ABSTRACT
Copolymers of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and poly(acrylic acid) (PAA) are mucoadhesive and gel at the temperature of human body owing to the formation of micellar aggregates acting as cross-links. The copolymer-drug formulation is injected or sprayed as a liquid into the nasal cavity and quickly gels. The gelation lowers the rate of diffusion and erosion of the polymer and associated drug, thereby enhancing drug retention and bioavailability. The micelles stabilize proteins and allow solubilization of hydrophobic drugs. Several patents and international patent applications on topical drug delivery utilizing the copolymers have been published [1-5].
