CHUNG-BUK, Korea—Rosmarinic acid (RA), which is found in many Lamiaceae herbs, is touted for its biological activities such as anti-viral, anti-bacterial, anti-inflammatory and antioxidant, which is stronger than vitamin E’s. But despite its strong antioxidant activity, its use in cosmetics is limited because of the low water solubility, discoloration and chemical instability.
Fortunately, Korean researchers found RA may be stably and efficiently encapsulated into polycaprolactone (PCL), a biodegradable polymer, microspheres (Int J Cosmet Sci. 2010;32(3):185-91). They prepared an RA-loaded PCL microspheres using emulsion solvent evaporation method and characterize them with different surfactants used in the formation process. PCL microspheres were found to be spherical in shape, with zwitterionic surfactant-PCL particles being the smallest size distribution and highest entrapment efficiency of RA. Emulsions containing RA-loaded PCL microspheres showed a better long-term stability of the RA compared with those containing only RA.