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Shikha P Barman, Moli Liu, Kathryn Crawford, Kevin Ward; Sustained Release of Travoprost for Glaucoma Therapy via a Biodegradable Wafer, NanoM-TP. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4020.
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© ARVO (1962-2015); The Authors (2016-present)
Glaucoma is a chronic ocular disorder that is one of leading causes of blindness. Characterized by high intraocular pressure (IOP), glaucoma is primarily treated by prostaglandin analogues. These compounds lower IOP by modification of the aqueous humor outflow via the uveoscleral pathway. These compounds are delivered by once daily eye-drops. However, eye drops have significant limitations, which include lack of patient compliance, inefficient placement of the drop and losses of ~90% of the dosage by naso-lacrimal drainage. Clinical studies in glaucoma have included the sustained release of prostaglandins via punctal plugs, corneal rings, drug-loaded contact lens or intracameral depots. These approaches have merit, but significant safety concerns remain for long term ophthalmic use.We have developed a self-administered, biodegradable, biocompatible wafer to release Travoprost at therapeutic levels daily, for at least 30 days. The sterile drug-containing polymer system is placed in the conjunctival cul de sac. We have adopted a bioengineering approach to drug delivery; the properties of the device were matched to the tissue to maximize biocompatibility and minimize a foreign-body response to the device. We have focused on wafer design characteristics critical to the in-vivo performance of the drug delivery system
Test parameters included polymeric compositions, device thickness, shape of the device, oxygen permeability, rate of hydration and device-tissue moduli as it affects outcome parameters such as in-vitro drug release, in-vivo biocompatibility and corneal permeability. The devices were analyzed by HPLC for encapsulation, SEM, in-vitro release by HPLC, % hydration gravimetrically and corneal permeability by Franz diffusion experiments. Mucoadhesion of wafers were tested on freshly excised bovine ocular tissue.
Flexural modulus, shape/thickness were critical parameters in biocompatibility/biodegradation. All wafers had thicknesses between 0.13-0.34 mm and drug content 65-75 µg/g. Polymeric composition is a key variable in mucoadhesivity, biodegradation and drug release. Each device had 10% burst and 1.5-2.5 µg/day. The nanowafer hydrated rapidly in 20 seconds. Mucoadhesion was a function of surface chemistry of the wafer; in-vivo studies demonstrated adherence through 30 days.
The data demonstrate feasibility of sustained release Travoprost therapy for glaucoma.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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