Albumin Levels in Tear Film Modulate the Bioavailability of Medically-Relevant Topical Drugs

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Moody, Leah
Mochel, Jonathan
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Mochel, Jonathan
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Biomedical Sciences

The Department of Biomedical Sciences aims to provide knowledge of anatomy and physiology in order to understand the mechanisms and treatment of animal diseases. Additionally, it seeks to teach the understanding of drug-action for rational drug-therapy, as well as toxicology, pharmacodynamics, and clinical drug administration.

The Department of Biomedical Sciences was formed in 1999 as a merger of the Department of Veterinary Anatomy and the Department of Veterinary Physiology and Pharmacology.

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  • College of Veterinary Medicine (parent college)
  • Department of Veterinary Anatomy (predecessor, 1997)
  • Department of Veterinary Physiology and Pharmacology (predecessor, 1997)

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Veterinary Clinical Sciences
The mission of the Veterinary Clinical Sciences Department and the Veterinary Medical Center is to be strong academically, to provide outstanding services, and to conduct research in the multiple areas of Veterinary Clinical Sciences. Our goals are to teach students in the multiple disciplines of Veterinary Clinical Sciences, to provide excellent veterinary services to clients, and to generate and disseminate new knowledge in the areas of Veterinary Clinical Sciences. Our objectives are to provide a curriculum in the various aspects of Veterinary Clinical Sciences which ensures students acquire the skills and knowledge to be successful in their chosen careers. We also strive to maintain a caseload of sufficient size and diversity which insures a broad clinical experience for students, residents, and faculty. In addition, we aim to provide clinical veterinary services of the highest standards to animal owners and to referring veterinarians. And finally, we strive to provide an environment and opportunities which foster and encourage the generation and dissemination of new knowledge in many of the disciplines of Veterinary Clinical Sciences.
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Veterinary Diagnostic and Production Animal Medicine
The mission of VDPAM is to educate current and future food animal veterinarians, population medicine scientists and stakeholders by increasing our understanding of issues that impact the health, productivity and well-being of food and fiber producing animals; developing innovative solutions for animal health and food safety; and providing the highest quality, most comprehensive clinical practice and diagnostic services. Our department is made up of highly trained specialists who span a wide range of veterinary disciplines and species interests. We have faculty of all ranks with expertise in diagnostics, medicine, surgery, pathology, microbiology, epidemiology, public health, and production medicine. Most have earned certification from specialty boards. Dozens of additional scientists and laboratory technicians support the research and service components of our department.
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Biomedical SciencesVeterinary Clinical SciencesVeterinary Diagnostic and Production Animal Medicine

The breakdown of blood-tear barrier that occurs with ocular pathology allows for large amounts of albumin to leak into the tear fluid. This process likely represents an important restriction to drug absorption in ophthalmology, as only the unbound drug is transported across the ocular tissue barriers to exert its pharmacologic effect. We aimed to investigate the effects of albumin levels in tears on the bioavailability of two commonly used ophthalmic drugs: tropicamide, an antimuscarinic that produces mydriasis and cycloplegia, and latanoprost, a PGF2α analog used for the treatment of glaucoma. Eight female beagle dogs underwent a randomized, vehicle-controlled crossover trial. For each dog, one eye received 30 µl of artificial tears (control) or canine albumin (0.4 or 1.5%) at random, immediately followed by 30 µl of 1% tropicamide (2 days, 24 h washout) or 0.005% latanoprost (2 days, 72 h washout) in both eyes. Pupil diameter (digital caliper) and intraocular pressure (IOP; rebound tonometry) were recorded at various times following drug administration (0 to 480 min) and compared between both groups with a mixed model for repeated measures. Albumin in tears had a significant impact on pupillary diameter for both tropicamide (P ≤ 0.001) and latanoprost (P ≤ 0.047), with no differences noted between 0.4% and 1.5% concentrations. Reduction in the maximal effect (pupil size) and overall drug exposure (area under the effect time-curve of pupil size over time) were significant for tropicamide (6.2–8.5% on average, P ≤ 0.006) but not for latanoprost (P ≥ 0.663). The IOP, only measured in eyes receiving latanoprost, was not significantly impacted by the addition of either 0.4% (P = 0.242) or 1.5% albumin (P = 0.879). Albumin in tear film, previously shown to leak from the conjunctival vasculature in diseased eyes, may bind to topically administered drugs and reduces their intraocular penetration and bioavailability. Further investigations in clinical patients and other commonly used ophthalmic medications are warranted.


This article is published as Sebbag, Lionel, Leah M. Moody, and Jonathan P. Mochel. "Albumin Levels in Tear Film Modulate the Bioavailability of Medically-Relevant Topical Drugs." Frontiers in Pharmacology 10 (2020): 1560. DOI: 10.3389/fphar.2019.01560. Posted with permission.

Wed Jan 01 00:00:00 UTC 2020