Response surface and tolerance analysis approach for optimizing HPLC method

Abstract

We simultaneously determined tinidazole (TIN), miconazole nitrate (MIC), propylparaben (PP), and methylparaben (MP) using response surface and tolerance analysis approach. The selected critical to quality characteristics (CTQs) were tailing factor (Tf), resolution between peaks (Rs), and number of plates (N). The gradient steepness (ΔG) and, the column oven temperature were the critical to process characteristics (CTPs). The chromatographic separation was on a C18 column with a gradient elution program using methanol as organic modifier and 10 mM sodium acetate buffer (pH 4.9) as the aqueous part of the mobile phase at 2 ml/min flow rate, with UV detector at 235 nm and, a column oven temperature of 34.5 °C. SFSTP guidelines were used to validate the method; it was accurate over the concentration range of 18.75–150, 2.5–20 and 12.5–100 μg ml−1 for TIN, MP, PP, and MIC, respectively.