Development of analytical method for identification of sibutramine hydrochloride in traditional medicine using solid phase extraction: High-performance liquid chromatography

Abstract

Objective: The purpose of this study is to develop a rapid and sensitive method for identifying sibutramine hydrochloride (HCl). Methods: Reversed-phase solid phase extraction (SPE) method with hydrophilic-lipophilic balance cartridge was selected to be developed and optimized. Optimization was done by optimizing solvent in the sample preparation and rinse solvent in the washing step. The extract of SPE was injected into reversed-phase high-performance liquid chromatography (HPLC) with C18 column with photodiode array detector. Furthermore, the optimized results were validated which included specificity and limit detection. Validated analytical method was used to analyze sibutramine HCl qualitatively in slimming herbal medicine which was obtained from the market. Results: Analysis method optimization showed that 3% orthophosphoric acid was the optimum solvent to extract sibutramine HCl in SPE. Then, it was shaken for 30 minutes and filtered; the filtrate was put in SPE cartridge that had been conditioned using ethanol and water. After rinsing with ammonium hydroxide (NH4OH) solution in water and NH4OH solution in 80% ethanol, the analyte was eluted with acetonitrile. Identification of sibutramine HCl was done by HPLC at wavelength 254 nm. Sibutramine HCl gave maximum wavelength at 222 nm. Sibutramine HCl calibration curve gave quite linear results ranging from 0.10 to 0.50 mg/ml with R2=0.9966. The limit of detection of this assay was 2.326 µg/ml. Specificity of this method is quite good. Simulation sample gave resolution for diethylpropion as 2.415; sibutramine HCl as 2.877, and amphetamine sulfate as 5.673. The recovery of this method was 38.0-45.0%. Conclusion: This study showed faster and specific method for identifying sibutramine HCl in the traditional medicine.