Patent ID: 7317070

Claim:
A process for the preparation of a polyamino acid, the process comprising (i) forming a reaction mixture comprising a N-carboxyanhydride compound and a metal alkoxide initiator, (ii) polymerizing the N-carboxyanhydride compound to form a polymer having a mass-average molecular weight of at least 10,000 and a repeat unit, the repeat unit comprising an alkyl ester moiety having the formula —C(O)OR 1 and (iii) hydrolyzing the alkyl ester moiety of the repeat unit in the presence of a base to form a polyamino acid, wherein the N-carboxyanhydride corresponds to Formula 1 the polymer repeat unit corresponds to Formula 2 the polyamino acid comprises a repeat unit corresponding to Formula 3 R 1 is alkyl; m is 1 or 2; n is an integer; and X is hydrogen or a metal; and wherein the polyamino acid has less than about 0.5 mole % of repeat units containing the moiety R 1 when analyzed by NMR.