Controlled brimonidine release from nanostructured lipid carriers-laden silicone contact lens to treat glaucoma

Biopolymeric Coatings for Local Release of Therapeutics from Biomedical Implants

The deployment of structures that enable localized release of bioactive molecules can result in more efficacious treatment of disease and better integration of implantable bionic devices. The strategic design of a biopolymeric coating can be used to engineer the optimal release profile depending on the task at hand. As illustrative examples, here advances in delivery of drugs from bone, brain, ocular, and cardiovascular implants are reviewed. These areas are focused to highlight that both hard and soft tissue implants can benefit from controlled localized delivery. The composition of biopolymers used to achieve appropriate delivery to the selected tissue types, and their corresponding outcomes are brought to the fore. To conclude, key factors in designing drug-loaded biopolymeric coatings for biomedical implants are highlighted.

Nanoparticles for the treatment of glaucoma-associated neuroinflammation

Recently, a considerable amount of literature has emerged around the theme of neuroinflammation linked to neurodegeneration. Glaucoma is a neurodegenerative disease characterized by visual impairment. Understanding the complex neuroinflammatory processes underlying retinal ganglion cell loss has the potential to improve conventional therapeutic approaches in glaucoma. Due to the presence of multiple barriers that a systemically administered drug has to cross to reach the intraocular space, ocular drug delivery has always been a challenge. Nowadays, studies are focused on improving the current therapies for glaucoma by utilizing nanoparticles as the modes of drug transport across the ocular anatomical and physiological barriers. This review offers some important insights on the therapeutic advancements made in this direction, focusing on the use of nanoparticles loaded with anti-inflammatory and neuroprotective agents in the treatment of glaucoma. The prospect of these novel therapies is discussed in relation to the current therapies to alleviate inflammation in glaucoma, which are being reviewed as well, along with the detailed molecular and cellular mechanisms governing the onset and the progression of the disease.

In vitro and in vivo evaluation of brimonidine loaded silica nanoparticles-laden silicone contact lenses to manage glaucoma

Glaucoma is treated by frequent instillation of 0.2% w/v brimonidine tartrate eye drop solution, which showed poor ocular bioavailability of 1-3%. Medicated contact lenses can be used to improve the ocular drug bioavailability. However, drug loading in the contact lens matrix showed high burst release and changes the optophysical properties of the contact lens material. In this paper, a novel brimonidine loaded silica nanoparticles-laden silicone contact lenses (Bri-Si) were designed to achieve controlled drug delivery without altering the optophysical properties of the contact lens. Silica nanoparticles were prepared by polymerizing octadecyltrimethoxysilane (OTMS) molecules at the oil/water interface of microemulsion. Traditional soaking method (Bri-SM), direct brimonidine-loading method (Bri-DL) and microemulsion-laden contact lens (Bri-ME) were developed for comparison. The Bri-Si lens showed improved swelling, transmittance, oxygen permeability and lysozyme adherence compared to Bri-SM, Bri-DL and Bri-ME lenses. The Bri-DL lens showed high brimonidine leaching during extraction and sterilization steps, with low cumulative drug release. While, Bri-Si lens show controlled brimonidine release for 144 h. In a rabbit tear fluid model, the Bri-Si lens showed high brimonidine concentration for 96 h compared to Bri-ME lens and eye drop therapy. Based on histopathological studies of cornea, the Bri-Si lens was found to be safe for human applications. The data demonstrated the novel application of silica nanoparticles to control brimonidine release from the contact lens without altering the optophysical properties of the contact lens.