Dicyclomine-loaded Eudragit®-based Microsponge with Potential for Colonic Delivery: Preparation and Characterization

Purpose: The purpose of this work was to develop a prolonged microsponge drug delivery system containing dicyclomine.
Methods: Dicyclomine-loaded, Eudragit-based microsponges were prepared using a quasi-emulsion solvent diffusion method. The compatibility of the drug with formulation components was established by differential scanning calorimetry (DSC) and Fourier transform infra-red (FTIR). Process parameters were modulated to optimise the formulation. Shape and surface morphology of the microsponges were examined using scanning electron microscopy.
Results: The results of compatibility tests showed that no chemical interaction or changes took place during preparation of the formulations; furthermore, the drug was stable in all the formulations. In increase in drug:polymer ratio resulted in a reduction in the release rate of the drug from the microsponges. Kinetic analysis showed that the main mechanism of drug release was by Higuchi matrix-controlled diffusion. Drug release was bi-phasic with an initial burst effect with 16 - 30 % of the drug was released in the first hour. Cumulative release for the microsponges over 8 hours ranged from 59 - 86 %.
Conclusion: This study presents an approach for the modification of microsponges for prolonged drug release of dicyclomine. The unique compressibility of microsponges can be applied to achieve effective local action since microsponges may be taken up by macrophages present in colon.

Keywords
Microsponge; Dicyclomine; Quasi-emulsion solvent diffusion; Eudragit RS-100; Colonic drug release