We report the development and validation of a rapid, specific, and sensitive liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method for analysis and pharmacokinetic study, in rats, of hyperoside and isoquercitrin, two bioactive structural isomers present in the leaves of Apocynum venetum L. After simple deproteinization by addition of acetonitrile, the analytes were separated on a C 18 column. Detection was by tandem mass spectrometry in multiple reaction monitoring mode. The method was linear over the concentration range 3.9-195 ng mL -1 for both hyperoside and isoquercitrin. Intra-day and inter-day precision for both hyperoside and isoquercitrin were \13.1%, and relative errors were all within 7.1% at all QC levels. The method was used to study the pharmacokinetic performance of the compounds after oral administration of an extract of Apocynum venetum L. leaves to rats.

Aim: Capmatinib is an orally bioavailable mesenchymal-epithelial transition factor inhibitor with anticancer activity, which has proved preclinical activity in multiple cancer trials. The present study aimed to develop a fast and reliable assay approach to quantify capmatinib in rat plasma. Methodology & results: After protein precipitation with acetonitrile, the chromatographic separation was achieved with an Acquity UPLC BEH C18 column, and subsequently detected with positive electrospray ionization via a triple quadrupole tandem mass spectrometer. The target quantitative ion pairs m/z 412.99 → 381.84 for capmatinib and 387.00 → 355.81 for the internal standard, respectively. The calibration curve for the assay was linear over the range of 1.0–4000 ng/ml. Conclusion: The method shows an excellent performance in linearity, accuracy, precision, stability, and has been successfully applied to a pharmacokinetic study after oral administration of capmatinib at three doses (5, 10 and 20 mg/kg) in rats.

Polymer hydrolysis polyacrylamide and microbes have been used to enhance oil recovery in many oil reservoirs. However, the application of this two-method combination was less investigated, especially in low permeability reservoirs. In this work, two bacteria, a rhamnolipid-producing Pseudomonas aeruginosa 8D and a lipopeptide-producing Bacillus subtilis S4, were used together with hydrolysis poly-acrylamide in a low permeability heterogeneous core physical model. The results showed that when the two bacterial fermentation liquids were used at a ratio by volumeof 1:3 (v:v), the mixture showed the optimal physicochemical properties for oil-displacement. In addition, the mixture was stable under the conditions of various temperature (20–70 °C) and salinity (0–22%). When the polymer and bacteria were mixed together, it had no significant effects in the viscosity of polymer hydrolysis polyacrylamide and the viability of bacteria. The core oil-displacement test displayed that polymer hydrolysis polyacrylamide addition followed by the bacterial mixture injection could significantly enhance oil recovery. The recovery rate was increased by 15.01% and 10.03%, respectively, compared with the sole polymer hydrolysis polyacrylamide flooding and microbial flooding. Taken together, these results suggest that the strategy of polymer hydrolysis poly-acrylamide addition followed by microbial flooding is beneficial for improving oil recovery in heterogeneous low permeability reservoirs.

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