Encapsulation devices for Vitamin C

Abstract

Vitamin C, also known as ascorbic acid, is a very important water-soluble vitamin. It is essential for preserving optimal health and it is used by the body for many purposes. Vitamin C promotes collagen biosynthesis, provides photoprotection, causes melanin reduction, enhances the immunity (anti-virus effect), etc. Vitamin C is a highly effective antioxidant. Even in small amounts vitamin C can protect indispensable molecules in the body, such as proteins, lipids (fats), carbohydrates, and nucleic acids (DNA and RNA) from damage by free radicals and reactive oxygen species that can be generated during normal metabolism as well as through exposure to toxins and pollutants (e.g. smoking). Vitamin C may be involved in the reduction of the risk of certain types of cancer. A number of in vitro and in vivo experiments have been performed in order to evaluate the ability of ascorbic acid to prevent the adverse effects, increase the effects of, and decrease resistance to chemotherapeutic agents. The problem is that ascorbic acid is very unstable to air, light, heat, moisture, metal ions, oxygen, and base, and it easily decomposes into biologically inactive compounds such as 2,3-diketo-L-gulonic acid, oxalic acid, L-threonic acid, L-xylonic acid and L-lyxonic acid. This makes its use very limited in the field of pharmaceuticals, dermatologicals and cosmetics. In order to overcome the chemical instability of the ascorbic acid numerous researches have been staged toward its encapsulation or immobilization. The ascorbic acid introduced in the body in the greater portion is isolated from the body. However, the encapsulated ascorbic acid within, for example, the polymeric matrix should have significantly higher efficiency. The present review attempts to address some important issues related to various methods which are employed to encapsulate ascorbic acid, such as thermal phase separation, melt dispersion, solvent evaporation, spray drying, homogenization of water and organic phases, etc. This review also gives a comparation of the characteristics of ascorbic acid nano and microparticles prepared by different methods. The materials in which ascorbic acid can be successfully encapsulated are poly (DL-lactide-co-glycolide), tripolyphosphate cross-linked chitosan, liposomes, maltodextrin, dendrimers, etc. Encapsulation efficiency, release rate, size distribution of particles with encapsulated ascorbic acid, are some of the parameters which are used for evaluating encapsulation system characteristics. © 2009 by Nova Science Publishers, Inc.