Tear film concentrations of doxycycline following oral administration in ophthalmologically normal dogs.

Gainsville – mechentel news – To determine tear film concentrations of doxycycline in ophthalmologically normal dogs following oral doxycycline administration, the autors performed a crossover study. with 10 privately owned dolichocephalic or mesaticephalic dogs free of ophthalmic disease. Dogs were randomly assigned to receive doxycycline hyclate first at 5 mg/kg (2.3 mg/lb) or 10 mg/kg (4.5 mg/lb), PO, every 12 hours for 5 days, beginning on day 1. Doxycycline was administered 1 hour prior to feeding. Tear samples were collected from days 1 through 10 approximately 3 hours after the morning dose was administered. Following a 3-week washout period, dogs received the alternative dose in the same conditions.Doxycycline concentration in tear samples from 1 eye (same eye used for both sessions) was measured via liquid chromatography-mass spectrometry and compared between the 2 doxycycline doses. Doxycycline was detected in tear samples of all dogs from days 1 through 10 for both doxycycline doses. Median peak doxycycline concentrations for the 5 mg/kg and 10 mg/kg doses were 2.19 ng/mL on day 3 and 4.32 ng/mL on day 4, respectively. Concentrations differed significantly with time, but this difference was not influenced by dose, dose order, or eye. A significant positive correlation was identified between doxycycline concentration and body weight (r = 0.22). Detectable doxycycline concentrations were achieved in the tear film of ophthalmologically normal dogs following oraladministration of doxycycline at 5 or 10 mg/kg, every 12 hours. Dose had no significant effect on tear film concentration of the drug. (pubmed, mm)

Autors: Collins SP, Labelle AL, Dirikolu L, Li Z, Mitchell MA, Hamor RE. Correspondence Ralph E. Hamor DVM, MS, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainsville, FL 32610. Electronic address: hamor@ufl.edu. Study: Tear film concentrations of doxycycline following oral administration in ophthalmologically normal dogs. Source J Am Vet Med Assoc. 2016 Sep 1; 249(5):508-14. doi: 10.2460/javma.249.5.508. Web: http://avmajournals.avma.org/doi/abs/10.2460/javma.249.5.508.