Purchase this article with an account.
Shikha P Barman, Koushik Barman, Kevin Ward; Single Administration Sustained Release Formats for Administration of Ophthalmic Medications to the Ocular Surface, Cornea and Anterior Chamber. Invest. Ophthalmol. Vis. Sci. 2014;55(13):456.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Our primary objective was to develop micro-engineered delivery systems to administer a precise concentration of drug to ocular surface tissues in a sustained fashion, with a single injection. For control of inflammation after cataract surgery, the biodegradable delivery system is modulated to release its payload in 2-4 weeks. The micro-encapsulated delivery systems are engineered to be injectable, have high drug encapsulation, have minimal burst release of drug and remain dispersed in the tissue, without agglomeration, or induction of a foreign body response. In this work, Loteprednol Etabonate, a soft steroid is encapsulated within polymer delivery systems. The systems are fabricated using a process that produces monolithic encapsulates. Process conditions were developed to achieve different size distributions and internal morphology, which affected drug burst and release rates.
Loteprednol Etabonate was encapsulated into PLG microparticles using a novel process to achieve the desired size distribution and high encapsulation efficiency. Encapsulation efficiency was measured by dissolution of the microparticles in ethyl acetate, then extracting the drug with isopropanol, to isolate the drug from the PLG polymer prior to analysis by HPLC. Particle size distribution was measured using a Horiba LA-950. Scanning electron microscopy was used to determine the internal microstructure of the microparticles. In-vitro release studies were performed in PBS/surfactant mixture, at 37°C, pH 7.4.
Loteprednol Etabonate was encapsulated in polylactide-co-glycolide with encapsulation efficiencies of 90-95%. The process was modulated to produce solid, monolithic prototypes, which produced burst less than 1% and sustained release of at least 10-50 micrograms/day, for at least 14 days. The drug-containing microparticles were injectable. Internal microstructure of the low burst microparticles measured by scanning electron microscopy showed solid, non-porous internal structures.
Precise release of a steroid from a single injected dose of drug-containing microparticles is a feasible concept for replacement of eye-drops delivered multiple times per day after cataract surgery.
This PDF is available to Subscribers Only