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Abstract #18326 Published in IGR 3-3
Preparation of controlled release ophthalmic drops, for glaucoma therapy using thermosensitive poly-N-isopropylacrylamide
Hsiue GH; Hsu SH; Yang CC; Lee SH; Yang IKBiomaterials 2002; 23: 457-462
In this study, controlled release ophthalmic agents for glaucoma therapy were developed based on the thermosensitivity of poly-N-isopropylacrylamide (PNIPAAm). The clear solution of PNIPAAm is known to undergo phase transition when the temperature is raised from the room temperature to about 32°C. The drug was entrapped in tangled polymer chains or encapsulated within cross-linked polymer hydrogel at room temperature, and released progressively after topical application (i.e., at a higher temperature). Linear PNIPAAm and cross-linked PNIAAm nanoparticles containing epinephrine were prepared. The drug release rate and cytotoxicity were investigated in vitro. Ophthalmic formulations, based on either linear PNIPAAm or the mixture of linear PNIPAAm and cross-linked PNIPAAm nanoparticles, were administered to rabbits, and the intraocular pressure (IOP)-lowering effect evaluated. The decreased pressure response of the formulation based on linear PNIPAAm lasted six-fold longer than that of the conventional eye drop. Furthermore, for formulation based on the mixture of linear PNIPAAm and cross-linked nanoparticles, the pressure-lowering effect lasted eight times as long. These results suggest that the use of thermosensitive polymer solutions or hydrogels has potential in controlled release antiglaucoma ophthalmic drugs.
Dr G.H. Hsiue, Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, Republic of China. ghhsiue@che.nthu.edu.tw
Classification:
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
