ACKNOWLEDGMENT The authors thank Umedica Laboratories selleckchem Pvt. Ltd. for supplying the authentic working standard for Diacerein. Footnotes Source of Support: Nil Conflict of Interest: None declared.
Tenofovir (TE);9[(R)2[[bis[[(isopropoxycarbonyl)oxy]methoxy]phosphinyl]methoxy] propyl and Emtricitabine (EM); 5-fluro-1-(2R, 5S)-[2-9hydroxymethyl]-1,3-oxathiolan-5-yl both are the antiviral agents, acts as the nucleoside reverse transcriptase enzyme inhibitors. These are the nucleoside analogues which are phosphorylated by host cell enzyme to give 5-triphosphate derivative. This moiety competes with the equivalent host cellular triphosphate substrates for pro viral DNA synthesis by viral reverse transcriptase which is viral RNA-dependent DNA polymerase.

Eventually, the incorporation of the 5-triphosphate moiety into the growing viral DNA chain results in chain termination. Mammalian ��–DNA polymerase is relatively resistant to the effect. Emtricitabine is potent and selective against HIV types I and II and hepatitis B virus. Tenofovir is active against a variety of drug resistant HIV-I strains. Recently, the combination of TE and EM has demonstrated significantly greater HIV RNA suppression compared to the combination of zidovudine and lamivudine.[1�C2] Several analytical methods that have been reported for the individual determination of TE in biological fluids and pharmaceutical formulations which include liquid chromatography coupled with spectrofluorimetric, UV, and mass spectroscopy detection.

[3�C8] For EM several analytical methods have been reported for its individual analysis which includes chiral liquid chromatography, liquid chromatography with UV detection[1,8�C11] Few bioanalytical methods are reported for combination of TE and EM which includes liquid chromatography with PDA and UV detection.[12] There are also few spectrophotometric methods reported in the literature for the simultaneous estimation of EM and TE in combined dosage form but no derivative spectroscopic, ratio derivative and simple absorbance corrected methods were reported.[13,14] This derivative spectroscopic technique offers various advantages over the conventional absorbance methods such as the discrimination of the sharp spectral features over the large bands and the enhancement of the resolution of overlapping spectra.

Therefore, the aim of this study was to develop and validate ratio derivative, first derivative spectroscopic methods, and simple absorbance corrected method for the determination of TE and EM in tablet dosage form. The Anacetrapib proposed methods were optimized and validated as per the International conference on harmonization (ICH) guidelines.[15] MATERIALS AND METHODS Instrumentation An UV-visible double beam spectrophotometer (Varian Cary 100) with 10 mm matched quartz cells was used. All weighing were done on electronic balance (Model Shimadzu AUW-220D).