Systemic Delivery for Extended Periods

Many proteins have short half-lives and must be administered frequently to produce continuous therapeutic concentrations in the blood. Nondeg-radable polymer matrices can be used for extended delivery of proteins to the systemic circulation. For example, insulin has been delivered systemi-cally using EVAc matrix systems (Fischel-Ghodsian et al, 1988 Brown et al, 1986 Langer and Folkman, 1977, Creque eta/., 1980). 

Balazs, A., Calef, D., Deutch, J., Siegel, R., and Langer, R., 1985, The role of polymer matrix structure and interparticle interactions in diffhsion-limited drug release, Biophys. J. 47 97-104. 

Ballal, G., and Zygourakis, K., 1985, Diffusion in particles with varying cross-section, Chem. Eng. Set 40 1477-1483. 

Batich, C., Williams, J., and King, R., 1989, Toxic hydrolysis product fiom a biodegradable foam implant, / Biomed. Mater. Res. 23(A3) 311-319. 

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