Development of stability-indicating HPLC-UV method and oxidative degradation kinetic study of montelukast in chewable tablet formulation

A simple and sensitive stability-indicating HPLC-UV method was developed and validated for the determination of montelukast in the development of chewable tablet formulation. Chromatographic separation was achieved using Atlantis® T3 3µm C18 (4.6mmID X 10cm) analytical column. The mobile phase was consisted of KH2PO4 (0.05mM)-ACN-TEA (450:550:1.33, v/v/v) adjusted to pH 2.0 with orthophosphoric acid. The analysis was run at a flow rate of 1.5 mL/min with detection wavelength at 255nm. Method validation was performed in accordance with ICH guideline. Stress degradation studies, comprising of acid and alkali hydrolysis (1M HCl and 1M NaOH), oxidative degradation (3% H2O2), photo degradation and heat degradation, were performed. The standard calibration curve was linear from 0.0025 - 0.375mg/mL. The LOD and LLOQ were 0.01μg/mL and 0.04μg/mL. Stress degradation result shows that montelukast sodium was sensitive to photo degradation, oxidation and acid hydrolysis. Oxidative degradation kinetic study of montelukast sodium followed first order reaction, with r2 =0.9877, apparent degradation rate constant, k= 0.1066 h-1, t1/2= 6.6151 hr and t90% = 1.0118hr. In conclusion, HPLC-UV method was successfully developed and validated for determination of montelukast sodium in chewable tablet formulation.