Box–Behnken–Optimized Essential-Oil–Alcohol Hand Rub Shows in-vitro Activity Against SARS-CoV-2, Dengue, Influenza A, Measles, Chikungunya, and Nipah

Abstract Aim: To develop and optimize an alcohol-anchored, essential-oil–augmented hand rub (EO-ABHR) that improves early-contact virucidal performance without compromising regulatory alcohol content. Methods: EO actives (eugenol, terpinen-4-ol, trans-anethole) were prioritized in silico via a standardized Schrödinger pipeline (LigPrep/Epik; Glide SP→XP; Prime MM-GBSA, OPLS4) against six crystallographically validated viral targets (6LU7, 3TRK, 7SKS, 1TG8, 2ZTT, 2VSM). A 3-factor, 3-level Box–Behnken design (17 runs; factors: EO ratio, glycerin, aloe) was applied to an isopropyl-alcohol base to balance MIC, viscosity, spreadability, pH, and evaporation; cytotoxicity (CC₅₀) constrained test ceilings. Results: Docking/MM-GBSA ranked eugenol highest overall (notably at 2ZTT and 1TG8), followed by terpinen-4-ol, with anethole weakest (especially at 2VSM). Response-surface modeling showed an excellent quadratic fit for viscosity (R²=0.9987; R²_adj=0.9958) and an acceptable fit for MIC (R²=0.7146). EO ratio primarily drove MIC, glycerin governed viscosity, and aloe improved spreadability with minimal viscosity penalty. The optimized ABHR met target CQAs (viscosity 1.47–5.09 cP; pH ~5–7; rapid evaporation) and achieved EO MICs of 739–1034 ng·mL⁻¹. In vitro, it produced contact-time–dependent reductions in infectivity across six matched virus–cell systems, modestly outperforming an alcohol-only control within CC₅₀-informed safety bounds. Conclusion: An integrated docking→MM-GBSA→DoE workflow linked EO prioritization to an alcohol-compliant ABHR with broad in-vitro activity. Alcohol remained the dominant virucidal driver, while eugenol/terpinen-4-ol–enriched blends yielded adjunct gains in early-time performance and user-centric attributes, providing a reproducible route to performance-tuned EO-ABHRs.