Thursday, June 8, 2017

PolySciTech PLGA-PEG-PLGA thermogel used in development of equine anti-fungal treatment to prevent blindness both in humans and horses


Keratomycosis, is a vision-threatening disease which occurs both in horses and humans. Horses, in particular, tend to be extremely sensitive to fungal diseases such as this and have similar pathology to humans. Voriconazole is commonly applied as an anti-fungal drug, but ocular administration is complicated by poor absorption, tear-excretion, and other factors which make high frequency repeat doses necessary. Unsurprisingly, horses do not typically like to receive eye-drops and administering medicine by this method is not a trivial task. There is a need to generate an extended release formulation for their treatment. Recently, researchers at Auburn University, and University of Queensland (Australia) utilized PLGA-PEG-PLGA thermogels from PolySciTech (www.polyscitech.com) (PolyVivo AK024, and AK019) to generate a Voriconazole loaded thermogel. They tested this gel formulation for delivery kinetics and safety. This research holds promise to provide treatment for this disease which can lead to blindness in both humans and horses. Read more: Cuming, Rosemary S., Eva M. Abarca, Sue Duran, Anne A. Wooldridge, Allison J. Stewart, William Ravis, R. Jayachandra Babu, Yuh-Jing Lin, and Terri Hathcock. "Development of a Sustained-Release Voriconazole-Containing Thermogel for Subconjunctival Injection in Horses Subconjunctival Voriconazole-Thermogel." Investigative Ophthalmology & Visual Science 58, no. 5 (2017): 2746-2754. http://iovs.arvojournals.org/article.aspx?articleid=2629760

“Abstract: Purpose: To determine in vitro release profiles, transcorneal permeation, and ocular injection characteristics of a voriconazole-containing thermogel suitable for injection into the subconjunctival space (SCS). Methods: In vitro release rate of voriconazole (0.3% and 1.5%) from poly (DL-lactide-co-glycolide-b-ethylene glycol-b-DL-lactide-co-glycolide) (PLGA-PEG-PLGA) thermogel was determined for 28 days. A Franz cell diffusion chamber was used to evaluate equine transcorneal and transscleral permeation of voriconazole (1.5% topical solution, 0.3% and 1.5% voriconazole-thermogel) for 24 hours. Antifungal activity of voriconazole released from the 1.5% voriconazole-thermogel was determined via the agar disk diffusion method. Ex vivo equine eyes were injected with liquid voriconazole-thermogel (4°C). Distension of the SCS was assessed ultrasonographically and macroscopically. SCS voriconazole-thermogel injections were performed in a horse 1 week and 2 hours before euthanasia and histopathologic analysis of ocular tissues performed. Results: Voriconazole was released from the PLGA-PEG-PLGA thermogel for more than 21 days in all groups. Release followed first-order kinetics. Voriconazole diffused through the cornea and sclera in all groups. Permeation was greater through the sclerae than corneas. Voriconazole released from the 1.5% voriconazole-thermogel showed antifungal activity in vitro. Voriconazole-thermogel was easily able to be injected into the dorsal SCS where it formed a discrete gel deposit. Voriconazole-thermogel was easily injected in vivo and did not induce any adverse reactions. Conclusions: Voriconazole-containing thermogels have potential application in treatment of keratomycosis. Further research is required to evaluate their performance in vivo.”
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