No abstract

Statistical experimental design was used to optimize the chromatographic separations of two potential impurities in fixed dose combination tablets. Risk assessment has been made based on knowledge gathered during development activity. The Critical Quality Attributes (CQA's) selected were Trifluoroacetic acid (TFA) concentration, organic solvent and column temperature. A Box-Behnken Design was utilized using Minitab software to study the effects of these CQA's on closely eluting peaks of S-Oxide and Tenofovir. The effect of these three CQA's on resolution is depicted in the form of the p and f values between the various combination and permutations of these three CQAs. The chromatographic method employed a HPLC, Zorbax SB-Phenyl C18 column (150 x 4.6 mm i.e., 3.5µm particle size) with the mobile phase consisting of a TFA buffer and Methanol: TFA ((85:15 v/v) in a gradient program. The flow rate, injection volume and detection were 1.0 mL/min, 15 μL and 262 nm respectively. As per design space, 15 validation runs were performed and out of which Run 11 gave more resolution, i.e., of 4.4 at 45 °C column temperature with 0.11 % TFA concentration in mobile phase A and Methanol: 0.1% TFA in water (85:15 % v/v) in mobile phase B which was studied with different plots like interaction plot and overlaid contour plots. The results clearly showed that the quality by design concept could be effectively applied to optimize HPLC chromatographic method parameters with fewer trials and error-free experimentation.

A simple, accurate and precise UPLC method was developed and validated for dissolution testing of Emtricitabine and Tenofovir disoproxil fumarate in tablet dosage form. The separation was achieved under optimized chromatographic condition on an Acquity UPLC HSS (50 mm X 2.1 mm, 1.7 μm) column with mobile phase consist of 20 mM Potassium dihydrogen phosphate buffer pH 3.5: Acetonitrile with gradient elution at a flow rate of 0.640 ml/min using 30°C column oven temperature with UV detection at 262 nm. The retention time for Emtricitabine and Tenofovir disoproxil fumarate were about 0.715 and 2.239 min respectively. The linearity was found to be in the concentration range of 20.14-120.86 μg/mL for Emtricitabine and 30.01-180.04 for Tenofovir disoproxil fumarate. The % recoveries at 20%, 100% and 120% were found to be within the limit of 98-102%. The method was validated as per ICH and USP guideline and the values were found to be within the limits. So, the proposed method was found to be simple, linear, accurate, precise, robust and specific.