Precorneal retention time of ocular lubricants measured with fluorophotometry in healthy dogs

Abstract

Objective: Determine the precorneal retention time of five different ocular lubricants commonly used in dogs.Animals Studied: Six healthy Beagle dogs (n = 12 eyes).Procedures: Five ocular lubricants were studied: Artificial Tears Solution® (1.4% polyvinyl alcohol), I-Drop® Vet Plus (0.25% hyaluronate), Optixcare® Eye Lube Plus (0.25% hyaluronate), Systane® Ultra (0.4% polyethylene glycol 400 and 0.3% propylene glycol), and Artificial Tears Ointment® (mineral oil/white petrolatum).Each lubricant was mixed with 10% sodium fluorescein to achieve 1% fluorescein formulations. Following topical administration of 35 mg in each eye, tear fluid was collected with capillary tubes at selected times (0, 1, 5, 10, 20, 30, 40, 50, 60, 90, 120, 180 min) and fluorescein concentrations were measured with a computerized scanning ocular fluorophotometer. Results: Tear fluorescence was significantly greater with Artificial Tears Ointment® compared with other lubricant formulations from 1 to 20 min postadministration. Median (range) precorneal retention times were significantly different among the 5 lubricants, ranging from 40 minutes (20-90 min) for Artificial Tears Ointment®, 35 min (20-90 min) for Systane® Ultra, 30 min (10-60 min) for I-Drop® Vet Plus, 25 min (10-60 min) for Optixcare® Eye Lube Plus, and 10 min (10-20 min) for Artificial Tears Solution®. Precorneal retention time was significantly lower for Artificial Tears Solution® compared with the other 4 formulations. Conclusions: This study established normative data for the retention time of common lubricants on the ocular surface of dogs, which may be used to guide clinicians with their choice of lubricant and frequency of administration.

Evaluation of a preservative-free, cross-linked sodium hyaluronate-based solution, Lacri +®, in dogs with dry eye: a pilot trial

“…One limitation of the trial is the possible influence of the product application on the STT values. In a recent article [ 10 ], published after the completion of our trial, the authors found that the precorneal retention time of 5 ocular lubricants ranged between 10 and 90 min, substantiating that the 2-h delay in the protocol could be relevant. A specific study to measure the residence time of the tested product would be of interest to confirm this hypothesis.…”

Increased drug concentration and repeated eye drop administration as strategies to optimize topical drug delivery: A fluorophotometric study in healthy dogs

“…Precorneal retention time was defined as the time (in min) that fluorescence of the tear film sample decreased below 5% of the baseline value. 9 Following the linear-log trapezoidal rule, the R software (version 3.6.0) was used to calculate the area under the concentration-time curves from 0 to 180 min (AUC 0-180 ) for each fluorescein concentration (0.3% or 1%) in the control experiment (single eye drop) and each of the five trials, that is, repeated eye drop administration at 30-s, 1-, 2-, 5-, and 10-min interval. The normality of the data was assessed with the Shapiro-Wilk test.…”