Elvitegravir is an integrase inhibitor used to treat HIV infection. It was developed by the pharmaceutical company Gilead Sciences, which licensed EVG from Japan Tobacco in March 2008. Elvitegravir binds the viral integrase active site and chelates the divalent metal cofactors required for strand transfer, blocking integration of viral DNA into host chromosomal DNA. As an oral antiretroviral, EVG is highly protein bound and is primarily metabolized by cytochrome P450 3A enzymes, so it is formulated and dosed in combination with a pharmacoenhancer to achieve therapeutic plasma concentrations. Clinically it is deployed in fixed dose combination products to simplify adherence and reduce pill burden. Analytical control during manufacture relies on stability-indicating reversed-phase liquid chromatography for assay and related-substance profiling, and LC-MS is used for structural elucidation of impurities and degradants.
Typical API and finished product control strategies identify process-related and degradation-related related substances such as dehalogenated or hydrolytic degradants, oxidative N-oxides, desalkylated species, and residual synthetic intermediates; common analytical limits used in specifications are individual identified impurities typically not greater than 0.2 to 0.5 percent by area or weight depending on qualification status, unspecified impurities often controlled at or below 0.10 percent, and total impurities commonly limited to about 1.0 percent. Genotoxic or mutagenic impurities are controlled to much lower levels in accordance with ICH M7 and product-specific PDE calculations, and residual solvents and elemental impurities are controlled to ICH Q3C and Q3D limits respectively. Methods used for release and stability testing include validated HPLC-UV for quantitation, LC-MS for identification, and where needed additional orthogonal methods such as GC for volatile impurities and ICP-MS for trace metals.
Elvitegravir is used as part of combination antiretroviral therapy to treat HIV infection by inhibiting the integrase enzyme and preventing viral DNA integration into host genomes; it is not typically used as monotherapy.
Elvitegravir is extensively metabolized by CYP3A enzymes, so a pharmacokinetic booster such as cobicistat is coadministered to inhibit CYP3A, increase EVG plasma exposure, prolong half-life, and maintain effective trough concentrations with once-daily dosing.
Bictegravir is another integrase strand transfer inhibitor used in fixed dose combination regimens for the treatment of HIV infection; it is the integrase component in contemporary single-tablet therapies designed to provide potent viral suppression with a high resistance barrier.
Efavirenz belongs to the class of non-nucleoside reverse transcriptase inhibitors, abbreviated NNRTIs, and it inhibits HIV reverse transcriptase through allosteric binding leading to reduced viral replication.
