Comparison of chitosan and gelatin coated microparticles: prepared by hot-melt method.

The aim of this study was to compare the performance of microparticles and their release properties after coating by chitosan and gelatin, respectively. All of the poly(epsilon-caprolactone) (PCL) microparticles were prepared by the hot-melt encapsulation method and indomethacin was selected as a model drug to be encapsulated. All of the coated microparticles retained their spherical shape irrespective of the type of coating material, and the particle size of coated microparticles was similar to the uncoated ones. The indomethacin encapsulation efficiency was in the range of 8.65 +/- 0.08 % - 8.81 +/- 0.04% for uncoated microparticles and 8.22 +/- 0.04% - 8.68 +/- 0.08% for coated microparticles. The release of indomethacin from uncoated microparticles followed a two-exponential release profile, where indomethacin was rapidly released within 4 h during the first release phase, after that approximately 20% of the drug was continuously and slowly released for up to 24 h in the second phase. The similar release profile was observed from coated microparticles irrespective of the times of coating and the types of coating material. Both the natural coating materials, chitosan and gelatin, efficiently reduced the initial burst release and the first phase of drug release, but did not alter the second phase of drug release. In other words, chitosan and gelatin could be used to protect the drug on the surface of microparticles from immediately contacting with the release medium and both possessed the same feature in the delay of drug release.