Zidovudine (ZDV), also known as azidothymidine (AZT), was the first antiretroviral medication used to prevent and treat HIV/AIDS. It is generally recommended for use in combination with other antiretrovirals. It may be used to prevent mother-to-child spread and is employed in prenatal, intrapartum and neonatal prophylaxis as part of combination regimens and in some post-exposure protocols. Chemically 3-azido-3-deoxythymidine, ZDV is a nucleoside reverse transcriptase inhibitor that is orally bioavailable, undergoes first-pass glucuronidation primarily by UGT2B7, has a short plasma half-life near 1 hour and an active intracellular triphosphate form with a longer residence time. Key clinical considerations include dose adjustment in renal impairment, hematologic toxicity risk including anemia and neutropenia, potential for lactic acidosis and myopathy with prolonged use, and the emergence of thymidine analog resistance mutations in HIV reverse transcriptase under monotherapy or inadequate combinations.
Parent: Olmesartan / Losartan / Candesartan/ Irbesartan / Zidovudine
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Typical quality control criteria for Zidovudine API and finished products use validated chromatographic and mass spectrometric methods. Representative acceptance ranges used by manufacturers and compendial monographs are assay by HPLC 98.0 to 102.0 percent of declared potency, water content typically not more than 0.5 percent by Karl Fischer, heavy metals below 20 parts per million, and residual solvents within ICH Q3C limits. Related substances limits commonly applied are any single known or unknown related compound not greater than 0.5 percent and total impurities not greater than 1.0 percent, with specific control of potential genotoxic impurities to 0.05 percent or lower in line with ICH M7 evaluation. Known related compounds and degradants monitored include thymidine-related analogs, 3′-amino-3′-deoxythymidine, 5′-O-acyl and 5′-O-arylsulfonyl derivatives such as 5′-O-acetyl-ZDV and 5′-O-tosyl-ZDV, de-azido degradation products and glucuronide metabolites; identification is performed by LC-MS, structural confirmation by NMR where required, and stability-indicating HPLC methods are used for release and shelf-life testing.
Zidovudine is used as part of combination antiretroviral therapy to treat HIV infection, and it is also used in prevention settings such as maternal to neonatal prophylaxis and selected post-exposure situations.
Zidovudine is given to newborns born to HIV positive mothers to reduce the risk of vertical transmission during and after delivery; neonatal regimens target early inhibition of viral replication while maternal and infant regimens are coordinated.
Both zidovudine and lamivudine are nucleoside reverse transcriptase inhibitors that require intracellular phosphorylation to active triphosphate forms; these analogues compete with natural deoxynucleoside triphosphates for incorporation by HIV reverse transcriptase, causing chain termination and blocking viral DNA synthesis.
Zidovudine is still used in specific settings but use has declined because newer antiretrovirals generally offer improved potency, better tolerability and simpler dosing with lower risks of hematologic toxicity and mitochondrial adverse effects; resistance patterns and safety profiles have led clinicians to prefer alternative agents in many first-line regimens.
