Study on the Effect of Pharmaceutical Excipient PEG400 on the Pharmacokinetics of Baicalin in Cells Based on MRP2, MRP3, and BCRP Efflux Transporters.

Pharmaceutical excipient PEG400 is a common component of traditional Chinese medicine compound preparations. Studies have demonstrated that pharmaceutical excipients can directly or indirectly influence the disposition process of active drugs in vivo, thereby affecting the bioavailability of drugs. In order to reveal the pharmacokinetic effect of PEG400 on baicalin in hepatocytes and its mechanism, the present study first started with the effect of PEG400 on the metabolic disposition of baicalin at the hepatocyte level, and then the effect of PEG400 on the protein expression of baicalin-related transporters (BCRP, MRP2, and MRP3) was investigated by using western blot; the effect of MDCKII-BCRP, MDCKII-BCRP, MRP2, and MRP3 was investigated by using MDCKII-BCRP, MDCKII-MRP2, and MDCKII-MRP3 cell monolayer models, and membrane vesicles overexpressing specific transporter proteins (BCRP, MRP2, and MRP3), combined with the exocytosis of transporter-specific inhibitors, were used to study the effects of PEG400 on the transporters in order to explore the possible mechanisms of its action. The results demonstrated that PEG400 significantly influenced the concentration of baicalin in hepatocytes, and the AUC0-t of baicalin increased from 75.96 ± 2.57 µg·h/mL to 106.94 ± 2.22 µg·h/mL, 111.97 ± 3.98 µg·h/mL, and 130.42 ± 5.26 µg·h/mL (p ˂ 0.05). Furthermore, the efflux rate of baicalin was significantly reduced in the vesicular transport assay and the MDCKII cell model transport assay, which indicated that PEG400 had a significant inhibitory effect on the corresponding transporters. In conclusion, PEG400 can improve the bioavailability of baicalin to some extent by affecting the efflux transporters and thus the metabolic disposition of baicalin in the liver.

Determination of acetochlor by UPLC-MS3 in cells and its application to a cellular pharmacokinetic study.

The aim of this work was to develop a fast, simple, and reliable UPLC-MS3 method for the sensitive detection of acetochlor in biological samples. In MS3 mode, the ion transition m/z 270.1 â†’ 224.1→148.1 was chosen for quantification with butachlor as the internal standard. In the UPLC system, separation was performed on a UPLC column (2.1 × 50 mm ID, 1.7 µm) with 0.1 % FA in water and acetonitrile as mobile phases. After simple protein precipitation via acetonitrile, the method was well validated with good linearity (0.5-20 ng/mL, r > 0.995), accuracy (-3.70 %-2.98 %), and precision (<15 %). The selectivity and sensitivity were improved obviously in MS3 mode than that in MRM mode. The developed UPLC-MS3 method was successfully applied to the cellular pharmacokinetics study of acetochlor in MCF-7 cells.

[Content determination of seven active components of Eucommiae Cortex in aortic vascular endothelial cells of spontaneously hypertensive rats by UPLC-MS/MS].

In the present study, the contents of seven active components [genipinic acid(GA), protocatechuic acid(PCA), neochlorogenic acid(NCA), chlorogenic acid(CA), cryptochlorogenic acid(CCA),(+)-pinoresinol di-O-ß-D-glucopyranosid(PDG), and(+)-pinoresinol 4'-O-ß-D-glucopyranoside(PG)] of Eucommiae Cortex in aortic vascular endothelial cells of spontaneously hypertensive rats(SHR) were simultaneously determined by ultra-high liquid chromatography-triple quadrupole mass spectrometry(UPLC-MS/MS). The qualified SHR models were selected. The primary aortic endothelial cells(VECs) of rats were separated and cultured by ligation and adherence, followed by subculture. After successful identification, an UPLC-MS/MS method for simultaneously determining the contents of GA, PCA, NCA, CA, CCA, PDG, PG in seven components of Eucommiae Cortex in VECs was established, including specificity, linearity, matrix effect, recovery, accuracy, precision and stability. The established method had the lo-west limit of quantification of 0.97-4.95 µg·L~(-1), accuracy of 87.26%-109.6%, extraction recovery of 89.23%-105.3%, matrix effect of 85.86%-106.2%, and stability of 86.00%-112.5%. Therefore, the established accurate UPLC-MS/MS method could rapidly and simultaneously determine the contents of the seven active components of Eucommiae Cortex in VECs of SHRs, which provided a refe-rence for the study of cellular pharmacokinetics of active components of Eucommiae Cortex extract.

A new triphenylphosphonium-conjugated amphipathic cationic peptide with improved cell-penetrating and ROS-targeting properties.

We study for the first time whether triphenylphosphonium (TPP) moiety can improve cellular delivery and redox properties of amphipathic cationic peptides based on YRFK/YrFK cell-penetrating and cytoprotective motif. TPP moiety was found to increase reducing activity of both stereoisomeric peptides in solution and on electrode surface in association with TPP-mediated intramolecular interactions. Among TPP-conjugated peptides, newly synthesized TPP3-YrFK featured both increased antioxidant efficacy and proteolytic resistance. TPP-conjugated peptides preferably mitigated endogenic ROS in mitochondria and cytoplasm of model glioblastoma cells with increased oxidative status. This anti-ROS effect was accompanied by mild reversible decrease of reduced glutathione level in the cells with relatively weak change in glutathione redox forms ratio. Such low interference with cell redox status is in accordance with non-cytotoxic nature of the compounds. Intracellular concentrations of label-free peptides were analyzed by LC-MS/MS, which showed substantial TPP-promoted penetration of YrFK motif across cell plasma membrane. However, according to ΔΨm analysis, TPP moiety did not profoundly enhance peptide interaction with mitochondrial inner membrane. Our study clarifies the role of TPP moiety in cellular delivery of amphipathic cationic oligopeptides. The results suggest TPP moiety as a multi-functional modifier for the oligopeptides which is capable of improving cellular pharmacokinetics and antioxidant activity as well as targeting increased ROS levels. The results encourage further investigation of TPP3-YrFK as a peptide antioxidant with multiple benefits.

In vitro co-culture systems of hepatic and intestinal cells for cellular pharmacokinetic and pharmacodynamic studies of capecitabine against colorectal cancer.

BACKGROUND: As a prodrug of 5-fluorouracil (5-FU), orally administrated capecitabine (CAP) undergoes preliminary conversion into active metabolites in the liver and then releases 5-FU in the gut to exert the anti-tumor activity. Since metabolic changes of CAP play a key role in its activation, a single kind of intestinal or hepatic cell can never be used in vitro to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) nature. Hence, we aimed to establish a novel in vitro system to effectively assess the PK and PD of these kinds of prodrugs. METHODS: Co-culture cellular models were established by simultaneously using colorectal cancer (CRC) and hepatocarcinoma cell lines in one system. Cell Counting Kit-8 (CCK-8) and flow cytometric analysis were used to evaluate cell viability and apoptosis, respectively. Apoptosis-related protein expression levels were measured using western blot analysis. A selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for cellular PK in co-culture models. RESULTS: CAP had little anti-proliferative effect on the five monolayer CRC cell lines (SW480, LoVo, HCT-8, HCT-116 and SW620) or the hepatocarcinoma cell line (HepG2). However, CAP exerted marked anti-tumor activities on each of the CRC cell lines in the co-culture models containing both CRC and hepatocarcinoma cell lines, although its effect on the five CRC cell lines varied. Moreover, after pre-incubation of CAP with HepG2 cells, the culture media containing the active metabolites of CAP also showed an anti-tumor effect on the five CRC cell lines, indicating the crucial role of hepatic cells in the activation of CAP. CONCLUSION: The simple and cost­effective co-culture models with both CRC and hepatocarcinoma cells could mimic the in vivo process of a prodrug dependent on metabolic conversion to active metabolites in the liver, providing a valuable strategy for evaluating the PK and PD characteristics of CAP-like prodrugs in vitro at the early stage of drug development.

Content determination of seven active components of Eucommiae Cortex in aortic vascular endothelial cells of spontaneously hypertensive rats by UPLC-MS/MS / 中国中药杂志

In the present study, the contents of seven active components [genipinic acid(GA), protocatechuic acid(PCA), neochlorogenic acid(NCA), chlorogenic acid(CA), cryptochlorogenic acid(CCA),(+)-pinoresinol di-O-β-D-glucopyranosid(PDG), and(+)-pinoresinol 4'-O-β-D-glucopyranoside(PG)] of Eucommiae Cortex in aortic vascular endothelial cells of spontaneously hypertensive rats(SHR) were simultaneously determined by ultra-high liquid chromatography-triple quadrupole mass spectrometry(UPLC-MS/MS). The qualified SHR models were selected. The primary aortic endothelial cells(VECs) of rats were separated and cultured by ligation and adherence, followed by subculture. After successful identification, an UPLC-MS/MS method for simultaneously determining the contents of GA, PCA, NCA, CA, CCA, PDG, PG in seven components of Eucommiae Cortex in VECs was established, including specificity, linearity, matrix effect, recovery, accuracy, precision and stability. The established method had the lo-west limit of quantification of 0.97-4.95 μg·L~(-1), accuracy of 87.26%-109.6%, extraction recovery of 89.23%-105.3%, matrix effect of 85.86%-106.2%, and stability of 86.00%-112.5%. Therefore, the established accurate UPLC-MS/MS method could rapidly and simultaneously determine the contents of the seven active components of Eucommiae Cortex in VECs of SHRs, which provided a refe-rence for the study of cellular pharmacokinetics of active components of Eucommiae Cortex extract.

Cellular toxicity and pharmacokinetic study of butachlor by ultra-performance liquid chromatography-tandem mass spectrometry based on tandem mass spectrometry cubed technique.

Butachlor is an aromatic amide compound that plays a role as a herbicide, a xenobiotic, and an environmental contaminant. The aim of this work was to develop a highly selective and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method based on the tandem mass spectrometry cubed technique to determine butachlor in a biological matrix. Butachlor and internal standard acetochlor were separated on a Waters Acquity ultra-performance liquid chromatography BEH C18 column (2.1 × 50 mm, 1.7 µm) with gradient elution using 0.1% formic acid aqueous solution (A) and acetonitrile (B) as mobile phases. The transitions selected for tandem mass spectrometry cubed quantitative analysis in positive ion mode were: for butachlor, mass-to-charge ratio 312.2→238.1→162.1; for acetochlor, mass-to-charge ratio 270.1→224.0→148.1. The total running time for each sample was 5.5 min. The ultra-performance liquid chromatography-tandem mass spectrometry cubed method showed a linear relationship (R2 ≥ 0.995) in the concentration range of 0.5-100 ng/ml. The intra and interday accuracies are within the range of -10.6%-4.3% and precisions are between 4.48% and 13.14%. The novelty of the method is the use of tandem mass spectrometry cubed scanning mode, which improves selectivity and sensitivity. The results indicated that butachlor was cellular toxic. The safety of butachlor should be considered when it is used as a herbicide.

Comparative pharmacokinetic study of the five anti-inflammatory active ingredients of Inula cappa in a normal and an LPS-induced inflammatory cell model.

Inula cappa is a commonly used medicine in the Miao area of Guizhou Province in China. We established an in vitro inflammatory model of mouse macrophage RAW264.7 cells to study the different pharmacokinetics of five anti-inflammatory active ingredients in the I. cappa extract namely luteolin (LUT), chlorogenic acid (CA), cryptochlorogenic acid (CCA), 3,4-dicaffeoylquinic acid (3,4-DCQA) and 4,5-dicaffeoylquinic acid (4,5-DCQA), in a normal and an inflammatory cell model. First, RAW264.7 cells were treated in vitro with l µg/mL lipopolysaccharide (LPS) for 24 h to establish an inflammatory cell model. Then, the pharmacokinetic characteristics of the five ingredients were compared in normal and inflammatory cells after treatment with 200 µg/ml and 800 µg/ml of I. cappa extracts. After treatment with 1 µg/ml LPS for 24 h, the volume of RAW264.7 cells was increased, the morphology was changed, the antennae were obvious, and the secretion of inflammatory factors nitric oxide and TNF-α was increased. The pharmacokinetics results showed that the five ingredients in normal and inflammatory cells exhibited an increase in Cmax and AUC values with increasing doses, and the Cmax and AUC values of five ingredients were positively correlated with the extract concentration. Each of these five ingredients presented nonlinear pharmacokinetic characteristics. After treatment with 200 µg/ml of I. cappa extract, the uptake of five ingredients increased in inflammatory cells, Tmax was prolonged, MRT and t1/2 were prolonged, and CL_F and Vz_F were decreased, while after treatment with 800 µg/ml of I. cappa extract, the uptake of five ingredients decreased, Tmax was prolonged, absorption was faster, and MRT and t1/2 were prolonged. The five analyzed components in I. cappa extract exerted different effects on normal cells and LPS-induced inflammatory cells. Compared to normal cells, the uptake of five ingredients in inflammatory cells was faster and the AUC and Cmax values increased with increasing doses, showing a dose-dependent nonlinear pharmacokinetic profile. These results indicate that the pharmacokinetic effects of the five analyzed ingredients in I. cappa extract are changed in the inflammatory state.

Development and validation of a liquid chromatography-tandem mass spectrometry method for CPUL1, a novel antitumor candidate compound, and its application to pharmacokinetic studies.

An active substance of pyrano[3,2-a]phenazine, also called CPUL1, is a synthesized phenazine derivative and displays broad-spectrum anticancer activities. Quantitative assessment of CPUL1 in biological samples has not been well established, hindering pharmaceutical development and application. According to international guidelines, a sensitive and selective liquid chromatography-tandem mass spectrometry method in negative ion mode was developed and validated for quantification of CPUL1 in human plasma, colorectal cancer cell lines, and rat plasma, whereby linearity and accuracy were demonstrated for the range of 1-1000 ng/ml. The validated liquid chromatography-tandem mass spectrometry method was successfully employed in pharmacokinetic studies of CPUL1 in vitro and in vivo. Notably, the cellular pharmacokinetic behavior of CPUL1 varies in colorectal cancer cell lines. Regarding the pharmacokinetic processes in vivo, oral absorption was less effective than an injection, with a bioavailability of 23.66%. CPUL1 was linearly eliminated after a single administration; however, it could accumulate in tissues (heart, liver, spleen, lung, and kidney) after multiple injections. In summary, this study established a capable bioanalytical method for CPUL1 and provided exploratory pharmacokinetic data, paving the way for use of this promising derivative in disease models.

Advanced Research in Cellular Pharmacokinetics and its Cutting-edge Technologies.

Pharmacokinetics (PK), as a significant part of pharmacology, runs through the overall process of the preclinical and clinical research on drugs and plays a significant role in determining the material basis of efficacy and mechanism research. However, due to the limitations of classical PK, cellular PK was put forward and developed rapidly. Many novel and original technologies have been innovatively applied to cellular PK research, thereby providing powerful technical support. As a novel field of PK research, cellular PK expands the research object and enriches the theoretical framework of PK. It provides a new perspective for elucidating the mechanism of drug action and the dynamic process of drug in the body. Furthermore, it provides a scientific basis and guiding significance for the development of new drugs and clinical rational drug use. Cellular PK can explain the dynamic process of certain drugs (e.g., antineoplastic drugs and antibiotics) and the disposition kinetics characteristics in some specific tissues (e.g., brain and tumor) in a clearer and more accurate manner. It is a beneficial supplement and the perfection of traditional PK. In the future, traditional and cellular PKs will complement each other well and improve into an all-around research system in drug developments. Briefly, this paper reviews the conceptual development of cellular PK and key associated technologies, explores its main functions and applications, and looks forward to the important pioneering significance and promising value for the development of PK.

Biodistribution and pharmacokinetic profile of berberine and its metabolites in hepatocytes.

BACKGROUND: Berberine has been shown in clinical studies to have many health benefits, including anti-inflammatory and antioxidant properties, along with gut-flora balancing properties. However, its clinical efficacy is hindered by its low oral bioavailability and rapid metabolism. PURPOSE: This study aims to identify the berberine metabolites' forms and characterize their biodistribution patterns in and out of HepG2 cells. METHODS: The qualitative analysis of metabolites of berberine in HepG2 cells was performed using the LC/MSn-IT-TOF method. Subsequent cellular pharmacokinetics characterization of intracellular and extracellular berberine and its metabolites was performed by LC-MS/MS analysis. RESULTS: Berberine's metabolites of phase I metabolism were demethyleneberberine, jatrorrhizine, columbamine, berberrubine, etc., while its phase II metabolites were sulfate and glucuronide conjugates of phase I metabolites. Among the phase I metabolites of berberine, jatrorrhizine+columbamine accounted for over two-thirds of the total, followed by demethyleneberberine, which accounted for about a quarter. The intracellular demethyleneberberine is 25.14 times more enriched than extracellular demethyleneberberine. On the other hand, jatrorrhizine+columbamine and berberrubine were primarily distributed extracellularly, and their extracellular concentrations were 7.13 times and 15.61 times of their intracellular concentrations, respectively. Berberine metabolites produced in phase II metabolism are predominantly sulfate conjugates. CONCLUSION: Our results show that demethyleneberberine is highly concentrated intracellularly in HepG2, possibly because it is an essential metabolite of berberine that likely contributes to berberine's efficacy. In light of our findings, berberine's poor plasma concentration-effectiveness characteristics have been partially explained.

Development and application of a rapid and sensitive liquid chromatography-mass spectrometry method for simultaneous analysis of cytarabine, cytarabine monophosphate, cytarabine diphosphate and cytarabine triphosphate in the cytosol and nucleus.

In this study, a sensitive and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous analysis of cytarabine (ara-C), cytarabine monophosphate (ara-CMP), cytarabine diphosphate (ara-CDP) and cytarabine triphosphate (ara-CTP) in the cytosol and nucleus. The separation of analytes and endogenous interferents was achieved in 8 min on a hypercarb column (2.1 mm × 100 mm, 3 µm) by using a gradient elution with 95% acetonitrile and aqueous 5 mM hexylamine with 0.4% (v/v) diethylamine adjusted to pH 10. The analytes were detected with both negative and positive electrospray ionization in multiple reaction monitoring (MRM) mode. The calibration curve demonstrated good linearity ranging from 5 to 750 nM for ara-C, 50-7500 nM for ara-CMP, 20-3000 nM for ara-CDP and 1-150 nM for ara-CTP in the cytosol. In the nucleus, good linearity was achieved over a concentration range of 1-100 nM for ara-C, 5-500 nM for ara-CMP, 2.5-250 nM for ara-CDP and 0.5-50 nM for ara-CTP. Intra- and interbatch accuracies and precisions met the standards of validation. The matrix effect, recovery and stability were also within acceptable ranges. After incubation with 10 µM ara-C for 3 h, the levels of ara-C, ara-CMP, ara-CDP and ara-CTP in the cytosol and nucleus of HL-60 cells and HL-60/ara-C cells were determined. Most of the metabolites were found within the quantitation range. The results showed that the nuclear ara-CTP level was significantly different than the intracellular ara-CTP level between HL-60 and HL-60/ara-C cells.

[Establishment of PK-PD model in anti-inflammatory active components in Inula cappa extract based on lipopolysaccharide-induced in vitro inflammation model].

In the present study, a pharmacokinetics(PK)-pharmacodynamics(PD) model in the anti-inflammatory active components in Inula cappa extract was established based on the lipopolysaccharide(LPS)-induced in vitro inflammation model in order to clarify the relationship between the dynamic changes of anti-inflammatory active components in inflammatory cells and their efficacy. Firstly, the inflammation model in vitro was induced by 1 µg·mL~(-1) LPS in RAW264.7 cells for 24 h. After treatment with 400 µg·mL~(-1) I. cappa extract, the pharmacokinetics(PK) of five anti-inflammatory active components, including luteolin(LUT), chlorogenic acid(CA), cryptochlorogenic acid(CCA), 3,4-dicaffeoylquinic acid(3,4-DCQA), and 4,5-dicaffeoylquinic acid(4,5-DCQA), in normal cells and inflammatory cells was compared. Meanwhile, the PD study was carried out by measuring the inflammatory factors NO and TNF-α in the cell supernatant at each time point, which was fitted with PK by the Phoenix Model in the WinNonlin 8.2 to establish the PK-PD model for five components including LUT, CA, CCA, 3,4-DCQA, and 4,5-DCQA. The results showed that compared with normal cells, the model cells showed increased or decreased uptake of five components, advanced T_(max), faster absorption, prolonged MRT and t_(1/2), and increasing or decreasing trend of CL_(z/F) and V_(z/F). When NO was used as the efficacy index, the PK-PD model after the integration of the multi-effect components in I. cappa was E=7.45×\[1-Ce~(5.74)/(78.24~(5.74)+Ce~(5.74))\], while with TNF-α as the efficacy index, the PK-PD model after the integration of the multi-effect components in I. cappa was E=79.28×[1-Ce~(6.45)/(85.10~(6.45)+Ce~(6.45))]. The results of the study suggested that the inflammatory state could change the cellular PK of I. cappa. The anti-inflammatory effect of active components in I. cappa might be related to the down-regulation of the secretion of NO and TNF-α in inflammatory cells, and NO and TNF-α might serve as the anti-inflammatory targets of active components of I. cappa.

[Pharmacokinetic study of Polygonum orientale extract in H9c2 cells by UPLC-MS/MS].

A detection method of ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was established to detect concentrations of isoorientin, orientin, quercetin, vitexin and kaempferol-3-O-ß-D-glucoside in H9 c2 cells and applied to the pharmacokinetic study of Polygonum orientale extract in the cells. H9 c2 cells were treated with 100 µg·mL~(-1) P. orientale extract and then they and the corresponding nuclei, mitochondria and Golgi bodies were collected at the set time. After protein precipitation, UPLC-MS/MS was used to determine concentrations of isoorientin, orientin, quercetin, vitexin and kaempferol-3-O-ß-D-glucoside in the whole cells and subcellular structures. Also, related pharmacokinetic parameters were calculated. The results showed that the peak time was 8 h for all these components. Orientin, vitexin, quercetin and isoorientin have high affinities to nuclei and mitochondria, while the affinity of kaempferol-3-O-ß-D-glucoside is higher with mitochondria compared to nuclei. It is suggested that these chemical components of P. orientale may mainly act on nuclei or mitochondria to exert pharmacological effects of protecting cardiomyocytes.

Ginsenoside 20(S)-Rh2 promotes cellular pharmacokinetics and intracellular antibacterial activity of levofloxacin against Staphylococcus aureus through drug efflux inhibition and subcellular stabilization.

Intracellular Staphylococcus aureus (S. aureus) often causes clinical failure and relapse after antibiotic treatment. We previously found that 20(S)-ginsenoside Rh2 [20(S)-Rh2] enhanced the therapeutic effect of quinolones in a mouse model of peritonitis, which we attributed to the increased concentrations of quinolones within bacteria. In this study, we investigated the enhancing effect of 20(S)-Rh2 on levofloxacin (LVF) from a perspective of intracellular bacteria. In S. aureus 25923-infected mice, coadministration of LVF (1.5 mg/kg, i.v.) and 20(S)-Rh2 (25, 50 mg/kg, i.g.) markedly increased the survival rate, and decreased intracellular bacteria counts accompanied by increased accumulation of LVF in peritoneal macrophages. In addition, 20(S)-Rh2 (1, 5, 10 µM) dose-dependently increased the uptake and accumulation of LVF in peritoneal macrophages from infected mice without drug treatment. In a model of S. aureus 25923-infected THP-1 macrophages, we showed that 20(S)-Rh2 (1, 5, 10 µM) dose-dependently enhanced the intracellular antibacterial activity of LVF. At the cellular level, 20(S)-Rh2 increased the intracellular accumulation of LVF by inhibiting P-gp and BCRP. PK-PD modeling revealed that 20(S)-Rh2 altered the properties of the cell but not LVF. At the subcellular level, 20(S)-Rh2 did not increase the distribution of LVF in lysosomes but exhibited a stronger sensitizing effect in acidic environments. Molecular dynamics (MD) simulations showed that 20(S)-Rh2 improved the stability of the DNA gyrase-LVF complex in lysosome-like acidic conditions. In conclusion, 20(S)-Rh2 promotes the cellular pharmacokinetics and intracellular antibacterial activities of LVF against S. aureus through efflux transporter inhibition and subcellular stabilization, which is beneficial for infection treatment.

Research progress on metabolism and efficacy of small molecular prodrug nanosystems responsive to tumor redox microenvironment / 药学学报

Compared with normal tissues and cells, the tumor microenvironment has significant differences. For example, glutathione-related metabolic enzymes and reactive oxygen species are highly expressed in different subcellular structures, resulting in an unbalanced redox state. Aiming at the specific redox state in tumor tissues and cells, a series of small molecule prodrug self-assembled nanoparticles can be designed and connected by intelligent response linkers including disulfide bonds, sulfide bonds, and selenium bonds, thioketal bonds, etc. The in vitro and in vivo efficiency and metabolic mode of these nanoparticles are related to the type of linker. This review will summarize the tumor redox microenvironment, the design of intelligent responsive small molecule prodrug nanoparticles, and the metabolic pathways of small molecule prodrug nanoparticles with different connecting linkers and their relationship with drug efficacy.

Pharmacokinetic study of Polygonum orientale extract in H9c2 cells by UPLC-MS/MS / 中国中药杂志

A detection method of ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was established to detect concentrations of isoorientin, orientin, quercetin, vitexin and kaempferol-3-O-β-D-glucoside in H9 c2 cells and applied to the pharmacokinetic study of Polygonum orientale extract in the cells. H9 c2 cells were treated with 100 μg·mL~(-1) P. orientale extract and then they and the corresponding nuclei, mitochondria and Golgi bodies were collected at the set time. After protein precipitation, UPLC-MS/MS was used to determine concentrations of isoorientin, orientin, quercetin, vitexin and kaempferol-3-O-β-D-glucoside in the whole cells and subcellular structures. Also, related pharmacokinetic parameters were calculated. The results showed that the peak time was 8 h for all these components. Orientin, vitexin, quercetin and isoorientin have high affinities to nuclei and mitochondria, while the affinity of kaempferol-3-O-β-D-glucoside is higher with mitochondria compared to nuclei. It is suggested that these chemical components of P. orientale may mainly act on nuclei or mitochondria to exert pharmacological effects of protecting cardiomyocytes.

Cellular pharmacokinetics and pharmacodynamics mechanisms of ginkgo diterpene lactone and its modulation of P-glycoprotein expression in human SH-SY5Y cells.

Ginkgo diterpene lactone (GDL) is the raw material for ginkgo diterpene lactone meglumine injection, which is used for treating cerebral ischemia. The aims of this study were to explore the cellular pharmacokinetics of GDL in whole cells and subcellular fractions, and detect cellular pharmacodynamics on the human SH-SY5Y cells induced by oxygen-glucose deprivation and reoxygenation (OGD/R). Firstly, a simple, sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for assessing the amount of ginkgolide A (GA), B (GB) and K (GK) in cellular/subcellular samples. Then, phosphatidylserine and mitochondria membrane potential were assayed to evaluate the extent of apoptosis effect. The study showed that the cellular/subcellular accumulation of GA and GB were increased in a concentration-dependent manner; the levels of GA and GB in cytosol were the highest among these subcellular organelles. Meanwhile, GDL also attenuated the OGD/R-induced increases in the percentage of apoptotic and mitochondria membrane potential. In addition, verapamil increased the rate and amount of GA and GB entering cellular/subcellular compartments through inhibition of P-glycoprotein activity, and promoted the protective effect of GDL. The present study reports the cellular pharmacokinetics profiles of GA and GB in normal and OGD/R-induced SH-SY5Y cells in vitro for the first time, which provided valuable information for clinical safety application.

Mitochondrial membrane potential played crucial roles in the accumulation of berberine in HepG2 cells.

Berberine is a natural alkaloid that has antineoplastic effects. However, in hepatoma cells like HepG2, the expressions of uptake transporters are minimal but efflux transporters are relatively high. Hence, how berberine enters and reaches a cytocidal concentration remains to be elucidated. In the present study, we revealed the accumulation mechanism of berberine in HepG2 cells. Cell organelles were isolated based on differential centrifugation; berberine concentration was measured using a liquid chromatography-tandem mass chromatography method or flow cytometry. Subcellular distribution of berberine was observed using a laser scanning confocal microscopy. The results showed that berberine was concentration-, temperature-, and time-dependently taken up and accumulated in HepG2 cells. Membrane drug transporters and cell membrane potential had limited effects in berberine uptake. However, qualitative and quantitative studies showed that berberine was enriched in the mitochondria; inhibition of mitochondrial membrane potential (MMP) by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) significantly decreased the intracellular berberine by up to 70%. More importantly, MMP not only significantly enhanced berberine uptake driven by cell membrane potential (P<0.01) but also inhibited p-glycoprotein (P-gp)-mediated berberine efflux (P<0.01). In brief, our results for the first time showed that MMP played crucial roles in berberine accumulation in HepG2 cells.

A Cell-Level Systems PK-PD Model to Characterize In Vivo Efficacy of ADCs.

Here, we have presented the development of a systems pharmacokinetics-pharmacodynamics (PK-PD) model for antibody-drug conjugates (ADCs), which uses intracellular target occupancy to drive in-vivo efficacy. The model is built based on PK and efficacy data generated using Trastuzumab-Valine-Citrulline-Monomethyl Auristatin E (T-vc-MMAE) ADC in N87 (high-HER2) and GFP-MCF7 (low-HER2) tumor bearing mice. It was observed that plasma PK of all ADC analytes was similar between the two tumor models; however, total trastuzumab, unconjugated MMAE, and total MMAE exposures were >10-fold, ~1.6-fold, and ~1.8-fold higher in N87 tumors. In addition, a prolonged retention of MMAE was observed within the tumors of both the mouse models, suggesting intracellular binding of MMAE to tubulin. A systems PK model, developed by integrating single-cell PK model with tumor distribution model, was able to capture all in vivo PK data reasonably well. Intracellular occupancy of tubulin predicted by the PK model was used to drive the efficacy of ADC using a novel PK-PD model. It was found that the same set of PD parameters was able to capture MMAE induced killing of GFP-MCF7 and N87 cells in vivo. These observations highlight the benefit of adopting a systems approach for ADC and provide a robust and predictive framework for successful clinical translation of ADCs.