Interfacial properties and micellization of triblock poly(ethylene glycol)-poly(ε-caprolactone)-polyethyleneimine copolymers

This study aimed to explore the link between block copolymers’interfacial properties and nanoscale carrier formation and found out the influence of length ratio on these characters to optimize drug delivery system.A library of diblock copolymers of PEG-PCL and triblock copolymers with additional PEI(PEG-PCL-PEI)were synthesized.Subsequently,a systematic isothermal investigation was performed to explore molecular arrangements of copolymers at air/water interface.Then,structural properties and drug encapsulation in self-assembly were investigated with DLS,SLS and TEM.We found the additional hydrogen bond in the PEG-PCL-PEI contributes to film stability upon the hydrophobic interaction compared with PEG-PCL.PEG-PCL-PEI assemble into smaller micelle-like(such as PEGPCL4006-PEI)or particle-like structure(such as PEG-PCL8636-PEI)determined by their hydrophilic and hydrophobic block ratio.The distinct structural architectures of copolymer are consistent between interface and self-assembly.Despite the disparity of constituent ratio,we discovered the arrangement of both chains guarantees balanced hydrophilic-hydrophobic ratio in self-assembly to form stable construction.Meanwhile,the structural differences were found to have significant influence on model drugs incorporation including docetaxel and siRNA.Taken together,these findings indicate the correlation between molecular arrangement and self-assembly and inspire us to tune block compositions to achieve desired nanostructure and drug loading.

Preparation and characterization of drop pills of effective part from safflower for anti-Parkinson's disease

Parkinson’s disease(PD) is a common degenerative disease of the central nervous system, and the pathologic features are mainly degeneration of substantianigra and dopamine neurons. Studies have shown that safflower flavonoid extract(SAFE) exhibits the neuroprotective effect. In this study, the safflower flavonoid extract drop pills(SAFE-DPs) for anti-PD were prepared by the heating and melting method using SAFE and matrix PEG6000. The performances of the pills were evaluated with powder X-ray diffraction(PXRD), differential scanning calorimetry(DSC), Fourier transform infrared spectroscopy(FT-IR), scanning electron microscopy(SEM) and dissolution testing. The analysis results demonstrated an amorphous state for SAFE dispersion in the matrix PEG6000 without any chemical reaction. The SAFE-DPs demonstrated acceptable chemical and physical stability irrespective of the manufacturing process and the storage period. Dissolution testing in three dissolution media(pH 1.0, pH 6.8 and pH 7.5) indicated that SAFE-DPs had excellent dissolution property. The transport of Kaempferol-3-rutinoside(K3 R) on the Caco-2 monolayer and the absorption of K3 R in situ intestinal perfusion revealed that the principal component of SAFE had a good transport and absorption capacity. Therefore, the drop pills had better release and absorption in the gastrointestinal tract, corresponding with the pharmacological and pharmacodynamic results for PD in vivo.