Pharmacokinetics of kadsurenone and its interaction with cyclosporin A in rats using a combined HPLC and microdialysis system

Study on the hepatobiliary behavior of Ermiao wan formula by microdialysis- LC-qTOF-MS

An improved bile microdialysis sampling technique was established and coupled with liquid chromatography quadrupole time-of-flight mass spectrometry (LC-qTOF-MS) analysis. This method was successfully applied to investigate the metabolic profiles of Ermiao wan (EMW) formula in the bile of Sprague-Dawley (SD) rats. Based on accurate mass information and fragment patterns, 23 alkaloids and lactones metabolites were tentatively identified. Their metabolic pathway involved in glucuronidation, sulfation, hydroxylation and hydrolysis. Because of the high time resolution of microdialysis, the metabolic profiles of EMW were also investigated. Jatrorrhizine, columbamine and other components showed a "double-peak" profiles, suggesting the existence of enterohepatic circulation. The developed microdialysis sampling/ LC-qTOF-MS method provides a simple and efficient research tool for understanding and clarifying the mechanism of hepatobiliary excretion of complex components.

Kadsurenone is a useful and promising treatment strategy for breast cancer bone metastases by blocking the PAF/PTAFR signaling pathway

Breast cancer (BC) is characterized by high incidences of bone metastases. Current treatment strategies for BC bone metastases primarily focused on breaking the ‘vicious osteolytic cycle’. Platelet-activating factor (PAF) is a potent phospholipid mediator, which has previously reported biological activities in BC progression and osteoclast differentiation by activating its receptor PAF receptor (PTAFR). However, the role of PAF in the mediation of BC bone metastases remains elusive. In the present study, it was revealed that the upregulation of PTAFR was associated with an increased incidence of bone metastases. It was also revealed that PAF significantly enhanced the processes of BC cell migration and BC mediated osteoclastogenesis. These results suggest that PAF serves a promotion role in BC bone metastases. It was further demonstrated that the natural PAF antagonist Kadsurenone may effectively attenuate each process by partially blocking the PAF/PTAFR signaling pathway. Therefore, targeting PAF/PTAFR by Kadsurenone may be a promising treatment strategy for BC bone metastases.

Development of an LC-MS/MS method for quantification of kadsurenone in rat plasma and its application to a pharmacokinetic study

A sensitive and rapid LC-MS/MS method was developed and validated for the determination of kadsurenone in rat plasma using lysionotin as the internal standard (IS). The analytes were extracted from rat plasma with acetonitrile and separated on a SB-C18 column (50 × 2.1 mm, i.d.; 1.8 µm) at 30 °C. Elution was achieved with a mobile phase consisting of methanol-water-formic acid (65:35:0.1, v/v/v) at a flow rate of 0.30 mL/min. Detection and quantification for analytes were performed by mass spectrometry in the multiple reaction monitoring mode with positive electrospray ionization m/z at 357.1 → 178.1 for kadsurenone, and m/z 345.1 → 315.1 for IS. Calibration curves were linear over a concentration range of 4.88-1464 ng/mL with a lower limit of quantification of 4.88 ng/mL. The intra- and inter-day accuracies and precisions were <8.9%. The LC-MS/MS assay was successfully applied for oral pharmacokinetic evaluation of kadsurenone using the rat as an animal model.

Direct pharmacokinetic analysis of puqietinone by in vivo microdialysis sampling and turbulent-flow chromatography coupled with liquid chromatography-mass spectrometry

Sample pretreatment is a key step in bioanalytical process because of possible interference and matrix effects in mass spectrometry analysis. In this work, a novel strategy towards high speed and sensitivity was developed combining in vivo microdialysis (MD) sampling, turbulent-flow chromatography (TFC), and liquid chromatography-mass spectrometry (LC-MS). The procedures of cleanup, preconcentration, and separation were completed on-line in one step within 10min. During the MD optimization procedure, 1% hydroxypropyl-β-cyclodextrin (HP-β-CD) was used to improve the relative recovery of the analyte. Untreated MD samples were directly injected, and a TFC precolumn was flushed for 1min with aqueous phase of 4mL/min flow rate to desalt and concentrate biosamples. The retained analytes were then back-flushed by a switching valve onto a fast LC column (4.6mm×50mm, 1.8μm) for separation. Another diverter valve was employed to prevent the HP-β-CD that interferes with the ESI process from entering the MS. Puqietinone, a lipophilic alkaloid from Fritillaria puqiensis, was used as a case for validation. Results showed that the limit of quantification for puqietinone was 0.10ng/mL, and good linearity (R(2)=0.9993) was maintained over the range of 1.02-200.02ng/mL. Accuracy and precision were satisfactory within the range of the standard curve. This approach was able to effectively eliminate the influences of matrix effect and carry-over as the injection volume increased up to 20μL. The developed method was successfully applied to pharmacokinetic study of puqietinone after intravenous administration to rat. Results demonstrate the potential of using MD with TFC-LC/MS for in vivo monitoring experiments.

Analysis of the interactions of multicomponents in Cornus officinalis Sieb. et Zucc. with human serum albumin using on-line dialysis coupled with HPLC

Interactions of three iridoid glycosides extracted from Cornus officinalis Sieb. et Zucc. (CIG) with protein were simultaneously explored by on-line dialysis sampling coupled with high-performance liquid chromatography (DS-HPLC). Three main compounds in CIG were unequivocally identified as loganin, sweroside and cornuside by comparing their t(R), MS data and UV spectra with those of reference compounds. Dialysis recoveries and quantitative characteristics of DS-HPLC for three iridoid glycosides were determined. Recoveries of dialysis sampling ranged from 73.9 to 91.7% with the RSD below 3.0%. Based on the determination of concentrations before and after interaction with human serum albumin (HSA), the binding parameters of loganin, sweroside and cornuside with HSA were obtained and the binding mechanisms were investigated.

Analysis of biliary excretion of icariin in rats

Icariin is a bioactive herbal ingredient isolated from Epimedii Herba. This study evaluates the distribution of icariin in rats by microdialysis sampling and high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Microdialysis probes were simultaneously placed in the jugular vein, brain striatum, and bile duct of each anesthetized rat for sampling after the administration of icariin (dose=10 or 20 mg/kg) via the femoral vein. The role of P-glycoprotein (P-gp) on icariin distribution was assessed by pretreatment with cyclosporine (CsA, dose=20 mg/kg). This study is the first report of the biliary excretion of icarin in rats, defined as the blood-to-bile distribution (k value), calculated by dividing the area under the concentration-time curve (AUC) of icariin in bile by that in blood (k=AUCbile/AUCblood). The k values were 19.0±5.9 and 18.8±3.8 at the doses of 10 and 20 mg/kg, respectively. The decreased biliary excretion of icariin due to pretreatment with CsA was evidenced by the reduced k values (18.8±3.8 vs 9.9±1.9, p=0.005). This work demonstrates that biliary excretion is the major elimination pathway for icariin disposition and that transporters, such as P-gp, might be related to icariin's biliary excretion.

Determination of sinigrin in vegetable seeds by online microdialysis sampling coupled to reverse-phase ion-pair liquid chromatography

A hollow fiber microdialysis sampling coupled online to ion-pair liquid chromatography was investigated as an alternative to sample pretreatment for the direct determination of sinigrin in cruciferous vegetables without desulfation. After microdialysis, the dialysate was online injected into the chromatographic system to analyze the sinigrin with UV detection at 227 nm. Parameters affecting the microdialysis efficiency, such as flow rate, polarity modifier, pH in perfusion stream, pH, and salt added in sample solution, were studied. Through ion suppression in the donor phase and ion-pair formation in the acceptor phase, the microdialysis efficiency of sinigrin was enhanced. Experimental results revealed that the microdialysis of a sample solution (pH 2.0) using 0.1 M tetrabutylammonium (pH 12) as a perfusate at 10 microL/min flow rate maximized the extraction efficiency. Detection was linear in the concentration of 1.0-100 mg/L with a detection limit of 0.3 mg/L. Three seed samples were analyzed, with sinigrin at 49.8 (3.15% RSD), 20.0 (4.43% RSD), and 19.8 mg/g (4.22% RSD) for brussels, cauliflower, and cabbage, respectively. When 40 mg/g sinigrin was spiked in brussels seed powder, the recovery was 102.4% with 3.15% RSD (n = 3). The proposed method was proven to provide a very simple, rapid, and eco-friendly procedure to determine sinigrin in the seeds of cruciferous vegetables.