Application site dependent ocular absorption of timolol

A. Urtti, Toshiaki Sendo, J. D. Pipkin, G. Rork, A. J. Repta

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Ocular absorption of timolol in rabbits was studied after topical ocular administration of 3H-timolol in an eyedrop or in silicone cylindrical devices that released timolol at 7.2 μg/h. The devices were applied in either the inferior or superior conjunctival sac. Timolol concentrations were nearly equal in the inferior and superior portions of ocular tissues when the drug was administered in an eyedrop. Administration in the devices resulted in unequal timolol distribution in the cornea, conjunctiva, sclera, and iris-ciliary body. Timolol concentrations were higher in the part of each tissue that was closer to the site of the device application. Unequal concentrations of timolol in the superior and inferior part of the eye and very low timolol concentrations in the aqueous humor indicated that timolol was absorbed mainly via a noncorneal route from the device placed in the inferior conjunctival sac. Induced blinking at one minute intervals did not change ocular absorption of timolol. Compared with inferior conjunctival sac applications, placement of the devices in the superior conjunctival sac resulted in increased corneal and total ocular absorption of timolol as indicated by higher timolol concentrations in the aqueous humor and by a smaller difference between concentrations in the superior and inferior portions of the examined tissues. The application site dependent ocular absorption indicated that controlled release of timolol in the tear fluid did not result in a uniform timolol distribution in the preocular tear fluid of rabbit eyes.

Original languageEnglish
Pages (from-to)335-343
Number of pages9
JournalJournal of Ocular Pharmacology
Volume4
Issue number4
Publication statusPublished - 1988
Externally publishedYes

Fingerprint

Timolol
Lacrimal Apparatus
Equipment and Supplies
Aqueous Humor
Ophthalmic Solutions
Ocular Absorption
Tears
Ophthalmic Administration
Rabbits
Topical Administration
Blinking
Ciliary Body
Sclera
Conjunctiva
Iris
Silicones
Cornea

ASJC Scopus subject areas

  • Ophthalmology
  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Urtti, A., Sendo, T., Pipkin, J. D., Rork, G., & Repta, A. J. (1988). Application site dependent ocular absorption of timolol. Journal of Ocular Pharmacology, 4(4), 335-343.

Application site dependent ocular absorption of timolol. / Urtti, A.; Sendo, Toshiaki; Pipkin, J. D.; Rork, G.; Repta, A. J.

In: Journal of Ocular Pharmacology, Vol. 4, No. 4, 1988, p. 335-343.

Research output: Contribution to journalArticle

Urtti, A, Sendo, T, Pipkin, JD, Rork, G & Repta, AJ 1988, 'Application site dependent ocular absorption of timolol', Journal of Ocular Pharmacology, vol. 4, no. 4, pp. 335-343.
Urtti, A. ; Sendo, Toshiaki ; Pipkin, J. D. ; Rork, G. ; Repta, A. J. / Application site dependent ocular absorption of timolol. In: Journal of Ocular Pharmacology. 1988 ; Vol. 4, No. 4. pp. 335-343.
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