In vitro and in vivo studies of drug-releasing poly(amino acids).

Preliminary efforts directed toward the synthesis and characterization of steroid-polyamino acid conjugates indicate that the preparation of these systems is feasible. Studies have indicated that the steroids may be released from the macromolecule resulting in long-term controlled release systems. Table 4 lists several of the variables that are important in controlling biocompatibility, biodegradation, and drug release characteristics. The biocompatibility, biodegradation, and drug release characteristics are all important in the design and preparation of a drug-polyamino acid delivery system. The variables listed in Table 4 may interact and interrelate to varying degrees when considering each of these factors independently. Although perhaps preliminary, efforts to date indicate that steroids bound to polyglutamic acid or polyglutamic acid derivatives are biocompatible, capable of undergoing biodegradation, and can release drugs at appropriate rates for extended periods of time.