Preparation and characterization of O/W nanoemulsion with eucalyptus essential oil and study of in vitro antibacterial activity

Objective(s): Eucalyptus essential oil is widely used pharmaceutical, medicine and ornamental industries having antimicrobial as well as antioxidant activities. Eucalyptus oil is highly unsteady under ordinary conditions, so simply lose its bactericidal action. To protect this bioactive herbal product, nano-based emulsion technology is an outstanding method to micro-encapsulate and hydrophilize it. Due to special properties, oil-in-water (O/W) essential oil nanoemulsionsare expanding day by day as a delivery system in food, cosmetic and agrochemical industries. This study prepare eucalyptus oil based nanoemulsions, its characterization and in vitro evaluation of its antimicrobial activity. Methods: O/W nanoemulsionswere prepared by using eucalyptus essential oil in the presence of surfactants like tween 20, tween 80 and sodium dodecyl sulphate (SDS). Physiochemical parameters like pH, conductivity, optical density and antibacterial activity were studied. Stability of nanoemulsions was studied for 120 days. Results: Nanoemulsions prepared with tween 20/80 and SDS were smaller in size than those prepared with tween 20/80. Formulated nanoemulsions were stable even after 120 days as no significant change in pH, conductivity, size of droplet was observed. Substantial in vitro antibacterial activity against Bacillus subtilis was observed with nanoemulsions prepared with tween 20 only. Conclusion: The findings suggested that eucalyptus oil based nanoemulsions can be used as key drug carrier in pharmaceutical, food and cosmetic industries.