To improve the efficiency of topical ocular drug administration, we focused on development of a nanoparticles loaded contact lens to deliver the hydrophobic drug over a prolonged period of time. The cross-linked nanoparticles based on PCL (poly ε-caprolactone), 2-hydroxy ethyl methacrylate (HEMA), and poly ethylene glycol diacrylate (PEG-DA) were prepared by surfactant-free miniemulsion polymerization. The lens material was prepared through photopolymerization of HEMA and N-vinylpyrrolidone (NVP) using PEG-DA as the cross-linker. Effects of nanoparticles loading on critical contact lens properties such as transparency, water content, modulus and ion and oxygen permeabilities were studied. Nanoparticles and hydrogel showed high viability, indicating the absence of cytotoxicity and stimulatory effect. Drug release studies revealed that the hydrogel embedded with nanoparticles released the drug for a period of 12 days. The results of this study provide evidence that nanoparticles loaded hydrogels could be used for extended delivery of loteprednol etabonate and perhaps other drugs.

A new unsymmetrical diamine monomer, 2,4-diaminophenyl [4 0 -(2 00 ,6 00 -diphenyl-4 00 -pyridyl)phenyl]ether, was successfully synthesized by nucleophilic substitution of 1-chloro-2,4-dinitrobenzene with 4-(2 0 ,6 0 -diphenyl-4 0 -pyridyl) phenol. The diamine monomer was characterized by FTIR, 1 H and 13C NMR, and elemental analysis techniques and used for the preparation of novel polyimides (PIs) by reaction with commercially available tetracarboxylic dianhydrides such as pyromellitic dianhydride, 3,3 0 ,4,4 0 -benzophenone tetracarboxylic dianhydride, and bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride. These PIs with inherent viscosities ranged from 0.43 to 0.48 dL/g were readily soluble in many organic solvents and afforded tough and flexible films by solution casting. These polymers exhibited T g s between 237 and 294 C, and 10% weight loss temperatures in excess of 500 C with up to 56% char yield at 600 C in air. Their maximum fluorescence emission in dilute (0.2 g/dL) NMP solution appeared at 450 nm.

A series of poly(carbazole-quinoxaline-amide)s (PCQAs) containing phenyl and long alkyl chain as pendants was synthesized from polycondensation between a new diamine with a synthesized and several commercial dicarboxylic acids using Yamazaki's method. PCQAs had inherent viscosities and weight average molecular weights (M w ) in the range of 0.48-0.62 dL g 21 and 51,600-58,500 g mol 21 , respectively. These luminescent polymers are readily soluble in a variety of organic solvents and formed low-colored and tough thin films. In this study, silane modified SiO 2 (mSiO 2 ) nanoparticles were prepared, characterized and used with PCQAs in preparation of nanocomposites via solution blending method. The interfacial interaction strength between mSiO 2 and the polymer-matrix enhanced thermal stability (T 10% , from 463 C to 500 C) and mechanical strength (from 100 MPa to 150 MPa) for composite containing 30 wt % mSiO 2 in comparison with the pure polyamide. These materials showed good ability for extractionelimination of metal ions such as Cr 61 , Cr 31 , Co 21 , Zn 21 , Pb 21 , Cd 21 , and Hg 21 from aqueous solutions either individually or in the mixture at various pH.

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