as well as associated regulations. Much of this regulatory-enforcement work is not d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Transcriptase
A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes. Contrary to a widely held belief, the process does not violate the flows of genetic information as described by the classical central dogma, as transfers of information from RNA to DNA are explicitly held possible. Retroviral RT has three sequential biochemical activities: RNA-dependent DNA polymerase activity, ribonuclease H (RNase H), and DNA-dependent DNA polymerase activity. Collectively, these activities enable the enzyme to convert single-stranded RNA into double-stranded cDNA. In retroviruses and retrotransposons, this cDNA can then integrate into the host genom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminotransferase
Transaminases or aminotransferases are enzymes that catalyze a transamination reaction between an amino acid and an α-keto acid. They are important in the synthesis of amino acids, which form proteins. Function and mechanism An amino acid contains an amine (NH2) group. A keto acid contains a keto (=O) group. In transamination, the NH2 group on one molecule is exchanged with the =O group on the other molecule. The amino acid becomes a keto acid, and the keto acid becomes an amino acid. Most transaminases are protein enzymes. However, some transamination activities of the ribosome have been found to be catalyzed by ribozymes (RNA enzymes). Examples being the hammerhead ribozyme, the VS ribozyme and the hairpin ribozyme. Transaminases require the coenzyme pyridoxal phosphate, which is converted into pyridoxamine in the first half-reaction, when an amino acid is converted into a keto acid. Enzyme-bound pyridoxamine in turn reacts with pyruvate, oxaloacetate, or alpha-ketogluta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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