Formulation, Evaluation, and Antimicrobial Efficacy of a Polyherbal Hand Sanitizer Gel Utilizing Aloe barbadensis Miller, Azadirachta indica, and Ocimum sanctum

Abstract

Background: Frequent use of conventional alcohol-based hand sanitizers often triggers adverse dermatological effects such as skin barrier disruption, contact dermatitis, and severe dryness. Integrating medicinal plant extracts offers a viable path to mitigate these side effects while preserving broad-spectrum antimicrobial action.

Objectives: The objective of this study was to formulate a stable polyherbal hand sanitizer gel using Aloe vera (gel), Neem, and Tulsi (leaf extracts) combined with 70% w/w isopropyl alcohol (IPA), and evaluate its physicochemical attributes, skin tolerability, and antimicrobial performance.
Methods: Neem and Tulsi extracts were prepared via cold maceration using 50% aqueous ethanol. A 1% w/w Carbopol 940 gel base was hydrated and neutralized using Triethanolamine. Physicochemical features, viscosity, spreadability, drying time, and accelerated stability (over 30 days at 25°C, 40°C, and 60°C) were comprehensively evaluated. Antimicrobial efficacy was verified against Staphylococcus aureus and Escherichia coli via the agar well diffusion method. Skin safety was monitored using a standard patch test on human volunteers.
Results: The developed formulation was a smooth, homogeneous, clear pale-yellow gel with a pleasant minty aroma, a physiological skin-compatible pH range of 6.8–7.2, and an optimal viscosity of 4800–5200 cP. It demonstrated a rapid skin drying time of 15–20 seconds and produced zero irritation, erythema, or edema during patch testing. Agar diffusion assays revealed significant zones of inhibition (ZOI) against S. aureus (~18 mm) and E. coli (~16 mm), which closely parallel standard 70% IPA controls. The formulation maintained structural integrity across 30 days of ambient and accelerated stability testing.
Conclusion: The polyherbal hand sanitizer gel effectively balances potent broad-spectrum antimicrobial performance with enhanced dermoprotective benefits, establishing a highly acceptable, green pharmacy alternative for healthcare and domestic sanitation.