PH sensitive graft copolymer

摘要

Graft copolymer (P) which exhibit pH dependent swelling/dissolution properties comprising a hydrophobic back-bone and graft chains comprising acidic monomer. This Graft copolymer (P) do not swell or dissolve at acidic pH prevalent in the stomach and they swell/dissolve at near neutral pH prevalent in the intestinal region. The graft copolymer (P) is useful for the development of drug delivery formulations particularly for oral drug delivery formulations.

主权项

1. A graft copolymer (P) of formula 1comprises:
a. a backbone having the formula P [A(x) B(y) C(Z)] comprising a diol (A), a dicarboxylic acid or acid anhydride (B) and a monomer containing pendant unsaturation (C), wherein (x)=37-46%, (y)=49-55% (z)=5-8% by mole; and b. a graft which is a polymer of the acidic monomer (D) and ‘w’ is weight percent of the total weight of the graft copolymer such that ‘w’ is 22-56%; wherein the graft copolymer swells at pH>4.7.