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Abstract #13182 Published in IGR 7-3
Efficacy and systemic side-effects of topical 0.5% timolol aqueous solution and 0.1% timolol hydrogel
Uusitalo H; Nino J; Tahvanainen K; Turjanmaa V; Ropo A; Tuominen J; Kahonen MActa Ophthalmologica Scandinavica 2005; 83: 723-728
PURPOSE: The objective of this randomized, double-blind, controlled crossover trial was to compare 0.1% timolol hydrogel formulation eyedrops with 0.5% timolol aqueous solution in terms of systemic effects, hypotensive efficacy and pharmacodynamics. METHODS: Twenty-four healthy subjects underwent careful ocular, cardiovascular and pulmonary function evaluation before and after 2 weeks of topical treatment with 0.1% timolol hydrogel or 0.5% aqueous timolol maleate. Intraocular pressure (IOP), heart rate, blood pressure, forced expiratory volume and plasma levels of timolol were measured. RESULTS: There was a statistically significant difference in the systemic absorption of timolol between these two ophthalmic timolol solutions. The peak concentration and mean area under the plasma drug concentration-time curve (AUC) were about 10-fold higher after 0.5% timolol aqueous solution. The mean peak heart rate during exercise was reduced by 19 bpm (SD 6.4 bpm) after 0.5% timolol aqueous solution and by only 4.6 bpm (SD 3.8 bpm) after 0.1% timolol hydrogel (p < 0.0001). There was no difference between the two formulations in efficacy in reducing IOP. No differences between treatments were found in respect of pulmonary function. CONCLUSIONS: The lower timolol concentration in the hydrogel vehicle and its better bioavailability resulted in reduced systemic absorption and side-effects without loss of efficacy.
Dr. H. Uusitalo, Department of Ophthalmology, Tampere University Hospital, Tampere, Finland. hannu.uusitalo@uku.fi
Classification:
11.3.4 Betablocker (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
