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James Brodie, Ben Davis, Lisa Turner, Shereen Nizari, M Francesca Cordeiro; Eyedrop Formulation and Evaluation of Quercetin - a component of Ginkgo biloba. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4156.
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© ARVO (1962-2015); The Authors (2016-present)
Quercetin, a component of Ginkgo biloba, has been shown to possess a wide range of antioxidant and neuroprotective properties which may have therapeutic potential in ophthalmic disorders such as glaucoma and diabetic retinopathy. Due to its relative insolubility in water, in vivo studies investigating the neuroprotective effects of Quercetin have so far been limited to administering it as an oral preparation. The objective of this study was to formulate Quercetin to enable topical drug delivery to the eye, thereby increasing the stability and bioavailability of the drug, and to evaluate its characteristics and suitability for future in vivo studies.
A polymeric micellar formulation was developed which encapsulated Quercetin using a lipid-film hydration method. The particle size and encapsulation efficiency of the prepared micelles were measured by dynamic light scattering and UV absorption spectroscopy, respectively. The addition of a lyoprotectant to the formulation allowed the micellar preparations to be freeze-dried in order to maintain stability over the course of the study. Quercetin-loaded micelles were prepared and administered topically to normal and glaucomatous rat eyes to assess corneal and ocular toxicity.
The Quercetin-loaded micelles had an average particle size of 18.10 nm and encapsulation efficiency of 77.03%. Stability was maintained in the freeze-dried formulations and once reconstituted the preparation was stable for an additional 72 hours at 25°C. The formulation had a pH of 7.0 that is within the ideal range of pH for ophthalmic solutions. Preliminary studies showed that the quercitin formulation was well-tolerated in vivo with no evidence of corneal or ocular toxicity during the study.
Quercetin has proven potential as a neuroprotective agent; however the in vivo studies have been limited by the challenges to formulation it poses. The utilisation of polymeric nanoparticles as vehicles for drug delivery appears to be a promising method of incorporating otherwise insoluble compounds with therapeutic potential. This study demonstrates that topical ophthalmic delivery of Quercetin can be achieved by encapsulation of the drug in a pluronic-based polymeric micelle vehicle, and future studies will look to investigate the efficacy of this formulation in vivo.
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