Preparation of a Molecularly Imprinted Soft Contact Lens as a New Ocular Drug Delivery System for Dorzolamide

In the present work a series of imprinted (MIPs) and non-imprinted (NIPs) hydrogels were prepared using 2-hydroxyethyl methacrylate (HEMA) as a backbone monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker monomer, methacrylic acid (MAA) as a functional monomer and dorzolamide (DZD) as the template molecule. Different concentrations of MAA (0, 100, 200, 400 mM) were used for preparation of NIPs. Two DZD: MAA molar ratios (1:8 and 1:4) and 400 mM MAA were also applied in imprinting process. The hydrogels (0.4 mm thickness) were synthesized by thermal polymerization at 50 degrees C in 24h in a polypropylene mould. Then, the swelling and binding properties of hydrogels were evaluated in water. Their loading and releasing properties were also studied in NaCl 0.9% and artificial lachrymal fluid. The results showed that using MAA as co-monomer and applying molecular imprinting technique increased loading capacity of hydrogels. The optimized imprinted hydrogel (MIP1:4), prepared with 400 mM MAA and DZD: MAA molar ratio of 1:4, had the highest affinity for DZD and the greatest ability to control the release process in aqueous media. Our data indicated that the use of suitable co-monomer and applying a molecular imprinting technique had important influence on loading and releasing properties of hydrogels.