Virus directed enzymes have been identified in host cells
If too hydrophilic, the drug cannot cross the lipid cell membrane; if too lipophilic, the drug is not soluble enough to cross the water layer adjacent to the cell. Drugs may not be absorbed because of a reverse transporter associated with P-glycoprotein. This process actively pumps drug out of gut wall cells back into the gut lumen. Inhibition of P-glycoprotein and gut wall metabolism, eg, by grapefruit juice, may be associated with substantially increased drug absorption.
Any of a group of viruses that, unlike most other viruses and all cellular organisms, carry their genetic blueprint in the form of RNA. Retroviruses are responsible for some cancers and viral infections of animals, and they cause at least one type of human cancer. The retrovirus HIV is the cause of AIDS in humans. The name signifies that they use RNA to synthesize DNA, the reverse of the usual cell process. This process makes it possible for genetic material from a retrovirus to enter and become a permanent part of the genes of an infected cell.
A point mutation , or single base substitution , is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA. Often the term point mutation also includes insertions or deletions of a single base pair. One can categorize point mutations as follows:
Gag and Gag-Pol gene products
Antiviral Drugs Department of Pharmacology NEIGRIHMS, Shillong
Acyclovir - MOA Step 2: Incorporation into growing DNA chain Inhibits DNA-polymerase irreversibly
Acyclovir – MOA (Summary) Acyclovir Acyclovir Monophosphate Acyclovir triphosphate Herpes virus specific thymidine kinase Cellular kinases Inhibits herpes virus DNA Polymerase competitively Gets incorporated in viral DNA and stops lengthening of DNA strands. The terminated DNA Inhibits DNA-polymerase irreversibly