Stability Indicating RP-HPLC Simultaneous Estimation of Hyoscine Butylbromide and Paracetamol in Tablets

A stability indicating method was developed and validated for the quantitative simultaneous estimation of hyoscine butylbromide (HBB) and paracetamol (PAR) in a combined dosage form by means of isocratic reverse-phase high-performance liquid chromatography (RP-HPLC). Separation was performed on a YMC C18 (250 × 4.6 mm, 5 μm) column using phosphate buffer–Methanol (60:40, v/v) in the isocratic elution regime at a flow rate of 1 mL/min. Quantification was achieved with UV detection at 210 nm. The retention time obtained for HBB was 9.509 min and that for PAR was 4.198 min in a continuous run up to 20 min. The detector response was found to be linear in a concentration range of 2.5 – 7.5 μg/mL for HBB and 125 – 375 μg/mL for PAR. The proposed method was validated as per ICH guidelines and shown to be specific, precise, linear, accurate, and robust. The samples were subjected to various accelerated stress conditions. The degradation products were well resolved at significantly different retention times. Thus, the proposed method can be applied successfully for the simultaneous estimation of PAR and HBB in combined pharmaceutical formulations and for their stability studies.