MICROENCAPSULATION OF IBUPROFEN BY A COACERVATION PROCESS USING EUDRAGIT L100-55 AS AN ENTERIC POLYMER

Ibuprofen microcapsules were prepared using Eudragit as enteric coatin g material and a simple coacervation method as coating process. Prelim inary experiments based on results published with cellulose acetate ph thalate led to the formation of a precipitate rather than a coacervate . Adjusting the polarity of the solvent in the Eudragit system by the addition of cosolvents enabled the transformation of the precipitate i nto a coacervate. This behaviour was qualitatively explained using the solubility parameter approach. The coacervate phase obtained from a s ystem containing 2-propanol as cosolvent was assayed quantitatively in the absence and in the presence of ibuprofen. Due to the increased so lubility of the drug in the cosolvent containing system, the compositi on of the coacervate phase was significantly altered when compared to a system without drug. The surface morphology of the microcapsules was assessed by scanning electron microscopy. The enteric properties of t he microcapsules were tested according to the USP XXII test procedures . The permeability of the wall was evaluated by a dissolution test per formed at pH 4. During stability testing over a period of 6 months the quality of the ibuprofen microcapsules remained almost unchanged.