BACKGROUND:In recent years, the use of prednisolone has good achievements in functional recovery after peripheral nerve injury, but its short half-life, instable plasma concentrations and greater adverse reactions limit its clinical application. OBJECTIVE:To prepare prednisolone implantable films and to explore the sustained-release property of prednisolone implantable films. METHODS:Novel reverse micellar emulsion-solvent evaporation method was used to prepare nanoparticles which contains prednisolone, and we investigated the properties of prednisolone-loaded nanoparticles, including morphological form, diameter, drug loading, encapsulation efficiency, in vitro release properties. Then, composite film was prepared with the nanoparticles above and col agen, chitosan, soybean phosphatidylcholine. The properties of composite films, such as morphological form, the interaction among film materials, in vitro releasing curve, were investigated. RESULTS AND CONCLUSION:The prednisolone-loaded nanoparticles displayed favorable microstructure such as smooth surface, consistent diameters. The mean diameter of the nanoparticle was 500 nm and the max encapsulation efficiency of the nanoparticle was more than 90%. The nanoparticle displayed obvious sustained-release effect in vitro, but it exhibited a certain burst release phenomenon. We found that the nanoparticles were uniformly distributed inside and on the surface of the composite film;and the in vitro release rate of the film was slower and more stable than the nanoparticles. The composite film displayed favorable sustained-release effect with no burst release. From what we have il ustrated above, we can safely come to a conclusion that the prednisolone-loaded film possesses good sustained-release effects.