Development and validation of a reverse-phase HPLC method for analysis of efavirenz and its related substances in the drug substance and in a capsule formulation.

A stability-indicating high performance liquid chromatographic (HPLC) method was developed for the assay of efavirenz, a non-nucleoside reverse transcriptase inhibitor used in the treatment of AIDS. The HPLC method, which is used to determine potency in efavirenz capsules and related substances in efavirenz drug substance and capsules, was validated per ICH guidelines. This method, which uses a cyano column, is capable of separating efavirenz from its trans-alkene reduction product. This paper will discuss development and validation of this method, which, to the best of our knowledge, is the first known separation of homologs containing double and triple bonds using reverse-phase HPLC.