Stability-Indicating Chromatographic Methods for the Investigation of Ritodrine Hydrochloride Stability and Characterization of the Oxidative Degradation Product.

Two simple and sensitive chromatographic methods were developed and validated for quantitative determination of ritodrine hydrochloride in presence of its oxidative degradation product. The first method depends on densitomeric determination of thin-layer chromatograms of the intact drug in presence of its oxidative degradate. Excellent separation was achieved at 220 nm using a mobile phase of dichloromethane-methanol-glacial acetic acid (15 : 5 : 0.25, v/v/v). The second was an HPLC method, in which efficient separation was carried out on C18 column (150 × 4.6 × 5 μm) using a mobile phase consisting of water: acetonitrile (70,30, v/v) at a flow rate of 1 mL min-1 and UV detection at 220 nm. Beer's law was obeyed in the range of 0.025-0.3 μg/spot and 5-40 μg mL-1 of the intact drug using the two methods, respectively. The proposed methods were validated according to International Conference on Harmonization guidelines and successfully applied for the determination of ritodrine hydrochloride in bulk powder, laboratory prepared mixtures and pharmaceutical dosage form with good accuracy and precision. The results obtained were compared with those of the reported method and were found to be in good agreement.