Objective Microbial infection has been reported to cause blepharitis, conjunctivitis and keratitis. We evaluated the safety and efficacy of a foam formulation of 2% 4-terpineol (T4O) against common ocular microorganisms.
Material and methods The antimicrobial effect of a 2% T4O formulation was evaluated by the United States Pharmacopeia 51 (USP <51>) antimicrobial effectiveness test for 14 and 28 days, as well as by a Time Kill Study (ASTM E2315) with a 60 s exposure time. Its potential of causing skin and ocular irritation was evaluated by the Repeated Insult Patch Test and the Hen’s Egg Chorioallantoic Membrane Test, respectively.
Results and discussion It was seen that 2% T4O formulation did not cause ocular irritation, skin irritation, sensitisation or allergic contact dermatitis in human subjects. Most importantly, it killed microorganisms listed in USP <51> at both 14 and 28 days and exerted a rapid killing effect within 60 s against 13 bacteria, 1 fungus and Acanthamoeba castellanii.
Conclusion The above finding suggests that 2% T4O formulation is safe and effective in killing microorganisms related to common ocular and skin infective diseases.
Translational relevance Although the clinical efficacy in treating ocular disease was not directly studied; this foam formulation containing 2% T4O, based on the in vitro results of this work, demonstrated that it can potentially be used as a preservative-free cleansing agent for ocular hygiene maintenance due to its ability to exert a broad-spectrum antimicrobial effect without causing ocular or skin irritation.
- eye lids
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Contributors C-WS planned the study, analysed the data to draft manuscript and submitted the study. ST assisted in data analysis and manuscript drafting. HS and AMSC conducted manuscript review. SCGT oversaw the entire study, provided guidance and conducted final manuscript review.
Funding This work is supported by grants from National Institutes of Health, National Eye Institute, Bethesda, MD R43EY019586 (to SCGT), and TissueTech, Inc. and Ocular Surface Center, Miami, FL (contract grant sponsor).
Competing interests SCGT is an inventor, shareholder and employee of TissueTech, Inc. He has filed two patents for the use of tea tree oil and its ingredients for treating demodecosis. No other authors have any proprietary interest in any material in this study.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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