Proteins delivery, polyanhydrides

Lucas, P. A., Laurencin, C., Syftestad, G. T., Domb, A., Goldberg, V. M., Caplan, A. I., and Langer, R., Ectopic induction of cartilage and bone by water-soluble proteins from bovine bone using a polyanhydride delivery vehicle, J. Control. Rel. In Press. 

Tabata, Y., Gutta, S., and Langer, R. (1993), Controlled delivery systems for proteins using polyanhydride microspheres, Pharm. Res., 10,487—496. 

Polyanhydrides have also been investigated as protein carriers.f Poly(SA) and 20 80 CPH SA copolymer microspheres were foimd to conserve both the primary structure of the released protein [bovine serum albumin (BSA)] and the secondary structure of the encapsulated and released protein, and showed a sustained delivery for approximately 15 and 30 days, respectively. As the CPH content in the copolymer increased, the secondary structure of BSA was not conserved, as indicated by the steep decrease in the a-helix content. 

Septicin antibacterial implant for the treatment of chronic bone infections have been developed [21-24]. The multidisciplinary concept of polymeric implants has expanded to include research on the chemistry and characterization of polymers, experimental and theoretical polymer degradation and drug release, toxicology and metabolism, and research in specific fields of applications such as cancer, proteins and hormones delivery, infectious diseases, and brain disorders. This chapter concentrates on the chemistry and characterization of polyanhydrides with a brief description on recent applications of polyanhydrides. 

The remaining polymers listed in Table I are not soluble in aqueous solutions and require organic solvents or elevated temperatures for fabrication into microspheres and encapsulation of proteins. Two recent reviews describe the use of polylactides, poly(ortho esters), and polyanhydrides, all of which have been used for the controlled release of several proteins and peptides (Langer, 1993 Heller, 1993). Polyiminocarbonates are relatively new biodegradable polymers that, like polycaprolactones, have not yet been extensively characterized as controlled release matrices for therapeutic proteins (Pulapura et al, 1990). While all of these polymers require relatively harsh conditions for entrapment of the protein, their release properties may allow for a prolonged delivery (e.g., up to one year) because... 

There are many polymers that are suitable for the production of nanoparticles employed for drug delivery, which can generally be divided into two groups natural polymers, e.g., polysaccharides (chitosan), proteins (albumin, gelatin), as well as synthetic polymers, e.g., polyesters (poly(lactic add), poly(glycolic add), poly(hydroxy butyrate), poly-e-caprolactone, poly-p-malic add, poly(dioxanones)) polyanhydrides (poly(adipic add)) polyamides (poly(amino acids)) phosphorous-based polymers (polyphosphate) poly(cyano acrylates) polyurethanes polyortho esters and polyacetals. Extreme attention has to be paid to the biodegradability and biocompatibility of the polymers. It is essential that polymers used for medical applications are not detrimental for the tissue or cells and that they can be easily decomposed into simple harmless molecules and eliminated by the human body [ 18-22]. 

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