Purchase this article with an account.
B. Asgharian, L. Nolen, D. Meadows, R. Stone; Novel Gel-Forming Ophthalmic Polymer System for Artificial Tear Solution . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2472.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine the pre-clinical performance attributes of a novel in-the-eye gel forming polymer system that will be used as an artificial tear solution for dry eye treatment or as a drug delivery system to improve bioavailability. Method: This new ophthalmic gel system is based on the natural polysaccharide, hydroxypropyl guar, that has the unique characteristic of forming reversible crosslinks with tetravalent borate ions contained in the formulation at a pH above 7.0. Viscosity profiles were measured as a function of HP-Guar and borate ions concentration at various pHs and ionic strengths. Results: The HP Guar/borate polymer system exhibits a very strong viscosity change from a fluid to a gel in a narrow pH range from 7 to 9 (typically ranging from 10cp up to 10,000 cp). The gel point decreases with increases in concentration of polymer (from 0.25% to 0.75%) or increases in borate concentration (from 0.1% to 1.0%). The gel point additionally decreases with the inclusion of various monovalent and divalent salts (ion sensitivity). Conclusion: This novel polymeric system can be incorporated in an artificial tear solution that is a free flowing liquid at neutral pH such that upon insertion into the eye a soft, comfortable gel is formed due to the slight increase in pH caused by the tear fluid. These types of polymer systems have the potential for increased ocular retention and superior lubrication properties which will lead to better efficacy because they more closely resemble the natural mucins found in the precorneal tear film.
This PDF is available to Subscribers Only