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Ocular penetration of oral doxycycline in the horse
Author(s) -
Gilmour Margi A.,
Clarke Cyril R.,
MacAllister Charles G.,
Dedeo Jacqueline M.,
Caudell David L.,
Morton Rebecca J.,
Pugh Martin
Publication year - 2005
Publication title -
veterinary ophthalmology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.594
H-Index - 50
eISSN - 1463-5224
pISSN - 1463-5216
DOI - 10.1111/j.1463-5224.2005.00422.x
Subject(s) - doxycycline , horse , oral administration , aqueous humor , medicine , pharmacokinetics , pharmacology , antibiotics , chemistry , ophthalmology , biology , biochemistry , paleontology
Objective To investigate intraocular penetration of orally administered doxycycline in the normal equine eye and to compare intraocular and serum doxycycline concentrations. Procedures Six mares were administered doxycycline at 10 mg/kg every 12 h by nasogastric tube for 5 days. Blood, aqueous, and vitreous samples were collected on days 1 and 5. All samples were assayed for doxycycline concentrations. Aqueous and vitreous samples were also assayed for protein quantitation. Results Doxycycline was rapidly absorbed after the first dose ( T max value of 1.42 ± 1.28 h); and elimination of doxycycline occurred slowly (median t 1/2 = 10.88 h). Doxycycline could not be detected in the aqueous on days 1 and 5, nor could it be detected in the vitreous on day 1. On day 5, the mean vitreous doxycycline concentration was 0.17 ± 0.04 µg/mL at 2 h after drug administration. Conclusions Repeated oral administration of doxycycline in the horse resulted in steady state serum concentrations of < 1 µg/mL; however, it did not result in appreciable concentrations of drug in the aqueous and vitreous in normal eyes.