Abstract
Purpose:
To evaluate the uptake and release of the antifungal agent natamycin encapsulated within poly(D,L-lactide)-dextran nanoparticles (Dex-b-PLA NPs) from model silicone hydrogel contact lens materials.
Methods:
Six model contact lens materials (gel A: poly(hydroxyethyl methacrylate, pHEMA); gel B: 85% pHEMA: 15% [Tris(trimethylsiloxy)silyl]-propyl methacrylate (TRIS); gel C: 75% pHEMA: 25% TRIS; gel D: 85% N,N dimethylacrylamide (DMAA): 15% TRIS; gel E: 75% DMAA: 25% TRIS; gel F: DMAA) were prepared using photoinitiation. The resulting lens materials were incubated in two conditions: (1) natamycin dissolved in deionized (DI) water, and (2) natamycin encapsulated within Dex-b-PLA NPs in 9.1 % dimethylsulfoxide (DMSO)/DI water for 7 days (d) at 25±3 oC. The release of natamycin from these materials in 2 mL of unpreserved saline solution, pH 7.4 at 32±2 oC was monitored using UV-Visible spectrophotometry at 304 nm over 7 d. The release solution was replenished every 24 hours (h).
Results:
The uptake of natamycin by all model lens materials increased between 1 and 7 d (p<0.001). There were no differences in drug uptake between lens materials containing pHEMA and DMAA. However, the uptake of natamycin encapsulated with NPs was higher than the uptake of the drug dissolved in DI water (p<0.05). The release of the drug was observed to be higher in materials containing DMAA than pHEMA (p<0.05). Additionally, all gels loaded with natamycin NPs also released more drug compared to gels soaked with natamycin in DI water (p<0.001). The drug release by all materials reached equilibrium within 12 h. After replenishing the release solution every 24 h, gels loaded with natamycin NPs continued to release drugs for up to 4 d (p<0.05).
Conclusions:
Model contact lens materials loaded with drug-Dex-b-PLA NPs provides a drug delivery vehicle capable of releasing natamycin for up to 12 h. In addition, materials containing DMAA-TRIS may be more suitable for drug delivery of natamycin due to the higher drug release observed with these materials.
Keywords: 477 contact lens •
422 antibiotics/antifungals/antiparasitics •
607 nanotechnology