Liquid Chromatographic Method with Ultraviolet Absorbance Detection for Measurement of Rimonabant in Human Plasma

Rimonabant is a selective cannabinoid CB1 receptor antagonist licensed in Europe for treatment of obesity when a risk factor is associated. The objective of this study was to develop and validate a method for measurement of rimonabant in human plasma using high-performance liquid chromatography coupled to an ultraviolet (UV) detector. Rimonabant and loxapine (internal standard) were extracted from 500L of plasma. Chromatography was performed on a 250mm4.6mm C18 column using a mobile phase constituted of 0.05M ammonium acetate/methanol (25:75, v/v) at a flow rate of 1ml/min followed by UV detection at 250nm. Calibration curves covered a range from 13 (lower limit of quantification) to 1000.0ng/mL. Validation results demonstrated that rimonabant could be accurately and precisely quantified in human plasma. Limit of quantification was 13ng/mL. This simple method can be used for measuring rimonabant concentrations in human plasma in clinical practice.