Abstract
Purpose: :
We evaluated the relation of corneal damage and ocular penetration of timolol maleate of antiglaucoma fixed combination.
Methods: :
Rabbit corneal cells line (SIRC) were exposed to 3 kinds of antiglaucoma fixed combination drugs, Xalacom (Latanoprost+Timolol Maleate), Duotrav(Travoprost+Timolol Maleate) and Cosopt(Dorzolamide Hydrochloride+Timolol Maleate), for 0-60min, and each 50% cell death time (CDT50) was calculated based on the results the number of survival cells. Also, corneal resistance(CR, Ω) were measured after topically administration of the three antiglaucoma fixed combination drugs at the dosage of three time with 15min-intervals into rabbit eyes, and CR(Ω) and CR (%) were calculated from measured voltage (V) and current(A) according to the following calculating formula.CR (Ω)=voltage(V)/current(A)CR (%) =CR at 10min after administration x 100/CR before administrationIn another study, rabbit aqueous humor concentrations of timolol maleate after single administration(50μl) of the three antiglaucoma fixed combination drugs and 0.5% timolol maleate ophthalmic solution were measured until 240 min using HPLC..
Results: :
CDT50 of Duotrav, Cosopt and Xalacom were 39.2, 9.0 and 4.1, respectively. The value of CR (%) was in order of Duotrav, Cosopt, and Xalacom.Cmax of timolol maleate after administration of Duotrav, Cosopt, Xalacom and 0.5% timolol ophthalmic solution were 3.3±1.3 μg/mL(60min), 2.7±1.4 μg/mL(120min), 1.2±0.6 μg/mL(60min), and 2.5±0.5 μg/mL, respectively.
Conclusions: :
As corneal damage became hard, aqueous humor concentration of timolol after administration shifted to decreased.
Keywords: aqueous • cornea: epithelium • drug toxicity/drug effects