Abstract:
This research aimed to fabricate microspheres from gelatin type A (G) blended with Thai silk fibroin (SF) as controlled curcumin release system for in vivo anticancer effect. The microspheres with two weight blending ratios of G80SF50 and G50SF50 were produced by water in oil emulsion technique using Span 80 as an oil-soluble emulsifier. The microspheres were crosslinked by dehydrothermal treatment at 140oC. In this study, the percentage yield of the obtained microspheres with the size of 32-75 µm were heighest, around 46-55 %, and their shape was round with smooth surface. From in vitro enzymatic biodegradation test, the results showed that both microspheres were rapidly degraded in protease XIV solution after incubating for 24 h and the microspheres with high SF content were degraded slower than the ones with low SF content. When the microspheres were used to adsorb curcumin in mixed solvent of ethanol and deionized water at various volume ratios, the result showed that increasing water content in mixed solvent resulted in an increased entrapment efficiency of curcumin, possibly due to water swelling ability of gelatin leading the diffusion of curcumin into the microspheres. In addition, the microspheres containing high content of silk fibroin could entrap more curcumin because of hydrophobic interaction between curcumin and silk fibroin. From the release of curcumin from microspheres in phosphate buffer saline (PBS) solution containing protease XIV, it was found that the release kinetics were governed by diffusion and degradation mechanisms. The release of curcumin from G50SF50 microspheres seemed to be manipulated by both the diffusion and the microspheres degradation mechanisms. On the other hand, the G80SF20 microspheres could release curcumin mainly by the degradation of gelatin. The tumor suppression effect in CaSki-induced tumor in BALB/c-nude mice treated with G50SF50 absorbed curcumim was clearly seen within 21 days after treatment. The effect was possibly explained by the anti-angiogenesis of released curcumin. The result of this study indicated the potential of controlled release of curcumin from the gelatin blended with Thai silk fibroin microspheres for in vivo anticancer activity.