Introduction In previous studies carried out in our laboratory,\na bile acid (BA) formulation exerted a hypoglycaemic effect in\na rat model of type-1 diabetes (T1D). When the antidiabetic\ndrug gliclazide (G) was added to the bile acid, it augmented the\nhypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-cholic acid (G-CA), with good structural\nproperties, excipient compatibility and exhibits\npseudoplastic-thixotropic characteristics. The aim of this study\nis to test the slow release and pH-controlled properties of this new\nformulation. The aim is also to examine the effect of CA on G\nrelease kinetics at various pH values and different temperatures.\nMethod Microencapsulation was carried out using our Buchibasedmicroencapsulating\nsystemdeveloped in our laboratory.\nUsing sodium alginate (SA) polymer, both formulations were\nprepared: G-SA (control) and G-CA-SA (test) at a constant\nratio (1:3:30), respectively. Microcapsules were examined for\nefficiency, size, release kinetics, stability and swelling studies\nat pH 1.5, pH 3, pH 7.4 and pH 7.8 and temperatures of 20 and\n30 �°C.\nResults The new formulation is further optimised by the addition\nof CA. CA reduced microcapsule swelling of the microcapsules\nat pH 7.8 and pH 3 at 30 �°C and pH 3 at 20 �°C,\nand, even though microcapsule size remains similar after CA\naddition, percent G release was enhanced at high pH values\n(pH 7.4 and pH 7.8, p<0.01).\nConclusion The new formulation exhibits colon-targeted delivery\nand the addition of CA prolonged G release suggesting\nits suitability for the sustained and targeted delivery of G and\nCA to the lower intestine.
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