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Abstract #22885 Published in IGR 11-1
Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in aqueous humor
Volotinen M; Maenpaa J; Kautiainen H; Tolonen A; Uusitalo J; Ropo A; Vapaatalo H; Aine EEuropean Journal of Pharmaceutical Sciences 2009; 36:-3 292-296
Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare aqueous humor timolol concentrations after administration of 0.1% hydrogel and aqueous 0.5% timolol in patients scheduled for a cataract operation. The concentration in the aqueous humor was 210 ±175 ng/ml (mean (± S.D.) 2 h after administration of timolol 0.1% hydrogel and 538 ±304 ng/ml after aqueous 0.5% timolol. In the aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the aqueous humor. β(1)-receptors and β(2)-receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the aqueous humor. Only a weak correlation was seen between corneal thickness and the aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. In conclusion, in contrast to the conventional aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the aqueous humor.
Dr. E. Aine, Tampere University Hospital, Department of Eye, Ear and Oral Diseases, Tampere, Finland. Esko.aine@pshp.fi
Classification:
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
