Controlled release of prednisolone acetate from molecularly imprinted hydrogel contact lenses

Abstract

The aim of this work was to study the influence of methacrylic acid (MAA) as a comonomer and the application of a molecular imprinting technique on the loading and release properties of weakly crosslinked 2-hydroxyethyl methacrylate (HEMA) hydrogels, with a view toward their use as reloadable soft contact lenses for the administration of prednisolone acetate (PA). The hydrogels were prepared with HEMA (95.90-98.30 mol %) as a backbone monomer, ethylene glycol dimethacrylate (140 mM) as a crosslinker, and MAA (0, 50, 100, or 200 mM) as a functional monomer. Different PA/MAA molar ratios (0, 1 : 8, 1 : 6, and 1 : 4) in the feed composition of the hydrogels were also applied to study the influence of the molecular imprinting technique on their binding properties. The hydrogels (0.4 mm thick) were synthesized by thermal polymerization at 60 C for 24 h in a polypropylene mold. The hydrogels were then characterized by the deter-mination of their swelling and binding properties in water. Their loading and release properties were also studied in 0.9% NaCl and artificial lachrymal fluid. Increasing the MAA content of the hydrogel and applying the molecular imprinting technique led to an increase in the loading capacity of the hydrogel. The optimized imprinted hydrogel showed the highest affinity for PA and the greatest ability to control the release process, sustaining it for 48 h. The results obtained clearly indicate that the incorporation of MAA as a comonomer increased the PA loading capacity of hydrogel. Our data showed that the molecular imprinting technique also had a significant effect on the loading and release properties of the hydrogels.

Preparation and in vitro/pharmacokinetic/pharmacodynamic evaluation of a slow-release nano-liposomal form of prednisolone

“…The DSC thermograms of PA, lactose and PEL are shown in Figure 4. As shown, crystalline PA exhibited clear endothermic peak at 244 C, in agreement with the melting point of the crystalline drug (Malaekeh-Nikouei et al, 2012). DSC thermal profile of lactose monohydrate showed three endothermic peaks.…”

Sustained drug release by contact lenses for glaucoma treatment—A review

“…It involves the use of a template drug and functional monomers during the CLs polymerization process which results in the formation of macromolecular memory sites with a suitable size and chemical groups to stably accommodate the drug 30 . The molecularly imprinted pockets mimic the drug's receptors and its structurally similar analogs, therefore increasing the drug loading capacity, while providing an adequate release rate 69,70 (Fig. 3).…”

“…Drug release by molecularly imprinted CLs.This technology has been successful in increasing the loading capacity and optimizing the release profile of several active ingredients such as norfloxacin75 , diclofenac 71,76 , hyaluronic acid 77 , hydroxypropylmethylcellulose78 , prednisolone70 and ketotifen fumarate79 . The first attempt to use molecularly-imprinted soft-CLs was conducted for timolol80 .…”

Synthesis of poly(2-hydroxyethyl methacrylate)-based molecularly imprinted polymer nanoparticles containing timolol maleate: morphological, thermal, and drug release along with cell biocompatibility studies

“…They are excellent materials for many applications including biomimetic sensors, [20] catalysis, [21] selective solid-phase extraction supports, [22] recognition of proteins, [23] and carriers for drug delivery. [24] Moreover, imprinted carriers of some ocular drugs such as naphazoline, [25] prednisolone acetate, [26] and dorzolamide [27] that are anticongestion, anti-inflammatory, and antiglaucoma, respectively, have been synthesized to improve their efficacy. Besides these drugs, timolol maleate (TM) that is the major therapeutic drug for treatment of glaucoma is an excellent drug model as template for the preparation of MIP-based controlled release systems due to its multiple functional interacting sites available for complex formation during MIP preparation.…”