Simultaneous determination of ticarcillin and clavulanate in rabbit serum and tissue cage fluid by liquid chromatography

Pharmacokinetics study of amoxycillin and clavulanic acid (8:1)--a new combination in healthy Chinese adult male volunteers using the LC-MS/MS method

New oral granules of amoxicillin and clavulanic acid in 8:1 ratio have recently been developed and approved to conduct clinical trial in China. To date, there has been no report studying the pharmacokinetic characteristics of amoxicillin and clavulanic acid in man. Therefore, it is urgent to investigate the pharmacokinetic properties of amoxicillin and clavulanic acid in man. The aim of the study was to assess the pharmacokinetic properties of amoxicillin and clavulanic acid in 8:1 with different dosage in healthy volunteers and provide support for this drug to obtain marketing authorization in China. A liquid chromatography-tandem mass spectrometry method for determining the concentration of amoxicillin and clavulanic acid in human plasma was developed and applied to this open-label, single- and multiple-dose Pharmacokinetics study. Subjects were randomized to receive a single dose of 1, 2, and 4 pouches of the test granulation of amoxicillin and clavulanic acid in 8:1 ratio (amoxicillin is 250 mg and clavulanic acid is 31.25 mg per pouch). In the single-dose phase, blood samples were collected before dosing and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 5, 8, 12, and 24 h after drug administration. In the multiple-dose phase, samples were obtained before drug administration on days 1, 2, 3, and 4 to determine the Cmin of amoxicillin and clavulanic acid. In the 4th day, samples were collected from 0.25 to 24 h after drug administration. Profiles of the concentration-time curves of amoxicillin and clavulanic acid were best fitted to two-compartment model. In this group of healthy Chinese subjects, the pharmacokinetics of amoxicillin fitted the linear dynamic feature at doses of 250,500 and 1,000 mg, and not obviously about clavulanic acid at doses of 31.25, 62.5, and 125 mg. The t 1/2 of single dose and multidoses were (1.45 ± 0.12) and (1.44 ± 0.26) h of amoxicillin and (1.24 ± 0.23) and (1.24 ± 0.17) of clavulanic acid, respectively; The AUC0-24 of single dose and multidoses were (27937.85 ± 4265.59) and (24569.80 ± 3663.63) ng h mL(-1) of amoxicillin and (891.45 ± 194.30) and (679.61 ± 284.05) ng h mL(-1) of clavulanic acid, respectively; The Cmax of single dose and multidoses were (8414.58 ± 1416.78) and (7929.17 ± 1291.54) ng mL(-1) of amoxicillin and (349.00 ± 89.54) and (289.00 ± 67.36) ng h mL(-1) of clavulanic acid, respectively. t 1/2, AUC0-24, and Cmax were similar after multiple-dose administration and after single-dose administration, suggesting that amoxicillin and clavulanic acid do not accumulate with multiple-dose administration of 500 and 62.5 mg, respectively.

Quantitative analysis of clavulanic acid in porcine tissues by liquid chromatography combined with electrospray ionization tandem mass spectrometry

The purpose of this study was to develop and validate a method for the determination of clavulanic acid (CLAV) residues in edible tissues of swine by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). After a simple extraction of CLAV using an aqueous phosphate buffer solution of pH 6.0, an ultrafiltration step was performed for protein removal. Chromatography of CLAV and the internal standard tazobactam (TAZO) was achieved on a reversed-phase PLRP-S polymeric column (150 mm x 2.1 mm i.d., 100 A) using a mixture of 0.05 (v/v)% formic acid in water and acetonitrile. The mass spectrometer was operated in the MS/MS selected reaction monitoring (SRM) mode. The method was validated for the analysis of porcine muscle, skin plus fat, liver and kidney, according to the requirements defined by the European Community. Calibration curves were prepared for all tissues and good linearity was achieved over the concentration ranges tested (correlation coefficient > or = 0.99 and goodness-of-fit coefficient < or = 10%). Limits of quantification of 50 ng g(-1) were obtained for the analysis of CLAV in the various tissues which corresponds in all cases to at least half the maximum residue limits (MRLs). Limits of detection ranged between 8.0 and 15.14 ng g(-1). The within-day, between-day precisions and trueness fell within the ranges specified in the EMEA/CVMP/573-00/FINAL document. Biological samples from pigs that received an oral or intravenous bolus of a commercial amoxicillin/clavulanic acid formulation were analyzed using the described method.

Determination of clavulanic acid in calf plasma by liquid chromatography tandem mass spectrometry

A method for the quantification of clavulanic acid in calf plasma using high-performance liquid chromatography combined with electrospray ionization (ESI) mass spectrometry, operating in the negative ionization mode (LC-MS/MS), is presented. Sample preparation includes a simple and fast deproteinization with acetonitrile and a back-extraction of the acetonitrile with dichloromethane. Chromatography is performed on a reversed-phase PLRP-S polymeric column using 0.05% formic acid in water and acetonitrile. The limit of quantification is 25 ng/ml, which is lower than other published methods using ultraviolet (UV), fluorimetric or mass spectrometric detection. The limit of detection is calculated to be 3.5 ng/ml. The stability of clavulanic acid was demonstrated according to The Guidelines of Bioanalytical Method Validation of The Food and Drug Administration (FDA): freeze and thaw stability, short-term stability, long-term stability, stock solution stability and postpreparative stability. The method is used in a pharmacokinetic and bioequivalence study of amoxycillin/clavulanic acid formulations in calves.

Chromatographic analysis of penicillins in pharmaceutical formulations and biological fluids

Natural penicillin (benzylpenicillin) is the oldest antibiotic observed by Alexander Fleming in 1928. To broaden its spectrum of activity, natural penicillin was modified, giving rise to a group of antibiotics under the name 'penicillins'. Although an increasing number of bacteria appear to be resistant to them, penicillins are used to treat a variety of bacterial infections including Gram-positive, Gram-negative aerobic and anaerobic bacteria. Consequently, they are widely used in human and veterinary medicine to prevent and treat diseases. This review covers the analytical methodologies, mainly chromatographic, employed to the penicillins determination in pharmaceutical formulations, biological fluids and in production-scale fermentations reported in the literature. Results of published assays are comparatively presented focusing on sample preparation regarding isolation and purification, chromatographic conditions and method validation. Information on chemical structure, spectrum of activity and action mechanism of common penicillins has also been given.

Simultaneous analysis of piperacillin and tazobactam in rabbits: application to pharmacokinetic study

A simple and rapid assay is developed for the simultaneous analysis of piperacillin and tazobactam in rabbit serum and tissue cage fluid (TCF). To eliminate endogenous interferences, a wavelength switch technique was applied, in which the programmable UV detector changed the monitoring wavelength from 218 to 254 nm at 10 min. After liquid-liquid extraction, sample analyses were performed on a C(18) column by gradient elution; the mobile phase consisted of acetonitrile and phosphate buffer (0.014 m, pH 2.4). Owing to the limited amount of rabbit TCF available, a cross-validation of a proxy matrix was evaluated. The relative standard deviation of the between- and within-batch precision of both compounds was less than 5.1%; the relative error of the between- and within-batch accuracy was less than 7.3%. The recoveries of both compounds in serum and TCF were larger than 80%. This assay was successfully applied to simultaneously analyze piperacillin and tazobactam in rabbit serum and TCF samples.