Microemulsions of Rosmarinus officinalis (Rosemary) Leaf Oil
Beata W. Domagalska, Tatiana Dworieckaja
ydział Kosmetologii, Wyższa Szkoła Zawodowa Kosmetyki i Pielęgnacji Zdrowia w Warszawie
Introduction. Rosemary essential oil (OR) shows bactericidal, insecticidal, antifungal, antioxidant and antiproliferative activity. However, because of hydrophobic character of its constituents, OR utility in water-based products may pose a challenge and is possible by use of surfactants and micellar solubilization.
Aim. The aim of this study was to obtain a water-dilutable microemulsion concentrate with OR.
Materials and methods. The materials used in this study were natural OR, surfactants (Polysorbate 80 (P80), Polysorbate 20) and cosurfactants (Isopropanol (IP), Propylene Glycol). The aqueous-phase titration method with visual evaluation was used for the preparation of all microemulsion systems. The Veusz 1.26.1 software was used for the graphic evaluation of Gibbs triangles. For the quantitative evaluation three parameters describing the microemulsion area were determined: extent of microemulsion formation, extent of microemulsion formation with water ≥50% and solubilization efficiency.
Results. The phase diagrams for 10 emulsifier (surfactant:cosurfactant) /OR/water systems were obtained. The effect of the addition and type of cosurfactant on ability of aqueous solutions of two selected surfactants to solubilize OR was confirmed.
Conclusions. It was proposed to use the concentrate containing 72% of P80 and IP mixture (3:1 w/w) and 28% of OR. The concentrate can be diluted with water in the ratio 1:4 maintaining a product transparency. The study results could be useful in production of cosmetic and pharmaceutical preparations.
Key words: rosemary oil, surfactant, micellar solubilization, microemulsion, cosurfactant, phase diagram, microemulsion concentrate