Optimization of Copaiba oil-based nanoemulsions obtained by different preparation methods

Copaiba oil has been widely used in popular medicine because of its anti-inflammatory properties. The oil is extracted from trees of the genus Copaifera, found mainly in the Brazilian Amazon. A study was conducted using a 2(IV)(4-1) fractional factorial design to evaluate the effects of oil core and surfactants composition on physicochemical properties of nanoemulsions produced by high-pressure homogenization and spontaneous emulsification. Also, the stability of the formulations stored at 4 degrees C and 25 degrees C was monitored for 90 days. The high-pressure homogenization method proved to be the most efficient technique to obtain stable Copaiba oil nanoemulsions with reduced loss of volatile fraction within 90 days of storage at the recommended temperature (4 degrees C). The most suitable nanoemulsion composition was achieved adding 20% Copaiba oil, 10% medium chain triglycerides, 3% Span 80(R) and 1% Tween 20(R). The use of medium chain triglycerides was shown to be a good strategy to fix volatile fractions of Copaiba oil incorporated into nanoemulsions during preparation and storage. (C) 2014 Elsevier B.V. All rights reserved.