Biologically active materials, controlled release

Baker, R., Controlled Release of Biologically Active Materials, John Wiley and Sons, New York, 1987. 

A block copolymer effective as a controlled release agents of biologically active materials have been prepared. This agent consisted of ethylene oxide-propylene sulfide-ethylene oxide teipolymer that had been end-capped with a selected cysteine-containing peptide. These materials resist degradation prior to reaching their intended targets because they behave as multilamellar vesicles. 

Biodegradable hydrogels have also been developed for use in controlled drug delivery as carriers of biologically active materials such as hormones, enz5mes, antibiotics, antineoplastic agents, and cell suspensions. Temporary preservation of functional properties of a carried species, as well as the controlled release of the species into local tissues or systemic circulation, have been achieved. 

Engstrom, S., Lindman, B., and Larsson, K., 1992, Method of preparing controlled release preparations for biologically active materials and resulting compositions, U.S. Patent 5,151,272, September 29,1992. 

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