Timolol in aqueous humour after topical administration. A pilot study.

The concentration of timolol in aqueous humour after one single drop of timolol ophthalmic solution was studied in 19 patients. Relatively high concentrations were found (mean: 626 ng/ml), but the individual differences were great (range: 0 ng/ml - 2080 ng/ml). Possible explanations are discussed. No detectable levels of timolol were found in plasma (detection level greater than or equal to 1 ng/ml).