Copolymer lactic acid-polyethylene glycol

A number of delivery systems have been developed for the controlled release of bone morphogenic protein-2 (BMP-2). For example, calcimn phosphate cement-based materials have shown the ability to deliver recombinant human bone morphogenic protein-2 (rhBMP-2) to increase alkaline phosphatase (ALP) activity in MC3T3-E1 cells in vitro,and enhance bone formation both ectopically and in an ulna osteotomy model. In addition to cement-based systems, polymeric materials have also been heavily researched as potential delivery vehicles of BMP-2. Saito et al. have developed a temperature sensitive poly(D,L-lactic acid-polyethylene glycol) (PLA-PEG) block copolymer as an... 

Saito N, Okada T, Horiuchi H, Murakami N, Takahashi J, Nawata M, et al. Biodegradable poly-D,L-lactic acid-polyethylene glycol block copolymers as a BMP delivery system for inducing bone. J Bone Jt Surg 2001 83 S92-8. 

Synthetic or man-made, e.g., PVAl, CA, polylactams e.g., polycaprolactam), polyglycols (e.g., polyethylene glycol), poly(aspartic acid), poly(butylene succinate-co-adipate), as well as poly(3-hydroxy butyrate) or PHB, poly(P-hydroxybutyric acid) or PHBA, poly(hydroxy-valerate) or PHV, poly(lactic acid) or PLA, polyCglycolic acid), polyglycolides, polybu-tyric acid, their copolymers and mixtures. 

In terms of pharmaceutical applications, copolymers have been used as drug carriers for controlled release applications. Controlled release polymer vesicles are prepared using hydrolysable block copolymers such as PLAEG, which is poly-lactic acid co-polyethylene glycol, PLAEG (ie, polycaprolactone-co-polyethylene glycol). 

Minamitake, Y., Gref, R., Hrkach, J., Peracchia, M. T., Domb, A., and Langer, R., 1994, Injectable nanospheres made of biodegradable polyethylene glycol-poly(lactic-co-glycolic) acid diblock copolymers. Paper in preparation. 

Two of the most commonly used synthetic polymers in combination with HA are polyethylene glycol (PEG) and poly(lactic-co-glycolic acid) (PLGA). Hybrid hydrogels of PEG and HA can be formed by combining methacrylated HA with acrylated PEG via photopolymerisation [44]. HA has also been combined with an amine-terminated PLGA-PEG diblock copolymer. The -COOH groups of HA can be activated with l-ethyl-3-(3-dimethylaminopropyl)... 

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