Polylactic acid-polyethylene glycol block copolymer. A new biodegradable synthetic carrier for bone morphogenetic protein.
A new biodegradable polymer, a polylactic acid-polyethylene glycol (PLA-PEG) block copolymer, proved to be an effective and suitable carrier for bone morphogenetic protein (BMP). Composites of semipurified BMP and PLA-PEG consisting of a PLA segment with a molecular weight (MW) of 650 d and a PEG segment with a MW of 200 d (PLA-PEG 650-200) were implanted under the fasciae of the dorsal muscles of mice. Three weeks after implantation, the PLA-PEG 650-200/BMP composites were completely absorbed and replaced by newly induced bone with hematopoietic marrow. The composites induced twice as much bone as composites of BMP and a 650-d PLA homopolymer. Results indicate that of all the biodegradable synthetic polymers the authors have tested, PLA-PEG 650-200 is the most suitable and effective BMP carrier. Composites of PLA-PEG 650-200/BMP and hydroxyapatite powder (HAP) also induced ectopic bone formation. Because PLA-PEG 650-200/BMP is viscous and semiliquid and PLA-PEG 650-200/BMP/HAP is doughy and plastic, the former can be used as an injectable osteoinductive material and the latter as a plastic mold.
Miyamoto
S
S
Department of Orthopaedic Surgery, Osaka University Medical School, Japan.
Takaoka
K
K
Okada
T
T
Yoshikawa
H
H
Hashimoto
J
J
Suzuki
S
S
Ono
K
K
D000818:Animals; D019485:Bone Morphogenetic Proteins; D004337:Drug Carriers; D006133:Growth Substances / Q000008:administration & dosage*; D007773:Lactates / Q000737:chemistry; D019344:Lactic Acid; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009363:Neoplasm Proteins / Q000008:administration & dosage; D010012:Osteogenesis; D011091:Polyesters; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011506:Proteins / Q000008:administration & dosage*
D019485:Bone Morphogenetic Proteins; D004337:Drug Carriers; D006133:Growth Substances; D007773:Lactates; D009363:Neoplasm Proteins; D011091:Polyesters; D011108:Polymers; D011506:Proteins; D019344:Lactic Acid; D011092:Polyethylene Glycols; C033616:poly(lactide)