Electron capture detection of oxybutynin in plasma: precolumn derivatization approach and application to a pharmacokinetic study

Abstract

Oxybutynin is an antimuscarinic agent used for the treatment of an overactive bladder. Because of its poor chromophore, it is difficult to determine oxybutynin by HPLC-UV analysis The difficulty increases when the analysis involves a complex biological matrix like plasma. Precolumn derivatization with trifluoroacetic anhydride followed by GC separation and ECD was used to solve this problem. The developed GC-ECD method had good linearity in the concentration range 2-20 ng ml À1 with a correlation coefficient of 0.9959. The accuracy and sensitivity for the determination of the halogenated derivative by this method was better than that for GC-MS. NMR and mass spectroscopy data confirmed the derivatization reaction.The developed GC-ECD method was used to study the pharmacokinetic parameters of an oxybutynin transdermal patch (36 mg/39 cm 2 ) and oxybutynin gel (10% w/w). The C max , T max and AUC 0-96 values for the oxybutynin transdermal patch and oxybutynin gel were equivalent. Fig. 1 Chemical structure of oxybutynin and trifluoroacyl oxybutynin (TFA-OXB).

Voltammetric Determination of Oxybutynin Hydrochloride Utilizing Pencil Graphite Electrode Decorated with Gold Nanoparticles

“…The literature comprises different methods for the determination of OXB either alone, in combination with other drugs or in presence of its degradation product. Some of these methods include: spectrophotometric methods [3][4][5], HPLC [6][7][8], gas chromatography [9,10], thin layer chromatography [5], capillary electrophoresis [11] and potentiometric methods [12][13][14][15]. To the best of our knowledge, only one voltammetric method has been applied for the analysis of OXB using differential pulse and square wave cathodic adsorptive stripping voltammetry on mercury electrode surface [16].…”

Analysis of oxybutynin and N-desethyloxybutynin in human urine by dispersive liquid–liquid microextraction (DLLME) and capillary electrophoresis (CE)

“…21,[23][24][25][26] For OXY and DEO, few studies involving their analysis in biological matrices have been described and most of them involved plasma and liquid-liquid extraction, 8,[27][28][29] plasma and solid phase extraction 12,30 or plasma and precipitation method. 31 The separation techniques used for the quantication of these analytes and, in some cases, of their enantiomers were HPLC, 11,27 LC-MS/MS 12,[28][29][30] and GC. 8,31 Thus, to the best of our knowledge, no method has been reported for the extraction of OXY and DEO from human urine samples using a microextraction technique and no capillary electrophoresis (CE) method is available for their determination.…”

“…31 The separation techniques used for the quantication of these analytes and, in some cases, of their enantiomers were HPLC, 11,27 LC-MS/MS 12,[28][29][30] and GC. 8,31 Thus, to the best of our knowledge, no method has been reported for the extraction of OXY and DEO from human urine samples using a microextraction technique and no capillary electrophoresis (CE) method is available for their determination. Therefore, in this study, a simple, rapid and accurate CE method for the simultaneous analysis of OXY and DEO in urine using DLLME as the sample preparation technique was developed.…”