Abstract

EFFECT OF ACTIVATED CHARCOAL ON THE DISSOLUTION RATE AND ADSORPTION PROFILE OF METRONIDAZOLE IN THE PRESENCE AND ABSENCE OF ESCHERICHIA COLI 0157: H7

Abstract

This work examines the effect of activated charcoal (AC) on the dissolution/adsorption profile of metronidazole in the absence and presence of Escherichia coli 0157:H7 (E. coli). The purpose of this investigation is to present two methods used to elucidate equilibrium adsorption data and apply these methods to 2-component combinations. The adsorption of metronidazole was studied in the absence and presence of 102cfu/ml bacteria E. coli as the test organism in simulated intestinal fluid (SIF), without pancreatin, by AC using the rotating bottle method and adsorption utilizing the dissolution apparatus. The concentrations of each drug remaining in solution at equilibrium were determined using Ultra violet visible (UV/Vis) spectrophotometry. The isotherm obtained for the adsorption of Metronidazole alone showed a close fit to the type V Langmuir isotherm. However, in the presence of E. coli excellent agreement with the type IV isotherm was obtained an increased adsorption of metronidazole was observed. This takes into account formation of a monolayer with subsequent multilayer formation. Interaction between the adsorbed species is clearly evident as this account for the variation in adsorption profile in the presence of the bacteria. The adsorbing species are not merely competing for the same binding sites they are also interacting on these sites of adsorption. The results of these studies indicate that the adsorbate utilizes firstly similar binding sites and that there is both a physical and chemical interaction between the adsorbed species on the surface of the AC. This information is thus very useful in the prediction of in vivo / in vitro correlations, buttressing the advantage of the metronidazole and AC combination in treatment of diarrhea.

Keywords: Activated charcoal, metronidazole, Langmuir isotherms, Adsorption.