Effect of hydrophilic-lipophilic balance (HLB) value on the virgin coconut oil-based O/W emulsion stability and rheological behaviours

Abstract

The moisturising cream is commonly formulated in an emulsion system either oil-in-water (O/W) or water-in-oil (W/O). Due to instability of the system, it is crucial to ensure emulsions are physically and mechanically stable in the development of topical applications.Virgin coconut oil (VCO) has been proven clinically to possess anti-inflammatory characteristics that could enhance our skin barrier function by suppressing the inflammatory markers in the body. In this study, VCO-based moisturising cream was formulated by mixing various blends of surfactants in different percentages to produced different hydrophilic-lipophilic balance (HLB) values. This study aims to identify the most suitable HLB values to stabilise the VCO-based moisturising cream. We had determined emulsion characterisation such as particle size, thermal stability, rheological behaviours and viscoelasticity properties. The freeze thaw test was conducted to investigate the stability of the emulsion. The assessments were conducted on day 1 and day 35 after the emulsions were formulated. The results of the characterisation and stability tests revealed the surfactant blended with a HLB value of 6.04 the most stable to formulate VCO-based moisturising cream due to its lowest creaming index (2%). Therefore, stable VCO-based moisturising cream was successfully formulated, with a consistent and stable emulsion condition throughout the storage period.