A sustained release system that composed of biodegradable core-sheath nanofibers in 3D hierarchy has been developed through electrospinning of water-inoil precursor emulsion, in which theophylline dissolved in water was labeled as 'aqueous phase' and PLA solution was considered as 'organic phase'. SEM images revealed that the fibers crossed and overlapped with each other, forming a 3D network-like structure. TEM indicated that the drug was well incorporated into PLA nanofibers, forming a core-sheath structure, which represented a reservoir-type delivery system. The fiber scaffolds were further characterized by FTIR, XRD, TGA, and DSC, which proved theophylline was successfully loaded into the fibers in an amorphous form. The release of drug consisted of three sequential stages, in which the release rate decreased successively. The changes on release rate were proved to be related to the drug diffusion and polymer degradation. At nearly 30 days, the drug still released continuously. This was accomplished by the gradually swelling and degradation of PLA. The successful preparation of the 3D core-sheath nanofibers can incorporate a water-soluble drug in a biodegradable polymer, which effectively protected the activity of the drug, inhibited a sudden release and accomplished sustained release.

The aim of this study was to improve the stability of eugenol–casein nanoparticles (EL–CS-NPs) through polyethylene glycol (PEG) modification.

Curcumin possesses beneficial biological functions, namely anti-inflammation and anti-diabetic functions. However, due to its low solubility and crystallinity, its applications are limited. In this work, curcumin was encapsulated in casein micelles in order to form curcumin-casein nanoparticles by ultrasound treatment (5 min). The ultrasound treatment induced the entry of the hydrophobic groups to the inner micelles and the polar sulfydryl groups to the surface of the micelles in order to form compact curcumin-casein nanoparticles of an appropriate size (100–120 nm) for cellular endocytosis. The product exhibited excellent stability during 8 months of cold storage, 6 days at room temperature, and 2 days at body temperature. Advanced in vitro experiments demonstrated that curcumin-casein nanoparticles displayed significantly greater inhibitory activity against the proliferation and proinflammatory cytokines of human fibroblast-like synoviocyte-osteo arthritis (HFLS-OA) cells and HFLS-rheumatoid (RA) cells than native curcumin due to better cellular uptake as a result of the low crystallinity and the appropriate nano-size of the nano-form. The results provide a reference for the use of ultrasound treatment to encapsulate other drug molecules and curcumin-casein nanoparticles as potential treatment for arthritis.

No abstract