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.

开发并验证了一种稳定性指示方法，可通过等度反相高效液相色谱 (RP-HPLC) 对组合剂型中的丁溴铵 (HBB) 和扑热息痛 (PAR) 进行定量同时评估。在 YMC C ₁₈上进行分离(250 × 4.6 mm, 5 μm) 柱，使用磷酸盐缓冲液–甲醇 (60:40, v/v) 在等度洗脱方式中，流速为 1 mL/min。用 210 nm 的 UV 检测实现定量。在长达 20 分钟的连续运行中，HBB 的保留时间为 9.509 分钟，PAR 的保留时间为 4.198 分钟。发现检测器响应在 HBB 的 2.5 – 7.5 µg/mL 和 PAR 的 125 – 375 µg/mL 的浓度范围内呈线性。所提出的方法根据 ICH 指南进行了验证，并显示出特异性、精确、线性、准确和稳健。样品经受各种加速应力条件。降解产物在显着不同的保留时间下得到了很好的分离。因此，