Development of a Resorbable Tricalcium Phosphate (TCP) Amine Antibiotic Composite

Calcium phosphate collagen composites are currently being used to rebuild bone. Commercial collagen preparations have been claimed to he hvpo-antigenic but none are non-antigenic. The collagen in calcium phosphate collagen composites is eventually degraded to its component amino acids. Two thirds of collagen consists of glvcine, hvdroxvproline, and proline. Since both tricalcium phosphate (TCP) and collagen are resorbable and both can he utilized to form bone, incorporation of amino acids into TCP-amino acid composites should nrovide the building blocks for formation of new bone. Stich composites should also be non-antigenic. Previous work conducted with composites of amino acids with aluminum calcium phosphorous oxide (ALCAP) ceramics, has shown that these composites can be uised to repair traumatized bone in rats. In our study, experiments conducted with TCP cysteine, Ivsine, or proline composites showed that the composites, after setting to hardness, degrade slowly and can he molded into different froms. Dissolution studies were conducted with composites of TCP with each of the above amino acids in Tris-MCl buffer (PH 7.4) at 37°C in vitro. Experiments conducted with antibiotics showed that antibiotics such as penicillin and ervthromvcin can be incorporated into the TCP amino acid composite. Subcutaneous implants of TCP amino acid composites in rats showed that most of the TCP-proline composite was degraded bv day 4, TCP-lvsine composite he day 7, and TCP-cysteine composite by day 21. Our results suggest that TCP amino acid composites are biocomnatible and can he used to repair experimentally traumatized bone.