UV SPECTROPHOTOMETRIC, DERIVATIVE SPECTROPHOTOMETRIC AND RP-HPLC-DAD DETERMINATION OF SIBUTRAMINE

Simple and rapid new methods were developed and validated as an alternative to the quantification methods of sibutramine presented in the literature. UV-Vis. and derivative spectrophotometry methods were based on the determination of sibutramine pharmaceutical preparations (capsule dosage forms) in different solvent media (methanol and water). All UV-Vis. absorbance spectra of sibutramine were recorded with maximum absorbance of 224 nm and with spectral bandwidth of 2 nm and all first- and second-order derivative spectra of sibutramine were recorded at 217 and 223 nm with spectral bandwidth of 5 nm in wavelength range of 200-400 nm in methanol and water media. The other method was a new RP-HPLC with DAD detector method developed for the determination of sibutramine by using Donepezil as the internal standard in human plasma samples (in-vitro) and in pharmaceutical preparations (capsule dosage forms). HPLC was performed using mobile phase comprising of methanol-acetonitrile (90:10) on a reversed phase C-18 column and the detection was carried out at 224 nm. The recovery of capsule by standard addition method was found to be in the range of 101.10-104.08% and 91.96-107.68%, respectively. The developed methods were applied directly and easily to the analysis both of pharmaceutical preparations and biological fluids without extraction or evaporation steps prior to drug assays. Also bioanalytical method validation was achieved successfully for comparison as statistical of developed methods both in pharmaceutical preparations and plasma levels in vivo outside, and validation results on linearity, specificity, accuracy and precision were effectively performed.