Abstract
Purpose: :
To determine the use of an interpenetrating network of hydrogel as a vehicle for the delivery of ocular topical antibiotics. We characterized and measured drug release of two commonly use topical antibiotics, vancomycin and tobramycin, from a hydrogel.
Methods: :
Hydrogels composed of a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) double-network with high strength and high water content were synthesized and cut into 1cm diameter discs. The hydrogel discs were then dried overnight in a dessicator. They were then loaded with vancyomycin 50mg/ml or tobramycin 40 mg/ml, by soaking for 48 hours. Antibiotic release was monitored by measuring the percentage transmittance at 201 nm for vancomycin and 198 nm for tobramycin using UV/VIS spectrophotometer (Helios, ThermoSpectronic). Vancomycin and tobramycin concentrations were expressed as mg per ml of elution medium using a corresponding calibration curve. Samples were measured hourly for 6 hours.
Results: :
For vancomyin, amount of drug released at time 0, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours were 0 mg, 11.13 mg, 12.03 mg, 11.60 mg, 9.01 mg, 8.60 mg and 12.81 mg, respectively. For tobramycin, amount of drug released at time 0, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours concentrations were 0.76 mg, 1.78 mg, 2.80 mg, 0.89 mg, 2.28 mg, 3.03 mg, 6.25 mg.
Conclusions: :
A hydrogel composed of a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) double-network may serve as a candidate for ophthalmic drug delivery. In this study, most of the drug is released in the first few hours. Future studies on hydrogel modification may serve to extend drug release for longer periods.
Keywords: cornea: basic science • contact lens