Effect of chondroitin sulfate modification on rhBMP-2 release kinetics from collagen delivery system.

Protein delivery systems focus on protecting the protein that directly affects release kinetics. This study was carried out to determine the effect of surface polar group and fiber structure in a recombinant human bone morphogenetic protein-2 (rhBMP-2) protecting system based on a collagen matrix on its pharmacokinetics (PK) and osteoinductive activity In this study, two types of collagen carriers were made for rhBMP-2 protecting system. The PKs of rhBMPs within collagen (Col) and collagen-chondroitin sulfate (Col-CS) carriers were determined using (125)I-labeled proteins in rat ectopic assay. The two carriers were characterized with surface energy and hydrophilicity. We observed that the osteoinductivity of these two scaffolds seemed to depend on two parameters: the nature of the carrier material and the release kinetics of the carriers. Results indicated that with CS modification, the initial burst release of rhBMP-2 from Col-CS scaffold was much higher than collagen scaffold. The subsequent PKs at longer times were not strongly dependent on the carriers. These differences were expected to affect the osteoinductive activity of the implants. It was concluded that surface energy played a significant role in the release PK of implanted rhBMP and higher initial burst is favorable to bone regeneration near the matrix. (c) 2009 Wiley Periodicals, Inc.