STABILITY INDICATING AN LC-ESI-MS/MS METHOD FOR THE QUANTIFICATION OF MINOXIDIL IN PHARMACEUTICAL DOSAGE FORMS

Objective: The aim of the present study was to develop and validate a novel stability-indicating LC-ESI-MS/MS method for the quantification of Minoxidil in pharmaceutical dosage forms, ensuring specificity, accuracy, and robustness as per ICH guidelines. Methods: A stability-indicating method was established using an AB SCIEX LC-ESI-MS/MS Triple Quad 5500+QTRAP system equipped with an Agilent ZORBAX C18 column (150 mm × 4.6 mm, 3 µm). The mobile phase consisted of 5 mmol ammonium formate, methanol, and 0.01% acetic acid in the ratio 28.9:71:0.1 (v/v/v) with isocratic elution at a flow rate of 1.2 ml/min. The detection was performed at 230 nm. The method was validated for linearity (2–150 µg/ml), precision, accuracy, limit of detection (LOD), limit of quantification (LOQ), and stress degradation studies under acidic, basic, thermal, and oxidative conditions. Results: Minoxidil showed good linearity with an R² value of 0.9999. The LOD and LOQ were found to be 0.0621 µg/ml and 0.1853 µg/ml, respectively. The percentage RSD for intra-day and inter-day precision was below 2%, confirming the method’s precision. Accuracy studies showed recovery between 99.25%–99.81%. Stress degradation studies indicated Minoxidil undergoes degradation under acidic, basic, and oxidative conditions but is stable under thermal conditions. The method was successfully applied for the assay of marketed Minoxidil tablet and topical solution formulations with recoveries in the range of 98.64%–99.58%. Conclusion: The developed LC-ESI-MS/MS method is simple, fast, precise, accurate, and stability-indicating. It is suitable for routine quantitative analysis of Minoxidil in various pharmaceutical dosage forms without interference from excipients or degradants.