Environmentally responsive hydrogel promotes vascular normalization to enhance STING anti-tumor immunity.

The immunosuppressive microenvironment of malignant tumors severely hampers the effectiveness of anti-tumor therapy. Moreover, abnormal tumor vasculature interacts with immune cells, forming a vicious cycle that further interferes with anti-tumor immunity and promotes tumor progression. Our pre-basic found excellent anti-tumor effects of c-di-AMP and RRx-001, respectively, and we further explored whether they could be combined synergistically for anti-tumor immunotherapy. We chose to load these two drugs on PVA-TSPBA hydrogel scaffolds that expressly release drugs within the tumor microenvironment by in situ injection. Studies have shown that c-di-AMP activates the STING pathway, enhances immune cell infiltration, and reverses tumor immunosuppression. Meanwhile, RRx-001 releases nitric oxide, which increases oxidative stress injury in tumor cells and promotes apoptosis. Moreover, the combination of the two presented more powerful pro-vascular normalization and reversed tumor immunosuppression than the drug alone. This study demonstrates a new design option for anti-tumor combination therapy and the potential of tumor environmentally responsive hydrogel scaffolds in combination with anti-tumor immunotherapy.

Determination and pharmacokinetics of periplocin in rat plasma by LC-MS.

A simple and sensitive LC-MS method for the determination of periplocin in rat plasma was developed and validated. The chromatographic separation was carried out using a reverse-phase Kromasil C(18) column(150 × 4.6 mm, i.d., 5 µm) with a mobile phase composed of methanol-water (76:24, v/v). The flow rate of mobile phase was 0.8 mL/min. The calibration curve was linear within the concentration range 1-1000 ng/mL. The intra- and inter-day precisions across three validation days over the entire concentration range was lower than 9.2% in terms of relative standard deviation. Accuracy determined at three quality control concentrations ranged from -2.0 to 6.0% in terms of relative error. The validated method was applied to the pharmacokinetic study of periplocin in rat plasma after intravenous and intramuscular administration.

[RP-HPLC simultaneous determination of five triterpenoid acids in different parts of Poria cocos by UV wavelengths switch].

To establish a method for simultaneous determination of dehydrotumulosic acid, polyporenic acid C, 3-epi-dehydrotumulosic acid, dehydropachymic acid and pachymic acid in Poria, a RP-HPLC method detected by UV wavelengths switch had been developed, including 210 nm (48-55 min) for pachymic acid and 241 nm (0-48 min) for dehydrotumulosic acid, polyporenic acid C, 3-epi-dehydrotumulosic acid, dehydropachymic acid, separately. The system consisting of a Kromasil C18 column (250 mm x 4.6 mm, 5 microm) and a mixture of acetonitrile and 0.05% phosphate acid as the mobile phase was adopted; The flow rate was 1.0 mL x min(-1). The linear response range was 30.5-610.0 microg x mL(-1) (r = 0.999 6) for dehydrotumulosic acid, 12.66-253.2 microg x mL(-1) (r = 0.999 5) for polyporenic acid C, 2.99-59.7 microg x mL(-1) (r = 0.999 7) for 3-epi-dehydrotumulosic acid, 6.13-122.5 microg x mL(-1) (r = 0.999 5) for dehydropachymic acid and 11.3-226.0 microg x mL(-1) (r = 0.9995) for pachymic acid. The average recoveries of these compounds were 98.5% (RSD = 1.9%), 99.4% (RSD = 1.7%), 97.9% (RSD = 1.2%), 96.7% (RSD = 2.5%) and 97.9% (RSD = 2.3%), respectively. The method is simple, accurate and reproducible for quality control of Poria.