pH and thermoresponsive hydrogel nanoparticles

摘要

Oral delivery of drugs can be significantly improved by using nanoparticles as carriers. The extent and the pathway of uptake of the nanoparticles ahve been found to be different in different parts of intestine. The phenomenon and the mechanism of orally administered particles into the bloodstream are indeed complex. Investigation of the fate of the particles of less than 60nm diameter orally administered for delivery into the lymphatic system or blood is expected to come into sharp focus in future studies. Anticipating this we got interested in the preparation of hydrophilic polymeric nanoparticles of 10nm to 100nm diameter with narrow size distribution [6-8]. We used aqueous core of reverse micellar droplets as host nanoreactors to regulate the size of these particles. In this paper we report the preparation of nanoparticles of upto 50nm diameter which are made of pH sensitive hydrogels containing pendant acidic group and which change ionisation in response to change in the pH. These hydrogels are copolymers of vinylpyrrolidone(VP) and acrylic acid(AA) monomers cross-linked with N,N'methylene bis acrylamide. FITC dextran was used as a marker compound which was entrapped into these nanoparticles.