Co-delivery of Brinzolamide and Timolol from Micelles-laden Contact Lenses: In vitro and In Vivo Evaluation

Traditional eye drops exhibit a modest bioavailability ranging from 1 to 5%, necessitating recurrent application. Thus, a contact lens-based drug delivery system presents substantial benefits. Nonetheless, pharmaceutical agents exhibiting poor solubility may compromise the quintessential characteristics of contact lenses and are, consequently, deemed unsuitable for incorporation. To address this issue, the present study has engineered a novel composite drug delivery system that amalgamates micellar technology with contact lenses, designed specifically for the efficacious conveyance of timolol and brinzolamide.

Utilizing mPEG-PCL as the micellar material, this study crafted mPEG-PCL micelles loaded with brinzolamide and timolol through the film hydration technique. The micelle-loaded contact lens was fabricated employing the casting method; a uniform mixture of HEMA and EGDMA with the mPEG-PCL micelles enshrouding brinzolamide and timolol was synthesized. Following the addition of a photoinitiator, 50 μL of the concoction was deposited into a contact lens mold. Subsequently, the assembly was subjected to polymerization under 365 nm ultraviolet light for 35 min, resulting in the formation of the micelle-loaded contact lenses.

In the present article, we delineate the construction of a micelle-loaded contact lens designed for the administration of brinzolamide and timolol in the treatment of glaucoma. The study characterizes crucial properties of the micelle-loaded contact lenses, such as transmittance and ionic permeability. It was observed that these vital attributes meet the standard requirements for contact lenses. In vitro release studies revealed that timolol and brinzolamide could be gradually liberated over periods of up to 72 and 84 h, respectively. In vivo pharmacodynamic evaluation showed a significant reduction in intraocular pressure and a relative bioavailability of 10.84 times that of commercially available eye drops. In vivo pharmacokinetic evaluation, MRT was significantly increased, and the bioavailability of timolol and brinzolamide was 2.71 and 1.41 times that of eye drops, respectively. Safety assessments, including in vivo irritation, histopathological sections, and protein adsorption studies, were conducted as per established protocols, confirming that the experiments were in compliance with safety standards.

The manuscript delineates the development of a safe and efficacious micelle-loaded contact lens drug delivery system, which presents a novel therapeutic alternative for the management of glaucoma.