Development and evaluation of natural gum based ibuprofen matrix tablets for colonic drug delivery

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September, 2015.
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The purpose of this study was to investigate the suitability of xanthan gum, cashew gum and shea gum as matrix carriers for the delivery of ibuprofen into the colon for systemic management of pain and inflammation and as a chemopreventive agent for colon cancer. Also, the direct delivery of ibuprofen into the colon may reduce the risk of peptic ulceration. The physicochemical properties of the gums were evaluated, namely: moisture content, insoluble matter, ash value, pH, viscosity, flow properties, antimicrobial activity, micronutrient content, toxic metals content and infrared spectra. The gums generally exhibited good physicochemical properties, but showed no antimicrobial activity against test microorganisms. Five batches of matrix tablets containing cashew gum and xanthan gum alone or combined in different proportions were prepared by direct compression without a binder except a diluent and a lubricant. The tablets passed the uniformity of weight, hardness and drug content tests but failed the friability test. The tablets exhibited higher swelling indices in phosphate buffers (pH 6.8 and 7.4) than in 0.1 M HCl. Tablets containing xanthan gum showed higher swelling behavior in aqueous media than tablets containing cashew gum. In vitro ibuprofen release studies in simulated physiological environment of the stomach (pH 1.2; 2 h), small intestines (pH 7.4; 3 h) and the colon (pH 6.8; 7 h) showed that batch C containing 50 % cashew gum and 50 % xanthan gum was most promising for colonic drug delivery since it released < 5 % and < 15 % ibuprofen in simulated stomach and small intestines, respectively. Batch C also showed a zero order drug release in the simulated gastrointestinal media. All the batches demonstrated a super case II transport mechanism of drug release from the matrix tablets. From the results obtained, it can be concluded that xanthan gum, cashew gum and shea gum are good matrixing agents for colonic delivery of ibuprofen due to their biocompatibility, degradation by colonic microflora, hydrophilicity and good physicochemical properties
A thesis submitted to the School of Graduate Studies in partial fulfillment of the requirements for the degree of Masters of Philosophy (Pharmaceutics) At the Department of Pharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, 2015