The effects of pressure and direct compression on tabletting of microsponges

Microsponges are porous, polymeric microspheres that are used mostly for topical and recently for oral administration. Ketoprofen was used as a model drug for systemic drug delivery of microsponges in the study. Ketoprofen microsponges were prepared by quasi-emulsion solvent diffusion method with Eudragit RS 100 and afterwards tablets of microsponges were prepared by direct compression method. Different pressure values were applied to the tablet powder mass in order to determine the optimum pressure value for compression of the tablets. Results indicated that microsponge compressibility was much improved over the physical mixture of the drug and polymer and owing to the plastic deformation of sponge-like structure, microsponges produce mechanically strong tablets.