Determination of the active metabolites of sibutramine in rat serum using column‐switching HPLC

Abstract

A simple and direct analysis using column-switching HPLC method was developed and validated for the quantification of active metabolites of sibutramine, N-mono-desmethyl metabolite (metabolite 1, M1) and N-di-desmethyl metabolite (metabolite 2, M2) in the serum of rats administered sibutramine HCl (5.0 mg/kg, p.o.). Rat serum was directly injected onto the precolumn without sample prepreparation step following dilution with mobile phase A, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (8.3:4.5:87.2 by volume). After the endogenous serum components were eluted to waste, the system was switched and the analytes were eluted to the trap column. Active metabolites M1 and M2 were then back-flushed to the analytical column for separation with mobile phase B, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (35.8:19.2:45 by volume) and detected at 223 nm. The calibration curves of active metabolites M1 and M2 were linear in the range of 0.1-1.0 microg/mL and 0.15-1.8 microg/mL. This method was fully validated and shown to be specific, accurate (10.4-10.7% error), and precise (1.97-8.79% CV). This simple and rapid analytical method using column-switching appears to be useful for the pharmacokinetic study of active metabolites (M1 and M2) of sibutramine.

Quantification of sibutramine and its two metabolites in human plasma by LC–ESI-MS/MS and its application in a bioequivalence study

“…Literature survey reveals that quantification of sibutramine in pharmaceutical, synthetic/dietary supplements and herbal products was reported using LC–MS [4] , [5] , [6] , [7] and HPLC [8] , [9] , [10] , [11] in biological matrices, e.g. rats [12] , [13] , [14] , [15] , [16] , [17] , [18] . Only a few methods were reported for the quantification of sibutramine and its two metabolites in human plasma using LC–MS/MS [19] , [20] , [21] , [22] , [23] , [24] .…”

Counterfeit formulations: analytical perspective on anorectics

“…Anorectics (or anorexics) refer to medicines or dietary supplements used for weight-loss purposes [23]. Medicines sold over-the-counter and from Internet sources adulterated with anorectics and/or their analogues or metabolites have been reported [24][25][26][27][28][29]. Similarly, phytotherapeutic (i.e., plant-based) formulations that are deemed "natural product" alternative treatment for obesity have been demonstrated to contain non-declared anorectics and adjuvants that boost their efficacy [24,[30][31][32][33][34][35].…”

“…Despite the major advancements and production of powerful analytical instruments (e.g., sensors, microscopy, chromatography, spectroscopy), direct sample analyses, especially in biological and pharmaceutical formulations samples are often not possible owing to factors, such as matrix interference and low analyte concentrations [169]. This necessitates the use of some pretreatment steps aimed at sample [26,27,103], polytetrafluoroethylene [24] or cellulose acetate [170] filter following sample dissolution in organic solvent and sonication; solid-phase extraction (SPE) [171]; liquid-liquid extraction (LLE) [28], microwaveassisted extraction (MAE) [172], liquid-phase microextraction (LPME) [173,174] and solid-phase micro-extraction (SPME) [175].…”

Analytical Methodologies for the Stereoselective Determination of Sibutramine: An Overview

“…A variety of analytical methods (chromatographic, electrophoretic) have been reported in the past decade for the determination of SIB in pharmaceutical preparations and in biological materials. However the large majority of the published methods report achiral analysis of SIB by reversed-phase liquid chromatography (RP-LC) in pharmaceutical products [12], ultra-high-pressure liquid chromatography with diode-array detection in adulterated weight-loss formulations [13], column-switching high performance liquid chromatography (HPLC) in rat serum [14] or liquid chromatography-mass spectrometry (LC-MS/MS) in human plasma [15]. Despite the pharmaceutical importance of the stereoselective analysis of this compound, only a few studies have been reported for chiral separation of SIB and its metabolites.…”