Preparation of isometric Liesegang patterns and application in multi-pulsed drug release system

In this paper, the feasibility was demonstrated to turn Liesegang patterned gelatin hydrogel into the multi-pulsed drug release system. Calcium hydrogen phosphate (CaHPO 4 ) crystals were selected as the Liesegang rings (LRs) materials. The structure of CaHPO 4 /gelatin was well tailored by adding the sodium dodecyl benzene sulfonate (SDBS) micelles or SDBS/cholesterol microcapsules. As a result, the completely isometric CaHPO 4 /gelatin LRs were prepared. The enzymolysis of gelatin with isometric LRs and cholesterol/SDBS microcapsules was carried out by using typsin. A stepwise kinetic curve of enzymolysis was obtained due to the obstacles of CaHPO 4 rings. This result indicated that CaHPO 4 /gelatin LRs were potentially a versatile platform for the multi-pulsed release of various drugs.