A novel simultaneous high performance liquid chromatography-PDA method for the determination of Tenofovir AF, Darunavir, Emtricitabine and Cobicistat in bulk and its application to marketed formulation

Background The present research article involves the simultaneous determination of Tenofovir alafenamide, Darunavir, Emtricitabine and Cobicistat in bulk as well as in tablet dosage form using high performance liquid chromatography. Result The separation was performed using DIKMA Spursil, C18, ODS, (4.6 × 150 mm × 5 µm) analytical column using the mobile phase acetonitrile and 0.1% Orthophosphoric acid in the volume ratio of 70:30 at pH 3. The eluents were detected using PDA detector at 254.0 nm. After optimization subsequent validation study of different parameters was performed by utilizing the optimised condition as per the ICH guidelines. Under this optimised conditions Tenofovir alafenamide, Darunavir, Emtricitabine and Cobicistat were eluted at 2.287 min, 2.507 min, 4.062 min, 6.011 min respectively. Percentage assay was found 99.21% for Tenofovir alafenamide, 99.80% for Darunavir, 99.80% for Emtricitabine and 99.84% for Cobicistat. Tenofovir alafenamide was found linear in the range of 2.0–10.0 µg/mL, Darunavir (160.0–800.0 µg/mL), Emtricitabine (40.0–200.0 µg/mL) and for cobicistat (30.0–150.0 µg/mL). The corelation coefficient was found 0.999 for all the APIs. The detection limit was found 0.14 µg/mL for Tenofovir alafenamide, 2.14 µg/mL for Darunavir, 0.6 µg/mL for Emtricitabine and 7.32 µg/mL for cobicistat. In the LOQ study the quantitation limit was found 0.47 µg/mL for Tenofovir alafenamide, 7.12 µg/mL for Darunavir, 2.10 µg/mL, for Emtricitabine and 24.42 µg/mL for cobicistat. Conclusion All the studied API’s has been highly resolute utilizing the optimised condition and found extremely suitable for the determination of all of them simultaneously in marketed dosage form as well as in the bulk form.