Recent Advances in Ocular Drug Delivery Systems

Abstract

Abstract:Transport of drugs applied by traditional dosage forms is restricted to the eye, and therapeutic drug concentrations in the target tissues are not maintained for a long duration since the eyes are protected by a unique anatomy and physiology. For the treatment of the anterior segment of the eye, various droppable products to prolong the retention time on the ocular surface have been introduced in the market. On the other hand, direct intravitreal implants, using biodegradable or non-biodegradable polymer technology, have been widely investigated for the treatment of chronic vitreoretinal diseases. There is urgent need to develop ocular drug delivery systems which provide controlled release for the treatment of chronic diseases, and increase patient's and doctor's convenience to reduce the dosing frequency and invasive treatment. In this article, progress of ocular drug delivery systems under clinical trials and in late experimental stage is reviewed.

Emerging Trends in Ocular Drug Delivery: A Review on Recent Updates

“…Each implant is 0.08 inches wide and 0.04 inches high [23]. An episcleral implant developed by 3T Ophthalmics can be re-filled with drugs in any form, such as a solution, gel or matrix [24,25]. In pre-clinical studies with model drug (sodium fluorescein), the episcleral implant delivered high levels in the retina and posterior vitreous [25].…”

Corticosteroids and Anti-Complement Therapy in Retinal Diseases

“…Subconjunctival/episcleral implants require a small incision in the conjunctiva. Surodex™ is a biodegradable anterior chamber insert made of poly(lactic-coglycolic acid) (PLGA) and provides sustained-release dexamethasone for about (Chang et al 1987) Lipophilic esters Increase in corneal permeation Decrease in systemic drug exposure PGF2α (Chien et al 1997) Lipophilic esters Increase in corneal permeation Acyclovir (Hughes and Mitra 1993;Katragadda et al 2006;Vadlapudi et al 2012aVadlapudi et al , b, 2014 Aliphatic acyl esters Amino acid prodrugs Peptide prodrugs Lipid prodrugs Increase in corneal permeation Enhancement of stability Increase in efficacy Increase in cell accumulation Ganciclovir (Tirucherai et al 2002;Majumdar et al 2005) Lipophilic esters Increase in solubility Increase in corneal permeation Increase in activity Dexamethasone (Civiale et al 2004) Esters Increase in corneal permeation Cyclosporine A (Lallemand et al 2005(Lallemand et al , 2007RodriguezAller et al 2012) Phosphate ester Therapeutic concentrations in precorneal area immediately after application Increase in water solubility Flurbiprofen (Shen et al 2011) Flurbiprofen axetil Less irritation Increase in efficacy Cannabinoid receptor (CB 1/2 ) agonist (Mainolfi et al 2013 (Kuno and Fujii 2011). LX201 (Lux Biosciences) is a cyclosporine A-loaded silicone matrix episcleral implant designed to sustain drug release for a year in order to prevent corneal transplant rejection.…”

“…Phase II studies were conducted for latanoprost and bimatoprost punctal plug formulations (QLT Inc. and Vistakon Pharmaceuticals) for glaucoma and ocular hypertension (Kuno and Fujii 2011). The system used for latanoprost is also being studied for the anti-allergy drug olopatadine.…”

Preparation and Characterization of Atenolol Laden Nanoparticles

“…Nanoparticulates are designed to ensure low irritation, adequate bioavailability, and ocular tissue compatibility. Several nanocarriers, such as nanoparticles, nanosuspensions, liposomes, nanomicelles and dendrimers have been developed for ocular drug delivery [4][5][6].…”