Stability-indicating high-performance thin-layer chromatography method for the simultaneous estimation of emtricitabine and tenofovir alafenamide fumarate

A simple, precise, rapid and accurate high-performance thin-layer chromatographic method was developed and validated for the simultaneous estimation of emtricitabine (EMT) and tenofovir alafenamide fumarate (TAF) in combined dosage forms and forced degradation studies were carried out as per the International Council for Harmonisation (ICH) guidelines. The stationary phase used was Merck TLC silica gel 60 F254 aluminum plates. The mobile phase used was ethyl acetate‒n-hexane‒methanol‒ammonia solution (4:4:2:0.2, V/V). Densitometric evaluation was carried out at 260 nm, EMT and TAF. The concentration ranges used for the study are 400–2000 ng/band for EMT, 50–250 ng/band for TAF. EMT and TAF gave well defined and sharp peaks at retardation factor 0.43 and 0.56, respectively. The stability study showed that samples degraded with acid, base, hydrogen peroxide and light gave well separated peaks of EMT and TAF as well as some additional peaks at different retardation factor values. The proposed method is simple, suitable, accurate and stable in accordance with the ICH guidelines.