Establishment of a method for detecting propofol concentration in plasma and its application in patients with lymphedema / 中国药房

OBJECTIVE To establish a method for the determination of propofol concentration in human plasma and apply it in patients with lymphedema. METHODS The concentration of propofol was determined by UPLC-MS/MS after protein precipitation of plasma samples using thymol as internal standard. The sample was eluted on a Kinetex C18 column with a mobile phase consisting of acetonitrile （A）-water （B） for gradient elution at the flow rate of 200 μL/min. The sample size was 5 μL， and the column temperature was set at 40 ℃. The sample chamber temperature was 15 ℃. Using multi-reaction monitoring mode， the ion pairs for quantitative analysis were m/z 177.0→161.2 （propofol） and m/z 149.0→133.1 （internal standard）， respectively. The above method was used to determine the plasma concentration of propofol in 6 patients with lymphedema. RESULTS The linear range of propofol was 50-5 000 ng/mL （r＝0.995 0）. RSDs of within- and between-batch precision were not more than 8.08%； no endogenous interference， carryover effect， or dilution effect was observed in blank plasma. The extraction recovery ranged from 89.80% to 93.73%， and matrix effects were within the range of 97.93%-101.73%. RSDs of the stability test were all lower than 3.27%. During intraoperative TCI 2-30 min， the plasma concentration of propofol in 6 patients was maintained in the range of 1 865.3-6 056.2 ng/mL， and the propofol was almost excreted within 4-8 h after operation. CONCLUSIONS The established UPLC-MS/MS method in this study can achieve the determination of propofol and a simple and fast sample pretreatment process without derivatization； it is proved to be suitable for the concentration monitoring of propofol in plasma samples of patients with lymphedema.

Establishment of UPLC-MS/MS method for the determination of plasma concentration of three common carbapenem antibiotics / 中国药房

OBJECTIVE To establish a UPLC-MS/MS method for the determination of plasma concentration of three carbapenem antibiotics， i.e. ertapenem （ETP）， imipenem （IPM） and meropenem （MEM）. METHODS After protein precipitation with methanol， the plasma samples were separated by ACQUITY UPLC BEH C18 column （2.1 mm×50 mm， 1.7 μm） using stable isotopes of three antibiotics （ETP-D4， IPM-D4， MEM-D6） as the internal standard. The mobile phases were 98% acetonitrile +2% water +0.1% formic acid and 98% water +2% acetonitrile +0.1% formic acid， by gradient elution. The flow rate was 0.3 mL/min and the column temperature was 40 ℃. Scanning analysis was performed in the positive ion and multiple reaction monitoring mode. RESULTS The method had good specificity， good linearity （r2≥0.993） in the range of 0.2-200， 0.1-100 and 0.1-100 μg/mL of ETP， IPM and MEM， and good intra-batch and inter-batch precision and accuracy （all RE≤5.14%， all RSD≤11.15%）， the matrix effect and extraction recovery were consistent （RSD≤12.99%）. CONCLUSIONS This study establishes the UPLC-MS/MS method to simultaneously quantify the plasma concentration of ETP， IPM and MEM. The method has the advantages of simple pretreatment， short detection time and small sample quantity to meet clinical requirement.

Research progress in therapy drug monitoring of levetiracetam / 中国药房

Levetiracetam （LEV） is the second generation of broad-spectrum anti-epileptic drug. LEV has the advantages of rapid absorption， short half-life， precise efficacy， good tolerance and few drug interactions. In order to improve the clinical efficacy of LEV， and reduce the occurrence of adverse reactions， children， pregnant women， the elderly， and patients with renal insufficiency should receive therapeutic drug monitoring （TDM）. Clinically， the samples are usually plasma or serum， and the TDM methods are mostly immunoassay or chromatography. There is currently no consensus on the effective concentration range of LEV， and the correlation between plasma concentration and adverse reactions is also unclear. The main factors affecting LEV plasma concentration include age， pregnancy， and patient compliance. How to interpret TDM results and adjust dosage based on the results will be the focus of future work.

Determination of polymyxin B concentration in plasma and its application in critically ill patients / 中国药房

OBJECTIVE To establish a method for the determination of polymyxin B concentration in plasma and apply it to clinical practice. METHODS After precipitated with 5% trichloroacetic acid solution， using polymyxin E2 as internal standard， the concentrations of polymyxin B1 and B2 in plasma sample were determined by UPLC-MS/MS. The determination was performed on BEH C18 chromatographic column with water （0.1% formic acid）-acetonitrile （0.1% formic acid） as mobile phase （gradient elution） at the flow rate of 0.5 mL/min. The sample size was 10 µL. The detection was accomplished with electrospray ionization operated in positive ion scanning by multi-reaction monitoring mode. The ion pairs for quantitative analysis were m/z 603.2→101.2 （polymyxin B1）， m/z 595.7→101.1 （polymyxin B2） and m/z 578.5→101.1 （internal standard）. The plasma concentration of polymyxin B in 79 critically ill patients was measured by the above method， the occurrence of acute renal injury （AKI） was recorded and the relationship of polymyxin B concentration in plasma with AKI was analyzed. RESULTS The linear ranges of polymyxin B1 and polymyxin B2 were 200-20 000， 50-5 000 ng/mL （r＞0.995）， and the lower limits of quantification were 200 and 50 ng/mL， respectively. RSDs of intra‐day and inter‐day precision tests were not higher than 12.06%， the average extraction recovery was 103.04%-117.44%， and RSDs of matrix effect test and stability test were all not higher than 7.42%. Steady state trough and peak plasma concentration were （2.54±2.52） and （8.17±5.20） mg/L for 79 clinical patients using polymyxin B. Eighteen patients out of 27 included patients developed AKI， with an incidence of 66.67%. The peak concentration of polymyxin B of patients without AKI was significantly lower than that of patients with AKI （P＜0.05）， but there was no significant difference in the trough concentration between two groups （P＞0.05）. CONCLUSIONS The established UPLC-MS/MS has the advantages of simple operation and high sensitivity， and can be used to monitor the plasma concentration of polymyxin B in patients. The occurrence of AKI is correlated with the peak concentration of polymyxin B.

Simultaneous determination of lacosamide and perampanel concentration in human plasma by LC-MS/MS / 中国药房

OBJECTIVE To establish a method for simultaneous determination of two third-generation anti-epileptic medicines such as lacosamide and perampanel in human plasma and apply this method in clinical practice. METHODS Using clozapine as internal standard， the concentrations of lacosamide and perampanel of plasma samples in 10 epileptic patients were determined by LC-MS/MS after protein precipitation with acetonitrile and dilution with acetonitrile-water （20∶80，V/V）， and the plasma minimum concentrations were obtained by dilution of multiple. The determination was performed on Welch Ultimate XB-C18 column， with mobile phase A consisted of 10 mmol/L ammonium formate and mobile phase B consisted of methanol-acetonitrile-isopropanol （0.2% formic acid） mixed solution （7∶1.5∶1.5， V/V/V） for gradient elution at the flow rate of 0.4 mL/min. The column temperature was set at 40 ℃ ， and the sample size was 5 μL. The electrospray ion source and multi-reaction monitoring mode were used for positive iron scanning. The ion pair used for quantitative analysis of lacosamide， perampanel and internal standard were m/z 251.2→ 144.1， m/z 350.2→219.2 and m/z 327.2→270.0， respectively. RESULTS The linear ranges of lacosamide and perampanel were 0.001 25-0.125 μg/mL（r＞0.99）， 0.037 5-3.75 ng/mL （r＞0.99）； the limits of quantification were 0.001 25 μg/mL and 0.037 5 ng/mL， respectively. The precision and accuracy within and between batches， extraction recovery rate， matrix effect， and stability all met relevant requirements. The minimum concentrations of lacosamide in No. 1-5 patients were 5.3-12.2 μg/mL， and the minimum concentrations of perampanel in No.6-10 patients were 208-510 ng/mL， respectively. CONCLUSIONS The established method is simple， rapid and suitable for the therapeutic drug monitoring of lacosamide and perampanel.

Monitoring results and influencing factors of clozapine plasma concentration in patients with mental disorders / 中国医师杂志

Objective:To analyze the influencing factors of clozapine plasma concentration in patients with mental disorders after oral administration, so as to provide reference for individualized treatment.Methods:Retrospective analysis was made on 221 inpatient reports of Clozapine blood concentration monitoring in the Therapeutic Drug Monitoring Laboratory (TDM) of the Pharmacy Department of the Chaohu Hospital Affiliated to Anhui Medical University from January to October 2021, and information such as patient gender, age, body mass index (BMI), smoking history, clozapine dose, combined drug use and blood concentration monitoring results were collected; Single factor analysis of variance and binary logistic regression were used to analyze the monitoring results of clozapine blood concentration in patients with mental disorders and its influencing factors.Results:Among 221 monitoring reports, 74 cases (normal concentration group) had clozapine plasma concentration within the effective plasma concentration range (350-600 ng/ml), 103 cases (low concentration group) were lower than the effective plasma concentration range (<350 ng/ml), and 44 cases (high concentration group) were higher than the effective plasma concentration range (>600 ng/ml). The results of single factor analysis of variance showed that there were statistically significant differences in daily dose of clozapine, standard dose, smoking history, course of disease, and abnormal liver function of patients in different blood concentration groups of clozapine (all P<0.05). The most frequently used antipsychotic drugs in 221 patients with clozapine were sodium valproate, amisulpride, aripiprazole and lithium carbonate in turn. The proportion of clozapine combined with ≥2 antipsychotics in the normal concentration group was higher than that in the low concentration group and the high concentration group, and the difference was statistically significant ( P<0.05). The results of binary logistic regression analysis showed that the combination of one antipsychotic drug and ≥ two antipsychotic drugs might help the blood concentration of clozapine in patients with mental disorders reach the target concentration (350-600 ng/ml), and the combination of two drugs was more beneficial [ OR(95% CI): 1.795(0.753-4.282)], with a statistically significant difference ( P<0.05). Conclusions:Clozapine plasma concentration varies greatly among individuals, and the therapeutic window is narrow. It is necessary to adjust the dosage in combination with the basic information and clinical information of patients, and regularly monitor the plasma concentration, so as to achieve the safety and effectiveness of individualized drug use.

Effect of continuous renal replacement therapy on plasma concentration, clinical efficacy and safety of colistin sulfate / 中华危重病急救医学

Objective:To investigate the effects of continuous renal replacement therapy (CRRT) on plasma concentration, clinical efficacy and safety of colistin sulfate.Methods:Clinical data of patients received with colistin sulfate were retrospectively analyzed from our group's previous clinical registration study, which was a prospective, multicenter observation study on the efficacy and pharmacokinetic characteristics of colistin sulfate in patients with severe infection in intensive care unit (ICU). According to whether patients received blood purification treatment, they were divided into CRRT group and non-CRRT group. Baseline data (gender, age, whether complicated with diabetes, chronic nervous system disease, etc), general data (infection of pathogens and sites, steady-state trough concentration, steady-state peak concentration, clinical efficacy, 28-day all-cause mortality, etc) and adverse event (renal injury, nervous system, skin pigmentation, etc) were collected from the two groups.Results:A total of 90 patients were enrolled, including 22 patients in the CRRT group and 68 patients in the non-CRRT group. ① There was no significant difference in gender, age, basic diseases, liver function, infection of pathogens and sites, colistin sulfate dose between the two groups. Compared with the non-CRRT group, the acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and sequential organ failure assessment (SOFA) were higher in the CRRT group [APACHE Ⅱ: 21.77±8.26 vs. 18.01±6.34, P < 0.05; SOFA: 8.5 (7.8, 11.0) vs. 6.0 (4.0, 9.0), P < 0.01], serum creatinine level was higher [μmol/L: 162.0 (119.5, 210.5) vs. 72.0 (52.0, 117.0), P < 0.01]. ② Plasma concentration: there was no significant difference in steady-state trough concentration between CRRT group and non-CRRT group (mg/L: 0.58±0.30 vs. 0.64±0.25, P = 0.328), nor was there significant difference in steady-state peak concentration (mg/L: 1.02±0.37 vs. 1.18±0.45, P = 0.133). ③ Clinical efficacy: there was no significant difference in clinical response rate between CRRT group and non-CRRT group [68.2% (15/22) vs. 80.9% (55/68), P = 0.213]. ④ Safety: acute kidney injury occurred in 2 patients (2.9%) in the non-CRRT group. No obvious neurological symptoms and skin pigmentation were found in the two groups. Conclusions:CRRT had little effect on the elimination of colistin sulfate. Routine blood concentration monitoring (TDM) is warranted in patients received with CRRT.

Anestesia total intravenosa libre de opioides guiada por qCON y qNOX en paciente obesa / Total Intravenous anesthesia in patients with intestinal occlusive syndrome

Introducción: En los últimos años la anestesia libre de opioides ha constituido una alternativa más a las técnicas tradicionales de anestesia general. Con la exclusión de este grupo de fármacos se evitan los múltiples efectos adversos y complicaciones asociados al mismo. A pesar de que la anestesia libre de opioides tiene sus indicaciones y que ha demostrado sus beneficios en cierto grupo de pacientes, existen aún controversias en relación con su utilidad en el paciente obeso. Características como la obesidad hacen que los modelos multimodales empleados para programar la anestesia libre de opioides sean cada vez más complejos. Objetivos: Describir un caso clínico realizado con la técnica de anestesia libre de opioides que constituye la primera experiencia en Ecuador. Presentación del caso: Se presenta el caso de una paciente obesa intervenida de colecistectomía laparoscópica mediante infusión de propofol, ketamina, lidocaína, sulfato de magnesio, y dexmedetomidina. La titulación de estos fármacos se realizó mediante cálculo de concentraciones plasmáticas a través de modelos farmacocinéticos y guiada por monitorización de profundidad anestésica y analgésica, con lo cual se logró optimizar el consumo de fármacos, disminuir las complicaciones y una evolución clínica favorable. Hasta donde se conoce a nivel local y de país (Ecuador) es la primera experiencia que se reporta con esta técnica. Conclusiones: La anestesia libre de opioides puede resultar una elección en el paciente obeso ya que asegura una adecuada recuperación sin efectos adversos asociados(AU)

Introduction: In recent years, opioid-free anesthesia has become another alternative in front of traditional general anesthesia techniques. The exclusion of this group of drugs avoids the numerous adverse effects and complications associated with its usage. Although opioid-free anesthesia has its indications and has showed its benefits in a certain group of patients, there is still controversy regarding its usefulness in the obese patient. Characteristics such as obesity make the multimodal models used to program opioid-free anesthesia increasingly complex. Objectives: To describe a clinical case involving the opioid-free anesthesia technique, which is the first experience in Ecuador. Case presentation: The case is presented of a female obese patient who underwent laparoscopic cholecystectomy by infusion of propofol, ketamine, lidocaine, magnesium sulfate and dexmedetomidine. Titration of these drugs was carried out by calculating plasma concentrations through pharmacokinetic models and guided by monitoring of anesthetic and analgesic depth, thus optimizing drug consumption, reducing complications and achieving a favorable clinical evolution. As far as known locally and in the country (Ecuador), this is the first reported experience with this technique. Conclusions: Opioid-free anesthesia may be a choice in the obese patient, since it ensures adequate recovery without associated adverse effects(AU)

Pharmacokinetics of a Novel Sustained-Release Vitamin C Oral Tablet: A Single Dose, Randomized, Double-Blind, Placebo-Controlled Trial

Objectives To evaluate the pharmacokinetics of a novel sustained-release oral tablet (C-Fence, Inventia Healthcare Limited, Mumbai, India). Methods We conducted a randomized, placebo controlled, parallel-design, 500 mg single-dose pharmacokinetic study of this new preparation in 18 healthy adult human subjects (nine in each group) under fasting conditions. The concentration-time profile and pharmacokinetic parameters of L-ascorbic acid, including Cmax (maximum plasma concentration), Tmax (time to reach Cmax), and AUC0-24h (area under the plasma concentration versus time curve from time 0 h to 24 h) were calculated using baseline-corrected values. Results The sustained-release tablets resulted in mean Cmax and AUC0-24h, respectively, of 1.39 ± 1.21 µg/mL and 11.72 ± 10.73 µg.h/mL against 0.18 ± 0.10 µg/mL and 0.89 ± 0.27 µg.h/mL, respectively, in the placebo group. The mean Tmax with the sustained-release tablets was 4.3 ± 2.5 h. At 12, 16, and 24 h from dosing, the concentrations were 0.6, 0.4, and 0.3 µg/mL, respectively, above baseline values. Conclusion Novel sustained-release formulations of vitamin C are expected to help achieve plasma vitamin C values above the homeostatic saturation level and result in higher steady-state plasma concentration, which might result in better cellular uptake.

Analysis of Adherence to Fluoxetine Treatment through its Plasma Concentration

Abstract Depression plays an important role in non-adherence to medical recommendations. Fluoxetine is a first line of depression treatment. This study aimed to evaluate adherence to drug therapy in fluoxetine users by different methods. A cross-section study was conducted with 53 depressed patients on fluoxetine for at least six months. Drug therapy adherence was assessed by validated questionnaires [Brief Medication Questionnaire (BMQ) and Morisky-Green test (MG)] and by the blood concentration of fluoxetine and its active metabolite norfluoxetine. Blood samples were taken before the daily first dose of fluoxetine. The plasmatic concentration of fluoxetine and norfluoxetine indicated that 58.5% volunteers were within the recommended therapeutic range and thus considered adherent to drug therapy. However, questionnaires indicated a non-adherent majority: 41.5% patients had a high degree of adherence in MG and only 13.2% were adherent to pharmacological treatment in BMQ. Most fluoxetine users showed a plasma concentration of fluoxetine and norfluoxetine within the therapeutic range, despite the low adherence to the drug therapy evaluated by the questionnaires. Thus, we suggest that plasma levels of fluoxetine and norfluoxetine could be used as the main method to check adherence to treatment.

Effect of dexmedetomidine on blood concentrations of ropivacaine during sciatic nerve block in rabbits / 中华麻醉学杂志

Objective:To evaluate the effect of dexmedetomidine on the blood concentrations of ropivacaine during sciatic nerve block in rabbits.Methods:Twelve New Zealand rabbits of both sexes, weighing 2-3 kg, were randomly divided into ropivacaine group (R group) and ropivacaine mixed with dexmedetomidine group (RD group). The right femoral vein was cannulated for blood sampling in both groups, 0.375% ropivacaine 3 ml was injected around the left sciatic nerve in group R, and 0.375% ropivacaine 3 ml containing 1.5 μg/kg dexmedetomidine was injected instead in group RD.Blood samples from the right femoral vein were collected before nerve block (T 0) and at 15, 30, 45, 60, 120 and 180 min after nerve block (T 1-6) for determination of plasma concentrations of ropivacaine using high-performance liquid chromatography after centrifugation, and concentration-time curves were plotted. Results:Compared with group R, the blood concentrations of ropivacaine were significantly decreased at T 1-3 ( P<0.05), no significant change was found in the blood concentrations of ropivacaine at T 4-6 ( P>0.05), the peak blood concentration of ropivacaine was significantly decreased ( P<0.01), and no significant change was found in the time to peak blood concentrations of ropivacaine or area under the concentration-time curves in group RD ( P>0.05). Conclusions:Dexmedetomidine can decrease the blood concentrations of ropivacaine during sciatic nerve block in rabbits.

Application of artificial neural network model in bioequivalence study of candesartan cilexetil tablets / 中国临床药理学与治疗学

AIM: To evaluate the bioequivalence of two candesartan cilexetil tablet formulations in healthy Chinese subjects after administration of a single dose, and an artificial neural network model was established to predict the candesartan plasma concentration, and provide a basis for clinical rational use of drugs. METHODS: Thirty-two healthy Chinese subjects were enrolled for oral administration of a single 8 mg dose of candesartan cilexetil tablet (test or reference product) under fasting or fed conditions to conduct a bioequivalence study. The bioequivalence results were used to build a back-propagation artificial neural network model by MATLAB software, and the model was internally and externally verified to predict the plasma concentration. RESULTS: Under both fasting and fed conditions, the C

Correlationship between ATP binding cassette subfamily B member 1 2677G>T/A gene polymorphism and cyclosporine blood concentration in patients with autoimmune diseases / 中华风湿病学杂志

Objective:To investigate the distribution of blood concentration of cyclosporine (CsA) in patients with autoimmune disease in China, and analyze the effect of genetic polymorphisms of CsA-metabolizing enzymes, transporters and target enzymes on CsA levels.Methods:Steady-state trough blood concentrations (CsA C 0) of 193 patients' were detected by enzyme multiplied immunoassay technique. The genotype of the following sites in the included patients were sequenced by reverse transcription-polymerase chain reaction (RT-PCR): cytochrome P450 (CYP) 3A420230C>T, CYP3A56986A>G, ATP binding cassette subfamily B member 1 (ABCB1)1236C>T, ABCB12677G>T/A, ABCB13435C>T, cytochrome P450 oxidoreductase (POR) 1508 C>T and formyl peptide receptor 1 (FPR1) C>G were sequenced by RT-PCR. The influence of the gene polymorphism of the above-mentioned sites on the blood concentration of CsA was analyzed by using One-way analysis of variance (ANOVA), LSD- t test, Chi-square test. Results:One hundred and ninety-three patients included took CsA. The doses ranged from 75-200 mg/d and the patients' blood concentration distribution span was wide (33.0-313.8 ng/ml). The daily dose ( χ2=21.908, P=0.001) and age( F=4.262, P=0.006) had significant effect on the plasma concentration of CsA. ABCB12677G>T/A (rs2032582) gene polymorphism impacted on the unit dose of CsA C 0 (CsA C 0/d), CsA C 0/d [(0.81±0.42) ng·ml -1·mg -1] in wild type (GG) was higher than heterozygous mutant [GT/GA, (0.65±0.30) ng·ml -1·mg -1, P=0.023) and homozygous mutant (TT/AA/TA, (0.66±0.34) ng·ml -1·mg -1, P=0.039). Conclusion:The blood concentration of patients varies greatly among individuals. The Cold of CsA in wild type patients with ABCB12677G>T/A gene is signifficantly higher than that in mutant patients.

Effects of Virus Inactivation Treatment of Plasma Specimen on Plasma Concentration Determination of Vorico- nazole，Linezolid，Vancomycin and Teicoplanin / 中国药房

OBJECTIVE：To study the effects of virus in activation treatment of plasma specimen on plasma concentration determination of voriconzole ，linezolid，vancomycin and teicoplanin. METHODS ：The remaining plasma of 36 inpatients in our hospital after routine blood concentration examination of voriconazole ，linezolid，vancomycin and teicoplanin were collected as specimen（9 drug-contained plasma specimens for each drug ），and merged into three different concentration levels （low，medium， high）of mixed samples according the results of routine blood test. Then the mixed samples with different concentration levels were divided into inactivated group and non-inactivated group ，with 3 samples in each group. The inactivated plasma samples were heated at 56 ℃ for 30 min in metal bath with constant temperature. Non-inactivated group were not treated. After pretreating plasma sample of 2 groups，2-dimensional liquid chromatography was used to detect plasma concentration of the four drugs ；the difference of detection result between inactivated group and non-inactivated group were analyzed. RESULTS ：Plasma samples containing voriconazole，linezolid，vancomycin and teicoplanin were still stable after heating at 56 ℃ for 30 min in metal bath with constant temperature. Compared with non-inactivated group ，relative error of plasma concentration detection result of above 4 drugs were all lower than 15％ in low ，medium，high concentration mixed samples of inactivated group. CONCLUSIONS ：Plasma samples can be inactivated by heating at 56 ℃ for 30 min in metal bath with constant temperature ，when the plasma concentration of voriconazole，linezolid，vancomycin and teicoplanin are determined by 2-dimensional liquid chromatography.

Effect of CYP2C19 gene polymorphism on clopidogrel concentration, platelet inhibition rate and safety in patients after PCI / 药学实践杂志

Objective To explore the effect of CYP2C19 gene polymorphism on clopidogrel plasma concentration, rate of platelet inhibition and safety. Methods We screen the patients who took clopidogrel after PCI in our hospital, according to the inclusion and exclusion criteria. Blood samples were collected on the 6th day after clopidogrel administration. Clopidogrel blood concentration was determine by RP-HPLC. The CYP2C19 genotype was detected by non-amplified immune hybridization. The rate of platelet inhibition was evaluated by the thromboelastogram. The results were analyzed by SPSS 20.0 software. Results A total of 87 patients were recruited, including 46 males and 41 females. Among them, 34 cases were fast metabolism. 38 cases were medium metabolism. 15 cases were slow metabolism. The result showed that there was no significant difference in drug concentration between fast and intermediate metabolism(P=0.667). There was a significant difference in drug concentration between slow metabolism and fast metabolism or medium metabolism(P<0.05). Analysis of variance and chi-square test showed that CYP2C19 gene polymorphism has a significant effect on clopidogrel platelet inhibition rate and safety (P<0.05). Conclusion Guiding clopidogrel clinical medication based on CYP2C19 genotype alone does not necessarily achieve better therapeutic effects. CYP2C19 genotype detection and blood concentration monitoring can be combined to guide the clinical individualized administration of clopidogrel

Determination of Pyrrotinib Concentration in Human Plasma by LC-MS/MS and Its Clinical Application / 中国药房

OBJECTIVE：To establish a method for the determination of pyrrotinib concentration in plasma ，and apply it in clinic. METHODS ：After precipitated with methanol ，the plasma sample was determined by LC-MS/MS using imatinib as internal standard. The determination was performed on Ultimate AQ-C 18 column with mobile phase consisted of methanol （containing 0.1％ formic acid ）and water （containing 0.1％ formic acid ）（gradient elution ）at the flow rate of 0.4 mL/min. The column temperature was 40 ℃，and the sample size was 5 µL. The ion source was electrospray ionization source ，and the positive ion scanning was carried out in multiple reaction mode. The ion pairs for quantitative analysis were m/z 583.4→138.3（pyrrotinib）and m/z 494.5→ 393.4（internal standard ），respectively. Thirty breast cancer patients taking pyrrotinib were collected from the Affiliated Hospital of Qingdao University during Jun.-Nov. 2020 to determine their steady-state trough concentrations of pyrrotinib after a week of treatment. RESULTS ：The linear range of pyrrotinib were 5-300 ng/mL（r＝0.999 3）. The lower limit of quantification was 5 ng/mL. RSDs of intra-day and inter-day were not higher than 9.30％，and relative errors （REs）ranged －6.70％-5.04％. REs of stability tests were in the range of －1.92％-5.42％. The extraction method ，matrix effect and residual effect did not affect the quantitative analysis of the substance to be tested. The steady-state trough concentrations of pyrrotinib were 32.6-82.8 ng/mL，with an average plasma concentration of 53.8 ng/mL；there was about 2.54 fold individual difference. CONCLUSIONS ：Established LC-MS/MS method is simple ，sensitive and accurate ，and can be used for the plasma concentration monitoring of pyrrotinib in breast cancer patient.

Determination of Aloesin in Rat Plasma by LC-MS/MS and Its Pharmacokinetic Study / 中国药房

OBJECTIVE：To establish a method for the determination of aloesin in plasma of rats ，and to investigate pharmacokinetic characteristics of aloesin. METHODS ：The plasma samples were precipitated with methanol. Using aloeresin D as internal standard ，the plasma concentration of aloesin was determined by LC-MS/MS. The determination was performed on Synergi Hydro-RP column with mobile phase consisted of 0.1‰ formic acid-methanol （gradient elution ）at the flow rate of 0.50 mL/min. The column temperature was 30 ℃，and sample size was 5 µL. The electrospray ionization source was applied to carry out negative ion detection with multiple reaction monitoring mode . The ion transitions for quantitative analysis were m/z 393.1→272.9（aloesin） and m/z 555.3→144.9（internal standard ），respectively. The concentration of aloesin in venous blood was determined by above method at 0.083，0.167，0.333，0.667，1，1.5，2.5，4，6，8，10 h after intravenous injection （3.35 mg/kg）and intragastric administration（16.75 mg/kg）of aloesin. DAS 3.0 software was used to calculate pharmacokinetic parameters. RESULTS ：The linear range of aloesin were 1-600 ng/mL（r＝0.994 5）. The lower limit of quantification was 1 ng/mL，and RSDs of within and between batches were less than 15％；accuracies within and between batches were within ±15％. The matrix factors were （92.74± 4.33）％-（94.84±2.57）％，and extraction recoveries were （69.04±2.13）％-（75.03±2.84）％；the deviation between the measured results of the stability test and the theoretical values were within ±15％. After intravenous injection and intragastric administration of aloesin ，main pharmacokinetic parameters were as follows ：cmax were（10 693.3±2 745.3）and（223.3±36.2）ng/mL；t1/2 were （2.45±1.45）and（3.33±1.91）h；AUC0－24h were（4 190.6±883.6）and（1 210.1±93.9）ng·h/mL（n＝3）. Absolute bioavailabi- lity was 11.13％. CONCLUSIONS ：The established method is rapid and sensitive for plasma determination of aloesin ，and suitable for its pharmacokinetic study.

The assay of monohydroxy carbamazepine, the active metabolite of oxcarbazepine, in human plasma by HPLC / 药学实践杂志

Objective To establish an assay method for monohydroxy carbamazepine, the active metabolite of oxcarbazepine, in human plasma. Methods Ornidazole was used as the internal standard. Plasma samples were processed with methanol and analyzed by HPLC. The column was ZORBAX Eclipse XDB-C18(150 mm×4.6 mm, 5 μm) with the mobile phase of water-acetonitrile (80∶20, V/V) at a flow rate of 1.0 ml/min. Dual wavelength detection is applied. The detection wavelength of monohydroxy carbamazepine was set at 192 nm and ornidazole at 318 nm. Results There was an excellent liner relationship for monohydroxy carbamazepine from 2 to 50 μg/ml(r= 0.998 6). The limit of quantification was 2 μg/ml with the range of accuracy between 95.57% and 100.59%. The RSD of intra-day and inter-day precisions were less than 15%. The average extraction recovery rate of MHC and internal standard were in the range of 89.62% to 98.76%. The RSD of stability was less than 6%. Conclusion This method is specific, sensitive, and easy to operate. It is suitable for the clinical assay of monohydroxy carbamazepine in human plasma.

Feasibility of the determination of plasma vardenafil level in rat by performance liquid chromatography-tandem mass spectrometry / 中华心血管病杂志

Objective: To develope and validate a reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of vardenafil concentration in plasma of rat. Methods: Plasma samples of normal Sprague-Dawley rats were collected. A Phenomenex Synergi Polar-RP 80A column (2.0 mm×50 mm, 4 µm) was used. Column temperature was set at 30 ℃. Mobile phase A was 0.1% formic acid in water; mobile phase B was 0.1% formic acid in acetonitrile. The flow rate was 0.4 ml/minutes. Quantitative determination was performed by electrospray ionization, operating in positive ion multiple reaction monitoring (MRM) mode. Cisapride was used as the internal standard. The feasibility of the method was evaluated by examining its specificity, linearity and quantitative range, precision and accuracy, matrix effects, and stability. Results: Under the selected chromatographic and mass spectrometry conditions, the monitoring ions of vardenafil and internal standard were mass-to-charge ratio（m/z) 489.3/151.2 and 466.4/234.2, the retention times of vardenafil and internal standard were 2.62 and 2.80 minutes, respectively, and the peak shape was satisfactory. The method has good linearity in the concentration range of 0.2-200 ng/ml. The intra-batch precision (%CV) and accuracy (%DEV) of vardenafil were 1.5%-9.7% and -6.8%-6.6%, respectively. The inter-batch precision and accuracy of vardenafil were 3.1% -8.4% and -3.7%-4.6%, respectively. In this sample processing method, the extraction recovery rate of vardenafil was obtained at range of 88.2%-104.6%, which met the requirements for the investigation of extraction recovery rate. In this sample processing method, the normalized matrix factor of each quality control concentration of vardenafil was 1.04, 0.85, and 1.04, and the coefficient of variation (%CV) was in the range of 1.7%-10.7%, which met the requirements for the investigation of matrix effects. Variations of short-term stability, long-term stability, and stability of 4 freeze-thaw cycles of vardenafil was within ±15%, and the coefficient of variation were within 5%. Conclusion: The high performance liquid chromatography-tandem mass spectrometry method established in this study is feasible for the measurement of concentration of vardenafil in rat plasma and this method has good specificity and high accuracy, and can be used to detect the concentration of vardenafil in rat plasma.

Pharmacokinetics Study of PELGE-crebanine Nanoparticles in Rabbits / 中国药房

OBJECTIVE：To stud y the pharmacok inetics of PELGE-crebanine nanopartic les （PELGE-Cre-NPs） in rabbits. METHODS：Totally 6 rabbits were collected ，and injected with PELGE-Cre-NPs （3.5 mg/kg）via ear vein. 1 mL of blood samples were collected at 5，15，30，60，90，120，150，180，240，300 min after administration from the ear vein. After the plasma were isolated and Cre were extracted with ethyl acetate ，HPLC method was adopted to determine the plasma concentration of Cre by using verapamil hydrochloride as internal standard. The plasma concentration-time curve was drawed and pharmacokinetic parameters were calculated by using DAS 2.0 software. Chromatographic conditions such as the chromatographic column was Agilent ZORBAX Extend-C 18；the mobile phase consisted of methanol- 0.01％ triethylamine solution （75 ∶ 25，V/V）；the flow rate was 1 mL/min；the detection wavelength was 280 nm；the column temperature was 30 ℃；the injection volume was 20 μL. RESULTS：The linear range of Cre were 45.0-3 600 µg/L（R2＝0.999 9）. RSDs of inter-day and intra-day precision and stability tests were all lower than 5％（n＝6 or n＝12）；the accuracies were （97.44±2.41）％-（98.45±3.87）％（n＝6）. PELGE-Cre-NPs was in a two-compartment model in rabbits. Main pharmacokinetic parameters included that t1/2 was（109.357±33.917）min；CL was（0.016±0.001）L/（min·kg）；MRT was （76.733±7.502）min；cmax was（3 699.458±287.713）μg/L. CONCLUSIONS：The half-life period of PELGE-Cre-NPs in rabbits is longer than that of Cre injection；its retention time in the body is prolonged ，and sustained-release effect is obvious.