Glaucoma therapy by extended release of timolol from nanoparticle loaded silicone-hydrogel contact lenses

Ocular Drug Delivery Role of Contact Lenses

“…While eye drops are comfortable to instill, the low bioavailability of less than 5% is a major drawback. 3,17 Contact lenses are arguably the most successful biomaterial currently available,with estimates of over 140 million wearers worldwide.They have already been demonstrated to successfully correct refractive errors in patients.The addition of drug delivery can potentially increase the quality of life in patients by decreasing dosing frequency, while also potentially increasing compliance rates in ophthalmic treatment. There is some evidence that concurrent contact lens and topical ophthalmic treatment is more effective than topical treatment alone.…”

“…The limited mixing in the tear film between the lens and the cornea leads to a residence time of more than 30 minutes for drugs released from the lenses compared to about 5 minutes for eye drops. 3 The enhanced residence time leads to significant increases in bioavailability.…”

“…3,4,5 The purpose of topical ophthalmic drug delivery devices is to deliver an adequate amount of medication to the anterior segment of the eye, with accurate targeted dosing at a sustained and controlled rate, to increase bioavailability of the drug. Several commercial ocular delivery devices are currently available, including surface located inserts, degradable or non-degradable implants, and in situ forming gels.…”

“…The particle loaded gels released timolol in phosphate buffered saline for about a month at room temperature. 3 Using nanoparticles/ colloid carriers to increase the release duration from the contact lenses has also been proposed by some other authors. [33][34][35][36] …”

A novel ion-exchange carrier based upon liposome-encapsulated montmorillonite for ophthalmic delivery of betaxolol hydrochloride

“…1,2 During the past few decades, great efforts have been made to improve the effects of conventional ophthalmic dosage forms to eliminate this ocular disease, but the drawback of blurred vision has mainly hindered their wide acceptance. 3 Betaxolol hydrochloride (BH) has been employed for the treatment of this problem, due to its superior ability of selective β 1 -receptor and calcium-channel blocking.…”