ANALYTICAL METHOD DEVELOPMENT BY SOLID PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY FOR DIPHENHYDRAMINE QUANTIFICATION IN SYRUPS

Abstract

Objective: To develop a method for the determination of diphenhydramine hydrochloride in syrups.Methods: The developed method is based on the active ingredient recovery from the pharmaceutical formulation using a cartridge for selective solid phase extraction. This procedure is simple and fast as compared to the methods that require liquid/liquid extraction. Once the sample is eluted from the cartridge, it is injected directly into a reversed-phase chromatographic system containing a mixture of acetonitrile: 10 mmol ammonium acetate: triethylamine 60:39.5:0.5.Results: The proposed method fulfilled the validation parameters (linearity R2>0.99, precision CV<2% and accuracy 98-102%).Conclusion: The proposed method proved to be reliable when it was applied in the quantification of diphenhydramine hydrochloride of two commercial syrup products.