Topical administration lowers IOP; effect mediated in part by facilitation of outflow
WEDNESDAY, May 6, 2015 (HealthDay News) — Topical baicalein, a natural flavonoid derived from the root of Scutellaria baicalensis, may transiently lower intraocular pressure (IOP), according to an experimental study presented at the annual meeting of the Association for Research in Vision and Ophthalmology, held from May 3 to 7 in Denver.
Hoi Lam Li, from the Hong Kong Polytechnic University, and colleagues examined whether topical application of baicalein lowers IOP in rodents. Topical baicalein was applied to the treatment eye, and phosphate buffered saline to the fellow eye, of adult C57BL/6J mice. IOP measurements were performed before and after administration of baicalein in light and dark phases. In freshly enucleated mice eyes the outflow facility was determined by measuring the flow rates at sequential pressure steps.
The researchers found that within six hours after drug treatment there was a significant IOP reduction with topical administration of 10 mM baicalein. Under light and dark conditions, the maximum IOP-lowering effect was 1.44 ± 0.25 and 2.16 ± 0.37 mm Hg, respectively (both P < 0.01). In paired mouse eyes, 10 mM baicalein significantly enhanced the outflow facility.
“Topical application of baicalein triggered a transient IOP reduction, although its effect was smaller than that of intraperitoneal injection,” the authors write. “The ocular hypotensive effect was mediated, at least in part, by the facilitation of aqueous outflow. The precise mechanism of action remains to be determined.”
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