Biomechanical forces and force-triggered drug delivery in tumor neovascularization.

Tumor angiogenesis is one of the typical hallmarks of tumor occurrence and development, and tumor neovascularization also exhibits distinct characteristics from normal blood vessels. As the number of cells and matrix inside the tumor increases, the biomechanical force is enhanced, specifically manifested as solid stress, fluid stress, stiffness, and topology. This mechanical microenvironment also provides shelter for tumors and intensifies angiogenesis, providing oxygen and nutritional support for tumor progression. During tumor development, the biomechanical microenvironment also emerges, which in turn feeds back to regulate the tumor progression, including tumor angiogenesis, and biochemical and biomechanical signals can regulate tumor angiogenesis. Blood vessels possess inherent sensitivity to mechanical stimuli, but compared to the extensive research on biochemical signal regulation, the study of the regulation of tumor neovascularization by biomechanical signals remains relatively scarce. Biomechanical forces can affect the phenotypic characteristics and mechanical signaling pathways of tumor blood vessels, directly regulating angiogenesis. Meanwhile, they can indirectly regulate tumor angiogenesis by causing an imbalance in angiogenesis signals and affecting stromal cell function. Understanding the regulatory mechanism of biomechanical forces in tumor angiogenesis is beneficial for better identifying and even taming the mechanical forces involved in angiogenesis, providing new therapeutic targets for tumor vascular normalization. Therefore, we summarized the composition of biomechanical forces and their direct or indirect regulation of tumor neovascularization. In addition, this review discussed the use of biomechanical forces in combination with anti-angiogenic therapies for the treatment of tumors, and biomechanical forces triggered delivery systems.

Optimization of preparation technology of baicalin lipid nano foam aerosol / 中国药房

OBJECTIVE To optimize the pr eparation technology of the baicalin lipid nano foam aerosol （BC-LN-FA）. METHODS Baicalin lipid nanoparticle （BC-LN）and BC-LN-FA were prepared by the thin film dispersion method and homogeneous emulsification method ，respectively，using baicalin （BC） as the model drug. The preparation technology was optimized by Box-Behnken design-response surface methodology using particle size and encapsulation efficiency （EE）as indexes ，with dosage ， emulsifier dosage ，co-emulsifier dosage and homogenization time as factors. The morphology ，particle size ，polymerdispersity index（PDI），EE，the viscosity ，the foam dissolution rate and in vitro transdermal release of BC-LN-FA were characterized. RESULTS The optimal technology included 25 mg BC ，40 mg emulsifier （mass ratio of stearic acid-soybean lecithin-glycerol was 1∶1∶1），30 mg co-emulsifier （mass ratio of octadecanol-lactic acid was 1∶1），homogenization time of 20 min. Results of 3 times of validation tests showed that particle size of prepared BC-LN-FA was （151.70±2.40）nm，EE was （68.62±1.16）％；the deviation of them from the predicted value （particle size of 150.80 nm，EE of 67.02％）were 0.60％ and 2.39％ respectively. The BC-LN-FA prepared by the optimal process was light yellow opalescence ，uniform in particle size and round-like in shape. The viscosity，the foam dissolution rate ，the content of BC and PDI were （122.92±5.09）mPa·s，（65.32±3.22）％，（7.01±0.12）％ and（0.199±0.006），respectively. At 48 h，the cumulative release rates of BC-LN-FA in phosphate buffer saline （PBS）at pH 7.4， 6.8，5.0 were（54.12±2.69）％，（57.85±4.25）％ and（59.47±1.83）％，respectively；those of free BC in PBS at pH 7.4 was only （15.04±1.43）％. CONCLUSIONS The optimized technology is stable and feasible. Prepared BC-LN-FA has a uniform particle size，high digestion rate and certain viscosity.