CYP2C19 and CYP2J2 genotypes predict praziquantel plasma exposure among Ethiopian school-aged children.

Metabolism of praziquantel (PZQ), a racemic mixture and the only drug approved to treat S. mansoni infection, is mediated by genetically polymorphic enzymes. Periodic school-based mass drug administration (MDA) with PZQ is the core intervention to control schistosomiasis. However data on the impact of pharmacogenetic variation, nutrition, and infection status on plasma PZQ exposure is scarce. We investigated genetic and non-genetic factors influencing PZQ plasma concentration and its metabolic ratios (trans-4-OH-PZQ/PZQ and cis-4-OH-PZQ/PZQ). Four hundred forty-six school children aged 7-15 years from four primary schools in southern Ethiopia who received albendazole and PZQ preventive chemotherapy through MDA campaign were enrolled. Genotyping for common functional variants of CYP3A4 (*1B), CYP3A5 (*3, *6), CYP2C19 (*2, *3, *17), CYP2C9 (*2, *3), and CYP2J2*7 was performed. Plasma concentrations of PZQ, trans-4-OH-PZQ, and cis-4-OH-PZQ were quantified using UPLCMS/MS. Carriers of CYP2C19 defective variant alleles (*2 and *3) had significantly higher mean PZQ plasma concentration than CYP2C19*1/*1 or *17 carriers (p = 0.005). CYP2C19*1/*1 and CYP2C19*17 carriers had higher trans-4-OH-PZQ/PZQ and cis-4-OH-PZQ/PZQ metabolic ratios compared with CYP2C19*2 or *3 carriers (p < 0.001). CYP2J2*7 carriers had lower mean PZQ plasma concentration (p = 0.05) and higher trans-4-OH-PZQ/PZQ and cis-4-OH-PZQ/PZQ metabolic ratios. Male participants had significantly higher PZQ concentration (p = 0.006) and lower metabolic ratios (p = 0.001) than females. There was no significant effect of stunting, wasting, S. mansoni or soil-transmitted helminth infections, CYP3A4, CYP3A5, or CYP2C9 genotypes on plasma PZQ or its metabolic ratios. In conclusion, sex, CYP2C19 and CYP2J2 genotypes significantly predict PZQ plasma exposure among Ethiopian children. The impact of CYP2C19 and CYP2J2 genotypes on praziquantel treatment outcomes requires further investigation.

Using maximum plasma concentration (Cmax) to personalize taxane treatment and reduce toxicity.

Taxanes are a widely used class of anticancer agents that play a vital role in the treatment of a variety of cancers. However, toxicity remains a major concern of using taxane drugs as some toxicities are highly prevalent, they can not only adversely affect patient prognosis but also compromise the overall treatment plan. Among all kinds of factors that associated with taxane toxicity, taxane exposure has been extensively studied, with different pharmacokinetic (PK) parameters being used as toxicity predictors. Compared to other widely used predictors such as the area under the drug plasma concentration curve versus time (AUC) and time above threshold plasma drug concentration, maximum plasma concentration (Cmax) is easier to collect and shows promise for use in clinical practice. In this article, we review the previous research on using Cmax to predict taxane treatment outcomes. While Cmax and toxicity have been extensively studied, research on the relationship between Cmax and efficacy is lacking. Most of the articles find a positive relationship between Cmax and toxicity but several articles have contradictory findings. Future clinical trials are needed to validate the relationship between Cmax and treatment outcome and determine whether Cmax can serve as a useful surrogate endpoint of taxane treatment efficacy.

Overexposure to venetoclax is associated with prolonged-duration of neutropenia during venetoclax and azacitidine therapy in Japanese patients with acute myeloid leukemia.

PURPOSE: An observational study was conducted to evaluate the pharmacokinetics of venetoclax and its impact on the efficacy and safety for Japanese patients with acute myeloid leukemia (AML) treated with venetoclax and azacitidine therapy. METHODS: The association between the plasma concentration, after the first cycle of azacitidine and venetoclax therapy, and the efficacy and safety was evaluated in 33 patients with untreated or relapsed/refractory AML. RESULTS: Full dose of venetoclax was administered to all patients. Venetoclax treatment was 28 day long in 82% of patients; the relative dose intensity of azacitidine was 82%. Trough concentration was significantly higher among patients with complete remission (CR) and CR with incomplete hematologic recovery (CRi) than those with the morphologic leukemia-free state and partial remission, and no response groups (P = 0.01). Median duration of grade 3 neutropenia was 28 days (range 8-46 days). Area under the concentration-time curve (AUC0-24) was significantly higher among patients with protracted grade 3 neutropenia (≥ 28 days) than those with a shorter duration (< 28 days) (P = 0.03); multivariate analysis revealed that a higher AUC0-24 was a significant predictor of a longer duration of neutropenia (odds ratio 54.3, P = 0.007). CONCLUSION: Plasma concentrations of venetoclax were variable in Japanese patients with AML. Higher plasma concentrations were associated with CR/CRi and protracted grade 3 neutropenia. Therefore, it is essential to adjust the duration of venetoclax administration based on individual pharmacokinetic data to limit total drug exposure, reduce severe neutropenia, and achieve higher efficacy.

Effect of a Declined Plasma Concentration of Valproic Acid Induced by Meropenem on the Antiepileptic Efficacy of Valproic Acid.

OBJECTIVE: This study aimed to indicate whether a declined plasma concentration of valproic acid (VPA) induced by co-administration of meropenem (MEPM) could affect the antiepileptic efficacy of VPA. METHODS: We retrospectively reviewed data of hospitalized patients who were diagnosed with status epilepticus or epilepsy between 2010 and 2019. Patients co-administered VPA and MEPM during hospitalization were screened and assigned to the exposure group, while those co-administerd VPA and other broad-spectrum antibiotics were allocated to the control group. RESULTS: The exposure group and control group included 50 and 11 patients, respectively. With a similar dosage of VPA, the plasma concentration of VPA significantly decreased during co-administration (24.6 ± 4.3 µg/mL) compared with that before co-administration (88.8 ± 13.6 µg/mL, p < 0.0001), and it was partly recovered with the termination of co-administration (39.8 ± 13.2 µg/mL, p = 0.163) in the exposure group. The inverse probability of treatment weighting estimated the treatment efficacy via changes in seizure frequency, seizure duration, and concomitant use of antiepileptic drugs, which were not significantly different between the exposure and control groups. In the exposure group, there was no significant differences in seizure frequency between the periods of before-during and before-after (p = 0.074 and 0.153, respectively). Seizure duration during VPA-MEPM co-administration was not significantly different from that before co-administration (p = 0.291). CONCLUSIONS: In this study, the reduced plasma concentration of VPA induced by the co-administration of MEPM did not affect the antiepileptic efficacy of VPA. This conclusion should be interpreted with caution, and more research is warranted. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2000034567. Registered on 10 July 2020.

Association between albumin-bilirubin grade and plasma trough concentrations of regorafenib and its metabolites M-2 and M-5 at steady-state in Japanese patients.

The aim of the present study was to determine whether the trough plasma concentrations (C0) of regorafenib and its metabolites, the N-oxide metabolite (M-2) and the desmethyl N-oxide metabolite (M-5), in 21 patients receiving regorafenib therapy were affected by albumin-bilirubin (ALBI) grade. Regorafenib was administered at dosages ranging from 40 to 160 mg once daily on a 3-week-on, 1-week-off cycle. C0 values of regorafenib and its major metabolites were measured by high-performance liquid chromatography on day 8 after treatment initiation. The C0 values of regorafenib and metabolites M-2 and M-5 were significantly lower in patients with ALBI grade 2 as compared with grade 1 (P = 0.023, 0.003 and 0.017, respectively). The total C0 of regorafenib and its metabolites was significantly higher in ALBI grade 1 patients relative to grade 2 (3.489 µg/mL vs. 1.48 µg/mL; P = 0.009). The median relative dose intensity (RDI) of patients categorized as ALBI grade 2 was significantly lower than that of grade 1 patients (21.9% vs. 62.9%; P = 0.006). In 15 colorectal cancer patients among the total 21 patients, patients with ALBI grade 2 (n = 9) had a significantly shorter median overall survival time than patients with grade 1 (n = 6; P = 0.013). Administering a low dose of regorafenib to patients with ALBI grade 2 reduces the RDI of regorafenib and lowers treatment efficacy, as an appropriate C0 of regorafenib is not maintained. Monitoring the C0 of regorafenib regularly is necessary to guide dose adjustment.

Effect of continuous renal replacement therapy on the clinical efficacy and pharmacokinetics of polymyxin B in the treatment of severe pulmonary infection.

Objective: This study aimed to evaluate the pharmacokinetics of polymyxin B in patients with ventilator-associated pneumonia caused by multi-drug resistant bacteria, and to analyze the effect of continuous renal replacement therapy (CRRT) on pharmacokinetics of polymyxin B. Methods: Thirty-five patients with ventilator-associated pneumonia caused by multi-drug resistant bacteria admitted to our hospital from June 2021 to January 2022 were selected as the subjects. The patients were divided into the standard group (n = 20) and the non-standard group (n = 15) based on the factors affecting the compliance of polymyxin B plasma concentration. The patients received with polymyxin B and the plasma concentration was monitored. According to the monitoring results, they were divided into the standard group and the non-standard group, to analyze the influencing factors of polymyxin B on the blood concentration. Besides, the patients were then divided into the control group (n = 28) and the observation group (n = 7) according to whether the patients received CRRT treatment. Patients in the control group treated with polymyxin B alone, while patients in the observation group received with polymyxin B and CRRT. The general data of patients in the two groups were compared. The levels of plasma concentration of polymyxin B measured before the next administration (Cmin), peak plasma concentration of polymyxin B measured immediately after end of infusion (Cmax) and intermediate plasma concentration measured 6 h after administration (midpoint of the dosing interval) (C1/2t) were detected and compared between the two groups. Correlation between pharmacokinetics and efficacy was analyzed by Spearman correlation. The incidence of complications and the 28-day mortality rate of the two groups were recorded. Results: The age, body mass index (BMI) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores in the non-standard group were higher than these in the standard group (p < 0.05). BMI and APACHE II scores were independent risk factors affecting the pharmacokinetics of polymyxin B in patients with severe pulmonary infection (p < 0.05). There were no significant differences in age, BMI, APACHEII score, alanine aminotransferase level, aspartate aminotransferase level, albumin level, gender and diabetes ratio between the control group and the observation group (p > 0.05). The levels of Cmin, Cmax, and C1/2t in the observation group were lower than these in the control group (p < 0.001). The response rate was 50.00% in the control group and 36.36% in the observation group (p > 0.05). The levels of Cmin, Cmax, and C1/2t in the observation group were no significant correlation with the clinical efficacy (p > 0.05), while these in the control group were positive correlation with the clinical efficacy (r = 0.485, p < 0.05). There was no significant difference in the incidence of skin pigmentation, nephrotoxicity and 28-day mortality between the two groups (p > 0.05). Conclusion: In patients with ventilator-associated pneumonia not receiving multidrug-resistant bacteria, the rate of achieving blood drug concentration with the usual recommended dose of polymyxin B was satisfactory. However, the proportion of patients with a 6-h plasma concentration exceeding the maximum plasma concentration was high. BMI and APACHE II scores were important factors affecting the pharmacokinetics of polymyxin B. In patients undergoing CRRT, the plasma concentration of polymyxin B was significantly reduced, suggesting that in patients with severe disease, plasma concentration monitoring played an important role in drug efficacy and patient safety. In patients treated with CRRT, the dose of polymyxin B may need to be increased.

Consumption of non-antibacterial drugs may have negative impact on Helicobacter pylori colonization in the stomach.

Background: Nineteen non-antibacterials were examined to show that their consumption for treatment of other diseases may inhibit Helicobacter pylori. Four antibiotics were used for comparison. Materials and methods: Agar dilution method was used to examine the susceptibility of 20 H. pylori isolates to 4 antibiotics; metronidazole (MTZ), clarithromycin (CLR), amoxicillin (AMX), tetracycline (TET) and 19 non-antibacterials; proton pump inhibitors (PPIs), H2-blockers, bismuth subsalicylate (BSS), antifungals, statins, acetaminophen (ACE), aspirin (ASA), B-vitamins (B-Vits; Vit B1, Vit B6 and Vit Bcomplex) and vitamin C (Vit C). Blood agar plates were prepared with different concentrations of drugs and spot-inoculated with bacterial suspensions. Plates were incubated at 37 °C under microaerobic conditions and examined after 3-5 days. The isolate #20 that was mucoid and resistant to 19 drugs, including MTZ and SMV was tested against combined MTZ (8 µg/mL) and SMV (100 µg/mL). Results were analyzed statistically. Results: Minimum inhibitory concentrations (MICs, µg/mL) of drugs and the frequency of susceptible H. pylori were determined as MTZ (8, 80%), CLR (2, 90%), AMX (1, 100%), TET (0.5, 70%), PPIs (8-128, 80%), H2-blockers (2000-8000, 75-80%), BSS (15, 85%), antifungals (64-256, 30-80%), statins (100-250, 35-90%), ACE (40, 75%), ASA (800, 75%), B-Vits (5000-20000, 80-100%) and Vit C (2048, 85%). Susceptibility of H. pylori isolates to 16 out of 19 non-antimicrobials (75-100%) was almost similar to those of antibiotics (70-100%) (P-value >0.05). The highest susceptibility rate (100%) belonged to Vit B1, Vit B6 and AMX. Out of 20 H. pylori isolates, 17 (85%) were susceptible to ≥13 non-antimicrobials and 3 (15%) were susceptible to < 13 (P-value <0.05). Mucoid H. pylori showed susceptibility to combination of MTZ and SMV. Conclusions: Most of non-antibacterials inhibited H. pylori isolates, similar to antibiotics but their MICs exceeded those of antibiotics and their plasma concentrations. At low plasma concentration, non-antimicrobials may act as weak antibacterials, antibiotic adjuvants and immunostimulators.

Creatine kinase elevation in chronic hepatitis B patients with telbivudine therapy: influence of telbivudine plasma concentration and single nucleotide polymorphisms of TK2, RRM2B, and NME4.

PURPOSE: To study the correlations of genetic variants of telbivudine phosphorylase kinases and telbivudine plasma concentration with creatine kinase elevation in chronic hepatitis B patients who received telbivudine. METHODS: An observational study was performed in China chronic hepatitis B patients receiving telbivudine therapy at 600 mg once daily. Plasma concentration was measured 12 h after taking telbivudine using ultra-performance liquid chromatography-tandem mass spectrometry and SNPs located in RRM2B, TK2, and NME4 was detected by MALDI-TOF mass spectrometry. All statistical analyses were performed with R 4.3.1 and all graphs were drawn by Origin 2023b and P value < 0.05 was considered statistically significant. RESULTS: A total of 140 patients receiving telbivudine therapy were recruited with a median plasma concentration of 952.49 (781.07-1238.98) ng/mL. The value of plasma concentration was proportional to the grade of creatine kinase elevation and the best telbivudine plasma concentration threshold to discriminate the grade 3/4 CK elevation was 1336.61 ng/mL. Multivariate analysis revealed that plasma concentration and rs3826160 were the independent risk factor of telbivudine-induced creatine kinase elevation. Patients with TC and CC genotype in rs3826160 not only had a higher incidence of creatine kinase elevation but also a higher plasma concentration than TT genotype carriers. CONCLUSION: Chronic hepatitis B patients with TC and CC genotype in rs3826160 have high telbivudine plasma concentration are at risk of elevated creatine kinase.

Application of Northern Goshawk Back-Propagation Artificial Neural Network in the Prediction of Monohydroxycarbazepine Concentration in Patients with Epilepsy.

INTRODUCTION: A northern goshawk back-propagation artificial neural network (NGO-BPANN) model was established to predict monohydroxycarbazepine (MHD) concentration in patients with epilepsy. METHODS: The data were collected from 108 Han Chinese patients with epilepsy on oxcarbazepine monotherapy. The results of 14 genotype variates were selected as the input layer in the first BPANN model, and the variables that had a more significant impact on the plasma concentration of MHD were retained. With demographic characteristics and clinical laboratory test results, the genotypes of SCN1A rs2298771 and SCN2A rs17183814 were used to construct the BPANN model. The BPANN model was comprehensively validated and used to predict the MHD plasma concentration of five patients with epilepsy in our hospital. RESULTS: The model demonstrated favorable fitness metrics, including a mean squared error of 0.00662, a gradient magnitude of 0.00753, an absence of validation tests amounting to zero, and a correlation coefficient of 0.980. Sex, BMI, and the genotype SCN1A rs2298771 were ranked highest by the absolute mean impact value (MIV), which is primarily associated with the concentration of MHD. The test group exhibited a range of - 20.84% to 31.03% bias between the predicted and measured values, with a correlation coefficient of 0.941 between the two. With BPANN, the MHD nadir concentration could be predicted precisely. CONCLUSION: The NGO-BPANN model exhibits exceptional predictive capability and can be a practical instrument for forecasting MHD concentration in patients with epilepsy. CLINICAL TRIAL REGISTRATION: www.chiCTR-OOC-17012141 .

Association of HTR1A Gene Polymorphisms with Efficacy and Plasma Concentrations of Atypical Antipsychotics in the Treatment of Male Patients with Schizophrenia.

Purpose: We investigate the association of HTR1A rs10042486 and rs6295 with efficacy and plasma concentrations of atypical antipsychotics in the treatment of male patients with schizophrenia. Patients and Methods: A total of 140 male patients diagnosed with schizophrenia who were treated with any single atypical antipsychotic between May 2020 and May 2022 were retrospectively included. Clinical symptoms were assessed using Positive and Negative Syndrome Scale (PANSS). All SNPs were typed using Agena Bioscience MassARRAY DNA mass spectrometry. Plasma concentrations of antipsychotics at week 3, 6 and 12 after treatment commence were analyzed using mass spectrometry. Results: For efficacy of atypical antipsychotics, we observed no significant difference between HTR1A rs10042486, rs6295 and positive symptom improvement, where the patients with heterozygous mutant at the rs10042486 and rs6295 locus were superior to those with wild-type or homozygous mutant genotypes on negative symptom improvement, especially at 12 weeks of follow-up when the difference between genotypes at the rs6295 locus have statistical significance (P = 0.037). For plasma concentration, we found that quetiapine plasma concentrations were significantly lower in patients with mutation-heterozygous types than in wild-type and homozygous mutation genotypes at week 6. In contrast, higher plasma concentrations were found for mutant heterozygous than wild genotypes in the risperidone monotherapy analysis, and the difference among genotypes at the rs6295 locus was statistically significant at 6 weeks of follow-up. Conclusion: The assessment of the correlation of genetic polymorphisms of HTR1A rs6295 and rs10042486 in male patients with schizophrenia with the monitoring of therapeutic drug concentrations and therapeutic efficacy provides a constructive foundation for the clinical individualization of antipsychotics, such as quetiapine and risperidone, which is important in selecting the dose of the medication and improving the improvement of negative symptoms.

Accurate prediction of Kp,uu,brain based on experimental measurement of Kp,brain and computed physicochemical properties of candidate compounds in CNS drug discovery.

A mathematical equation model was developed by building the relationship between the fu,b/fu,p ratio and the computed physicochemical properties of candidate compounds, thereby predicting Kp,uu,brain based on a single experimentally measured Kp,brain value. A total of 256 compounds and 36 marketed published drugs including acidic, basic, neutral, zwitterionic, CNS-penetrant, and non-CNS penetrant compounds with diverse structures and physicochemical properties were involved in this study. A strong correlation was demonstrated between the fu,b/fu,p ratio and physicochemical parameters (CLogP and ionized fraction). The model showed good performance in both internal and external validations. The percentages of compounds with Kp,uu,brain predictions within 2-fold variability were 80.0 %-83.3 %, and more than 90 % were within a 3-fold variability. Meanwhile, "black box" QSAR models constructed by machine learning approaches for predicting fu,b/fu,p ratio based on the chemical descriptors are also presented, and the ANN model displayed the highest accuracy with an RMSE value of 0.27 and 86.7 % of the test set drugs fell within a 2-fold window of linear regression. These models demonstrated strong predictive power and could be helpful tools for evaluating the Kp,uu,brain by a single measurement parameter of Kp,brain during lead optimization for CNS penetration evaluation and ranking CNS drug candidate molecules in the early stages of CNS drug discovery.

A preliminary study on plasma concentration, short-term efficacy, and safety profile of dolutegravir in Chinese people with HIV.

BACKGROUND: This study examined the plasma concentration, clinical efficacy, and safety of dolutegravir (DTG) in Chinese people with HIV (PWH). METHODS: In this observational study, HIV-positive individuals on DTG-based regimens for at least 6 months were included. Plasma DTG concentrations were measured 1 month after initiating treatment. Viral loads (VL) and CD4+ T cell counts were evaluated at baseline and after 1 and 6 months of therapy. High-performance liquid chromatography was used for measuring DTG concentrations, polymerase chain reaction for VL, and flow cytometry for CD4+ T cell counts. Safety assessments included monitoring liver enzymes, serum creatinine estimated glomerular filtration rate, and adverse reactions. RESULTS: Eighty-two Chinese PWH were enrolled. Average VL decreased significantly from baseline by 3.1 log at 1 month and 3.5 log at 6 months. CD4+ T cell counts increased from 273 cells/mm3 at baseline to 378 cells/mm3 and 446 cells/mm3 after 1 and 6 months, respectively. Seventy-five percent achieved undetectable VLs (<20 copies/mL) by 6 months. Cmax and Cτ were 4.63 and 1.98 µg/mL, respectively. The safety profile was favorable with only 4.88% experiencing transient dizziness. CONCLUSION: Preliminary findings suggest higher DTG plasma concentrations in Chinese PWH compared to Western populations, with promising short-term efficacy and safety.

Risperidone plasma level, and its correlation with CYP2D6 gene polymorphism, clinical response and side effects in chronic schizophrenia patients.

BACKGROUND: To explore the influence of CYP2D6 genetic polymorphism on risperidone metabolism, thereby affecting risperidone's effects and safeties in patients with chronic schizophrenia. METHODS: Sixty-nine subjects with chronic schizophrenia treated with risperidone were recruited. CYP2D6 genotypes was determined using targeted sequencing and translated into phenotype using activity system. Risperidone plasma concentrations were measured using HPLC. Positive and Negative Symptom Scale (PANSS) and Brief Psychiatric Rating Scale (BPRS) were used to evaluate the existence and severity of psychiatric symptoms, Barnes Akathisia Scale (BAS) and Extrapyramidal Symptom Rating Scale (ESRS) for neurological side effects. Metabolic and endocrine status assess were also included. RESULTS: The plasma drug concentrations varied hugely among individuals. Intermediate metabolizer (IM) group had higher plasma levels of RIP and dose corrected RIP concentration, RIP/9-OH-RIP ratio and C/D ratio than normal metabolizer (NM) group (p < 0.01). There was no statistic difference between responders and non-responders in dose-adjusted plasma concentrations and ratios of RIP/9-OH-RIP and C/D. The occurrence of EPS was related to active moiety levels in 4th week (p < 0.05). The prolactin (PRL) levels in two follow-ups were both significantly higher than baseline (p < 0.01). PRL change from baseline to week 4 and week 8 were both positively associated with active moiety concentration detected in week 4 (p < 0.05). CONCLUSIONS: The risperidone plasma levels have great inter- and intraindividual variations, and are associated with the CYP2D6 phenotypes, as well as the changes in serum prolactin in patients diagnosed with chronic schizophrenia.

Therapeutic drug monitoring of perampanel: Clinical utility and impact of co-medication on pharmacokinetic variability.

Background: Perampanel (PER) is a newly developed antiseizure medication (ASM). This study aimed to determine the utilization of therapeutic drug monitoring (TDM) for PER in a real-world clinical setting and investigate the influence of concomitant use of ASMs on the plasma concentration profile of PER. Method: We analyzed data from the Chang Gung Research Database, which is the largest multi-institutional electronic medical records database in Taiwan. The main outcomes were the comparisons of PER plasma concentration and the ratio of concentration to the weight-adjusted dose (C/D; [ng/mL]/[mg/kg/d]) among patients received TDM of different clinical indication and among different ASM co-medication subgroups. Results: Overall, 88 plasma samples were collected from 66 epilepsy patients treated with PER. The majority of patients (77.3 %) underwent PER TDM owing to poorly controlled seizures. There was a trend toward a higher plasma concentration and C/D ratio in those suspected of having PER toxicity owing to adverse events than of other indications. The PER concentration exhibited dose linearity. The mean PER plasma concentrations in patients co-medicated with enzyme-inducing ASMs were significantly lower than those in the patients who were not prescribed enzyme-inducing or enzyme-inhibiting ASMs, and co-medication with carbamazepine (CBZ) resulted in a significant reduction in the PER concentration. Conclusion: PER concentration exhibited a linear regression relationship with PER dose, and the plasma concentration of the drug was highly susceptible to the drug's interactions with enzyme-inducing ASMs. TDM with clear indication could help determine the influence of ASMs used concomitantly on PER concentrations and guide clinical adjustments.

In vitro release and bioaccessibility of oral solid preparations in a dynamic gastrointestinal system simulating fasted and fed states: A case study of metformin hydrochloride tablets.

Food and formulation characteristics are crucial factors affecting the gastrointestinal release and absorption kinetics of oral solid preparations. In the present study, the dynamic continuous release and bioaccessibility of metformin hydrochloride immediate-release (IR) and sustained-release (SR) tablets were investigated in the dynamic human stomach-intestine (DHSI-IV) system simulating fasted and fed states in healthy adults. Both tablet formulations (particularly IR tablet) exhibited a postponed release in the fed state compared to the fasted state. Correspondingly, the bioaccessible fraction of metformin from IR tablets in the presence of high-fat meal was significantly reduced to 76.2 % of the fasted state. However, the in vitro bioaccessibility was less impaired by food for SR tablets with a fed/fasted ratio of 95.5 %. A convolution-based approach was used to convert in vitro bioaccessibility results to plasma concentration data. The predicted plasma concentration curve showed good agreement with human data in terms of pharmacokinetic (PK) parameters. In the fasted state, the predicted Cmax, Tmax and AUC0-24h of IR tablets were 943.9 ± 25.7 ng/mL, 2.0 ± 0.4 h and 7090.7 ± 112.0 ng.h/mL, respectively, mirroring values observed in healthy subjects. Overall, the DHSI-IV system has demonstrated potential to assess and predict the impact of meal intake on the in vivo release and absorption behaviors of oral solid preparations.

A supervised machine-learning approach for the efficient development of a multi method (LC-MS) for a large number of drugs and subsets thereof: focus on oral antitumor agents.

OBJECTIVES: Accumulating evidence argues for a more widespread use of therapeutic drug monitoring (TDM) to support individualized medicine, especially for therapies where toxicity and efficacy are critical issues, such as in oncology. However, development of TDM assays struggles to keep pace with the rapid introduction of new drugs. Therefore, novel approaches for faster assay development are needed that also allow effortless inclusion of newly approved drugs as well as customization to smaller subsets if scientific or clinical situations require. METHODS: We applied and evaluated two machine-learning approaches i.e., a regression-based approach and an artificial neural network (ANN) to retention time (RT) prediction for efficient development of a liquid chromatography mass spectrometry (LC-MS) method quantifying 73 oral antitumor drugs (OADs) and five active metabolites. Individual steps included training, evaluation, comparison, and application of the superior approach to RT prediction, followed by stipulation of the optimal gradient. RESULTS: Both approaches showed excellent results for RT prediction (mean difference ± standard deviation: 2.08 % ± 9.44 % ANN; 1.78 % ± 1.93 % regression-based approach). Using the regression-based approach, the optimum gradient (4.91 % MeOH/min) was predicted with a total run time of 17.92 min. The associated method was fully validated following FDA and EMA guidelines. Exemplary modification and application of the regression-based approach to a subset of 14 uro-oncological agents resulted in a considerably shortened run time of 9.29 min. CONCLUSIONS: Using a regression-based approach, a multi drug LC-MS assay for RT prediction was efficiently developed, which can be easily expanded to newly approved OADs and customized to smaller subsets if required.

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.

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.

Plasma 6ß-hydroxycortisol to cortisol ratio as a less invasive cytochrome P450 3A phenotyping method.

AIM: A less invasive evaluation method of cytochrome P450 3A (CYP3A) activity provides an important tool for personalized medicine. We aimed to clarify the usefulness of the plasma 6ß-hydroxycortisol to cortisol concentration (6ß-OHF/F) ratio as a minimally invasive CYP3A phenotyping method. METHODS: Plasma 6ß-OHF and cortisol concentrations were measured via liquid chromatography/tandem mass spectrometry. The plasma 6ß-OHF/F ratio was compared with 6ß-hydroxylation clearance of endogenous cortisol (CLm(6ß); which we previously developed as an index of CYP3A activity) before, during and after oral contraceptive administration in 3 healthy women. The plasma 6ß-OHF/F ratio was observed during oral clarithromycin administration. The plasma 6ß-OHF/F ratio was also measured in 39 healthy participants. RESULTS: The plasma 6ß-OHF/F ratio in 3 healthy women on Day 21 of starting oral contraceptive administration decreased by 39, 49 and 61% compared with Day 0. These values were similar to CLm(6ß) values (43, 54 and 59%, respectively). Plasma 6ß-OHF/F ratio and CLm(6ß) exhibited a good correlation (r = .9053). The 6ß-OHF/F ratio decreased from 0.00921 to 0.00577 only 3 h following clarithromycin administration. The plasma 6ß-OHF/F ratio ranged 0.00565-0.01556 in 39 healthy participants. CONCLUSION: Based on its close relationship with CLm(6ß) and its decrease upon inhibition by clarithromycin, the plasma 6ß-OHF/F ratio serves as an index of CYP3A activity. Using this minimally invasive index, we can identify patients with extremely low CYP3A activity before treatment initiation and optimize the initial drug dose, thereby mitigating the risk of severe adverse reactions.