Application of a local drug delivery system to periodontal therapy: I. Development of collagen preparations with immobilized tetracycline.

For the purpose of applying a local drug delivery system to periodontal therapy, atelocollagen preparations with immobilized tetracycline (TC) were prepared by modifying the form of the collagen, the concentration of the immobilized TC, and the time of the cross-link process with glutaraldehyde. The course of the TC release from the collagen preparations into an aqueous solution was determined in relation to time. The preparations were also inserted into periodontal pockets, and the amount of TC remaining in the pocket was determined daily. The results obtained were as follows: 1) The degree of drug release could be controlled to some extent by adjusting the TC concentration and the time of the cross-link process; and 2) an amount of TC exceeding the effective dose in the gingival crevicular fluid was present in the periodontal pocket even 10 days after the insertion of TC fixed in the cross-linked processed collagen film in the periodontal pockets.