Development of a microparticulate system containing Brazilian propolis by-product and gelatine for ascorbic acid delivery: evaluation of intestinal cell viability and radical scavenging activity.

The use of propolis by-product (PBP) microparticles (MP) as delivery systems can be a promising tool to surpass drawbacks related to low stability of ascorbic acid (AA). The objective of this study was to develop and characterize MP prepared with PBP containing AA. The MP was characterized regarding morphology, particle size, polydispersity index (PDI), association efficiency (AE), drug loading (DL), infrared and Raman spectroscopy as well as antioxidant and radical scavenging activity, in vitro release, and cellular studies. MP was shown to be spherical with some agglomeration. Its particle size was 1654 ± 0.210 nm with a PDI of 0.7. The AE and DL were, respectively, 100.30 ± 2.66% and 13.16 ± 0.59. Spectroscopic studies indicated a possible interaction between the PBP and AA. 2,2-Diphenyl-1-picrylhydrazyl (DPPH˙), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) assays demonstrated that the MP containing AA have an excellent antioxidant capacity as well as a considerable scavenging activity against reactive oxygen and nitrogen species. The in vitro release profile showed a slow pattern of drug release of AA from MP. Viability studies with intestinal cells revealed that MP did not present toxicity in Caco-2 and HT29-MTX. Moreover, AA could permeate Caco-2 monolayers and triple co-culture substantially at the end of 8 h, opposite to the MP. Therefore, the proposed MP formulation represents a promising platform for oral delivery of AA with a local effect on intestines.