Development and validation of a column high-performance liquid chromatographic method for determination of...

The development and validation of a reversed-phase liquid chromatographic (LC) method for the determination of sibutramine hydrochloride monohydrate in capsules is described. An isocratic LC analysis was performed on a reversed-phase RP-18 column (250 x 4.6 mm id, 5 microm particle size). The mobile phase consisted of methanol-water-triethylamine (80 + 20 + 0.5, v/v/v), with pH adjusted to 5.65 with 85% phosphoric acid, and was pumped at a constant flow rate of 1.0 mL/min. Measurements were made at a wavelength of 223 nm. The calibration curve was linear over the range of 15-40 microg/mL [correlation coefficient (r2) = 0.9998]. The relative standard deviation (RSD) value for intraday precision was 0.84%. The RSD value for interday precision was 0.90%. Recoveries ranged from 99.64 to 100.66%. No interferences from the excipients were observed. Because of its simplicity and accuracy, the method is suitable for routine quality control analysis of sibutramine in capsules.