Amoxicillin/clavulanic acid (875/125): bioequivalence of a novel Solutab tablet and rationale for a twice-daily dosing regimen.

A new amoxicillin/clavulanic acid tablet formulation (Solutab tablet, Forcid Solutab) containing amoxicillin/clavulanic acid (875/125) has been developed. The aim of the present study was to demonstrate bioequivalence between the new tablet formulation (test), taken as an intact tablet and after prior dispersal, versus the originator product viz. Augmentan film-coated tablet (875/125) used as reference. The study was performed in 48 healthy volunteers according to an open, single-dose, crossover design. Bioequivalence was demonstrated using Cmax and AUC(0-infinity) as primary parameters of evaluation for both amoxicillin and clavulanic acid with 90% confidence intervals of the ratios Solutab tablet/Augmentan within the range of 0.8-1.25. The duration of the plasma concentration exceeding the amoxicillin minimal inhibitory concentration (MICs) was calculated using individual plasma concentration-time curves and compartmental analysis. The data showed that the bioavailability characteristics of the test tablet, taken intact or in dispersed form, and the reference tablets were very similar. The analysis, moreover, also confirmed the appropriateness of using a b.i.d. dosage regimen for both formulations, taking into account the pharmacodynamic breakpoint values for some major pathogens.

Bioequivalence study of a novel Solutab tablet formulation of amoxicillin/clavulanic acid versus the originator film-coated tablet.

With amoxicillin/clavulanic acid Solutab tablet, a new tablet formulation of amoxicillin/clavulanic acid (500/125), was developed. The aim of the present study was to demonstrate bioequivalence between the new tablet formulation, taken as an intact tablet and after prior dispersal, versus the originator product viz. Augmentan film-coated tablet. The study was performed in 48 healthy volunteers, according to an open, single-dose three-period, crossover design. Blood samples were taken prior to each administration and at 10 time points after dosing. Plasma concentrations of amoxicillin and clavulanic acid were determined by validated high performance liquid chromatography with UV detection. With regard to amoxicillin, the results were within the preset bioequivalence range of 0.8 to 1.25 for the ratios of the primary parameters AUC(0-t) and Cmax. In terms of clavulanic acid the 90% confidence intervals of the ratios for AUC(0-t) and Cmax versus the reference lay outside the predefined bioequivalence range of 0.75 to 1.33. This result, however, was mainly due to the large variability of the reference formulation compared to the amoxicillin/clavulanic acid Solutab tablet. Based on statistical indications that 3/48 subjects with extremely low levels on the reference formulation could be regarded as "outliers" and after excluding these subjects' data from the statistical analysis, results for clavulanic acid were within the predefined bioequivalence range of 0.75 to 1.33. Overall, the amoxicillin/clavulanic acid Solutab tablet provided, in comparison to the reference tablet, less variable levels of clavulanic acid, thus giving more appropriate protection to the available amoxicillin. Thirteen adverse events were reported post dosing by 7 subjects. There were no differences in incidence of adverse events between amoxicillin/clavulanic acid Solutab tablet taken intact or dispersed and Augmentan.

Impact of metronidazole resistance on the eradication of Helicobacter pylori.

We investigated how often Helicobacter pylori was resistant to metronidazole before treatment in 283 H. pylori positive patients and whether the in vitro susceptibility to metronidazole could predict the clinical outcome of several drug regimens containing metronidazole. Metronidazole susceptibility was tested using either disc diffusion or plates containing metronidazole. Metronidazole-resistant strains were found in 41% of patients before their first anti-H. pylori treatment course. In patients with metronidazole-susceptible isolates, eradication was achieved in 74% after colloidal bismuth subcitrate (CBS) with metronidazole and in 91% after triple therapies consisting of CBS, metronidazole and amoxicillin or tetracycline. Dual therapies of 1 or 4 weeks' duration and triple therapies lasting 1 week were ineffective in patients with metronidazole-resistant strains. A 4-week course of triple therapy could still eradicate H. pylori in 68% of patients with metronidazole-resistant strains, but at the cost of significant side-effects. It is concluded that metronidazole resistance is common and is generally associated with a poor outcome of anti-H. pylori therapies containing metronidazole. Alternative drug schedules are urgently needed for patients with metronidazole-resistant H. pylori.

Growth and cell wall composition of glucose-limited bean cells (Phaseolus vulgaris L.).

Glucose-limited bean cells (Phaseolus vulgaris L.) were grown in a modified bacterial fermentor at a constant pH of 4.8. The cultures were kept in steady state at different specific growth rates varying from 0.00216 h(-1) to 0.0106 h(-1). Culture conditions are described that are needed to start a continuous culture. First, it was essential to use log-phase cells as starting material. Second, it was important to increase the dilution rate gradually, otherwise cells in the culture aggregated. Cells grown at the highest dilution rate employed contained twice as much protein per gram dry weight as cells grown at the lowest dilution rate. The composition of the cell walls also varied with the dilution rate in contrast to their relatively constant composition when grown in batch culture.