Water‐soluble polyamides as potential drug carriers, IV: amine‐functionalized copolyaspartamides

Poly‐ D , L ‐succinimide ( 1 ) is converted to copolyaspartamides of the general type 2 by sequential treatment with diamine nucleophiles R′NH 2 and R″NH 2 , in which R′ is a group containing a tertiary amine function providing water solubility, and R″ represents a substituent comprising primary or secondary amino groups capable of interaction with suitably carboxyl‐ or carbonyl‐functionalized drug models. The reactions are performed in dimethylformamide medium under mild, yet carefully controlled conditions conducive to aminolytic imide ring opening in the educt polymer without causing crosslink formation through difunctional interaction of the R″NH 2 co‐nucleophile. The perfectly water‐soluble polymeric products (η inn , 5–30 ml/g), purified and isolated by dialysis (12,000–14,000 molecular mass cut‐off) and freeze‐drying, are of interest as macromolecular carrier species for pharmaceuticals and other biologically active agents. The drug‐binding potential of the target polymers is demonstrated by the coupling, through active ester intermediacy, of phenylacetic acid as a representative drug model to selected copolyamides.