Effect of gelatin on the drug release behaviors for the organic hybrid gels based on N-isopropylacrylamide and gelatin

A series of organic hybrid gels were prepared based on poly(N-isopropylacrylamide), poly(NIPAAm), and gelatin. The hybrid gels were crosslinked through a two-step process with genipin or glutaraldehyde. The swelling behavior and physical properties of the gels were investigated in the previous report. In this study, we loaded sulfanilamide, caffeine, vitamin B12, phenol red, and neutral red in the hybrid gels. The effects of gelatin on the drug release profile were demonstrated. The ionicity of hybrid gels strongly influenced the release of phenol red (anionic) and neutral red (cationic). However, the releases of sulfanilamide, caffeine and vitamin B12 were not influenced by the ionicity of hybrid gel. The drug released from the gels crosslinked with genipin was significantly smaller than that released from the gels crosslinked with glutaraldehyde.