Fabrication, in vitro degradation and the release behaviours of poly(dl-lactide-co-glycolide) nanospheres containing ascorbic acid

Ascorbic acid (vitamin C) is essential for preserving optimal health and is used by the body for many purposes. The problem is that ascorbic acid easily decomposes into biologically inactive compounds making its use very limited in the field of pharmaceuticals, dermatological and cosmetics. By encapsulating the ascorbic acid into a polymer matrix it is assumed that its chemical instability can be overcome as well as higher, more efficient and equally distributed concentration throughout extended period of time can be achieved. This paper is describing the process of obtaining poly(dl-lactide-co-glycolide) (DLPLG) nanospheres (110-170 nm) using chemical method with solvent/non-solvent systems where obtained solutions have been centrifuged. The encapsulation of the ascorbic acid in the polymer matrix is performed by homogenisation of water and organic phases. Nanoparticles of the copolymer DLPLG with the different contents of the ascorbic acid have different morphological characteristics, i.e. variable degree of uniformity, agglomeration, sizes and spherical shaping. The degradation of the nanospheres of DLPLG, DLPLG/ascorbic acid nanoparticles and release rate of the ascorbic acid were studied for 8 weeks in a physiological solution (0.9% sodium chloride in water). The samples have been characterised by infrared spectroscopy (IR), scanning electron microscopy (SEM), stereological analysis and ultraviolet (UV) spectroscopy.