V. Murugan

A linear, precise, accurate and simple reversed-phase high performance liquid chromatography (RP-HPLC) bioanalytical method was developed and validated for determination of sofosbuvir in human plasma (K2EDTA) using ledipasvir as an internal standard. Sofosbuvir and ledipasvir (ISTD) were separated from plasma using solid phase extraction technique and The chromatographic separation was accomplished by using a Zorbax eclipse XDB C18 Column (250×4.6 mm i.d, 5 μm particle size) with 1% orthophosphoric acid (pH6.4) and Acetonitrile in the ratio of 30:70% v/v, as mobile phase in an isocratic elution mode pumped at a flow rate 0.7 mL/min and the column oven temperature was maintained at 25?C. The wavelength selected for quantitation was 254 nm. Retention times of sofosbuvir and internal standard were found to be 3.8min and 7.4min, respectively. The standard curves were found to be linear in the range of 30.566-2000.381 ng/ml for sofosbuvir in human plasma. This method performed an intra-day and inter-day precision within the range of 2.44–11.14 and 5.01–8.70%, respectively. Additional intra-day and inter-day accuracy was within the range of 87.99–105.93% and 94.97–99.18% respectively. Total percentage mean recovery of sofosbuvir from spiked plasma was found to be 86.54%. All the validated parameters were found to be within the Acceptance limit.

A simple, accurate, precise high-performance thin-layer chromatographic method for simultaneous estimation of Gatifloxacin (GAT) and Loteprednol etabonate (LOTE) in ophthalmic formulation has been developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F254 as stationary phase. The solvent system consisted of methanol: ethylacetate: triethylamine (7:3:0.2v/v/v). Densitometric analysis was carried out at 272nm for LOTE and GAT. The system was found to give compact spots for LOTE and GAT at Rf value of0.70 and 0.29respectively. The linear regression analysis data showed a good linear relationship in the concentration range of 1-5µg/spot for LOTE and GAT. The% recovery was found to be 99-101% for GAT and 99-102% for LOTE. The correlation coefficient was found to be 0.999 for LOTE and GAT. The % RSD values indicated that the proposed method was precise. The specificity of the method was ascertained by peak purity profiling studies and the developed method was specific. The method has been successfully applied in the analysis of combined dosage form.