Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in aqueous humor

Eur J Pharm Sci. 2009 Feb 15;36(2-3):292-6. doi: 10.1016/j.ejps.2008.10.004. Epub 2008 Nov 1.

Abstract

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.) 2h 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. beta(1)-receptors and beta(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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adrenergic beta-Antagonists / administration & dosage
  • Adrenergic beta-Antagonists / metabolism
  • Adrenergic beta-Antagonists / pharmacokinetics
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Aqueous Humor / metabolism*
  • Cornea / anatomy & histology
  • Female
  • Humans
  • Hydrogel, Polyethylene Glycol Dimethacrylate / chemistry*
  • Male
  • Middle Aged
  • Pharmaceutical Vehicles / chemistry*
  • Receptors, Adrenergic, beta / metabolism
  • Tears / drug effects
  • Tears / metabolism
  • Timolol / administration & dosage*
  • Timolol / metabolism
  • Timolol / pharmacokinetics*

Substances

  • Adrenergic beta-Antagonists
  • Pharmaceutical Vehicles
  • Receptors, Adrenergic, beta
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Timolol