INFLUENCE OF EMULSIFICATION TEMPERATURE IN THE FORMATION OF NANO-EMULSIONS CONTAINING ANDIROBA SEED OIL

TF13

Oliveira, B. R., Oliveira, E. C. V., Rocha-Filho, P.A.

Department of Pharmaceutical Science, Faculty of Pharmaceutical Sciences of  Ribeirão Preto, University of  São Paulo, Brazil.

Purpose: To determine the influence of emulsification temperature in the formation of nano-emulsions by low energy method in the system containing Andiroba seed oil (Carapa guianensis), PEG-40 castor oil and sorbitan monooleate.Methods: Emulsions were yielded by low energy emulsification method. Blends of surfactants PEG-40 castor oil 3.85% (w/w) and sorbitan monooleate 1.50 % (w/w) were dissolved in the oil phase (andiroba seed oil 15% w/w). Oil and aqueous phases were separately heated to the temperatures: 25, 35, 45, 55, 65, 75, and 85^oC. Water phase (80.0 % w/w) was slowly added into oil phase. The mixer seed was set at 600 rpm by 20 minutes. After 24 hours emulsions were submitted to macro and microscopic analyses and droplet size were measured by photon correlation spectroscopy using Coulter Delsa 440 SX. Those analyses were repeated after 15 days. Results. After 24 hours the emulsions prepared at 25^oC showed creaming and light phase separation, and mean droplet size of 1800±155 nm. Emulsions prepared at 35 and 45^oC showed milky aspect, multiple globules, mean droplet size of 918±84 nm and 1990±255 nm respectively, wile those prepared at 55 to 75^oC, presented macroscopic characteristics of nano-emulsions such as bluish reflection and low viscosity. In microscopic analyze these emulsions showed small and uniform droplets with mean around of 264±32, 262±29, and 272±30 nm respectively. Emulsion prepared at 85^oC presented the same characteristics, but demonstrated instability (flocculation) in microscopic analyses, the mean droplet size was 237±45 nm. After 15 days at room temperature (25^oC) there was a not significant change in the droplet sizes, but macroscopically it was observed creaming in emulsions prepared at 35 and 45^oC, and phase separation in that prepared at 25^oC. Conclusions. Due to obtained results in can be concluded that temperature of emulsification plays an important hole in the shape and size of droplets, considering that there is an optimum temperature to the formation of nano-emulsions in the studied system.