title: Sodium hyaluronate 0.25% used as a vehicle increases the bioavailability of topically administered gentamicin.
abstract: Sodium hyaluronate (SH) solutions have a longer precorneal residence time than isotonic saline solution in rabbits and in humans. The present study investigates the effect of a 0.25% SH vehicle, compared with a phosphate buffer solution (PBS), on the tear concentration after topical administration of gentamicin sulfate (GS) in humans. Eight volunteers received 25 microliters 0.5% GS in PBS in the left eye and 25 microliters 0.5% GS in 0.25% SH in the right eye. Tear samples of 1 microliters were taken from the inferior sulcus using a capillary before instillation and 5, 10, 20, and 40 min after instillation. The tear concentration of GS was determined by radioimmunoassay. There was a statistically significantly higher concentration of GS in the inferior conjunctival sulcus of the SH-instilled eye at 5 min (P < 0.01) and at 10 min (P < 0.05) after instillation (paired t-test, n = 9). At 20 min the concentration of GS in the SH-instilled eye was only slightly higher, and at 40 min GS concentrations in left and right eyes were comparable. SH 0.25% used as a vehicle therefore increases the availability of GS at the ocular surface for at least 10 min. This effect could be due to the prolonged precorneal residence time of SH.
authors: Department of Pharmaceutical Technology, University of Geneva, Switzerland.
authors: S F
authors: SF
authors: Bernatchez
authors: C
authors: C
authors: Tabatabay
authors: R
authors: R
authors: Gurny
mesh_terms: D000287:Administration, Topical; D000328:Adult; D001682:Biological Availability; D004337:Drug Carriers; D005839:Gentamicins / Q000493:pharmacokinetics*; D006801:Humans; D006820:Hyaluronic Acid; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D011863:Radioimmunoassay; D013666:Tears / Q000378:metabolism*
chemical_list: D004337:Drug Carriers; D005839:Gentamicins; D009883:Ophthalmic Solutions; D006820:Hyaluronic Acid