Development of a Microemulsion High Performance Liquid Chromatography (MELC) Method for Determination of Salbutamol in Metered-Dose Inhalers (MDIS)

Introduction: A sensitive and rapid oil-in-water (O/W) microemulsion high performance liquid chromatography (MELC) method has been developed. The water-in-oil (w/o) microemulsion was used as a mobile phase in the determination of salbutamol in aqueous solutions. In addition, the influence of operating parameters on the separation performance was examined. Methods: The samples were injected into C18, (250mm×4.6mm) analytical columns maintained at 25oC with a flow rate 1 ml/min. The mobile phase was 95.5% v/v aqueous orthophosphate buffer 20 mM (adjusted to pH 3 with orthophosphoric acid), 0.5% ethyl acetate, 1.5% Brij35, and 2.5% 1-butanol, all w/w. The salbutamol and internal standard peaks were detected by fluorescence detection at the excitation and emission wavelengths of 267 and 313 nm respectively. Results: The method had an accuracy of > 97.78% and the calibration curve was linear (r2 = 0.99) over salbutamol concentrations ranging from 25 to 500 ng/mL. The intra-day and inter-day precisions (CV %) were <1.6 and <1.8, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were 9.61ng/ml and 29.13ng/ml, respectively. Conclusion: The method reported is simple, precise and accurate, and has the capacity to be used for determination of salbutamol in the pharmaceutical preparation.