Development and validation of a UPLC method for screening potentially counterfeit anti-hypertensive drugs using design of experiment

An isocratic reversed phase ultra performance liquid chromatography (RP-UPLC) method was developed for screening counterfeit medicines with UV detection at 210 nm. Chromatographic separation was performed on a Waters BEH C-18 column (50 x 2.1 mm, i.d., 1.7 mu m particle size) with isocratic elution of a mobile phase containing a mixture of acetonitrile-methanol-ammonium formate buffer (0.01 M) (31 : 30.5 : 38.5 v/v/v) with a flow rate of 0.4 mL min(-1) and pH 3 (adjusted with formic acid). A mixture design methodology was selected for the optimization and validation of the mobile phase composition. It was a trade-off between the experimental designs by graphical optimization of the technique using an overlay plot. In addition, the method validation was done as per the ICH guidelines using linearity, accuracy, precision, system suitability and robustness as parameters. The developed method was found to be sensitive, simple and highly robust for routine analysis and counterfeit detection of four selected drugs.