The purpose of this study is to investigate the effect of the structure and concentration of the crosslinking agent on the physical properties and drug elution in the fabrication of hydrogel contact lenses. For this objective, hydrogel contact lenses were fabricated at different concentrations using four different crosslinking agents to evaluate the physical properties of the samples and examine the drug elution.
The contact lenses were fabricated by using 2-Hydroxyethyl methacrylate (HEMA) and Methacrylic acid (MAA) monomers, Azobisisobutyronitrile (AIBN) as the initiator, and Ethylene glycol dimethacrylate (EGDMA), N,N’-Methylenebisacrylamide (MBAA), Glycerol dimethacrylate (GD), and Glycerol 1,3-diglycerolate diacrylate (GDD) as the crosslinking agents. The concentrations of the crosslinking agents were fixed at 0.3% and 3% to make a total of eight contact lenses. In addition, ofloxacin, an antibacterial substance, was mixed with the monomers at a concentration of 0.1% to perform thermal polymerization at 100°C for 1 hour. Physical properties such as water content, light transmittance, wettability, and compressive strength, were measured, and drug elution was calculated by measuring the absorbance with the eluate obtained by immersing the contact lenses containing ofloxacin in a PBS solution. By using Escherichia coli, the antimicrobial properties were examined according to the drug release time and concentration.
The water content and wettability of the contact lenses decreased, and the compressive strength increased as the concentration of the crosslinking agents increased. The amount of drugs released also decreased and continued to release slowly.
The contact lenses using hydrophilic crosslinking agents showed improved water content and wettability and decreased tensile strength compared to the lenses with hydrophobic crosslinking agents. In addition, the higher the number of hydrophilic functional groups, the higher the concentration of drug release.
As a result, this study confirmed that the concentrations and types of the crosslinking agents used to fabricate hydrogel contact lenses affected the physical properties and drug release effect.