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A curry a day keeps glaucoma away? – A curcumin study
Author(s) -
Balendra S.I.,
Davis B.M.,
Guo L.,
Cordeiro M.F.
Publication year - 2016
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2016.0687
Subject(s) - curcumin , in vivo , neuroprotection , chemistry , viability assay , pharmacology , bioavailability , in vitro , medicine , biochemistry , biology , microbiology and biotechnology
Purpose Curcumin's neuroprotective potential is challenged by its low solubility and stability at physiological pH. We aimed to solubilise curcumin into a formulation with high encapsulation efficiency (EE) and stability in phosphate buffer solution and to demonstrate its neuroprotective efficacy in vitro and in vivo upon topical administration in the well‐established ocular hypertensive (OHT) rat model of glaucoma. Methods A thin‐film hydration technique was employed to manufacture curcumin‐loaded micelles which were characterised for size and dispersity using dynamic light scattering and transmission electron microscopy. EE was assessed spectroscopically. Stability of the formulation was assessed by measuring changes in particle physical properties and EE over time. Assessment of curcumin mediated neuroprotection in vitro was achieved using an alamarBlue cell‐viability assay in paraquat‐treated primary retinal ganglion cells (RGCs) . In vivo assessment of topical curcumin micelle mediated neuroprotection was assessed in the OHT model with primary endpoint of whole retinal Brn3a histology. Results A solubilised micellar formulation was developed containing 4.5 mg/ml of curcumin with >90% EE. This was found to be stable at room temperature for >45 days, increasing to >6 months with lyophilisation in presence of a cryoprotectant. Curcumin versus vehicle‐only pre‐treated RGCs had a significantly higher IC50 in vitro (p < 0.05). Curcumin‐treated versus untreated OHT eyes had a significantly higher RGC density on Brn3a histology (p < 0.001). Conclusions A novel curcumin formulation is described which increases its solubility 100‐fold to 4.5 mg/ml and is stable for >60 days at room temperature and >6 months on lyophilisation. This formulation elicited significant neuroprotection in vitro and on 3 weeks of topical ocular instillation in vivo , with no toxicity findings.