Analytical Quality-by-Design-Based Systematic Optimization of RP-HPLC Method Conditions to Analyze Simultaneously Chloroquine Phosphate and Flavopiridol in Stress-Induced Combined Drug Solution and Pharmaceutical Emulsions.

A design of experiments (DoE)-driven RP-HPLC method conditions was employed to analyze simultaneously chloroquine (CQ) phosphate and flavopiridol (FLAP) in emulsions and solution. After subjecting the various critical method attributes to preliminary risk assessment and screening by Pareto-chart-based fractional factorial design, the 17 runs were produced in Box-Behnken design for optimization. Analysis of variance, lack of fit, prediction equations, 3D response surface plots and contour plots were used to evaluate the critical analytical attributes such as retention time, tailing factor and theoretical plate count. The optimized RP-HPLC method conditions include 262 nm as detection wavelength, 37°C temperature for column, 20-μl injection volume, 1-ml/min flow rate and mobile phase mixture [70:30 ratio of 0.4% triethylamine in methanol&sodium phosphate buffer (11 mM, pH 3.0)]. The studied validation parameters were found within the ICH-prescribed limits. Exposing the combined drug solution at oxidative stress condition resulted to diminish the FLAP recovery value (53.39 ± 0.86) and arrival of an extra chromatographic peak. However, the % drug entrapment efficiency values of 96.22 ± 2.47 and 85.86 ± 3.66, respectively, were noticed for CQ phosphate and FLAP in emulsions. Thus, DoE-driven approach could be helpful for systematically optimizing RP-HPLC method conditions.