Diabetic retinopathy is the most common complication in diabetic patients relates to high expression of VEGF and microaneurysms. Scutellarin (Scu) turned out to be effective against diabetes related vascular endothelial cell dysfunction. However, its clinical applications have been limited by its low bioavailability. In this study, we formulated and characterized a novel intestinal target nanoparticle carrier based on amphiphilic chitosan derivatives (Chit-DC-VB12) loaded with scutellarin to enhance its bioavailability and then evaluated its therapeutic effect in experimental diabetic retinopathy model. Chit-DC-VB12 nanoparticles showed low toxicity toward the human colon adenocarcinoma (Caco-2) cells and zebra fish within concentration of 250 μg/ml, owing to good biocompatibility of chitosan. The scutellarin-loaded Chit-DC-VB12 nanoparticles (Chit-DC-VB12-Scu) were then prepared by self-assembly in aqueous solution. Scanning electron microscopy and dynamic light scattering analysis indicated that the Chit-DC-VB12-Scu nanoparticles were spherical particles in the sizes ranging from 150 to 250 nm. The Chit-DC-VB12-Scu nanoparticles exhibited high permeation in Caco-2 cell, indicated it could be beneficial to be absorbed in humans. We also found that Chit-DC-VB12 nanoparticles had a high cellular uptake. Bioavailability studies were performed in Sprague–Dawley rats, which present the area under the curve of scutellarin of Chit-DC-VB12-Scu was two to threefolds greater than that of free scutellarin alone. Further to assess the therapeutic efficacy of diabetic retinopathy, we showed Chit-DC-VB12-Scu down-regulated central retinal artery resistivity index and the expression of angiogenesis proteins (VEGF, VEGFR2, and vWF) of retinas in type II diabetic rats. Chit-DC-VB12 nanoparticles loaded with scutellarin have better bioavailability and cellular uptake efficiency than Scu, while Chit-DC-VB12-Scu nanoparticles alleviated the structural disorder of intraretinal neovessels in the retina induced by diabetes, and it also inhibited the retinal neovascularization via down-regulated the expression of angiogenesis proteins. In conclusion, the Chit-DC-VB12 nanoparticles enhanced scutellarin oral delivery efficacy and exhibited potential as small intestinal target promising nano-carriers for treatment of type II diabetes induced-retinopathy.

In the present work, polylactic acid (PLA) microcapsules as novel drug delivery systems were successfully fabricated by one-step processing using an electrospray technique. Curcumin (Cur) was chosen as model drug with satisfactory loading capacity (LC%) and entrapment efficiency (EE%) greater than 95%. By judiciously adjusting spinning solvents, flow rates, polymer and drug concentrations, the monodisperse and spherical structures of Cur/PLA microcapsules observed using scanning electron microscopy (SEM) and optical microscopy were successfully generated with diameter distribution ranging from 3.8 μm to 4.4 μm. The physical-chemical characterization including, FTIR, XRD, TG, and DTA, are explored and in vitro release profiles described by Ritger–Peppas models were also investigated, showing sustained release for 200 h after a burst release in the initial 12 h. The drug-loaded microcapsules showed excellent anti-bacterial activities towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by using both disk diffusion and minimal inhibitory concentration methods. The anti-oxidant performance was also evaluated by using DPPH assays. In vitro cell tests, including Cell Counting Kit-8, hemolysis experiments, and cell adhesion revealed that PLA-based microcapsules had significant biocompatibility and low cytotoxicity. The study showed that the PLA-based electrospray strategy combined with spherical microcapsules has the potential for a broad range of applications in medical fields, especially in drug delivery.