Facile hydrolysis of mebeverine in vitro and in vivo: negligible circulating concentrations of the drug after oral administration

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.

Use of polarity switching for the simultaneous bioanalysis of analytes with three orders of magnitude difference in concentration by LC-MS/MS

BACKGROUND

The challenge of quantifying two compounds in a single assay with drastic dynamic ranges is to obtain linearity without source or detector saturation at the mass spectrometer.

RESULTS

In positive-ionization mode, the nonlinear relationships for Desmethyl Mebeverine Acid (DMAC) were demonstrated using three common strategies to overcome this issue: using offset voltage parameters, less-sensitive product ion or 13C mass SRM transitions. On the contrary, nonlinear relationships for DMAC were overcome if negative-ionization mode was used. Due to Mebeverine analytical LLOQ, dilution was not suitable for a single assay of Mebeverine and DMAC. However, polarity switching in negative mode for DMAC was successfully found to compensate for the nonlinearity at the mass spectrometer while preserving Mebeverine linear regression model in positive mode.

CONCLUSION

The polarity switching strategy has demonstrated the advantage of improving linearity for analytes having different ionization polarities and three orders of magnitude difference in concentration.

Simultaneous determination of sulpiride and mebeverine by HPLC method using fluorescence detection: application to real human plasma

A new simple, rapid and sensitive reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of sulpiride (SUL) and mebeverine Hydrochloride (MEB) in the presence of their impurities and degradation products. The separation of these compounds was achieved within 6 min on a 250 mm, 4.6 mm i.d., 5 m particle size Waters^®-C18 column using isocractic mobile phase containing a mixture of acetonitrile and 0.01 M dihydrogenphosphate buffer (45:55) at pH = 4.0. The analysis was performed at a flow rate of 1.0 mL/min with fluorescence-detection at excitation 300 nm and emission at 365 nm. The concentration-response relationship was linear over a concentration range of 10- 100 ng/mL for both MEB and SUL with a limit of detection 0.73 ng/mL and 0.85 ng/mL for MEB and SUL respectively. The proposed method was successfully applied for the analysis of both MEB and SUL in bulk with average recoveries of 100.22 ± 0.757% and 99.96 ± 0.625% respectively, and in commercial tablets with average recoveries of 100.04 ± 0.93% and 100.03 ± 0.376% for MEB and SUL respectively. The proposed method was successfully applied to the determination of MEB metabolite (veratic acid) in real plasma simultaneously with SUL. The mean% recoveries (n = 3) for both MEB metabolite (veratic acid) and SUL were 100.36 ± 2.92 and 99.06 ± 2.11 for spiked human plasma respectively. For real human plasma, the mean% recoveries (n = 3) were and respectively.

A Novel Formulation for Mebeverine Hydrochloride

The antispasmodic drug mebeverine hydrochloride was formulated into a film-forming gel to be used as a topical local anesthetic. A mixture of cellulose derivatives was used as a base. Additives were used to enhance the release as well as the residence time. Formulations were characterized in terms of drug release, mucoadhesion and rheology. Clinically, the selected formula has shown faster onset (p = 0.0156), longer duration (p = 0.0313), better film residence (p = 0.0313), and no foreign body sensation (p = 0.0313) in comparison to Solcoseryl dental paste. Histopathological examination showed no change in inflammatory cells count, concluding that this topical anesthetic is efficacious and safe orally.

Colon-specific drug delivery for mebeverine hydrochloride

Mebeverine Hydrochloride (MB-HCl), an effective spasmolytic drug, was formulated as CODES. A colon-specific drug delivery technology CODES was designed to avoid the inherent problems associated with pH- or time-dependent systems. To achieve more protection and control of drug release, MB-HCl was prepared as microspheres and compressed as core tablets of CODES (modified CODES). The core tablets contained the drug either in free form [Formula 1 (F(1))], or as microspheres with 2 different polymer:drug:lactulose ratios (1:1:0.5 [Formula 2 (F(2))] and 2:1:0.5 [Formula 3 (F(3))]. The release profiles of the coated CODES systems were compared with uncoated compressed tablets. The uncoated tablet showed a drug release of 94% after 1 h in simulated gastric condition (pH = 1.2). The release characteristics of the coated systems revealed that the enteric coating (Eudragit L(100)) prevented any drug release in simulated gastric or duodenal conditions in the first 3 h (pH 1.2-6.1), after which drug was slightly liberated in simulated intestinal fluid (pH 7.4) {Phase 1 (P1)}. After 4 h the pH was adjusted to 7 and beta-glucose-oxidase was added, which is an enzyme produced by enterobacteria present in the colon. The acid-soluble coat (Eudragit)E(100)) dissolved and the drug release suddenly increased to reach 95, 72 and 60.4% for F(1)-F(3), respectively. IR spectrum study showed a covalent bond between the drug and the polymer in the formulae F(2) and F(3) resulting in the sustained drug release from the microspheres with a significant difference (p>0.05) to F(1). The findings were confirmed by in vivo investigation using X-ray images for Guinea pigs ingested tablets containing barium sulphate (F(4)), where the tablet began to disintegrate after 10 h of tablet intake. The results of the study indicated that MB-HCl CODES colon-specific drug delivery can act as a successful trigger for drug targeting in the colon. Furthermore, a sustained release of the drug can be achieved from modified CODES containing the drug in the form of microspheres.

Formulation of an antispasmodic drug as a topical local anesthetic

Mebeverine hydrochloride, a spasmolytic agent on GIT smooth muscles, was reported to have a local anesthetic effect. Thus, it was desired in this study to formulate mebeverine HCl into a gel that could be used locally in the treatment of different oral painful conditions. Poloxamer 407 (P-407) was used as the base for this gel. Different additives were used to enhance drug release from the preparation while others were used to enhance the residence time for the preparation. Different formulae were characterized in terms of drug release and mucoadhesion. The formula which has shown the best compromise between the aforementioned parameters was selected for clinical evaluation in comparison to Lidocaine HCl gel and rheologically examined. The best drug release enhancer was cetrimide (0.005%, w/w), while hydroxypropylcellulose (0.5%, w/w) as a mucoadhesive additive has shown the best compromise between fast drug release and mucoadhesion. The gel formula (G) has shown a better pain reduction efficiency (p=0.0078) and longer duration (p=0.0313) than Lidocaine HCl gel. Histopathological examination has shown no change in the inflammatory cells count of rat oral mucosa. Therefore, it could be concluded that (G) is very promising as a local anesthetic preparation for the treatment of different oral painful conditions.

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.

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

A dual stable isotope-based GC-MS method was developed for the simultaneous determination of two metabolites of mebeverine, mebeverine alcohol and desmethylmebeverine alcohol, in human plasma. Plasma samples were treated with beta-glucuronidase to cleave the glucuronide conjugates of both compounds prior to analysis. The treated plasma was prepared for analysis by solid-phase extraction using octadecylsilane cartridges. The isolated metabolites were derivatized and analyzed by GC-MS using selected-ion monitoring. Plots of peak-area ratio were linear with metabolite concentration from 2 to 200 ng/ml and the limit of detection for both metabolites was 0.5 ng/ml. The GC-MS methodology was applied to the analysis of plasma from human subjects following peroral administration of mebeverine. Pharmacokinetic parameters for both metabolites were determined and suggest that relative systemic mebeverine exposure may potentially be assessed using metabolite kinetics, if the latter subsequently are demonstrated to be linear with mebeverine dose.

The metabolism of mebeverine in man: identification of urinary metabolites by gas chromatography/mass spectrometry

The urinary metabolites of orally administered mebeverine hydrochloride (270 mg) were studied in five healthy volunteers with the aid of gas chromatography/mass spectrometry. Mebeverine, which is an ester of veratric acid and 4-(ethyl-[2-(4-methoxyphenyl)-1-methylethyl]amino)butan-1-ol, was completely hydrolysed to the corresponding acid and alcohol moieties. The acid moiety was subsequently O-demethylated to vanillic acid and isovanillic acid, which in turn were further O-demethylated to protocatechuic acid. The alcohol moiety was O-demethylated to the corresponding phenol 4-(ethyl-[2-(4-hydroxyphenyl)-1-methylethyl]amino)butan-1-ol. In 24 hr, 44% of the dose was accounted for as follows: Veratric acid 32%, vanillic acid 2.7%, isovanillic acid 6.5%, 4-(ethyl-[2-(4-methoxyphenyl)-1-methylethyl]amino)butan-1-ol 0.9% and 4-(ethyl-[2-(4-hydroxyphenyl)-1-methylethyl]amino)butan-1-01 2.1%. Only trace amounts of protocatechuic acid were found in the urine. The results indicated that the metabolites were mostly excreted as conjugates. The total excretion of the acid moiety, unchanged or in the form of metabolites was 97.6%. The corresponding value for the alcohol moiety was 5.5%.

Evaluation of capillary supercritical fluid chromatography with mass spectrometric detection for the analysis of a drug (mebeverine) in a dog plasma matrix

Supercritical fluid chromatography with mass spectrometric detection was evaluated as a technique for the analysis of drugs in biological fluids. Dog plasma was spiked with a model drug, mebeverine, and with a deuterium-labeled analog of mebeverine. The spiked plasma was prepared for analysis by solid-phase extraction on octadecylsilane cartridges. Mebeverine levels in the spiked dog plasma samples were determined by interpolation from a standard curve. Accuracy and precision of the analysis were determined within and between days. In general, accuracy was found to be 100 +/- 15% for plasma samples spiked with 6 to 60 ng mebeverine/ml. The relative standard deviation for replicate sample analysis over this concentration range was between 5 and 12.5%.