Release behavior of salicylic acid in supramolecular hydrogels formed by L-phenylalanine derivatives as hydrogelator

Supramolecular hydrogels were prepared from L-phenylalanine derivatives as novel hydrogelators. Salicylic acid (SA), acting as a model drug, was entrapped in the supramolecular hydrogels. The release behavior of SA molecules in the supramolecular hydrogels was investigated by using UV-vis spectroscopy. The influence of the concentration of the hydrogelator, pH values of the accepting media, the temperature, and the concentration of SA on the release behavior of A was investigated under static conditions. The results indicated that the release rate of SA in the supramolecular hydrogels was slightly retarded with an increase of the hydrogelator concentration. Also, the release rates of SA increased with an increase of temperature and with the SA content. Furthermore, the release behavior of SA was found to be different at various pH values in buffers as accepting media. The study of the release kinetics indicated that the release behavior of SA was in accord with the Higuchi equation and the diffusion-controlled mechanism involved in the Fickian model. (C) 2008 Elsevier B.V. All rights reserved.