Biopolymer-hydrophobic drug fibers and the delivery mechanisms for sustained release applications

Drug release evaluation of Paclitaxel/Poly-L-Lactic acid nanoparticles based on a microfluidic chip

Paclitaxel is a commonly used drug in the medical field because of its strong anticancer effect. However, it may produce relatively severe side effects (i.e., allergic reactions). A major characteristic of paclitaxel is low solubility in water. Special solvents are used for dissolving paclitaxel and preparing the paclitaxel drugs, while the solvents themselves will cause certain effects. Polyoxyethylene castor oil, for example, can cause severe allergic reactions in some people, and the clinical use is limited. In this study, we developed a new Paclitaxel/Poly-L-Lactic Acid (PLLA) nanoparticle drug, which is greatly soluble in water, and carried out in vitro drug sustained release research on it and the original paclitaxel drug. However, because the traditional polymer drug carrier usually uses dialysis bag and thermostatic oscillation system to measure the drug release degree in vitro, the results obtained are greatly different from the actual drug release results in human body. Therefore, this paper adopts the microfluidic chip we previously developed to mimic the human blood vessels microenvironment to study the sustained-release of Paclitaxel/PLLA nanoparticles to make the results closer to the release value in human body. The experimental results showed that compared with the original paclitaxel drug, Paclitaxel/PLLA nanoparticles have a long-sustained release time and a slow drug release, realizing the sustained low-dose release of paclitaxel, a cell cycle-specific anticancer drug, and provided certain reference significance and theoretical basis for the research and development of anticancer drugs.

Antibacterial Porous Coaxial Drug-Carrying Nanofibers for Sustained Drug-Releasing Applications

The phenomenon of drug burst release is the main problem in the field of drug delivery systems, as it means that a good therapeutic effect cannot be acheived. Nanofibers developed by electrospinning technology have large specific surface areas, high porosity, and easily controlled morphology. They are being considered as potential carriers for sustained drug release. In this paper, we obtained polycaprolactone (PCL)/polylactic acid (PLA) core-shell porous drug-carrying nanofibers by using coaxial electrospinning technology and the nonsolvent-induced phase separation method. Roxithromycin (ROX), a kind of antibacterial agent, was encapsulated in the core layer. The morphology, composition, and thermal properties of the resultant nanofibers were characterized by scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). Besides this, the in vitro drug release profile was investigated; it showed that the release rate of the prepared coaxial porous nanofibers with two different pore sizes was 30.10 ± 3.51% and 35.04 ± 1.98% in the first 30 min, and became 92.66 ± 3.13% and 88.94 ± 1.58% after 14 days. Compared with the coaxial nonporous nanofibers and nanofibers prepared by uniaxial electrospinning with or without pores, the prepared coaxial porous nanofibers revealed that the burst release was mitigated and the dissolution rate of the hydrophobic drugs was increased. The further antimicrobial activity demonstrated that the inhibition zone diameter of the coaxial nanofibers with two different pore sizes was 1.70 ± 0.10 cm and 1.73 ± 0.23 cm, exhibiting a good antibacterial effect against Staphylococcus aureus. Therefore, the prepared nanofibers with the coaxial porous structures could serve as promising drug delivery systems.