Abstract
Abstract: :
Purpose: A new formulation of timolol with sorbic acid, Timolol-LA (TLA) has been developed which increases its ocular bioavailability (Higashiyama et al, ARVO 1999, S85). In the present study, we desired to evaluate the ocular comfort and systemic bioavailability of TLA in healthy volunteers in comparison to standard timolol maleate ophthalmic solution (TIM). Methods: This study was a randomized, double-masked, active-controlled, crossover evaluation of 0.5% TLA and 0.5% TIM, b.i.d., in 12 normal healthy volunteers. Visits were at Days 0, 1, 2, 4 and 8 in each period, and there was a minimum 7 day interperiod washout. Results: After 8 days of dosing, morning pre-dose values for TLA, 0.09 ng/mL, were 0.11 ng/mL less than with TIM, 0.20 ng/mL (p=0.034). On an individual basis, the highest concentration for TLA was 0.28 ng/mL, and for TIM was 0.69 ng/mL. Detectable timolol concentrations were found in 6 of 12 subjects treated with TLA, and with 7 of 12 subjects treated with TIM. Overall, the ocular and systemic safety profile of TLA was similar to that of TIM. In general, most symptoms were mild in intensity, and no subject discontinued treatment due to ocular discomfort. Both treatments decreased IOP to a similar level. Conclusion: 0.5% TLA was relatively comfortable, with a safety profile consistent with further clinical development, and with a systemic bioavailability similar to that of timolol maleate ophthalmic solution 0.5%.
Keywords: 514 pharmacology • 357 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • 369 cornea: clinical science