A pharmacokinetics-pharmacodynamics study of single-dose total glucosides of paeony capsule on reducing serum total bile acid in hepatic injury rats.

CONTEXT: Total Glucosides of Paeony (TGP) capsule possesses various hepatoprotective activities. No study is available concerning TGP's concentration-effect relationship on hepatoprotection. OBJECTIVE: To establish a pharmacokinetics-pharmacodynamics (PK-PD) modelling on TGP capsule's hepatoprotection after a single oral administration in hepatic injury rats. MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into five groups (n = 6): control, model (hepatic injury), treated-H (2.82 g/kg), treated-M (1.41 g/kg), and treated-L (0.705 g/kg) groups. All treated groups rats were intragastrically administered a single dose. An LC-MS/MS method was applied to determine paeoniflorin (Pae) and albiflorin (Alb) in rat serum. The effects of single-dose TGP on serum alanine transaminase (ALT), aspartate transaminase (AST) and total bile acid (TBA) were evaluated in hepatic injury rats. RESULTS: Single dose (2.82, 1.41, or 0.705 g/kg) TGP capsule could real-time down-regulate serum TBA but not ALT and AST in hepatic injury rats within 20 h. An inhibitory effect Sigmoid Emax of PK-PD modelling was established using Pae and Alb as PK markers and serum TBA as effect index. Pharmacodynamic parameters were calculated. For treated-H, treated-M and treated-L group, respectively, E0 were 158.1, 226.9 and 245.4 µmol/L for Pae, 146.1, 92.9 and 138.4 µmol/L for Alb, Emax were 53.0, 66.0, and 97.1 µmol/L for Pae, 117.4, 249.7 and 60.0 µmol/L for Alb, and EC50 were 9.3, 5.2 and 2.7 µg/mL for Pae, 2.3, 0.8, and 0.8 µg/mL for Alb. DISCUSSION AND CONCLUSIONS: Serum TBA is a sensitive effect index for TGP's single dose PK-PD modelling, and it is potential for further multi-dose studies of TGP' effect on hepatic injury. The study provides valuable information for TGP's mechanistic research and rational clinical application.

[Research advance in multi-component pharmacokinetics of Chinese herbal extracts in recent five years].

The multi-component pharmacokinetic study of Chinese herbal extracts elaborates the in vivo processes,including absorption,distribution,metabolism,and excretion,of multiple bioactive components,which is of significance in revealing pharmacodynamic material basis of Chinese herbal medicine. In recent years,with the innovation in ideas,and development of techniques and methods on traditional Chinese medicine( TCM) research,the pharmacokinetic studies of Chinese herbal extracts were extensively performed,and notable progress has been made. This paper reviewed the advancement of multi-component pharmacokinetics of Chinese herbal extracts in recent five years from analysis technology of biological sample,the pharmacokinetic characteristics of Chinese herbal medicine with complex system,and the impacts of processing and pathological state on pharmacokinetics of Chinese herbal extracts,aiming to provide a reference for quality control,product development and rational medication of Chinese herbal extracts.

[Advance on pharmacokinetics study of traditional Chinese medicine injections in recent ten years].

Traditional Chinese medicine(TCM) injections boast a definite efficacy and have been widely used in clinic. However, the problems in medication safety have been attracted increasing attention. Pharmacokinetics is of significance to guiding TCM injection administration regimen design and improving safety and effectiveness in clinical use. In recent years, with the improvement of ideas, technology and methods of TCM studies, the pharmacokinetic studies of TCM injections have been broadly performed, with a notable progress. This paper reviewed the advance in pharmacokinetics studies of TCM injections in recent ten years, which mainly focused on pre-clinical concentration-time course, distribution, metabolism and excretion in vivo based on analysis techniques, pharmacokinetic interactions of constitutes, impact of pathological state, pharmacokinetic interactions between TCM injection and chemical drugs, and clinical pharmacokinetics studies of TCM injections, in the expectation of providing reference for studies on quality control, product development and rational clinical use of TCM injections.

Oral Bioavailability Evaluation of Celastrol-Encapsulated Silk Fibroin Nanoparticles Using an Optimized LC-MS/MS Method.

Celastrol (CL), a compound isolated from Tripterygium wilfordii, possesses various bioactivities such as antitumor, anti-inflammatory and anti-obesity effects. In previous studies, we developed CL-encapsulated silk fibroin nanoparticles (CL-SFNP) with satisfactory formulation properties and in vitro cancer cytotoxicity effect. For further in vivo oral bioavailability evaluation, in this study, a simple and reliable LC-MS/MS method was optimized and validated to determine CL concentration in rat plasma. The separation of CL was performed on a C18 column (150 by 2 mm, 5 µm) following sample preparation using liquid-liquid extraction with the optimized extraction solvent of tert-butyl methylether. The assay exhibited a good linearity in the concentration range of 0.5-500 ng/mL with the lower limit of quantification (LLOQ) of 0.5 ng/mL. The method was validated to meet the requirements for bioassay with accuracy of 91.1-110.0%, precision (RSD%) less than 9.1%, extraction recovery of 63.5-74.7% and matrix effect of 87.3-101.2%. The developed method was successfully applied to the oral bioavailability evaluation of CL-SFNP. The pharmacokinetic results indicated the AUC0-∞ values of CL were both significantly (p < 0.05) higher than those for pure CL after intravenous (IV) or oral (PO) administration of equivalent CL in rats. The oral absolute bioavailability (F, %) of CL significantly (p < 0.05) increased from 3.14% for pure CL to 7.56% for CL-SFNP after dosage normalization. This study provides valuable information for future CL product development.

[Quantitative determination and optimun extraction technique of nine compounds of Paeoniae Radix Alba].

OBJECTIVE: To establish the optimum extraction technique and high performance liquid chromatographic (HPLC) method to simultaneously quantify nine compounds of gallic acid, hydroxy-paeoniflorin, catechin, albiflorin, paeoniflorin, pentagalloylglucose, benzoic acid, benzoylpaeoniflorin and paeonol in Paeoniae Radix Alba. METHODS: Linear gradient elution was applied using water containing 0.1%phosphoric acid and acetonitrile as the mobile phase with a flow rate of 0.8 mL/min, column temperature of 30℃ and wavelength of 230 nm. The method of ultrasound extraction was used. Methanol and ethanol were used as extraction solvents, and three factors and three levels of orthogonal experiments was designed using L 9(3 4) table to investigate the effects of solvent concentration, ratio of liquid to material and extraction time on the total content of nine components of Paeoniae Radix Alba. RESULTS: HPLC method was verified to have high specificity, sensitivity and accuracy through methodological validation, and it could be used for simultaneous quantitative analysis of nine components of Paeoniae Radix Alba. The results showed that the optimum extraction technology of nine components of Paeoniae Radix Alba was using 70%ethanol as extraction solvent, ratio of liquid to material was 200 mL/g and ultrasound extraction time was 30 min. CONCLUSIONS: HPLC method for the simultaneous determination of nine components of Paeoniae Radix Alba is established, and the optimum extraction technology is confirmed.

Localization of malonyl and acetyl on substituted saikosaponins according to the full-scan mass spectra and the fragmentation of sodium-adduct ions in the positive mode.

RATIONALE: Discriminating between aglycone-substituted and saccharide-substituted saikosaponins by liquid chromatography/tandem mass spectrometry (LC/MSn ) is a long-standing issue that is still to be resolved. It is necessary to characterize the two types of substituted saikosaponins taking into consideration the potential significant difference in their bioactivity. METHODS: Taking the substituents malonyl and acetyl as examples, we developed a MS strategy to discriminate between the aglycone-substituted and saccharide-substituted saikosaponins through comparing their Y0 - nH2 O (n = 1-2) ions from the protonated molecules in the full-scan mass spectra and their B ions in the MS2 spectra of sodium-adduct molecules in the positive mode. RESULTS: The deprotonated molecules of the aglycone-substituted saikosaponins presented similar fragmentation patterns to those of saccharide-substituted ones in the negative mode, which could not discriminate whether the substitutes were located on the aglycone or the saccharide. In contrast, the Y0 - nH2 O (n = 1-2) ions containing or no substituent were observed respectively in the mass fragmentation of the protonated molecules of aglycone-substituted or saccharide-substituted saikosaponins in the positive mode. In addition, the B ions containing or no substituent were observed respectively in the mass fragmentation of the sodium-adduct molecules of the saccharide-substituted or aglycone-substituted saikosaponins in the positive mode. Two aglycone-malonylated saikosaponins were reported for the first time. CONCLUSIONS: Whether the substituents were located on the aglycone or the saccharide could be determined according to the Y0 - nH2 O (n = 1-2) ions from the protonated molecules in the full-scan mass spectra and the B ions in the MS2 spectra of sodium-adduct molecules in the positive mode. Our results have updated the mass fragmentation patterns of substituted saikosaponins, which is helpful for the quality control of pharmaceutical preparations containing saikosaponins. More importantly, this MS strategy should be able to be extended to characterize other substituted saponins of bioactive significance in future studies.

Mir-382 Promotes Differentiation of Rat Liver Progenitor Cell WB-F344 by Targeting Ezh2.

BACKGROUND/AIMS: Liver progenitor cells (LPCs) were considered as a promising hepatocyte source of cell therapy for liver disease due to their self-renewal and differentiation capacities, while little is known about the mechanism of LPC differentiate into hepatocytes. This study aims to explore the effect of miR-382, a member of Dlk1-Dio3 microRNA cluster, during hepatic differentiation from LPCs. METHODS: In this study, we used rat liver progenitor cell WB-F344 as LPC cell model and HGF as inducer to simulate the process of LPCs hepatic differentiation, then microRNAs were quantified by qPCR. Next, WB-F344 cell was transfected with miR-382 mimics, then hepatocyte cell trait was characterized by multiple experiments, including that periodic acid schiff staining and cellular uptake and excretion of indocyanine green to evaluate the hepatocellular function, qPCR and Western Blotting analysis to detect the hepatocyte-specific markers (ALB, Ttr, Apo E and AFP) and transmission electron microscopy to observe the hepatocellular morphology. Moreover, Luciferase reporter assay was used to determine whether Ezh2 is the direct target of miR-382. RESULTS: We found that miR-382 increased gradually and was inversely correlated with the potential target, Ezh2, during WB-F344 hepatic differentiation. In addition, functional studies indicated that miR-382 increased the level of hepatocyte-specific genes. CONCLUSIONS: This study demonstrates that miR-382 may be a novel regulator of LPCs differentiation by targeting Ezh2.

[Experimental factors affecting in vitro recovery of puerarin in microdialysis].

OBJECTIVE: : To analyze experimental factors affecting in vitro recovery of puerarin in microdialysis. METHODS: : Puerarin concentration in microdialysate samples was determined by high performance liquid chromatography. The methods of direct dialysis, retrodialysis and the zero-net flux were used to calculate in vitro recovery, respectively. The effects of perfusate composition, the analyte concentration, perfusate flow rate, medium temperature and stir rates of the dialysis medium on recovery were investigated. RESULTS: : There were significant differences in the recovery values among direct dialysis, retrodialysis and zero-net flux methods. The recovery for 0.9% NaCl solution, Ringer's solution, PBS and anticoagulant dextrose solution as perfusate fluid were (71.25±2.36)%,(73.48±1.41)%,(68.50±2.43)% and (74.98±1.16)%, respectively. The composition of perfusate fluid had significant influence on the recovery(P<0.01). At the same flow rate, recovery was independent of the analyte concentration. At the same concentration, the recovery was decrease with the increasing flow rate in an exponential relationship. The recovery increased with the raising temperature and stir rate of the dialysis medium, and the recovery remained stable when the stir rate reached above 200 rpm. CONCLUSIONS: : A study method for in vitro recovery of puerarin in microdialysis has been established, and the recovery of puerarin is affected by calculating methods, perfusate fluids, flow rate, medium temperature and stir rate, but not affected by analyte concentrations.

[Application progress of proteomic in pharmacological study of Chinese medicinal formulae].

Chinese medicinal formulae are the important means of clinical treatment in traditional Chinese medicine. It is urgent to use modern advanced scientific and technological means to reveal the complicated mechanism of Chinese medicinal formulae because they have the function characteristics of multiple components, multiple targets and integrated regulation. The systematic and comprehensive research model of proteomic is in line with the function characteristics of Chinese medicinal formulae, and proteomic has been widely used in the study of pharmacological mechanism of Chinese medicinal formulae. The recent applications of proteomic in pharmacological study of Chinese medicinal formulae in anti-cardiovascular and cerebrovascular diseases, anti-liver disease, antidiabetic, anticancer, anti-rheumatoid arthritis and other diseases were reviewed in this paper, and then the future development direction of proteomic in pharmacological study of Chinese medicinal formulae was put forward. This review is to provide the ideas and method for proteomic research on function mechanism of Chinese medicinal formulae.

[Research progress of pharmacokinetics and pharmacodynamics of total glucosides of peony in hepatoprotective effects].

Total glucosides of peony (TGP), containing the effective components of paeoniflorin (Pae), albiflorin (Alb) and so on, are effective parts of Radix Paeoniae Alba. And it possesses extensive pharmacological actions, one of which is hepatoprotective effect. In recent years, abundant of pharmacokinetics and pharmacodynamics research of TGP in hepatoprotective effects have been performed. However, the relative medicine of TGP in hepatoprotective effect has not been developed for clinical application. In order to provide reference for the development and rational clinical application of TGP, the research progresses of pharmacokinetics and pharmacodynamics of TGP in hepatoprotective effect were summarized in this paper. Pharmacokinetics research has clarified the process of absorption, distribution, metabolism and excretion of TGP in vivo, and liver injury disease can significantly influence its metabolic processes. Pharmacodynamics studies suggested that TGP can protect against acute liver injury, non-alcoholic fatty liver diseases (NAFLD), chronic liver fibrosis and liver cancer. However, the action mechanism and in vivo process about hepatoprotective effects of TGP have not been clearly revealed. How liver injury influences the metabolism of TGP and its integrated regulation through multiple targets need to be further studied. The combined pharmacokinetics and pharmacodynamics studies should be performed in favour of medicine development and clinical application of TGP in hepatoprotective effects.

Development of a sensitive LC-MS/MS method for simultaneous quantification of eleven constituents in rat serum and its application to a pharmacokinetic study of a Chinese medicine Shengmai injection.

A sensitive LC-MS/MS method was developed and validated for simultaneous quantification of 11 constituents, ginsenoside Rg1, Re, Rf, Rg2, Rb1, Rd, Rc, ophiopogonin D, schisandrin, schisandrol B and schizandrin B, in rat serum using digoxin as the internal standard (IS). The serum samples were pretreated and extracted with a two-step liquid-liquid extraction. Chromatographic separation was achieved on a C18 analytical column with a proper gradient elution using 0.02% acetic acid aqueous solution and 0.02% acetic acid-acetonitrile as mobile phase at a flow rate of 0.5 mL/min. MS detection was performed using multiple reaction monitoring via an electrospray ionization source. Good linearity was observed in the validated concentration range for every analyte (r(2) ≥0.9929), and the lower limits of quantitation of the analytes were in the range of 0.044-1.190 ng/mL in rat serum. Intra- and inter-day precisions were <14.2%. The accuracy expressed as recovery was within the range of 85.1-112.8%. The extraction recoveries were >75.8%.The validated method was successfully applied to a pharmacokinetic study of all analytes in rats after single intravenous administration of Shengmai injection.

[Study on PK-PD characteristics of ginsenoside Rg1 and Rb1, in rats with myocardial ischemia following intravenous administration of shengmai injection].

It is the objective of this paper to study pharmacokinetics-pharmacodynamics (PK-PD) characteristics of ginsenoside Rg1 and Rb1 on the effect of inducing nitric oxide (NO) release after intravenous administration of Shengmai injection to rats with myocardial ischemia. The model of myocardial ischemia rats was produced by subcutaneous injection of isoproterenol. The serum samples were collected at different time points after intravenous administration of Shengmai injection to rats with the dose of 10.8 mL x kg(-1). The concentrations of ginsenoside Rg1 and Rb1 in serum were determined, and then the concentration-time curves were drawn. Pharmacokinetic parameters of ginsenoside Rg1 and Rb1 were calculated after the construction of pharmacokinetic models. Meanwhile, NO2- and NO3-, the metabolites of NO, in serum were determined, and then the effect-time curve was drawn. The combined PK-PD model was established based on the theory of effect compartment by Sheiner et al. Then pharmacodynamic parameters were calculated. The results indicated that the pharmacokinetics of ginsenoside Rg1 and Rb1 conformed to a two-compartment model. Ginsenoside Rg1 and Rb1 exhibited quick and slow elimination in rats respectively. The effect of Shengmai injection on inducing NO release did not relate directly with and lagged behind the concentrations of ginsenoside Rg1 and Rb1 in serum. The effect exhibited good correlation with ginsenoside Rg1 and Rb1 levels in effect compartment. The relationship between effect and serum concentration fits Sigmoid-E(max) model. This study successfully established the combined PK-PD model of ginsenoside Rg1 and Rb1 after intravenous administration of Shengmai injection to rats. The model can efficiently predict the concentration and effect of Shengmai injection in vivo.

Construction and validation of risk prediction model for gastrointestinal bleeding in patients after coronary artery bypass grafting.

This study aimed to develop a risk prediction model for gastrointestinal bleeding in patients after coronary artery bypass grafting (CABG) and assessed its accuracy. A retrospective analysis was conducted on 232 patients who underwent CABG under general anesthesia in our hospital between January 2022 and December 2022. The patients were divided into gastrointestinal bleeding (GIB) group (n = 52) and group without gastrointestinal bleeding (non-GIB) (n = 180). The independent risk factors for gastrointestinal bleeding in post-CABG patients were analyzed using χ2 test, t test and logistic multivariate regression analysis. A prediction model was established based on the identified risk factors. To verify the accuracy of the prediction model, a verification group of 161 patients who met the criteria was selected between January to June 2023, and the Bootstrap method was used for internal validation. The discrimination of the prediction model was evaluated using the area under the curve (AUC), where a higher AUC indicates a stronger discrimination effect of the model. The study developed a risk prediction model for gastrointestinal bleeding after CABG surgery. The model identified four independent risk factors: duration of stay in the intensive care unit (ICU) (OR 0.761), cardiopulmonary bypass time (OR 1.019), prolonged aortic occlusion time (OR 0.981) and re-operation for bleeding (OR 0.180). Based on these factors, an individualized risk prediction model was constructed. The C-index values of the modeling group and the verification group were 0.805 [95% CI (0.7303-0.8793)] and 0.785 [95% CI (0.6932-0.8766)], respectively, which indicated a good accuracy and discrimination of this model. The calibration and standard curves showed similar results, which further supported the accuracy of the risk prediction model. In conclusion, ICU time, cardiopulmonary bypass time, aortic occlusion time and re-operation for bleeding are identified as independent risk factors for gastrointestinal bleeding in patients after CABG. The risk prediction model developed in this study demonstrates strong predictive performance and provides valuable insights for clinical medical professionals in evaluating gastrointestinal complications in CABG patients.

Nano-carrier Polyamidoamine Dendrimer G4 Induces Mitochondrialdependent Apoptosis in Human Multidrug-resistant Breast Cancer Cells through G0/G1 Phase Arrest.

BACKGROUND: Multidrug-resistant tumor cells have special drug detoxification/inactivation mechanisms. The terminal amino groups of the polyamidoamine (PAMAM-NH2), which is cytotoxic to tumor sensitive cells, may have no cytotoxicity in tumor resistant cells with a mechanism different from tumor sensitive cells. OBJECTIVE: This study aimed to investigate the cytotoxic effects of PAMAM-G4-NH2 on human multidrug- resistant breast cancer cells (MCF-7/ADR cells) and identify the possible molecular mechanisms. METHODS: The cytotoxicity of PAMAM-G4-NH2 (10-1000 µg/mL) against MCF-7 and MCF-7/ADR cells was detected. Then, MCF-7 and MCF-7/ADR cells were treated with PAMAM-G4-NH2 (10, 100 and 1000 µg/mL), and apoptosis, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), activities of caspase-3, -8 and -9 and cell cycle distribution were determined. RESULTS: Within 48 h, the cell viabilities in MCF-7/ADR cells after treatment with PAMAM-G4-NH2 were significantly higher than that in MCF-7 cells in the concentration range of 200-500 µg/mL (P < 0.05). Viabilities of MCF-7/ADR cells treated with PAMAM-G4-OH and PAMAM-G4-COOH for 48 and 72 h were much higher than that of MCF-7/ADR cells treated with PAMAM-G4-NH2. Treated with high concentration (1000 µg/mL) of PAMAM-G4-NH2 for 24 h, the apoptosis ratio, ROS levels, as well as caspase-3 and -9 activities in MCF-7 and MCF-7/ADR cells increased, while MMP decreased, and the cells were arrested in the G0/G1 phase. CONCLUSION: PAMAM-G4-NH2 induced concentration-dependent cytotoxicity in MCF-7/ADR cells via G0/G1 arrest, and acted through h the mitochondria-dependent apoptotic pathway, which was similar to those in tumor sensitive cell, MCF-7 cells. The results suggest that PAMAM-G4-NH2, instead of PAMAM-G4-OH and PAMAM-G4-COOH, can be used as a carrier for drug delivery, concomitantly, it can also induce apoptosis in multidrug-resistant cancer cells in combination with the loaded drug through multiple apoptotic pathways.

A Quantitative Serum Proteomic Analysis Helps to Explore the Comprehensive Mechanism and Identify Serum Biomarkers of Shengmai Injection's Effect on Isoproterenol-Induced Myocardial Ischemia in Rats.

Shengmai injection (SMI), a traditional Chinese medicine formula with the nature of multicomponent and multi-target, has been widely used in clinic for treating cardiovascular diseases in China; however, its comprehensive mechanism of action remains unclear. In this study, a TMT-based quantitative serum proteomics was performed to explore SMI's global mechanism and help identify serum biomarkers of its effect on isoproterenol (ISO)-induced myocardial ischemia rats. The results of TMT-based proteomic analysis identified 227, 100, and 228 differentially expressed proteins (DEPs) for the model compared to the control group, SMI pretreatment + model compared to the model group, and SMI pretreatment + model compared to the control group, respectively. Based on bioinformatics analyses of gene ontology (GO), KEGG pathways, and the protein-protein interaction (PPI) networks for the DEPs, it is concluded that the comprehensive mechanism of SMI's effect on ISO-induced myocardial ischemia injury includes regulation of energy metabolism, reducing endothelial cell permeability, regulation of vessel and cardiac contractility, anti-inflammation, and prevention of cell apoptosis. Furthermore, 10 common DEPs were found, and six of them were regulated in model vs. control group, while back-regulated in SMI pretreatment + model vs. model group. Among them, three functional proteins of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Fas apoptotic inhibitory molecule 3 (FAIM3), and uncharacterized protein (M0R5J4), which were verified by the PRM analysis, might be the potential serum biomarkers on SMI's effects. Overall, this serum proteomics of SMI not only provides insights into the comprehensive mechanism underlying SMI's effects on ischemic heart disease but also helps identify serum biomarkers for directing SMI's cardioprotective effects.

Cancer Chemoprevention Using Nanotechnology-Based Approaches.

Cancer research in pursuit of better diagnostic and treatment modalities has seen great advances in recent years. However, the incidence rate of cancer is still very high. Almost 40% of women and men are diagnosed with cancer during their lifetime. Such high incidence has not only resulted in high mortality but also severely compromised patient lifestyles, and added a great socioeconomic burden. In view of this, chemoprevention has gained wide attention as a method to reduce cancer incidence and its relapse after treatment. Among various stems of chemoprevention research, nanotechnology-based chemoprevention approaches have established their potential to offer better efficacy and safety. This review summarizes recent advances in nanotechnology-based chemoprevention strategies for various cancers with emphasis on lung and bronchial cancer, colorectal, pancreatic, and breast cancer and highlights the unmet needs in this developing field towards successful clinical translation.

Novel 4-Acrylamido-Quinoline Derivatives as Potent PI3K/mTOR Dual Inhibitors: The Design, Synthesis, and in vitro and in vivo Biological Evaluation.

A novel structural series of quinoline derivatives were designed, synthesized and biologically evaluated as PI3K/mTOR dual inhibitors upon incorporation of C-4 acrylamide fragment. Consequently, all of them exerted remarkable inhibition against PI3Kα with IC50 values ranging from 0.50 to 2.03 nM. Besides, they exhibited sub-micromolar to low micromolar anti-proliferative activity against both prostate cancer PC3 and colorectal cancer HCT116 cell lines. In subsequent profiling, 8i, a representative compound throughout this series, also significantly inhibited other class I PI3Ks and mTOR. In PC3 cells, it remarkably down-regulated the crucial biomarkers of PI3K/Akt/mTOR signaling, including phos-Akt (Ser473), phos-Akt (Thr308), phos-S6 ribosomal protein (Ser235/236), and phos-4E-BP1 (Thr37/46), at a concentration as low as 5 nM. Moreover, 8i displayed favorable metabolic stability with long elimination half-life in both human liver and rat liver microsomes. A further in vivo pharmacokinetic (PK) study demonstrated 8i possessed acceptable oral exposure, peak plasma concentration, and elimination half-life. Taken together, 8i, as a potent PI3K/mTOR dual inhibitor, merited further investigation and structural optimization.

A simple blood microdialysis in freely-moving rats for pharmacokinetic-pharmacodynamic modeling study of Shengmai injection with simultaneous determination of drug concentrations and efficacy levels in dialysate.

Microdialysis is a powerful in vivo sampling technique for pharmacokinetic-pharmacodynamic (PK-PD) modeling of drugs in pre-clinical and clinical studies. However, the noticeable limitations of previous studies using microdialysis were that animals anesthesia in the whole experiment and the combination of microdialysis and blood sampling for drug and (or) effect detection, which can obviously influence PK and PD behavior of drugs. In this study, a simple blood microdialysis sampling system in freely-moving rats was established for simultaneous study of PK and PD of Shengmai injection (SMI) effect on inducing real-time nitric oxide (NO) release on isoproterenol (ISO) induced myocardial ischemia rats. The LC-MS/MS and HPLC with fluorescence detection (HPLC-FLD) methods were developed to determine ginsenside Rg1, Rg2, Re, Rf, Rb1, Rd and Rc, the main effective components of SMI, and NOx-, the main oxidation products of NO, in dialysates respectively. Through simultaneous determination of drug concentrations and NO efficacy levels in dialysate, the developed methods were successfully applied to set up concentration-time and effect-time profiles followed by PK-PD modeling of SMI effect on inducing NO release after intravenous administration of 10.8 mL kg-1 SMI in myocardial ischemia rats. The PK-PD modeling characterized the dose-effect relationships of SMI and behaved good prediction ability. The established blood microdialysis in freely-moving rats is an appealing technology for rational PK-PD studies when selecting suitable blood endogenous micromolecule as effect marker.