Comparative in vitro efficacy of ivermectin, lotilaner, lime sulfur, tea tree oil, and lemongrass oil against Demodex folliculorum.

Abstract

Aim: Excessive proliferation ofDemodex folliculorumhas been implicated in blepharitis and other inflammatory ocular conditions. Given the growing interest in safer and more effective alternatives to current treatments, this study aimed to evaluate and compare the in vitro acaricidal efficacy of lemongrass oil, tea tree oil (TTO), ivermectin 1%, lotilaner ophthalmic solution 0.25% (Xdemvy), lime sulfur, and olive oil (used as a negative control) againstDemodex folliculorum.

Materials and methods: Adult Demodex folliculorum mites were isolated from eyelash samples of blepharitis patients. Lashes were epilated under slit-lamp guidance using sterile forceps. The most motile mite per slide was selected and placed under a digital light microscope (40 × ) with 20 μL of each test agent. Mite viability was recorded in real time; death was defined as the cessation of all movement for 60 s despite mechanical stimulation. Ten mites were tested per group. Survival time data were statistically analyzed.

Results: Lotilaner 0.25 % exhibited the shortest median survival time (12.0 min), followed by ivermectin 1 % (14.0 min), lemongrass oil (14.5 min), lime sulfur (22.0 min), and TTO 5 % (27.0 min). Olive oil showed minimal acaricidal activity (median: 360.0 min). Lemongrass oil achieved the fastest complete kill time, while lotilaner demonstrated the lowest median survival time.

Conclusion: Lotilaner ophthalmic solution 0.25% demonstrated the shortest median survival time, followed closely by ivermectin 1% and lemongrass oil. While lemongrass achieved complete mite mortality most rapidly, lotilaner was most consistent in reducing survival time. These in vitro findings suggest that both pharmaceutical and natural agents may possess promising acaricidal activity. Further in vivo studies are warranted to confirm these findings and explore safety and clinical applicability.