Effects of Munc13-1 and Munc18-1 on dopamine secretion dysfunction in manganese-exposed SH-SY5Y cells / 环境与职业医学

Background Neurotransmitter secretion disorder induced by chronic manganese poisoning has always been one of the important causes of body injury, but the mechanism of neurotransmitter secretion disorder caused by manganese is not clear at present. Objective To investigate the effects of presynaptic membrane intracellular protein 13-1 (Munc13-1) and synapse fusion protein binding protein 18-1 (Munc18-1) on dopamine secretion dysfunction induced by manganese chloride (MnCl2) in human neuroblastoma (SH-SY5Y) cells. Methods A SH-SY5Y cell model induced by MnCl2 was established. Cell viability was measured by MTT assay. Four experimental groups were set up: control group and low-, medium-, and high-dose manganese groups (0, 100, 200, and 400 μmol·L−1 MnCl2). They were treated with corresponding doses of MnCl2 for 24 h. The secretion of dopamine was measured by enzyme-linked immunosorbent assay. The mRNA expression of Syntaxin-1 was detected by real-time quantitaive PCR. Total cell proteins were extracted, and the protein expression levels of Munc13-1, Munc18-1, and Syntaxin-1 were detected by Western blotting. The correlations of MnCl2 exposure and dopamine secretion with the protein expressions of Munc13-1 and Munc18-1 were also analyzed by Pearson correlation. Results Compared with the control group, the cell viability rate decreased gradually with the increase of manganese exposure concentration, and the difference between the medium- and the high-dose manganese groups was statistically significant (P<0.05). The concentration of dopamine in cell culture medium of all manganese exposure groups decreased with the increase of manganese concentration, and compared with the control group and the low-dose manganese group, the medium- and the high-dose manganese groups were statistically significant (P<0.05). The expression of Syntaxin-1 at mRNA or protein level did not change significantly among groups (P>0.05). Compared with the control group, the protein expression of Munc13-1 decreased and that of Munc18-1 increased with the increase of manganese concentration (P<0.05). Compared with the low-dose manganese group, the changes of Munc13-1 protein in the high-dose manganese group and Munc18-1 protein in the medium- and high-dose manganese groups had statistical significance (P<0.05). Compared with the medium-dose manganese group, the protein changes of Munc18-1 in the high-dose manganese group were statistically significant (P<0.05). The correlation analysis showed that MnCl2 dose was negatively correlated with Munc13-1 protein expression (r=−0.898, P<0.05), and positively correlated with Munc18-1 protein expression (r=0.678, P<0.05). Dopamine secretion was positively correlated with Munc13-1 protein expression (r=0.932, P<0.05), and negatively correlated with Munc18-1 protein expression (r=−0.817, P<0.05). Conclusion The inhibition of dopamine secretion in SH-SY5Y cells induced by manganese exposure is related to up-regulation of Munc18-1 and down-regulation of Munc13-1 expression levels, which may be one of the reasons for nerve injury caused by manganese.

Determination of plasma protein binding rate of Shuganning Injection using equilibrium dialysis and UPLC-MS/MS / 中国中药杂志

Traditional Chinese medicine(TCM) compound preparations have complex compositions. As a widely used TCM injection, Shuganning Injection, its in vivo processes are not yet fully understood. Determining the plasma protein binding rate is of great significance for pharmacokinetic and pharmacodynamic studies. In this experiment, the equilibrium dialysis method combined with UPLC-MS/MS technology was used to determine the plasma protein binding rates of 10 components, including p-hydroxyacetophenone, caffeic acid, baicalein, oroxylin A, geniposide, baicalin, cynaroside, oroxylin A-7-O-β-D-glucuronide, scutellarin, and hyperoside, in Shuganning Injection in rat and human plasma to provide a theoretical basis for further elucidating the in vivo processes of Shuganning Injection and guiding clinical medication. The results showed that, except for baicalein and geniposide, the plasma protein binding rates of the other eight components were higher in human plasma than in rat plasma, and there were interspecies differences. In human plasma, except for geniposide, caffeic acid, and baicalin, the plasma protein binding rates of the remaining seven components were above 80%, with baicalein and oroxylin A exceeding 90%. All components exhibit a high level of binding to plasma proteins, with the exception of geniposide.

Prediction of plasma protein binding rate based on machine learning / 中国药科大学学报

@#Predicting the protein binding rate of drugs in plasma is helpful to us in understanding the pharmacokinetic characteristics of drugs, with much value of reference for early research on drug discovery. In this study, plasma protein binding rate information of 2 452 clinical drugs were collected.Two pieces of software, Molecular Operating Environment (MOE) and Mordred, were used to calculate molecular descriptors, which were used as input features of the model.Extreme gradient boosting (XGBoost) algorithm and random forest (RF) algorithm were then used to build a machine learning model.The results showed that, compared with MOE, the prediction performance of the constructed model was better using the molecular descriptor calculated by Mordred as the input of the model.The prediction performance results of the model constructed using the XGBoost algorithm and the RF algorithm were similar, and the R2 of the optimal model were both 0.715.According to the research results, it can be concluded that the drug plasma protein binding rate is closely related to some physical and chemical properties of the drug molecule, such as water solubility, octanol/water partition coefficient and conjugated double bonds.Using these parameters to predict the plasma protein binding rate of drugs has the advantages of convenience and efficiency, which can provide reference for related pharmacokinetic studies.

Determination of Plasma Protein Binding Rate of 3 Components from Glechoma longituba by UHPLC Combined with Ultrafiltration / 中国药房

OBJECTIVE：To establish a method for the determination of plasma protein binding rate of rosmarinic acid ，caffeic acid and chlorogenic acid from Glechoma longituba . METHODS ：UHPLC method combined with ultrafiltration method was adopted to determine the plasma protein binding rate of rosmarinic acid ，caffeic acid and chlorogenic acid from G. longituba in the plasma of New Zealand rabbits. The determination was performed on a Phenomenex Luna ® C18 column with mobile phase consisted of acetonitrile （A）-0.1％ formic acid solution （B）（gradient elution ）at the flow rate of 0.5 mL/min. The column temperature was set at 45 ℃，and the detection wavelength was 327 nm. The sample size was 3 μL. RESULTS：At low ，medium and high concentrations，the plasma binding rates of rosmarinic acid were （97.78 ± 1.67）％ ，（94.32 ± 1.42）％ ，（95.12 ± 1.51）％ ， respectively（n＝3）；those of caffeic acid were （90.12±2.33）％，（89.53±1.98）％，（90.23±1.56）％，respectively（n＝3）；those of chlorogenic acid were （63.23 ± 2.12）％ ，（67.87 ± 1.06）％ ，（62.34 ± 1.34）％ ，respectively （n＝3）. CONCLUSIONS ： Established method is easy to operate and shorter time for analysis. It can be used to determine the plasma protein binding rate of rosmarinic acid ，caffeic acid and chlorogenic acid in G. longituba .

Comparison of Protein Binding Rate of DPP- 4 Inhibitor LGT- 6 in Different Species of Plasma / 中国药房

OBJECTIVE：To establish the method for determining protein binding rate of dipeptidyl peptidase- 4 inhibitor LGT- 6 in different species of plasma ，and to compare their difference. METHODS ：By equilibrium dialysis ，LGT-6（3，30，300，3 000 nmol/L）was equilibrated in rat ，monkey and human plasma （i. e. internal dialysis solution ）for 48 h，using phosphate buffer as the external dialysis solution. The concentration of LGT- 6 in internal and external dialysis solution was determined by UPLC-MS/MS using tolbutamide as internal standard ，and the plasma protein binding rate was calculated. The determination was performed on ACQUITY UPLC HSS T 3 column with water （containing 0.01％ formic acid ）-acetonitrile（containing 0.01％ formic acid ）as mobile phase at the flow rate of 0.6 mL/min. The column temperature was 40 ℃，and the sample size was 2 μL. The ion source was electrospray ion source ，and the multiple ion monitoring mode was used to carry out positive ionization scanning. The ion pairs for quantitative analysis were m/z 487.0→434.3（LGT-6），m/z 271.1→172.0（internal standard ），respectively. RESULTS ：At the concentrations of 3，30，300，and 3 000 nmol/L，the protein binding rates of LGT- 6 in rat plasma were （96.25±0.97）％，（84.16± 1.24）％，（78.25±0.61）％，（66.63±0.95）％；the protein protein binding rates in monkey plasma were （98.54±0.58）％，（87.27± 1.01）％，（79.35±0.86）％，（66.69±0.54）％；the protein binding rates in human plasma were （99.40±1.03）％，（84.48± 1.15）％，（77.62±0.77）％，（66.93±0.48）％. At the same concentration ，the protein binding rates of LGT- 6 in rat ，monkey and human plasma had no significant difference （P＞0.05）. In the same species of plasma ，there were significant differences in the plasma protein binding rates of different concentration of LGT-6 among those groups （P＜0.05），and it decreased with 才〔2016〕4015） the increase of drug concentration. CONCLUSIONS ： The method for the determination of plasma protein binding rate of LGT-6 is successfully established. The data revealed that the protein binding rate of LGT- 6 is concentration-dependent ， there was no obvious spec ies difference on protein binding rates of LGT- 6 in rat ，monkey and human plasma under the same concentration.

Population pharmacokinetics/pharmacodynamics of tigecycline in the treatment of different infectious diseases / 中国临床药理学与治疗学

AIM: To provide reference for the clinical application of tigecycline and subsequent population pharmacokinetic-pharmacodynamics study in the future. METHODS: The Chinese and English keywords of "Tigecycline", "population pharmacokinetics", "population pharmacokinetic model", "pharmacodynamics" or "Tigecycline" pharmacokinetics "were used to search the relevant references published from the time of self-establishment to June 1, 2021 in PubMed, China Knowledge Infrastructure, Wanfang and other databases. The research progress of population pharmacokinetics and pharmacodynamics of tigecycline was reviewed. RESULTS & CONCLUSION: A total of 73 relevant references were retrieved, including 8 tigecycline PPK studies and 7 tigecycline PK/PD studies. At present, tigecycline PPK models had been established in patients with complex intra-abdominal infections, skin and skin and soft tissue infections, community-acquired pneumonia, nosocomial pneumonia, septic shock and other severe infections, including 8 two-compartment models. The main covariates affecting tigecycline plasma clearance were weight-related, liver function and renal function-related parameters. Body weight was also an important factor influencing the apparent volume of distribution. The effect of different disease types on the pharmacokinetics of tigecycline was different, and it needed to be considered and selected in combination with the specific circumstances of patients when formulating clinical dosing regimens. Pharmacodynamics studies should consider not only the type of disease, pathogens and patient factors themselves, but also the characteristics of atypical nonlinear plasma protein binding of tigecycline. In order to accurately understand the efficacy of different dose regimens, it was necessary to monitor the therapeutic drugs of tigecycline.

Identification of key genes for type 1 diabetes mellitus by network-based guilt by association

SUMMARY OBJECTIVE This study aimed to propose a co-expression-network (CEN) based gene functional inference by extending the "Guilt by Association" (GBA) principle to predict candidate gene functions for type 1 diabetes mellitus (T1DM). METHODS Firstly, transcriptome data of T1DM were retrieved from the genomics data repository for differentially expressed gene (DEGs) analysis, and a weighted differential CEN was generated. The area under the receiver operating characteristics curve (AUC) was chosen to determine the performance metric for each Gene Ontology (GO) term. Differential expression analysis identified 325 DEGs in T1DM, and co-expression analysis generated a differential CEN of edge weight > 0.8. RESULTS A total of 282 GO annotations with DEGs > 20 remained for functional inference. By calculating the multifunctionality score of genes, gene function inference was performed to identify the optimal gene functions for T1DM based on the optimal ranking gene list. Considering an AUC > 0.7, six optimal gene functions for T1DM were identified, such as regulation of immune system process and receptor activity. CONCLUSIONS CEN-based gene functional inference by extending the GBA principle predicted 6 optimal gene functions for T1DM. The results may be potential paths for therapeutic or preventive treatments of T1DM.

RESUMO OBJETIVO O objetivo deste estudo é realizar uma inferência funcional genética baseada na rede de coexpressão (CEN), expandindo o escopo do princípio de "Culpa por Associação" (GBA - Guilt by Association) para prever as funções genéticas do diabetes mellitus tipo 1 (T1DM). MÉTODOS Primeiro, os dados transcritos do T1DM foram recuperados do repositório de dados genômicos para a análise dos genes diferenciais (DEGs), e foi gerada uma CEN diferencial ponderada. A área sob a curva ROC (AUC) foi escolhida para determinar a métrica de desempenho para cada termo de Ontologia Genética (GO). A análise da expressão diferencial identificou 325 DEGs no T1DM, e a análise de coexpressão gerou uma CEN diferencial com aresta de peso >0,8. RESULTADOS Um total de 282 anotações de GO com DEGs >20 foram mantidas para inferência funcional. Ao calcular a pontuação de multifuncionalidade dos genes, a inferência da função genética foi realizada para identificar as funções genéticas ideais para T1DM com base na lista de classificação genética ideal. Considerando um valor de AUC >0,7, foram identificadas seis funções genéticas ideais para a T1DM, tais como a regulação do processo imunológico e da atividade dos receptores. CONCLUSÕES A inferência funcional genética baseada em CEN, ao expandir o princípio de GBA, previu seis funções genéticas ideais para o T1DM. Os resultados podem ser caminhos potenciais para tratamentos terapêuticos ou preventivos do T1DM.

Estimation of In-vitro Plasma Protein Binding of Ampicillin in Horses Based on Spectrophotometric Method

Estimation of plasma protein binding (PPB) is of paramount importance in the pharmacokinetics characterization of drugs, as it can cause significant change in volume of distribution, clearance and half-life of the drug. Ampicillin (α-amino benzyl penicillin) is most commonly used drug in equine practice. This study was conducted to determine the extent of PPB of ampicillin in apparently healthy horses (n=6). A simple spectrophotometric method was applied for the determination of ampicillin at 320 nm wavelength, based on acid degradation product of penicillin at 75°C in presence of citrate buffer (pH 5.2) and traces of copper salt. In the study, it was observed that this method permits the detection of ampicillin to a level not beyond 1.0 μg/ml. Various concentrations of ampicillin (3.125, 6.25, 12.5, 25, 50, 100 μg/ml) were prepared in triplicate in pooled plasma collected from healthy animals. In vitro binding of ampicillin to plasma proteins was determined by employing the equilibrium dialysis technique. The study revealed that the plasma protein binding of ampicillin was to the extent of 12.8 ± 0.07 %. Binding capacity of ampicillin to plasma protein (βi) and dissociation rate constant of protein-drug complex (Kβ) in the present study were 0.34 × 10-6 ± 0.02 × 10-6 mol.gm-1 and 0.003 × 10-9 ± 0.0003 × 10-9 mol, respectively in horses. Hence, the study concluded that usage of spectrophotometric method helps in quick, cost effective and efficient results in estimation of PPB for ampicillin

Determination of plasma protein binding of peptide drug candidates by dextran-coated charcoal / 中国药科大学学报

@#The conventional equilibrium dialysis and ultrafiltration methods cannot be used to determine the protein binding of some peptides because of their non-specific adsorption on the semipermeable membrane or poor stability in the plasma. The method of dextran-coated charcoal adsorption combined with LC-MS/MS were used. Based on the kinetic principle of initial rate of candidate drugs absorbed to dextran-coated charcoal, seven phosphorylated peptides with the same amino acid sequence and different configurations in rat plasma were selected as the study model using; the protein binding in rat plasma were determined; the amino acid distribution rules affecting the changes in protein binding rates of peptide candidate drugs were summarized. The results suggest that the dextran charcoal adsorption method, as a supplementary method for the determination of plasma protein binding, is suitable for peptides or organic drug candidates that cannot be determined by traditional techniques.

In-vitro Plasma Protein Binding of Marbofloxacin in Healthy and Disease Condition of Buffalo Calves

Marbofloxacin is a broad-spectrum fluoroquinolone antibiotic developed for use in veterinary medicine for the treatment of skin and soft tissue infections in dogs and cats. Plasma protein binding plays a vital role in distribution, elimination and therapeutic effectiveness of drugs. In the present study we evaluated the plasma protein binding of marbofloxacin in healthy and liver dysfunctioned buffalo calves. In vitro binding of marbofloxacin to plasma proteins was determined by employing the equilibrium dialysis technique and further analyzed by High Performance Liquid Chromatography assay. The plasma protein binding for healthy calves ranges between 25.3±0.34% to 30.4±0.40% with an overall binding of 28.66 ± 0.421%. Kinetic constants (βi) and (Kβ) was 2.6±0.12×10-8 mole/g and 1.9±0.08×10-7 mole, respectively. The percentage of plasma protein binding for liver dysfunctioned buffalo calves extended from 24.5 - 30.3% with an overall mean of 28.59 ± 0.693%. The binding capacity of the drug to plasma proteins (βi) and dissociation rate constant of protein drug complex (Kβ) were 2.53±0.13 10-5 mole/g and 1.94±0.09×10-6 mole respectively. There was no significant change observed in plasma protein binding and the kinetic constant of liver dysfunctioned buffalo calves when compared to the healthy group

Determination of plasma protein binding rates of nine compounds of Inula cappa extraction based on method of equilibrium dialysis / 中国中药杂志

To determine the plasma protein binding rate of the nine compounds in Inula cappa extraction by the method of equilibrium dialysis. The proteins in plasma samples were precipitated by methanol, and the ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was developed for determination of the concentrations of the nine active compounds, namely chlorogenic acid, scopolin, neochlorogenic acid, cryptochlorogenic acid, 1,3-O-dicaffeoylquinic acid, galuteolin, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, 4,5-O-dicaffeoylquinic acid, with the internal standard of puerarin. We found that all components have a good linearity(r≥0.999), and accuracy, precision, extraction recovery and stability conformed to the requirements of determination, without endogenous compounds disturbing within the range of optimum concentration. This suggested that the method was stable and reliable, and could be used for the determination of the plasma protein binding rates of the nine active compounds in rat and human plasma of I. cappa. The plasma protein binding rates of the nine active compounds in rat and human plasma respectively were(41.07±0.046)%-(94.95±0.008)%, and(37.66±0.043)%-(97.46±0.013)%. According to the results, there were differences in the plasma protein binding rates of the nine compounds in I. cappa extraction between rat and human.

Determination of the protein-binding rates of gardenioside, paeoniflorin and naringin in Weiyanling granules in different species of plasma / 国际中医中药杂志

Objective To study the protein binding rates ofgardenioside,paeoniflorin and naringin in Weiyanling granules in bovine serum albumin,rat plasma and human plasma.Methods The equilibrium dialysis method was carried to determine the binding-rates of three components in Weiyanling granules in bovine serum albumin,rat plasma and human plasma.The HPLC method was used to determine the mass concentration of three components in weiyanling granules in inner and outer dialysis and to calculate the plasma protein-binding rates.Results The linear relationship,precision,extraction recovery and stability of gardenoside,paeoniflorin and naringin all conformed to the methodological requirements.Within the low,middle and high concentration (5.084,10.04 and 20.08 g/L) of Weiyanling granules,the protein-binding rates of gardenioside and bovine serum albumin were 23.77％ ± 13.39％,10.75％ ± 1.34％,5.82％ ± 6.53％,respectively;the protein-binding rates of paeoniflorin were 51.81％ ± 6.53％,30.12％ ± 6.61％,21.39％ ± 9.45％,respectively;the protein-binding rates of naringin were 70.21％ ± 3.31％,67.61％ ± 1.31％,56.00％ ± 3.46％,respectively;the protein-binding rates of gardenioside and rat plasma were 71.56％ ± 3.00 ％,43.56％ ± 12.22％,40.63％ ± 4.73％,respectively;the protein-binding rates ofpaeoniflorin and rat plasma were 55.72％ ± 1.60％,47.59％ ± 6.33％,40.07％ ± 0.72％,respectively;the protein-binding rates of naringin and rat plasma were 85.85％ ± 3.53％,85.38％ ± 0.99％,79.99％ ± 2.57％,respectively;the protein-binding rates of gardenioside and human plasma were 13.56％ ± 2.40％,3.02％ ± 2.41％,5.82％ ± 2.08％,respectively;the protein-binding rates of paeoniflorin and human plasma were 9.49％ ± 5.23％,5.01％ ± 1.10％,3.98％ ± 1.54％,respectively;the protein-binding rates of naringin and human plasma were 25.04％ ± 2.61％,26.09％ ± 13.82％,20.20％ ± 2.24％,respectively.Conclusions Within 5.084,10.04 and 20.08 g/L,the protein binding-rate of gardenioside,paeoniflorin and naringin were shown asfollow,rat plasma ＞bovine serum albumin ＞ human plasma.There were significant differences in species.

Neutrophilic Granule Protein Is a Novel Murine LPS Antagonist

Neutrophilic granule protein (NGP) was previously reported as a granular protein of neutrophils in mouse, but the function has not been known clearly. We found the presence of the possible signal peptide in NGP and validated this protein is circulating in the bloodstream. In our findings, NGP is being modified post-translationally in Golgi apparatus and endoplasmic reticulum, which is a universal character of secretory molecules with a signal peptide. The secreted NGP protein could be detected both in vitro and in vivo. NGP has sequence similarity with an antimicrobial protein cathelicidin, and we observed the aspect of inflammation of NGP. Interestingly, NGP interacts with the complex of LPS and LPS binding protein (LBP). This interaction blocks the binding of the complex of LPS and LBP to TLR4 and the downstream inflammatory signals. Furthermore, the inhibitory function of NGP against the inflammatory effect of LPS could be observed in both in vitro and in vivo. With these findings, we report NGP is a novel secretory protein to mask LPS and inhibit its function.

Study on Plasma Protein Binding Rate of Cajanonic Acid A with Different Species of Plasma by Ultrafiltration Combined with UPLC-MS/MS / 中国药房

OBJECTIVE： To compare plasma protein binding rate of cajanonic acid A with different species of plasma. METHODS：Using UPLC-MS/MS as the detection means. Plasma protein binding rate of low， medium and high concentrations of cajanonic acid A （2.5， 5， 20 μg/mL） with rats， rabbits and human plasma were determined by ultrafiltration method. The chromatographic conditions included that Waters BEH C18 as chromatographic column， WatersVanGuard BEH C18 as guard column， mobile phase consisted of ultrapure water solution containing 0.01％ formic acid （solvent A） and acetonitrile solution of 0.01％ formic acid （solvent B） gradient elution， at the flow rate of 0.15 mL/min， column temperature of 30 ℃， sample size of 2 μL. Mass spectrum condition included that ESI， negative ion mode acquisition， capillary voltage of 1.5 kV， cone voltage of 30 V， ion source temperature of 100 ℃， desolvent gas temperature of 400 ℃， cone gas flow of 50 L/h， desolvent gas flow of 800 L/h， scanning range of m/z 50→1 200. RESULTS： At the concentration of 2.5， 5 and 20 μg/mL， the plasma protein binding rates of cajanonic acid A were （75.63±0.90）％， （98.30±0.03）％ and （99.42±0.01）％ in the rats plasma； （79.61±1.08）％， （98.48±0.10）％ and （99.42±0.03）％ in rabbits plasma （n＝3）； （76.74±1.22）％， （97.99±0.11）％ and （99.37±0.01）％ in human plasma （n＝3）. At the concentration of 2.5 μg/mL， plasma protein binding rates of cajanonic acid A in plasma of rats and human were significantly lower than that in plasma of rabbits （P＜0.05）. CONCLUSIONS： The plasma protein binding rate of 5，20 μg/mL cajanonic acid A with rats， rabbits and human plasma are higher than that of 2.5 μg/mL cajanonic acid A. There is significant difference in plasma protein binding rate of 2.5 μg/mL cajanonic acid A with different species of plasma，and there is no significant difference in plasma protein binding rate of 5， 20 μg/mL cajanonic acid A with different species of plasma.

Study on Compatibility Proportion of Mongolian Medicine “Terminalia chebula Decomposing Poison of Aconitum kusnezoffii ” / 中国药房

OBJECTIVE： To investigate the best compatibility proportion of Mongolian medicine “Terminalia chebula decomposing the poison of Aconitum kusnezoffii”. METHODS： Totally 40 rats were randomly divided into blank control group （0.05％ CMC-Na）， raw A. kusnezoffii group （0.12 g/kg by crude drug） and raw A. kusnezoffii-T. chebula  （1 ∶ 3，1 ∶ 1，3 ∶ 1， mass ratio） group （0.12 g/kg raw A. kusnezoffii by raw material）， 8 rats in each group. They were given relevant medicine intragastrically once a day， for consecutive 28 d. 0.5 h after last medication， serum contents of cTn-I and MB were determined， and the changes of cardiological structure were observed； the detoxification effects of T. chebula on cardiotoxicity induced by A. kusnezoffii were investigated. Binding rates of 3 kinds of aconitine （concentrations of aconitine， mesaconitine and hypaconitine were 5， 10， 20， 40， 80， 160， 400 ng/mL） to binding rate of plasma protein with normal human plasma were determined by equilibrium dialysis combined with liquid chromtography-mass spectrometry. The concentrations of 3 kinds of aconitine were fixed as 100 ng/mL. After adding main detoxification component tannic acid in different proportions of T. chebula （1 ∶ 0.025， 1 ∶ 0.075， 1 ∶ 0.1， 1 ∶ 0.5）， the effects of them on plasma protein binding rate of 3 kinds of aconitine were investigated； the possible mechanism  of T. chebula decomposing the poison of A. kusnezoffii inducing cardiotoxicity were investigated. RESULTS： In detoxification experiment， compared with blank control group， serum contents of cTn-I and MB were increased significantly in raw A. kusnezoffii group （P＜0.05）. There were obvious pathological changes in myocardial tissue， such as disorder of cell arrangement， cell shrinkage and cytoplasm staining. Compared with raw A. kusnezoffii group， serum contents of cTn-I and MB in raw A. kusnezoffii-T. chebula （1 ∶ 3， 1 ∶ 1， 3 ∶ 1） groups were decreased significantly （P＜0.05）， and there was no significant difference between the raw A. kusnezoffii-T. chebula （3 ∶ 1， 1 ∶ 1） groups and blank control group （P＞0.05）； myocardial pathological changes were improved to varying degrees. The structure of myocardial tissue in raw A. kusnezoffii-T. chebula （3 ∶ 1） groups were similar to blank control group. In the mechanism investigation experiment under the condition of different concentrations， plasma protein binding rates of 3 kinds of aconitine with normal human plasma were about 30％， without statistical significance （P＞0.05） and significant concentration-dependent manner. After adding tannic acid， plasma protein binding rate of 3 kinds of aconitine in A. kusnezoffii was decreased to different extent； when 3 kinds of aconitine were combined with tannic acid in the ratio of 1 ∶ 0.1， 1 ∶ 0.075 and 1 ∶ 0.5， the plasma protein binding rate decreased significantly （P＜0.05）， in proportion-dependent manner. CONCLUSIONS： Compatible use of raw A. kusnezoffii-T. chebula （3 ∶ 1） show that best detoxification effect on A. kusnezoffii-induced cardiotoxicity. Under this compatibility ratio， the plasma protein binding rate of 3 kinds of aconitine in A. kusnezoffii with normal human plasma is relatively high and the free drug concentration is relatively low.

Binding characteristics of plasma protein in active parts of Daidai lipid-lowering flavonoid extract / 中国中药杂志

To study the binding capacity of active ingredients of Daidai lipid-lowering flavonoid extract and plasma protein,investigate the ways to improve the traditional formula for calculating protein binding rates based on ultrafiltration,and increase the stability and reliability of the experimental results. UPLC-MS/MS was used to establish a quantitative analysis method for simultaneous determination of active ingredients( neohesperidin and narngin) in ultrafiltrate. The protein binding rates were calculated by the traditional ultrafiltration formula. The correction factors( F) were introduced later,and the binding rates calculated with the correction factors were compared with those without the correction factors. The binding capacity of the extract and plasma protein was evaluated. The quantitative analysis method established by UPLC-MS/MS had a good specificity. The standard curve and linear range,method accuracy,precision and lower limit of quantitation all met the requirements. The method met the requirement for quantitative detection of the active ingredients in ultrafiltrate after the rat plasma was filtrated in the ultrafiltration tube. Under the experimental conditions,the binding rates of both active ingredients( neohesperidin and narngin) were higher than 90%. The active ingredients and rat plasma protein were bound in a concentration-dependent manner,with statistically significant differences( P<0. 01). There was no statistically significant difference between the protein binding abilities of the two active ingredients with rat plasma protein. Therefore,the active ingredients of Daidai lipid-lowering flavonoid extract had a relatively strong binding strength with rat plasma protein,and they were bound in a concentration-dependent manner. Additionally,when calculating protein binding rates by the traditional ultrafiltration formula,the correction factors could be introduced to effectively reflect the errors of multiple ingredient groups in traditional Chinese medicine extracts.This correction method could provide a reference thinking and practical reference for the improvement of the determination method of the traditional Chinese medicine plasma protein binding ability based on ultrafiltration.

Comparison of pharmacokinetics and tissue distribution of diosbulbin B in rats after intragastric administration of compound diosbuIbin B and ethanol extract from Dioscorea bulbifera L / 中国药理学与毒理学杂志

OBJECTIVE To characterize pharmacokinetics and tissue distribution of diosbulbin B (DIOB)in rats,and compare exposure and elimination of DIOB in plasma and tissues after ig adminis-tration of compound DIOB and ethanol extract of Dioscorea bulbifera L.(EEDB),respectively.METHODS Liquid chromatography coupled with tandem mass spectrometry method was developed and validated for quantitative determination of DIOB in plasma and tissue samples. The sensitivity, matrix effect, accuracy and precision of the method were determined. After a single ig administration of DIOB 1.3 mg·kg-1and EEDB 1.0 g·kg-1, respectively, plasma and tissues samples were collected separately from male SD rats at prescheduled time points.The drug-protein binding of DIOB in plasma and tissues was measured using Rapid Equilibrium Dialysis Assay. The concentration-time profiles of DIOB were analyzed using WinNonLin 6.4 to obtain pharmacokinetic parameters. RESULTS Rapid absorption and elimination of DIOB were observed in rats.The plasma maximum concentration(cmax),peak time(tmax) and eliminate half life(t1/2)of DIOB in rats receiving DIOB or EEDB were 312±67 and(131±84)μg·L-1(P<0.01), 0.12 ± 0.07 and (0.23 ± 0.17) h, and 1.17 ± 0.28 and (2.34 ± 0.83) h (P<0.05). DIOB was rapidly distributed in most tissues,with the AUC(0-24 h)of DIOB in lungs,liver and kidneys for DIOB and EEDB groups were 4527.0±557.7,183.0±51.1 and(64.4±22.4)ng·h·g-1,and 6507.9±424.3(P<0.01),467.5±202.7(P<0.05) and (238.6 ± 70.0) ng·h·g-1(P<0.05), respectively. The protein binding rate of DIOB was 38.7%-43.6%,61.3%-66.9% and 61.4%-64.7% in plasma,livers and lungs,respectively.The ratio of free concen-trations between tissue and plasma for lungs was more than 48,indicating the specific distribution of DIOB in lungs.CONCLUSION There is difference in pharmacokinetics and tissue distribution of DIOB in rats after taking compound DIOB and EEDB.Among the tissues detected,lungs are the major target of DIOB with the highest exposure level.These characterizations should be considered in pharmacological and toxicological studies of DIOB and relevant herbs.

Recovery rates of combination antibiotic therapy using in vitro microdialysis simulating in vivo conditions / 药物分析学报

Microdialysis is a technique used to measure the unbound antibiotic concentration in the interstitial spaces, the target site of action. In vitro recovery studies are essential to calibrating the microdialysis system for in vivo studies. The effect of a combination of antibiotics on recovery into microdialysate requires investigation. In vitro microdialysis recovery studies were conducted on a combination of vancomycin and tobramycin, in a simulated in vivo model. Comparison was made between recoveries for three different concentrations and three different perfusate flow rates. The overall relative recovery for vancomycinwas lower than that of tobramycin. For tobramycin, a concentration of 20μg/mL and flow rate of 1.0μL/min had the best recovery. A concentration of 5.0μg/mL and flow rate of 1.0μL/min yielded maximal recovery for vancomycin. Large molecular size and higher protein binding resulted in lower relative recoveries for vancomycin. Perfusate flow rates and drug concentrations affected the relative recovery when a combination of vancomycin and tobramycin was tested. Low perfusate flow rates were associated with higher recovery rates. For combination antibiotic measurement which includes agents that are highly protein bound, in vitro studies performed prior to in vivo studies may ensure the reliable measurement of unbound concentrations.

Determination of Rat Plasma Protein Binding Rate of Mesaconine by UPLC-MS/MS / 中国药学杂志

OBJECTIVE: To establish an analytical method for determination of mesaconine in rat plasma or dialysate, and study the rat plasma protein binding rate of mesaconine. METHODS: The equilibrium dialysis method was applied to determine the in vitro plasma protein binding rate of mesaconine. A UPLC-MS/MS method was established to determine mesaconine in the intra- and extradialysis samples and then the plasma protein binding rate was calculated. RESULTS: The specificity of the established UPLC-MS/MS method was very good. The calibration curve of mesaconine had good linearity over the range of 0.156 3 - 10 μg•mL-1. The intra-day and inter-day precisions and recovery met the requirements of methodology. The plasma protein binding rates of mesaconine were 18.73%, 20.20%, 26.59%, and 23.68% at the concentrations of 0.2, 0.5, 2.0, and 5.0 μg•mL-1, respectively. CONCLUSION: The method is simple, accurate and sensitive, and can meet the requirement for analysis method of biological samples. Mesaconine has a low rat plasma protein binding rate.

Application of a pharmacokinetics-pharmacodynamics approach to the free propofol plasma levels during coronary artery bypass grafting surgery with hypothermic cardiopulmonary bypass

OBJECTIVES: The objective of this study was to apply a pharmacokinetics-pharmacodynamics approach to investigate the free propofol plasma levels in patients undergoing coronary artery bypass grafting under hypothermic conditions compared with the off-pump procedure. METHODS: Nineteen patients scheduled for on-pump coronary artery bypass grafting under hypothermic conditions (n=10) or the equivalent off-pump surgery (n=9) were anesthetized with sufentanil and propofol target-controlled infusion (2 μg/mL) during surgery. The propofol concentration was then reduced to 1 μg/mL, and a pharmacokinetics-pharmacodynamics analysis using the maximum-effect-sigmoid model obtained by plotting the bispectral index values against the free propofol plasma levels was performed. RESULTS: Significant increases (two- to five-fold) in the free propofol plasma levels were observed in the patients subjected to coronary artery bypass grafting under hypothermic conditions. The pharmacokinetics of propofol varied according to the free drug levels in the hypothermic on-pump group versus the off-pump group. After hypothermic coronary artery bypass was initiated, the distribution volume increased, and the distribution half-life was prolonged. Propofol target-controlled infusion was discontinued when orotracheal extubation was indicated, and the time to patient extubation was significantly higher in the hypothermic on-pump group than in the off-pump group (459 versus 273 min, p=0.0048). CONCLUSIONS: The orotracheal intubation time was significantly longer in the hypothermic on-pump group than in the off-pump group. Additionally, residual hypnosis was identified through the pharmacokinetics-pharmacodynamics approach based on decreases in drug plasma protein binding in the hypothermic on-pump group, which could explain the increased hypnosis observed with this drug in this group of patients.