Validated stability indicating assay method for tenofovir implementing design of experiment approach for forced degradation

Tenofovir, an antiretroviral drug known as nucleoside analogue reverse transcriptase inhibitor, was evaluated for its degradation behavior. The study involved optimization of forced degradation study using the design of experiment (DoE) approach and validation of developed stability indicating assay method (SIAM) for tenofovir. Chromatographic separation was achieved on Kromasil C18 column using mixture of methanol and ammonium acetate buffer pH 8.5 as mobile phase in isocratic elution mode. Detection was done using PDA detector. Tenofovir showed degradation at alkali, acid hydrolysis and oxidative condition while it was stable to photolysis and thermal stress condition. The optimization of forced degradation conditions, like hydrolytic and oxidative, was done by application 3n full factorial designs, which helped to obtain desired drug degradation. The proposed method was successfully validated as per ICH Q2 (R1) guidelines.