Context: Microsponge is a novel approach for targeting the drug to the colon for the management of colon ailments such as inflammatory bowel disease.

Objective: Prednisolone loaded microsponges (PLMs) were prepared and coated with Eudragit S 100 (ES) and evaluated for colon specific drug delivery.

Materials and Methods: PLMs were prepared using quasi emulsion solvent diffusion technique using ethyl cellulose, triethylcitrate (1% v/v, plasticizer) and polyvinyl alcohol (Mol. Wt. 72kD, emulsifying agent). The developed microsponges were compressed into tablets via direct compression technique using sodium carboxymethyl cellulose (Na CMC) and magnesium stearate as super-disintegrant and lubricant, respectively. The tablets were then coated with ES to provide protection against harsh gastric environment and manifest colon specific drug release.

Results: PLMs were found to be nano-porous spherical microstructures with size around 35 µm and 86% drugencapsulation efficiency. Finally they were compressed into tablets which were coated with Eudragit S 100. In-vitro drug release from ES coated tablets was carried out at various simulated gastrointestinal fluids i.e. 1hr in SGF (pH 1.2), 2 to 3hr in SIF (pH 4.6), 4 to 5hr in SIF (pH 6.8), and 6 to 24hr in SCF (pH 7.4) and the results showed the biphasic release pattern indicating prolonged release for about 24 hrs.

Discussion and Conclusion: In vitro drug release studies revealed that drug starts releasing after 5 hrs by the time PLMs may enter into the proximal colon, Hence maximum amount of drug could be released in the colon that may result in reduction in dose and dose frequency as well as side effects of drug as observed with the conventional dosage form of prednisolone.

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