Progress of stimulus responsive nanosystems for targeting treatment of bacterial infectious diseases.

In recent decades, due to insufficient concentration at the lesion site, low bioavailability and increasingly serious resistance, antibiotics have become less and less dominant in the treatment of bacterial infectious diseases. It promotes the development of efficient drug delivery systems, and is expected to achieve high absorption, targeted drug release and satisfactory therapy effects. A variety of endogenous stimulation-responsive nanosystems have been constructed by using special infection microenvironments (pH, enzymes, temperature, etc.). In this review, we firstly provide an extensive review of the current research progress in antibiotic treatment dilemmas and drug delivery systems. Then, the mechanism of microenvironment characteristics of bacterial infected lesions was elucidated to provide a strong theoretical basis for bacteria-targeting nanosystems design. In particular, the discussion focuses on the design principles of single-stimulus and dual-stimulus responsive nanosystems, as well as the use of endogenous stimulus-responsive nanosystems to deliver antimicrobial agents to target locations for combating bacterial infectious diseases. Finally, the challenges and prospects of endogenous stimulus-responsive nanosystems were summarized.

Preparation and Evaluation of Valnemulin Hydrochloride Taste-Masking Granules.

BACKGROUND: The bitter taste and strong irritation of valnemulin hydrochloride limit its wide clinical application in pigs by oral. METHOD: In order to improve its palatability and residence time in the body, the valnemulin hydrochloride taste-masking granules with sustained-release were prepared by combining solid dispersion based on fatty acid with wet granulation. The formulation was screened by orthogonal test with content, yield, grain size and angle of repose as evaluation indexes. RESULT: The results showed that the optimal granules were composed of corn starch, sucrose, citric acid, valnemulin hydrochloride and myristic acid at a ratio of 40: 20: 20: 11: 19. The daily feed intake of pigs in the optimum taste-masking granule groups was similar to that of its self-control, and significantly higher than that in the valnemulin hydrochloride active ingredient group, suggesting that the optimum granules have satisfactory palatability. The prepared granules improved the oral bioavailability of valnemulin hydrochloride by 3.04 folds and extended its mean residence time (MRT) by 2.33 folds. CONCLUSION: The granules developed in this study could obviously improve the palatability and sustained release of valnemulin hydrochloride. The producing method of granules by combining solid dispersion powder with wet granulation can provide ideas for other drugs with poor palatability and a short half-life.

Improvement of Colonic Immune Function with Soy Isoflavones in High-Fat Diet-Induced Obese Rats.

Background: The damage to intestinal barrier function plays an important role in the development of obesity and associated diseases. Soy isoflavones are effective natural active components for controlling obesity and reducing the level of blood lipid. Here, we explored whether these effects of soy isoflavones were associated with the intestinal barrier function. Methods and Results: The obese rat models were established by high fat diet feeding. Then, those obese rats were supplemented with soy isoflavones at different doses for 4 weeks. Our results showed that obesity induced the expressions of pro-inflammatory cytokines, decreased the anti-inflammatory cytokine (IL-10) expression, elevated intestinal permeability, altered gut microbiota and exacerbated oxidative damages in colon. The administration of soy isoflavones reversed these changes in obese rats, presenting as the improvement of intestinal immune function and permeability, attenuation of oxidative damage, increase in the fraction of beneficial bacteria producing short-chain fatty acids and short-chain fatty acid production, and reduction in harmful bacteria. Furthermore, soy isoflavones blocked the expressions of TLR4 and NF-κB in the colons of the obese rats. Conclusions: Soy isoflavones could improve obesity through the attenuation of intestinal oxidative stress, recovery of immune and mucosal barrier, as well as re-balance of intestinal gut microbiota.