Development and Validation of UV Spectrophotometric and RP-HPCL Methods for Simultaneous Estimation of Montelukast and Acebrophylline from their Combined Dosage Form

Abstract

Two accurate, sensitive and reproducible methods are described for the quantitative determination of Montelukast (MKST) and Acebrophylline (ACE) in their combined dosage form. Potentiometric titration method was developed for determination of pKa value of ACE. ACE solution was titrated against standardized NaOH. pKa value was determined using henderson -hasselbalch equation. The first method involves UV spectrophotometric method. The method is based on determination of MKST at 366 nm using its absorptivity value and ACE at 249 nm and 366 nm using simultaneous equation method. The two drugs follow the Beer- Lambert’s law over the concentration range of 0.5-50 μg/mL for MKST and 10-100 μg/mL for ACE. The second method is based on RP-HPLC separation of two drugs on the ACE C18 column (150 mm length, 4.6 mm i.d, 5 μm particle size) at ambient temperature using a mobile phase consisting of acetonitrile: ammonium acetate buffer (25 mM, pH 6 with glacial acetic acid) (30:60 v/v). Quantitation was achieved with photo diode array detection at 282 nm based on peak area with linear calibration curves at concentration ranges 2.5-15 μg/mL and 50-300 μg/mL for MKST and ACE, respectively. Both the developed methods have been successively applied to marketed pharmaceutical formulation. No interference from the formulation excipients was found. Both methods were validated according to ICH guidelines in terms of accuracy, precision, specificity, robustness, limits of detection and limit of quantitation. RP-HPLC method was further extended for estimation of ACE, MKST and AMB in their single dosage form.