Ye Qianyu,Ding Meilai,Zhang Ping,Wu Peng,Wang Yong,Selomulya Cordelia,Chen Xiao Dong
Compared to traditional drug release monitoring with manual sampling and testing procedures, low-field nuclear magnetic resonance (LF-NMR) imaging is a one-step, visual, non-destructive, and non-invasive measurement method. Here, we reported the application of LF-NMR to image the morphology, component, sub-diffusion, and spatial distribution of a solid oral formulation, Biyankang tablets, during dissolution in vitro . The drug ingredients with characteristic relaxation times were distinguished and localized based on the signal of standards, such as patchouli oil, Xanthium strumarium extract, and starch. The hydration, swelling, disintegration, and sub-diffusion of tablets in simulated gastric fluids (SGF) were visualized statically. All tablets showed similar expansion (37.4–42.0%) along the direction of thickness at 25 min and reached a full disintegration at 145 min, at pH 1.80–6.15, indicating pH-independent swelling and disintegration. Compared to that static immersion within 20 mL SGF, the tablet disintegration time was shortened by ~ 11% in 30 mL SGF. The application of shear reduced the time by ~ 28%, suggesting a major role of hydrodynamic condition in tablet dissolution. The ability to simultaneously visualize, distinguish, and localize drug ingredients using LF-NMR is expected to provide valuable information to develop drug release monitoring systems in vitro and potentially in vivo using small animal studies. Graphical abstract
Emulsions stabilized by both nanoparticles and surfactants often display longer shelf life than those stabilized by nanoparticles or surfactants alone. Although numerous works have been conducted to understand the effect of nanoparticles and surfactants on the variation of interfacial tension, little is known about interfacial diffusion when both nanoparticles and surfactants are present at interfaces. In this work, we used single-particle fluorescence tracking to study the lateral diffusion of individual hydrophobic nanoparticles at hexane–glycerol interfaces adsorbed by different amounts of nonionic surfactants. When the surfactant concentration is over a threshold, we found that the nanoparticle diffusion exhibits a two-regime behavior involving short-time Brownian and the emergence of subdiffusive, non-Gaussian, and dynamically anticorrelated diffusion in the long lag time regime. A stepwise analysis rationalized diffusion in different lag time regimes, leading to a mechanistic interpretation regarding the two-regime behavior. These results could provide insight into the understanding of the synergistic effect for the surfactant-assistant Pickering emulsion.
危险品化学品经营许可证（带存储）