Abacavir is a synthetic guanosine analogue and a key active pharmaceutical ingredient (API) used in the manufacture of antiretroviral medications for the treatment of HIV infection. It functions as a nucleoside reverse transcriptase inhibitor (NRTI), blocking the reverse transcriptase enzyme essential for HIV replication, thereby reducing viral load and supporting immune system recovery. Typically incorporated into combination therapies such as highly active antiretroviral therapy (HAART), it helps prevent drug resistance. Abacavir is suitable for patients unresponsive to other antiretrovirals and is available in high-purity forms (>98% by HPLC) for pharmaceutical production, with formulations including tablets and oral solutions in final products. Molecular formula: C₁₄H₁₈N₆O; CAS No.: 136470-78-5. Adherence to quality specifications and regulatory standards is essential for therapeutic efficacy.