The effect of acute hypobaric hypoxia on bile acid composition in the small intestine of rats / 药学学报

In order to clarify the influence of acute hypobaric hypoxia on the bile acids of the rat small intestine, we used ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to identify bile acids in the contents of the small intestine from untreated and acute hypobaric hypoxia-treated rats. Thirty-nine bile acids were detected; PCA and OPLS-DA analysis revealed marked differences in the composition of bile acids between the untreated and the acute hypobaric hypoxia groups. Bile acids were screened with VIP > 1, |log2FC| ≥ 1, P < 0.05, and a total of 7 bile acids with significant differences in content between the two groups were obtained, including 5 conjugated bile acids, 2 unconjugated bile acids; in addition, the content of conjugated bile acids has risen in the treated group. This study demonstrated the influence of high-altitude hypoxic environment on bile acid composition and metabolism in rats. All the animal experiments in this study were approved by the 940th Hospital Ethics Committee (approval No: 2020KYLL012).

Advances in the study of gut pharmacomicrobiomics / 药学学报

The intestinal flora is a diverse microbial community living in the digestive tract of humans and animals. This microbial community can modify drugs in unpredictable ways, leading to changes in the pharmacokinetics of drugs in vivo and affecting their clinical efficacy. Here we review drug metabolism mediated by intestinal flora from three aspects: prodrug activation, drug inactivation, and toxicity. The effect of the stable hypoxic environment on the composition and quantity of intestinal flora and the effect on drug metabolism are discussed. Understanding the influence of intestinal flora on drug metabolism is not only conducive to individualized medication, but also conducive to rational drug design, allowing us to predict and understand individual drug response and regulate the intestinal microbiome to improve drug efficacy, thus promoting personalized medicine.

Modulation of drug-metabolizing enzymes and transporters under hypoxia environment / 生理学报

Drug metabolism is significantly affected under hypoxia environment with changes of pharmacokinetics, expression and function of drug-metabolizing enzymes and transporters. Studies have shown that hypoxia increases the release of a series of inflammatory cytokines which can modulate drug metabolism. Besides, both hypoxia inducible factor 1α (HIF-1α) and microRNA-mediated pathways play a role in regulating drug metabolism. This article reviewed the impact and single-factor modulating mechanisms of drug metabolism under hypoxia, and put forward the speculation and prospects of multi-factor modulating mechanisms.

Interaction of amoxicillin and nifedipine mediated by intestinal flora / 药学学报

In this study, the change of intestinal microflora in rat fecal samples after amoxicillin administration was observed. In vitro incubation experiments combined with LC-MS/MS assay were used to test the role of intestinal flora in the metabolism of nifedipine. The effect of changes of intestinal flora was determined after amoxicillin administration on the metabolism of nifedipine. We found that the number and types of intestinal flora decreased after taking amoxicillin. After incubation for 12 h, the results showed that the remaining amounts of nifedipine in the N1 group (nifedipine) and N2 group (amoxicillin + nifedipine) were 0.057 6 and 0.064 8 μmol·L-1, respectively, while the remaining amounts of nifedipine after 24 h of incubation were 0.039 6 and 0.050 4 μmol·L-1, respectively. These results show that the intestinal flora is involved in the metabolism of nifedipine. After administration of amoxicillin, the metabolism of nifedipine was slowed down, the AUC0-t was increased by 39.10%, tmax was advanced by 0.45 h, and the CL was reduced 34.71%. The data suggest that the combination may enhance the therapeutic effect of nifedipine. Therefore, drug-drug interactions mediated by gut microbiota cannot be ignored when combined with antibiotics and nifedipine, one of the important factors affecting drug efficacy.

Effect of amoxicillin on the expression of PEPT1 and pharmacokinetics upon acute hypoxia at high altitude in rat / 药学学报

The relationship between PEPT1 (peptide transporter) and drug efficacy has drawn more and more attention in the treatment of disease. PEPT1 represents a promising strategy for improvement of drug bioavailability and an important starting point for clinical rationalization of drug selection. The effect of PEPT1 on transport and pharmacokinetics of amoxicillin was investigated under hypoxia condition at high altitude in rat. The mRNA and protein expressions of PEPT1 were increased by 36.87%, 216.21%, 577.8% and 535.9% respectively in the hypoxia group in the small intestine and kidney of rats. However, the mRNA and protein expressions of PEPT1 were reduced by 43.90% and 84.7% in the liver. Compared with the control group, the AUC, tmax, Cmax, MRT and t1/2 of amoxicillin were significantly enhanced by 312.17%, 63.04%, 110.93%, 67.11% and 16.96% respectively in the hypoxia group, while the CL was significantly decreased by 74.51%. After acute exposure to high altitude, the expressions of drug transporter PEPT1 were distinctly changed in rat tissues, which can affect the pharmacokinetics of amoxicillin.

Detection of plasma and urine furosemide based on online enrichment and restricted- access media coupled with high-performance liquid chromatography / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a method based on restricted access media-high performance liquid chromatography for direct online sample injection and detection of plasma and urine furosemide in rats.</p><p><b>METHODS</b>The column of restricted access media was used as the pre-treatment column and a C18 column as the analytical column. The mobile phase of the pre- treatment column was water-methanol (95:5, V/V) with a volume percentage of formic acid of 0.1%. The mobile phase of the analytical column was methanol-water (65:35, V/V) for plasma and methanol-water (55:45, V/V) for urine samples, all containing a volume percentage of formic acid of 0.1% with a flow rate of 1 ml/min. The detection wavelength was 274 nm and the column temperature was maintained at 25 degrees celsius.</p><p><b>RESULTS</b>The calibration curve showed an excellent linear relationship in rat plasma furosemide concentration range of 0.1-3.2 µg/ml (r=0.9995) and in urine concentration range of 0.5-32 µg/ml (r=0.9991). The average recoveries of furosemide at 3 spiked levels ranged from 101.82% to 113.36% for plasma and from 98.75% to 112.27% for urine samples. The detection showed good intra- and inter-day assay precisions and accuracies with the relative standard deviations all below 5%. The pharmacokinetic parameters AUC(0→24) was 6.265 g/(ml·h) with a t(1/2) of 2.447 h and a C(Max) of 1.414 g/ml. The mean cumulative excretory rate of furosemide in the urine of rats over 24 h was 32.50%-39.08%.</p><p><b>CONCLUSION</b>Detection of furosemide in plasma and urine samples using restricted access media-high performance liquid chromatography is simple and efficient and allows direct online injection of the samples.</p>

Effects on the pharmacokinetics of furosemide after acute exposure to high altitude at 4010 meters in rats / 药学学报

The paper is to report the pharmacokinetics of furosemide in rats living at plain area and high altitude. After intragastric administration of furosemide (2.87 mg x kg(-1)), serial blood samples (0.5 mL) were collected by retro-orbital puncture at 0, 20 min, 40 min, 1, 1.5, 2, 3, 4, 6, 8, 12 and 24 h, samples were determined by LC-MS/MS, and plasma concentration-time data were analyzed by DAS 2.0 software to get the related pharmacokinetic parameters. The main pharmacokinetic parameters: area under curve (AUC), mean residence time (MRT), the biological half-life (t1/2) and the peak concentration (C(max)) of furosemide, were significantly increased at high altitude, the time to reach peak concentration (t(max)) and clearance (CL) was significantly decreased. This study found significant changes on the pharmacokinetics of furosemide under the special environment of high altitude. This finding may provide some references for clinical rational application of furosemide at high altitude.