Development of basil oil nanoemulsions and emulsion filled hydrogels

Abstract

The indiscriminate use of antibiotics has led to the emergence of drug -resistant bacteria which has become one of the biggest challenges of the twenty-first century for the researchers to combat and in turn search for novel targets which could lead to the development of effective and sustainable therapies. Inhibition of virulence of microbial pathogens is an emerging approach to address the challenges related to microbial infections. To suppress the virulence micro organism, we developed stable nanoemulsion filled hydrogel of Basil oil Ocimum basilicum). Basil oil based nanoemulsion were formulated by ultrasonic emulsification method. Increase in surfactant concentration and emulsification time decreased emulsion droplet size but increased viscosity aoptical transparency of emulsion system. Nanometric emulsion droplet size was determined by dynamic light               scattering technique using a particle size analyzer. SEM images confirmed the spherical morphology of emulsion droplets. Basil oil nanoemulsion (BNE -2) exhibited smallest droplet size and greater kinetic stability.  Hence, this BNE-2 formulation was selected for application studies. FormulatedBNE -2 hydrogel was evaluated for bactericidal activity against bacteria and fungi by dose and time dependent killing experiment. Alteration in  membrane permeability was confirmed by quantifying  leakage of 260 nm absorbing substances. Optical microscopic analysis suggested that hydrogel treatment resulted in alteration of permeability and surface features of bacterial cell membrane which lead to lysis and cell death.