Influence de la formulation d'une emulsion multiple cosmétique sur la libération des actifs encapsulés

Abstract

SynopsisStable multiple emulsions, which contain skin moisturizing factors, including glycolic acid in the internal aqueous phase, have been formulated. Drug incorporation and storage at 4 °C and 50 °C for 30 days do not modify macroscopic and microscopic aspects. The nature of the release mechanism for the active ingredients has been studied in different dilution conditions. Rheological and conductimetric analyses, successively realized in isoosmotic and hypoosmotic conditions, show that the active release appears after dilution by a swelling‐breakdown phenomenon. The release velocity of the water soluble active ingredients can be modulated by a modification of some formulation parameters: it can be decreased by an increase of the lipophilic surfactant concentration, it can also be increased by a hydrophilic surfactant concentration, by osmotic pressure and by a decrease of the internal globule size.