Determination of two mebeverine metabolites, mebeverine alcohol and desmethylmebeverine alcohol, in human plasma by a dual stable isotope-based gas chromatographic-mass spectrometric method

HPLC-MS/MS method for the simultaneous quantification of desmethylmebeverine acid, mebeverine acid and mebeverine alcohol in human plasma along with its application to a pharmacokinetics study

A new simple, rapid and sensitive high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for simultaneous analysis of mebeverine metabolites as: mebeverine alcohol (MAL), mebeverine acid (MAC) and desmethylmebeverine acid (DMAC) in human plasma. Sample preparation was performed by protein precipitation following the separation of analytes using an Acquity UPLC BEN C8 column 1.7 mm 2.1×50mm (Waters, USA). ²H₅-desmethylmebeverine acid (²H₅-DMAC) was used as the internal standard (IS). The proposed method was validated with linear ranges of 0.1-10ng/mL; 1-100ng/mL and 5-1000ng/mL for MAL, MAC and DMAC, respectively. Accuracy for all analytes (%RE), given as deviation between nominal and measured concentration and assay variability (CV) ranged from -4.04% to 4.60% and from 0.31% to 6.43% respectively both for within- and between-run. The overall recoveries for all metabolites were above 85%. The proposed method was used successfully for analysis of real samples from a pharmacokinetics study.

A validated chiral HPLC method for the determination of mebeverine HCl enantiomers in pharmaceutical dosage forms and spiked rat plasma

A new, precise, simple and accurate HPLC method was developed for the first time to separate and determine mebeverine enantiomers. Enantiomeric resolution was achieved on a cellulose Tris (3,5-dimethylphenyl carbamate) column known as Chiralcel OD, with UV detection at 263 nm. The mobile phase consisted of n-hexane, isopropyl alcohol and triethylamine (90:9.9:0.1 v/v/v). Sample run time was 18 min. On using the chromatographic conditions described, mebeverine enantiomers were well resolved with mean retention times of about 11 and 14 min. A linear response (r>0.999) was observed over the concentration range 0.5-20 microg/mL racemic mebeverine. Precision, accuracy and stability were studied according to ICH guidelines. The limit of detection was found to be 0.05 microg/mL for each enantiomer of mebeverine. The proposed method was applied for analysis of mebeverine in commercially available tablets dosage formulations. Examples of application to biological samples are also given. Reanalysis of samples several weeks after the initial analysis showed no degradation of mebeverine.

Spectrophotometric microdetermination of nefopam, mebevrine and phenylpropanolamine hydrochloride in pharmaceutical formulations using alizarins

Simple and rapid spectrophotometric procedures have been established for quantitation of nefopam hydrochloride (NF) mebevrine hydrochloride (MB) and phenylpropanolamine hydrochloride (PP). The procedures are based on the reaction between the examined drugs (NF, MB and PP) and alizarin (I), alizarin red S (II), alizarin yellow G (III) and quinalizarin (IV) producing ion-pair complexes which can be measured at the optimum wavelength. The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 0.5-30.0 microg ml(-1). The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was > or =0.9988 (n=6) with a relative standard deviation (R.S.D.) of < or =1.3, for six determinations of 20 microg ml(-1). The methods are successfully applied to the determination of NF, MB and PP in their pharmaceutical formulations.

Identification of mebeverine acid as the main circulating metabolite of mebeverine in man

The intestinal spasmolytic drug mebeverine is known to undergo fast in vivo enzymatic hydrolysis into mebeverine alcohol and veratric acid. A reversed-phase HPLC method with coulometric detection was developed in order to assay the hitherto unidentified secondary metabolite mebeverine acid. After intake of a single oral dose of 405 mg mebeverine hydrochloride in four healthy human volunteers, peak plasma concentrations of mebeverine acid were found to be 1000-fold higher than those of mebeverine alcohol, i.e. approximately 3 microg/ml versus 3 ng/ml. The appearance of mebeverine acid in plasma (median T(max)=1.25 h) as well as its disappearance (median apparent t(1/2)=1.1 h) were rapid. The urinary excretion of mebeverine acid within the first 4 h after dosing amounted to 67% of the mebeverine dose (median range: 23-107%). Mebeverine acid appears to be a valuable marker of oral exposure to mebeverine.