title: Triamterene measurements in the aqueous humor of rabbits.
abstract: The kinetics of topical triamterene penetration were estimated from the time-course measurements of triamterene (in Dyazide) concentrations in the anterior chamber of six rabbits (n=12, left and right eyes). The two-compartment model of Jones and Maurice (1) was fitted to the measurements. We found the apparent elimination rate constant oftriamterene A = 0.33 +/- 0.12 hr(-1), the apparent absorption rate constant of triamterene B = 2.68 +/- 0.55 hr(-1), the cornea-aqueous transfer coefficient in reference to the corneal volume of triamterene kc.ca = 0.28 +/- 0.05 hr(-1), the loss coefficient of triamterene from the anterior chamber ko = 0.43 +/- 0.16 hr(-1) and the amount of triamterene in the cornea at time zero Mo = 483 +/- 125 ng/ml. The mean of ko = 0.43 hr(-1) is significantly lower (p = 0.04% using ZTEST) than the lower limit of aqueous loss coefficient = 0.58 hr(-1) usually found in rabbits (2). We conclude that Dyazide lowers the aqueous flow rate in the positive direction, considering glaucoma treatment. Peak triamterene concentration in the anterior chamber was P = 120 +/- 32 ng/ml. Half-life for elimination from the aqueous humor was T1/2 = 1.84 +/- 0.65 hr (Mean +/- SD).
authors.affiliation: School of Physics, Universiti Sains Malaysia, Penang. omer@usm.my
authors.forename: O
authors.initials: O
authors.lastname: Hamid
authors.forename: A A
authors.initials: AA
authors.lastname: Tajuddin
mesh_terms: D000042:Absorption; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism*; D004232:Diuretics / Q000493:pharmacokinetics*; D006207:Half-Life; D011817:Rabbits; D014223:Triamterene / Q000493:pharmacokinetics*
chemical_list: D004232:Diuretics; D014223:Triamterene