Development and validation of a HPLC method for the analysis of promethazine hydrochloride in hot-melt extruded...

A simple and rapid stability-indicating HPLC method was developed for determination of promethazine hydrochloride (PMZ) in hot-melt extruded (HME) films and sustained release tablets. Chromatographic separation was achieved on a 150 mm x 4.6 mm i.d., 3 microm particle size, C8 (2) column with acetonitrile-25mM phosphate buffer (pH 7.0), 50:50 (v/v) as mobile phase at a flow rate of 1 mL min(-1). Quantitation was achieved with UV detection at 249 nm based on peak area. The method was validated in terms of linearity, precision, accuracy, robustness specificity, limits of detection and quantitation according to ICH guidelines. Specificity was validated by subjecting the drug to acid, base, oxidative, reductive and dry heat degradations. None of the degradation products obtained by forced degradation interfered with the PMZ peak. The method was successfully applied for assessing the stability of the drug in the HME films and sustained release tablet formulations. In addition, uniformity of PMZ content in HME films was also determined using the method developed. Excipients present in either of the dosage forms analyzed did not interfere with the analysis indicating the specificity of the method. Due to its simplicity and accuracy, the method is suitable for application to various dosage forms.