Evaluation of the sterility and clinical use of a disposable spray cap for ophthalmic medication delivery in equine patients

Objective To evaluate the sterility of a commercially available disposable spray cap in an equine barn environment and assess its clinical use. Methods This pilot study included an ex vivo microbiological study and an in vivo usability study. Ex vivo study: diclofenac 0.1% ophthalmic solution and neomycin-polymyxin B-dexamethasone 0.1% ophthalmic suspension were evaluated using either a traditional dropper or spray cap treatment method. Bottles were stored in an equine veterinary hospital barn and dispensed every 12 hours. Samples collected on day 0 and the final study day were analyzed for microbial contamination with next-generation DNA sequencing. In vivo usability study: client-owned horses were enrolled, and owners administered ophthalmic medications with the spray cap. A client survey evaluated owner satisfaction with the spray cap method. Results Next-generation DNA sequencing detected no microbial contamination in any of the ophthalmic samples. Five horses were enrolled in the in vivo usability study, and 3 horses seemed to tolerate the spray cap very well, with the highest mean score for a horse of 4.9/5. Two horses did not seem to tolerate the spray cap, with the lowest mean score of 2.0/5. Audible spraying sound produced during activation of the device was reported as the biggest problem. Conclusions The spray cap remained sterile in a barn environment and demonstrated favorable clinical use for some horses. Horse tolerance was variable depending on their temperament. Clinical Relevance Disposable spray cap devices may represent a practical alternative for topical ophthalmic medication administration in selected equine patients and may also have applications for other species in veterinary medicine.