Stability indicating simultaneous determination of domperidone (DP), methylparaben (MP) and propylparaben by high performance liquid chromatography (HPLC).

A simple, specific and precise high performance liquid chromatographic method has been developed and validated for the simultaneous determination of methylparaben (MP), propylparaben (PP), and domperidone (DP) in oral suspension. Isocratic mobile phase consists of 0.5% w/v aqueous ammonium acetate buffer:methanol, 40:60 (v/v). Column containing octylsilyl chemically bonded to porous silica particles (Optimapak, OP C8, 150 mmx4.6 mm, 5 microm, stainless steel analytical column from RS tech) is used as stationary phase. The detection is carried out using variable wavelength UV-vis detector set at 280 nm. The solutions are chromatographed at constant flow rate of 1.0 mL/min. The method separates MP, PP, DP and droperidol (DR) impurity in less than 12 min with good resolution, peak shapes and minimal tailing. Retention times (RT) for MP, PP, DP and DR are about 3.4, 7.0, 9.0 and 10.9 min, respectively. Linearity range and percent recoveries for MP, PP and DP are 90-270, 10-30, 50-1500 microg/mL and 100.30%, 100.78% and 100.48%, respectively. Method was validated according to ICH guidelines and proved to be suitable for stability testing, homogeneity testing and quality control of these compounds in pharmaceutical preparations.