Gentamycin-, tobramycin-, and cephalothin-polymethylmethacrylat beads were implanted into a bone cavity of the rabbit tibia. The antibiotic release of the implants was observed by measure of the antibiotic concentration of the secretion respectively of the neighbouring bone tissue in the surroundings of the beads produced by punction. An antibiotic concentration about 1 microgram/ml could be measured with gentamycin and tobramycin for 120 to 150 days and with cephalothin for 30 to 50 days in the surroundings of the beads.
