A laboratory method of preparing controlled release capsules floated in artificial gastric juice was developed by crosslinking the gelatin capsules with formaldehyde vapor.

AIM: to compare the property between genipin and glutaraldehyde crosslinked gelatin from the aspects of crosslinking index, cytotoxicity, swelling ratio and degradation rate.

With increasing reaction time, the cross linking reaction proceeded from the surface to core gradually to give a gelatin material with cross-linking degree gradient across the section.