Application of quality by design approach in RP-HPLC method development for simultaneous estimation of saxagliptin and dapagliflozin in tablet dosage form

A simple, sensitive, precise, accurate and robust high performance liquid chromatographic method has been developed for simultaneous estimation of saxagliptin (SAXA) and dapagliflozin (DAPA) in pharmaceutical formulation. Design of experiments (DoE) was applied for multivariate optimization of the experimental conditions of RP-HPLC method. Risk assessment was performed to identify the critical method parameters. Three independent factors; mobile phase composition, flow rate and column temperature were used to design mathematical models. Central composite design (CCD) was used to study the response surface methodology and to study in depth the effects of these independent factors. Desirability function was used to simultaneously optimize the retention time and resolution of SAXA and DAPA. The optimized and predicted data from contour diagram consisted of acetonitrile and ortho phosphoric acid (0.1%) in the ratio of 50:50 respectively, at a flow rate of 0.98 ml/min and column temperature 31.4 °C. Using these optimum conditions baseline separation of both drugs with good resolution and run time of less than 6 min were achieved. The optimized assay conditions were validated according to ICH guidelines. Hence, the results clearly showed that Quality by design approach could be successfully applied to optimize RP-HPLC method for simultaneous estimation of SAXA and DAPA.

Validated analytical study of the effect of Lycopene on the pharmacokinetics of Paracetamol and Chlorzoxazone in rats

Lycopene was reported to influence some cytochrome P450 enzymes activity. The present study investigates the effect of lycopene on the pharmacokinetics of paracetamol and chlorzoxazone. Lycopene (20 mg/kg) was intra-peritoneally administered to two groups of rats for eight consecutive days and two other groups were given vehicle. On the eighth day, chlorzoxazone and paracetamol were separately intravenously administered to a lycopene group and a control group. Blood samples were collected at different time intervals, treated and analyzed using HPLC. The HPLC method used for paracetamol analysis was based on isocratic elution using a mobile phase consisting of water: methanol, (77:23 v/v) at a flow rate 1 mL min−1, Kromasil C18 column, and UV detection at 254 nm using caffeine as internal standard. About chlorzoxazone, separation was carried out using water: acetonitrile (60: 40, v/v) as the mobile phase at a flow rate 1 mL min−1, Inertsil ODS-3 C18 column, UV detection at 283 nm and esomeprazole as internal standard. Statistical analysis of the pharmacokinetic data using student t test showed a significant increase in AUC 0-t , AUC 0-Inf and t1/2 of paracetamol (P<0.05) and of chlorzoxazone (P<0.05) in the groups pretreated with lycopene (20 mg/kg), significant increase in the volume of distribution of paracetamol (P < 0.05), but no significant difference in that of chlorzoxazone. In other words, paracetamol and chlorzoxazone showed significant decrease (P < 0.05), respectively. These results demonstrate that treatment of rats with Lycopene (20mg/kg, ip) has a significant effect on the metabolic clearance and the pharmacokinetics of both drugs