Sustained release of antibiotic from a fibrin-gelatin-antibiotic mixture.

To improve the therapeutic effect of antibiotics in the ear cavity postoperatively, a fibrin- and gelatin-based drug delivery system was designed and in vitro efficacy was evaluated. Four kinds of fibrin clot were made from ampicillin, gentamicin, and ofloxacin, and biologic assay was performed using Bacillus subtilis. The fibrin-gelatin-gentamicin mixture demonstrated antibiotic activity for up to 120 hours against B subtilis. Gentamicin was found to be released more slowly from the fibrin-gelatin mixture than from the fibrin mixture in this experiment. These results suggest that this device can be clinically used in a limited field such as postoperative care of ear infection.