Preparation and characterization of fluorometholone molecular imprinted soft contact lenses as ocular controlled drug delivery systems

Abstract

The molecular imprinted (MIP) and non-imprinted (NIP) lenses were synthesized in presence and absence of Fluorometholone (FML) as the template molecule. Hydroxyethyl methacrylate (HEMA), as a backbone monomer, methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker monomer were applied to preparing soft contact lenses with different FML: MAA molar ratios. The lenses were characterized by determination of swelling and binding properties in water. Transparency and differential scanning calorimetry (DSC) properties of Drug-loaded and drug-free MIP lenses were also studied. Their loading and release properties were also studied using Korsmeyer-Peppas equation in Normal Saline (0.9% NaCl) and Artificial Tears media. There was no significant difference in swelling percentage of MIP and NIP lenses (p-value>0.05). No endothermic peak was seen at the melting point of FML in thermograms of drug-free and drug-loaded MIP lenses. It was found that all MIP lenses had higher binding affinity to FML in comparison with NIP (p-value<0.05). According to drug release data, Korsmeyer-Peppas equation shows non-Fickian diffusion pattern from hydrogel in 0.9% Normal Saline and Artificial Tears media and MIP1:12 had superior binding and release properties. The results of the present work indicated that molecular imprinting technique had a significant effect on improving loading capacity and sustaining drug release from hydrogels. According to our data MIP1:12 had more FML loading capacity and superior controlled release properties compared to other polymers and can be evaluated, in future studies, for making FML imprinted soft contact lenses.