advertisement
Abstract #6480 Published in IGR 3-2
Plasma concentration of topically applied betaxolol in elderly glaucoma patients
Vainio-Jylhae E; Vuori ML; Pyykkoe K; Huupponen RJournal of Ocular Pharmacology and Therapeutics 2001; 17: 207-213
The authors' aim was to study the concentration of betaxolol in plasma after its topical ocular use during the normal 12-hour dosing interval. Twenty μl of betaxolol 0.5% solution was applied into both eyes of nine glaucoma patients, and the plasma concentrations of the drug were measured 12 hour thereafter using a radioreceptor assay. The same amount of betaxolol was then applied ocularly, and its concentration in plasma was measured at five, ten, 15, 30 minutes, and one, two, four, and eight hours thereafter. The mean (SD) concentration of betaxolol in plasma 12 hours after the first dose was 0.4 (0.2) ng/ml. After the second dose, the patients showed a biphasic concentration versus time curve, the first peak occurring at eight (four) minutes, and the second peak at 210 (132) minutes; the mean (SD) peak concentrations being 1.1 (0.3) and 2.0 (1.1) ng/ml, respectively. The area under the concentration versus time curve showed a four-fold variation among patients. Topically-applied betaxolol was rapidly absorbed into systemic circulation, and concentrations were detectable even at 12 hours. The interindividual variation in the systemic absorption of betaxolol was large.
Dr. E. Vainio-Jylhae, Department of Ophthalmology, Turku University Hospital, Kiinamyllynkatu 4-8, SF-20520 Turku; Finland
Classification:
11.3.4 Betablocker (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)
