Lycopene from tomatoes and tomato products exerts renoprotective effects by ameliorating oxidative stress, apoptosis, pyroptosis, fibrosis, and inflammatory injury in calcium oxalate nephrolithiasis: the underlying mechanisms.

Several mechanisms underlying nephrolithiasis, one of the most common urological diseases, involve calcium oxalate formation, including oxidative stress, inflammatory reactions, fibrosis, pyroptosis, and apoptosis. Although lycopene has strong antioxidant activity, its protective effects against CaOx-induced injury have not yet been reported. This study aimed to systematically investigate the protective effects of lycopene and explore its mechanisms and molecular targets. Crystal deposition, renal function, oxidative stress, inflammatory response, fibrosis, pyroptosis, and apoptosis were assessed to evaluate the renoprotective effects of lycopene against crystal formation in a CaOx rat model and oxalate-stimulated NRK-52E and HK-2 cells. Lycopene markedly ameliorated crystal deposition, restored renal function, and suppressed kidney injury by reducing oxidative stress, apoptosis, inflammation, fibrosis, and pyroptosis in the rats. In cell models, lycopene pretreatment reversed reactive oxygen species increase, apoptotic damage, intracellular lactate dehydrogenase release, cytotoxicity, pyroptosis, and extracellular matrix deposition. Network pharmacology and proteomic analyses were performed to identify lycopene target proteins under CaOx-exposed conditions, and the results showed that Trappc4 might be a pivotal target gene for lycopene, as identified by cellular thermal shift assay and surface plasmon resonance analyses. Based on molecular docking, molecular dynamics simulations, alanine scanning mutagenesis, and saturation mutagenesis, we observed that lycopene directly interacts with Trappc4 via hydrophobic bonds, which may be attributed to the PHE4 and PHE142 residues, preventing ERK1/2 or elevating AMPK signaling pathway phosphorylation events. In conclusion, lycopene might ameliorate oxalate-induced renal tubular epithelial cell injury via the Trappc4/ERK1/2/AMPK pathway, indicating its potential for the treatment of nephrolithiasis.

Model-based dosing optimization and therapeutic drug monitoring practices of teicoplanin in patients with complicated or non-complicated methicillin-resistant staphylococcus aureus infection.

AIMS: This study aims to establish a population pharmacokinetic (PK) model of teicoplanin in Chinese adult patients to evaluate the dosing regimen in the label sheet and optimize it. METHODS: Nonlinear mixed-effects modelling was used to estimate PK parameters. Monte Carlo simulations were used to evaluate the attainment of various dosing regimens in achieving the target trough concentrations in patients with normal or decreased renal function. RESULTS: A total of 115 patients were enrolled in this retrospective study. Creatinine clearance (CrCL) and albumin (ALB) were identified as covariates on the clearance of teicoplanin. For the treatment of non-complicated methicillin-resistant Staphylococcus aureus (MRSA) infections in patients with normal renal function and serum ALB concentration, the recommended dosing regimen was 600 mg q12h with five administrations as the loading dose followed by 600 mg qd as the maintenance dose; for the treatment of serious and/or complicated MRSA infections, the recommended dosing regimen was 800 mg q12h with five administrations as the loading dose followed by 800 mg qd as the maintenance dose. It is worth noting that both the loading and maintenance doses ought to be modified based on the patient's renal function and serum ALB concentration. In addition, trough concentrations of teicoplanin were significantly increased every other week. CONCLUSIONS: Both loading dosing and maintenance dosing regimens were recommended to be adjusted according to patient's renal function and serum ALB concentration. In addition, it is necessary to perform follow-up therapeutic drug monitoring of teicoplanin at least once every week.

Development of a UPLC-MS/MS method for the determination of lacosamide and its metabolite and its application to drug-drug interaction.

Lacosamide, a third-generation novel antiepileptic drug, was first approved in 2008 as an adjunct to partial seizures. In 2014, the U.S. Food and Drug Administration (FDA) approved it as a single agent for partial seizures. Since epilepsy is a chronic condition, most patients need long-term antiepileptic medicinal products, so it is even more important to consider the drug-drug interactions (DDIs). For the purpose of this experiment, an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay with accuracy and simplicity was optimized and fully validated for the simultaneous quantitative determination of lacosamide and O-Desmethyl-lacosamide (ODL), and DDIs between lacosamide and nisoldipine in vivo and in vitro was researched. The protein was precipitated with acetonitrile, the analytes were eluted with acetonitrile and a 0.1% formic acid solution in a gradient program, and lacosamide, ODL, and lamotrigine (Internal Standard, IS) were successfully separated by chromatography. The findings of the biological analysis revealed that the lower limit of quantification (LLOQ) for lacosamide in samples was 2 ng/mL and the linearity ranged from 2 to 10000 ng/mL. The LLOQ for ODL was 1 ng/mL, while the linearity range for this substance was 1-1,000 ng/mL. In rat liver microsomes (RLM), the LLOQ of ODL was 80 ng/mL and the linear range was 80-40000 ng/mL. The selectivity, stability, matrix effect and recovery rate were all satisfied with the need of quantitative analysis of samples. Then, the UPLC-MS/MS assay was employed successfully on the interactions of lacosamide and nisoldipine in vivo and in vitro. The half-maximal inhibitory concentration (IC50) was 3.412 µM in RLM, where nisoldipine inhibited the metabolism of lacosamide with a mixture of inhibition mechanism. In rat pharmacokinetic experiments, it was found that nisoldipine could significantly change the pharmacokinetic characteristics of lacosamide, including AUC(0-t), AUC(0-∞), Tmax, CLz/F and Cmax, but had no significant effect on ODL. In summary, the UPLC-MS/MS method could accurately and sensitively quantify lacosamide and ODL, and could be used for the interaction between nisoldipine and lacosamide in vivo and in vitro.

Applications of human and bovine serum albumins in biomedical engineering: A review.

Serum albumin, commonly recognized as a predominant major plasma protein, is ubiquitously distributed among vertebrates, demonstrating versatility and widespread accessibility. Numerous studies have discussed the composition and attributes of human and bovine serum albumin; nonetheless, few systematic and comprehensive summaries on human and bovine serum albumin exist. This paper reviews the applications of human and bovine serum albumin in biomedical engineering. First, we introduce the differences in the structure of human and bovine serum albumin. Next, we describe the extraction methods for human and bovine serum albumin (fractionation process separation, magnetic adsorption, reverse micellar (RM) extraction, and genetic engineering) and the advantages and disadvantages of recently developed extraction methods. The characteristics of different processing forms of human and bovine serum albumin are also discussed, concomitantly elucidating their intrinsic properties, functions, and applications in biomedicine. Notably, their pivotal functions as carriers for drugs and tissue-engineered scaffolds, as well as their contributions to cell reproduction and bioimaging, are critically examined. Finally, to provide guidance for researchers in their future work, this review summarizes the current state of human and bovine serum albumin research and outlines potential future research topics.

Effects of drug-drug interactions and CYP3A4 variants on alectinib metabolism.

In this study, the effects of 17 CYP3A4 variants and drug-drug interactions (DDI) with its mechanism on alectinib metabolism were investigated. In vitro incubation systems of rat liver microsomes (RLM), human liver microsomes (HLM) and recombinant human CYP3A4 variants were established. The formers were used to screen potential drugs that inhibited alectinib metabolism and study the underlying mechanism, and the latter was used to determine the dynamic characteristics of CYP3A4 variants. Alectinib and its main metabolite M4 were quantitatively determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The results showed that compared with CYP3A4.1, only CYP3A4.29 showed higher catalytic activity, while the catalytic activity of CYP3A4.4, .7, .8, .12, .14, .16, .17, .18, .19, .20, .23, and .24 decreased significantly. Among them, the catalytic activity of CYP3A4.20 is the lowest, only 2.63% of that of CYP3A4.1. Based on the RLM incubation system in vitro, 81 drugs that may be combined with alectinib were screened, among which 18 drugs had an inhibition rate higher than 80%. In addition, nicardipine had an inhibition rate of 95.09% with a half-maximum inhibitory concentration (IC50) value of 3.54 ± 0.96 µM in RLM and 1.52 ± 0.038 µM in HLM, respectively. There was a mixture of non-competitive and anti-competitive inhibition of alectinib metabolism in both RLM and HLM. In vivo experiments of Sprague-Dawley (SD) rats, compared with the control group (30 mg/kg alectinib alone), the AUC(0-t), AUC(0-∞), Tmax and Cmax of alectinib administered in combination with 6 mg/kg nicardipine were significantly increased in the experimental group. In conclusion, the metabolism of alectinib was affected by polymorphisms of the CYP3A4 gene and nicardipine. This study provides reference data for clinical individualized administration of alectinib in the future.

Development of UPLC-MS/MS method for the determination of colistin in plasma and kidney and its application in pharmacokinetics.

Recently, the frequent emergence of multidrug-resistant gram-negative bacterial infections has forced colistin to be used as one of the last-line options for the treatment of these infections. This study aimed to establish and validate a simple, rapid, and reliable method for the quantitative determination of colistin in plasma and kidney homogenates by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The pharmacokinetic parameters of colistin sulfate in rats and the relationship between renal accumulation and time of administration in rats were estimated by measuring plasma and renal colistin concentrations. The colistin in the sample was precipitated by acetonitrile, followed by extraction with nitrogen blow-drying and reconstitution. The chromatographic separation of analytes was conducted on an C18 column using a mobile phase consisting of 0.1% aqueous formic acid and acetonitrile. Polymyxin B was used as an internal standard (IS). Colistin and IS were monitored in positive ion mode with the following mass transition pairs: m/z 585.6→m/z 101.4 for colistin A，m/z 578.6→m/z 101.4 for colistin B and m/z 595.6→m/z 227.2 for IS, respectively. The established method expressed good linearity in 50 - 20000 ng·mL-1 of colistin, with the lower limit of quantification (LLOQ) of 50 ng·mL-1. Methodology validations, including accuracy, precision, matrix effect, recovery, stability, and dilution integrity met the US Food and Drug Administration (FDA) acceptance criteria for bioanalytical method validation. Noncompartmental pharmacokinetic parameters were obtained by the statistical moment theory. The estimates for the terminal half-life (t1/2), the peak time (Tmax), the peak concentration (Cmax), the area under the plasma concentration-time curve (AUC0-t), the volume of distribution (V), the total body clearance (CL) and the mean residence time (MRT0-t) were calculated to be 2.53 ± 1.6 h, 2.17 ± 1.57 h, 2913.01 ± 644.89 ng·mL-1, 15153.46 ± 3599.81 h·ng·mL-1, 0.98 ± 0.56 L·kg-1, 0.28 ± 0.09 L·h-1·kg-1 and 4.07 ± 1.13 h, respectively. And the concentrations of colistin in rat kidney tissue after continuous administration for 1, 3, 5, 7 days were 1.49 ± 0.35 µg·g-1, 2.88 ± 0.74 µg·g-1, 3.40 ± 0.25 µg·g-1 and 4.33 ± 0.63 µg·g-1, respectively. The established method provided a convenient, rapid, stable, sensitive, accurate way for the determination of colistin concentration, which has been successfully used for the pharmacokinetic analysis of colistin sulfate in rat and to explore the relationship between the renal accumulation of colistin and the duration of dosing.

Lack of pharmacokinetic interaction between derazantinib and naringin in rats.

CONTEXT: Derazantinib-an orally bioavailable, ATP competitive, multikinase inhibitor-has strong activity against fibroblast growth factor receptors (FGFR)2, FGFR1, and FGFR3 kinases. It has preliminary antitumor activity in patients with unresectable or metastatic FGFR2 fusion-positive intrahepatic cholangiocarcinoma (iCCA). OBJECTIVE: This experiment validates a novel sensitive and rapid method for the determination of derazantinib concentration in rat plasma by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), and applies it to the study of drug-drug interaction between derazantinib and naringin in vivo. MATERIALS AND METHODS: A Xevo TQ-S triple quadrupole tandem mass spectrometer was used for mass spectrometry monitoring in selective reaction monitoring (SRM) mode with transitions of m/z 468 96 → 382.00 for derazantinib and m/z 488.01 → 400.98 for pemigatinib, respectively. The pharmacokinetics of derazantinib (30 mg/kg) was investigated in Sprague-Dawley (SD) rats divided into two groups (with the oral pretreatment of 50 mg/kg naringin or not). RESULTS: The newly optimized UPLC-MS/MS method was suitable for the determination of derazantinib in rat plasma. It was also successfully employed to evaluate the effect of naringin on derazantinib metabolism in rats. After pretreatment with naringin, there was no significant difference in the pharmacokinetic parameters (AUC0→t, AUC0→∞, t1/2, CLz/F, and Cmax) of derazantinib when compared with derazantinib alone. CONCLUSION: Co-administration of naringin with derazantinib was not associated with significant changes in pharmacokinetic parameters. Thus, this study suggests that the combination of derazantinib with naringin can safely be administered concomitantly without dose adjustment.

Population Pharmacokinetics of Colistin Sulfate in Critically Ill Patients: Exposure and Clinical Efficacy.

Background: Presently, colistin is commercially available in two different forms, namely, colistin sulfate and its sulphomethylated derivative, colistimethate sodium (CMS). However, in the currently reported studies, most of the clinical studies on colistin for parenteral use are referred to as CMS. Data on the pharmacokinetics (PK), clinical efficacy, and side effects of colistin sulfate in clinical use have not been reported. Methods: This retrospective study was performed on carbapenem-resistant organism (CRO)-infected patients treated with colistin sulfate for more than 72 h. The population pharmacokinetic model was developed using the NONMEM program. The clinical outcomes including clinical treatment efficacy, microbiological eradication, and nephrotoxicity were assessed. Monte Carlo simulation was utilized to calculate the probability of target attainment (PTA) in patients with normal or decreased renal function. Results: A total of 42 patients were enrolled, of which 25 (59.52%) patients were considered clinical treatment success and 29 (69.06%) patients had successful bacteria elimination at the end of treatment. Remarkably, no patient developed colistin sulfate-related nephrotoxicity. A total of 112 colistin concentrations with a range of 0.28-6.20 mg/L were included for PK modeling. The PK characteristic of colistin was well illustrated by a one-compartment model with linear elimination, and creatinine clearance (CrCL) was identified as a covariate on the clearance of colistin sulfate that significantly explained inter-individual variability. Monte Carlo simulations showed that the recommended dose regimen of colistin sulfate, according to the label sheet, of a daily dose of 1-1.5 million IU/day, given in 2-3 doses, could attain PTA > 90% for MICs ≤ 0.5 µg/mL, and that a daily dose of 1 million IU/day could pose a risk of subtherapeutic exposure for MIC ≥1 µg/ml in renal healthy patients. Conclusion: Renal function significantly affects the clearance of colistin sulfate. A dose of 750,000 U every 12 h was recommended for pathogens with MIC ≤1 µg/ml. The dosage recommended by the label inserts had a risk of subtherapeutic exposure for pathogens with MIC ≥2 µg/ml. Despite higher exposure to colistin in patients with acute renal insufficiency, dose reduction was not recommended.

Dosage Strategy of Linezolid According to the Trough Concentration Target and Renal Function in Chinese Critically Ill Patients.

Background: Linezolid is associated with myelosuppression, which may cause failure in optimally treating bacterial infections. The study aimed to define the pharmacokinetic/toxicodynamic (PK/TD) threshold for critically ill patients and to identify a dosing strategy for critically ill patients with renal insufficiency. Methods: The population pharmacokinetic (PK) model was developed using the NONMEM program. Logistic regression modeling was conducted to determine the toxicodynamic (TD) threshold of linezolid-induced myelosuppression. The dosing regimen was optimized based on the Monte Carlo simulation of the final model. Results: PK analysis included 127 linezolid concentrations from 83 critically ill patients at a range of 0.25-21.61 mg/L. Creatinine clearance (CrCL) was identified as the only covariate of linezolid clearance that significantly explained interindividual variability. Thirty-four (40.97%) of the 83 patients developed linezolid-associated myelosuppression. Logistic regression analysis showed that the trough concentration (Cmin) was a significant predictor of myelosuppression in critically patients, and the threshold for Cmin in predicting myelosuppression with 50% probability was 7.8 mg/L. The Kaplan-Meier plot revealed that the overall median time from the initiation of therapy to the development of myelosuppression was 12 days. Monte Carlo simulation indicated an empirical dose reduction to 600 mg every 24 h was optimal to balance the safety and efficacy in critically ill patients with CrCL of 30-60 ml/min, 450 mg every 24 h was the alternative for patients with CrCL <30 ml/min, and 600 mg every 12 h was recommended for patients with CrCL ≥60 ml/min. Conclusion: Renal function plays a significant role in linezolid PKs for critically ill patients. A dose of 600 mg every 24 h was recommended for patients with CrCL <60 ml/min to minimize linezolid-induced myelosuppression.

Efficacy and Pharmacodynamic Target Attainment for Ceftazidime-Avibactam Off-Label Dose Regimens in Patients with Continuous or Intermittent Venovenous Hemodialysis: Two Case Reports.

Limited data are available for ceftazidime-avibactam (CZA) dosing in patients receiving renal replacement therapy, especially the data on the dosing in patients receiving intermittent hemodialysis (IHD). In this report, we firstly described a case in which CZA was administered as 2.5 g after each time of IHD, and a dose of 1.25 g was added on the 48th-hour for the 72-h interdialytic interval. Plasma concentrations of CZA measured at different time indicated that > 50% of administered ceftazidime and avibactam were removed during the 4-h hemodialysis. In addition, we described another case on continuous venovenous hemodialysis (CVVHD), in which CZA was administered as 2.5 g q12h in 2-h infusions. The dose regimen for these two cases could achieve trough concentration of ceftazidime higher than fourfold of the MIC and trough concentration of avibactam higher than the threshold of 1 µg/mL during the treatment, and exert efficient antimicrobial effect.

Intraventricular colistin sulphate as a last resort therapy in a patient with multidrug-resistant Acinetobacter baumannii induced post-neurosurgical ventriculitis.

Limited therapeutic options exist for multidrug-resistant/extensively drug-resistant Acinetobacter baumannii (MDR/XDR-Ab) meningitis/ventriculitis. A combination of intravenous and intraventricular (IVT)/intrathecal (IT) polymyxins achieves good therapeutic outcomes for cases of healthcare-associated MDR/XDR-Ab meningitis/ventriculitis. Colistin is commercially available as colistin sulphate and its sulphomethylated derivative. However, the effect and safety of colistin sulphate in the treatment of MDR/XDR-Ab meningitis/ventriculitis has not been reported. We report on a 66-year-old male patient who developed post-neurosurgical ventriculitis caused by MDR-Ab. IVT concomitant intravenous colistin sulphate was used as a last-resort antimicrobial therapy, the patient's ventriculitis was dramatically improved, and the concentrations of CSF colistin were higher than the MIC breakpoint throughout the treatment. Meanwhile, no nephrotoxicity or neurotoxicity was observed during the treatment.

Trough polymyxin B plasma concentration is an independent risk factor for its nephrotoxicity.

AIMS: Data regarding clinical pharmacokinetic/toxicodynamic (PK/TD) of polymyxin B is short of direct quantitative data. This study aims to investigate the risk factors of polymyxin B associated acute kidney injury (AKI) and to assess the relationship between polymyxin B plasma levels and its nephrotoxicity. METHODS: A retrospective study was performed in adult patients treated with polymyxin B. Risk factors associated with AKI and plasma trough concentrations of polymyxin B were identified via medical record review. A multivariate logistic regression model was established and the risk of polymyxin B-associated AKI were predicted by a receiver operating characteristic curve, with maximal Youden index used to identify safety thresholds among the study population. RESULTS: Fifty-four adult patients were included in the study. AKI was detected in 14 patients during polymyxin B treatment (25.9%, 14 out of 54). Cmin (odds ratio [OR] 2.071; 95% confidence interval [CI] 1.235-3.472) and baseline serum creatinine (OR 1.024; 95% CI 1.005-1.043) were significant independent risk factors for developing AKI. The area under the ROC curve of the combined predictor was larger based on the above factors. When the Youden index was at maximum, the optimal cut-off point was 6.678 of the ROC curve. When Cmin ≥ 3.13 mg/L, the probability of AKI was more than 50%. CONCLUSION: In this study, when the calculated combined predictor value was >6.678, there was an increased risk of AKI. Maintaining a polymyxin B Cmin level below 3.13 mg/L may be helpful in reducing the incidence of polymyxin B associated nephrotoxicity.

Machine learning-aided detection of heart failure (LVEF ≤ 49%) by using ballistocardiography and respiratory effort signals.

Purpose: Under the influence of COVID-19 and the in-hospital cost, the in-home detection of cardiovascular disease with smart sensing devices is becoming more popular recently. In the presence of the qualified signals, ballistocardiography (BCG) can not only reflect the cardiac mechanical movements, but also detect the HF in a non-contact manner. However, for the potential HF patients, the additional quality assessment with ECG-aided requires more procedures and brings the inconvenience to their in-home HF diagnosis. To enable the HF detection in many real applications, we proposed a machine learning-aided scheme for the HF detection in this paper, where the BCG signals recorded from the force sensor were employed without the heartbeat location, and the respiratory effort signals separated from force sensors provided more HF features due to the connection between the heart and the lung systems. Finally, the effectiveness of the proposed HF detection scheme was verified in comparative experiments. Methods: First, a piezoelectric sensor was used to record a signal sequences of the two-dimensional vital sign, which includes the BCG and the respiratory effort. Then, the linear and the non-linear features w.r.t. BCG and respiratory effort signals were extracted to serve the HF detection. Finally, the improved HF detection performance was verified through the LOO and the LOSO cross-validation settings with different machine learning classifiers. Results: The proposed machine learning-aided scheme achieved the robust performance in the HF detection by using 4 different classifiers, and yielded an accuracy of 94.97% and 87.00% in the LOO and the LOSO experiments, respectively. In addition, experimental results demonstrated that the designed respiratory and cardiopulmonary features are beneficial to the HF detection (LVEF ≤ 49 % ). Conclusion: This study proposed a machine learning-aided HF diagnostic scheme. Experimental results demonstrated that the proposed scheme can fully exploit the relationship between the heart and the lung systems to potentially improve the in-home HF detection performance by using both the BCG, the respiratory and the cardiopulmonary-related features.

Model Based Identification of Linezolid Exposure-toxicity Thresholds in Hospitalized Patients.

Evidence supports linezolid therapeutic drug monitoring as the exposure-response relationship has been identified for toxicity among patients receiving linezolid, but the data to establish the upper limit are limited and the published toxicity thresholds range widely. The purpose of this study was to determine the linezolid exposure-toxicity thresholds to improve the safety of linezolid. This is a multicenter retrospective study of adult patients treated with linezolid from 2018 to 2019. The population pharmacokinetic model of linezolid was established based on 270 plasma concentrations in 152 patients, which showed creatinine clearance and white cell count are covariates affecting the clearance of linezolid, and serum albumin is the covariate affecting the volume of distribution. Classification and regression tree analysis was used to determine the linezolid exposure thresholds associated with an increased probability of toxicity. Among 141 patients included for toxicity analysis, the rate of occurring toxicity was significantly higher among patients with an AUC0-24, d1 ≥163 mg h/L, AUC0-24, d2 ≥207 mg h/L, AUC0-24, ss ≥210 mg h/L, and Cmin,d2 ≥6.9 mg/L, Cmin,ss ≥6.9 mg/L, while no threshold was discovered for Cmin, d1. Those exposure thresholds and duration of linezolid treatment were independently associated with linezolid-related toxicity in the logistic regression analyses. In addition, the predictive performance of the AUC0-24 and Cmin thresholds at day 2 and steady state were close. Considering that the AUC estimation is cumbersome, Cmin threshold at 48 h and steady state with a value of ≥6.9 mg/L is recommended to improve safety, especially for patients with renal insufficiency and patients with low serum albumin.

A Novel UPLC-MS/MS Assay for the Measurement of Linezolid and its Metabolite PNU-142300 in Human Serum and its Application to Patients With Renal Insufficiency.

The contribution of the metabolites of linezolid to the associated myelosuppression is unknown in patients who are renal impairment. In this research, the purpose of our experiment was to explore and develop a quick and robust ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) assay for the determination of linezolid and its metabolite PNU-142300 in human serum simultaneously. The analytes were prepared using a simple and convenient approach with acetonitrile for protein crash, and then separated from the matrix on a Waters Acquity Ultra performance liquid chromatography (UPLC) BEH C18 (2.1 mm × 50 mm, 1.7 µm) column in a program of gradient elution, where the mobile phase was consisted of water with 0.1% formic acid and acetonitrile, and was placed at 0.40 ml/min flow rate. Multiple reaction monitoring (MRM) was employed and conducted for UPLC-MS/MS detection with ion transitions at m/z 338.01 → 296.03 for linezolid, m/z 369.96 → 327.98 for PNU-142300 and m/z 370.98 → 342.99 for tedizolid (Internal standard, IS), respectively. This method had good linearity respectively in the calibration range of 0.01-20 µg/ml for linezolid, and 0.05-100 µg/ml for PNU-142300. In the intra- and inter-day, the precision of linezolid and PNU-142300 was below 14.2%, and the accuracy in this method was determined to be from -9.7 to 12.8%. In addition, recovery and matrix effect of the analytes were all found to be acceptable, and the analytes during the assay and storage in serum samples were observed to be stable. The novel optimized UPLC-MS/MS assay was also successfully employed to determine the concentration levels of linezolid and PNU-142300 in human serum. The results showed that linezolid-associated myelosuppression occurs more frequently in patients with renal insufficiency, and the metabolite-to-parent concentration ratio of PNU-142300 is predicted to reduce this toxicity of myelosuppression.

Development of UPLC-MS/MS Method for Studying the Pharmacokinetic Interaction Between Dasatinib and Posaconazole in Rats.

BACKGROUND AND AIM: Dasatinib is approved for the treatment of leukaemia worldwide. Triazole agents such as posaconazole may be used for the control of secondary fungal infection with leukaemia. This work aimed to develop a bioanalytical method to study the potential interaction between dasatinib and posaconazole. METHODS: An ultrahigh-performance liquid chromatography-tandem mass spectrometry method was established to measure the plasma concentrations of dasatinib and posaconazole in rats simultaneously. Simple protein precipitation with acetonitrile was applied to extract dasatinib and posaconazole in samples. The chromatographic separation of analytes was conducted on an UPLC BEH C18 column using a mobile phase consisting of 0.1% aqueous formic acid and acetonitrile. Dasatinib and posaconazole were monitored in positive ion mode with the following mass transition pairs: m/z 488.2→401.1 for dasatinib and m/z 701.3→683.4 for posaconazole. The method was successfully applied for pharmacokinetic interaction between dasatinib and posaconazole. RESULTS: The established method expressed good linearity in 1-1000 ng/mL of dasatinib and 5-5000 ng/mL of posaconazole, with limit of detection was 1 ng/mL and 5 ng/mL, respectively. Methodology validations, including accuracy, precision, matrix effect, recovery, and stability, met the US Food and Drug Administration (FDA) acceptance criteria for bioanalytical method validation. Dasatinib strongly inhibited the clearance of posaconazole in vivo, while posaconazole expressed no significant effect on the pharmacokinetics of dasatinib. CONCLUSION: Dasatinib alters the pharmacokinetics of posaconazole. Attention should be paid to the unexpected risk of adverse clinical outcomes when posaconazole is co-administered with dasatinib.

[Predictive performance of Smart Dose, PharmVan and JPKD on Vancomycin plasma concentration].

OBJECTIVE: To evaluate the predictive performance of the individualized drug delivery decision-making system including Smart Dose, PharmVan and JPKD on predicting the Vancomycin plasma concentration and to analyze the related factors affecting the predictive performance. METHODS: The clinical data of patients who were treated with Vancomycin and received therapeutic drug monitoring (TDM) admitted to the First Affiliated Hospital of Wenzhou Medical University from January 2018 to July 2020 were retrospectively collected. Smart Dose and PharmVan were used to predict the plasma concentration of Vancomycin of the initial regimen. Smart Dose, PharmVan and JPKD were used to predict the plasma concentration of Vancomycin of the adjustment regimen for patients whose initial steady-state trough concentration were not qualified. The relative predictive error (PE) between the measured plasma concentration and predicted plasma concentration was calculated and box plotted. Mann-Whitney U test was used to evaluate the difference of the absolute value of PE (APE) predicted by each software for Vancomycin plasma concentration. The TDM results were divided into accurate prediction group (APE < 30%) and the inaccurate prediction group (APE ≥ 30%) according to the APE value. Patients and disease characteristics including gender, age, body weight complication, Vancomycin medication and TDM results were collected from electronic medical records. Univariate analysis and multivariate Logistic regression analysis were used to screen the related factors that influence the predictive performance of Smart Dose, PharmVan and JPKD; and receiver operating characteristic curve (ROC curve) was drawn to evaluate its predictive value. RESULTS: A total of 185 patients were enrolled, and 258 plasma concentration of Vancomycin were collected, including 185 concentrations of initial regimen and 73 concentration of adjustment regimen. There was no significant difference in the APE of the initial regimen of plasma concentration between Smart Dose and PharmVan. No significant difference in the APE of the adjustment regimen of plasma concentration was found among Smart Dose, PharmVan and JPKD. The accuracy of Smart Dose in predicting the plasma concentration of the adjustment regimen was better than that of the initial regimen [22.94% (10.50%, 36.24%) vs. 29.33% (13.07%, 47.99%), P < 0.05]. The univariate analysis of factors affecting the performance of Smart Dose in predicting the concentration of initial regimen showed that the proportion of patients with hypertension in the accurate prediction group was significantly higher than that in the inaccurate prediction group [43.3% (42/97) vs. 27.3% (24/88), P < 0.05]. The univariate analysis of factors affecting the performance of Smart Dose in predicting the concentration of adjustment regimen showed that the proportion of patients with valvular heart disease in the accurate prediction group was significantly lower than that in the inaccurate prediction group [23.4% (11/47) vs. 46.2% (12/26), P < 0.05]. The univariate analysis of factors affecting the performance of JPKD in predicting the concentration of adjustment regimen showed that the body weight of patients in the accurate prediction group was significantly higher than that in the inaccurate prediction group (kg: 62.8±14.9 vs. 54.8±12.8, P < 0.05). Multivariate Logistic regression analysis indicated that hypertension was a beneficial factor for Smart Dose to predict the initial plasma concentration of Vancomycin [odds ratio (OR) = 0.526, 95% confidence interval (95%CI) was 0.281-0.983, P = 0.044], and low body weight was an independent risk factor for the inaccurate prediction of JPKD for adjustment regimen (OR = 1.042, 95%CI was1.001-1.085, P = 0.043). ROC curve analysis indicated that the area underROC curve (AUC) of the body weight for evaluating the accuracy of JPKD in predicting Vancomycin plasma concentration was 0.663, and 95%CI was 0.529-0.796 (P = 0.023). When the body weight was less than 55.95 kg, the risk of inaccurate prediction of JPKD in predicting Vancomycin plasma concentration was increased, and the predictive sensitivityand specificity were 75% and 60% respectively. CONCLUSIONS: There is no significant difference in the predictive performance of Smart Dose, PharmVan or JPKD on Vancomycin plasma concentration. Smart Dose had a better predictive performance for the Vancomycin plasma concentration of adjustment regimen than initial regimen. Smart Dose had a better predictive performance when the patient was concomitant with hypertension. JPKD had a poor predictive performance for low-body weight patients. The predictive performance of JPKD was decreased when the body weight was lower than 55.95 kg.

Effect of Different Dosage Frequency of Polymyxin B on Rat Nephrotoxicity.

BACKGROUND: Polymyxin B, as the final treatment against multidrug-resistant Gram-negative bacilli, is widely used in clinical practice. However, little is known about the nephrotoxicity of polymyxin B. The purpose of this study was to elucidate the relationship between polymyxin B nephrotoxicity and daily administration frequency. METHODS: Sprague-Dawley rats were randomly divided into three groups: 18 mg/kg/q24 h group (Group A, once daily), 9 mg/kg/q12 h group (Group B, twice daily), and normal saline control group (Group C). The rats were injected subcutaneously for 5 consecutive days with the same daily total dose and different frequency of administration. The serum creatinine (SCr) and blood urea nitrogen (BUN) of each group before administration (0 h), and 8 and 24 h after administration, were measured by tail vein blood sampling. On the sixth day, the rats in each group were killed, the left kidney was taken for pathological section observation, and the results of each group were compared. RESULTS: After 96 h of administrated polymyxin B, the total average level of SCr in Group A was 56.98±12.42 µmol/L, that of Group B was 52.02±8.68 µmol/L, and that of Group C was 34.36±5.39 µmol/L. BUN was 9.86±4.58, 10.54±4.08, and 3.55±0.73 mmol/L in Groups A, B, and C, respectively. The daily urinary protein excretion was 5004.45±1333.84 µg in Group A, 4608.04±1444.42 µg in Group B, and 2096.33±215.28 µg in Group C. In addition, according to the observation of pathological slices, compared with Group A, the number of exfoliated and necrotic cells of renal tubules in Group B was higher, and the morphological changes were more serious. CONCLUSION: The experimental results showed that the renal toxicity in rats treated with a twice-daily subcutaneous dose of polymyxin B was higher than that in rats treated with once-daily dose of polymyxin B.

Population pharmacokinetic and optimization of polymyxin B dosing in adult patients with various renal functions.

AIMS: Current FDA-approved label recommends that the dosage of polymyxin B should be adjusted according to renal function. However, the correlation between polymyxin B pharmacokinetics (PK) and creatinine clearance (CrCL) is poor. This study aimed to develop a population PK model of polymyxin B in adult patients with various renal functions and to identify a dosing strategy. METHODS: A retrospective PK study was performed in 32 adult patients with various renal function. Nonlinear mixed effects modelling was applied to build a population PK model of polymyxin B followed by Monte Carlo simulations which designed polymyxin B dosing regimens across various renal function. RESULTS: Polymyxin B PK analyses included 112 polymyxin B concentrations at steady state from 32 adult patients, in which 71.9% of them were critically ill. In the final PK model, CrCL was the significant covariate on CL (typical value 1.59 L/h; between-subject variability 13%). The mean (SD) individual empirical Bayesian estimate of CL was 1.75 (0.43) L/h. In addition, a new dosing strategy combining the PK/pharmacodynamic (PD) targets and Monte Carlo simulation indicated that the reduction of polymyxin B dose in patients with renal insufficiency improved the probability of achieving optimal exposure. For severe infections caused by organisms with minimum inhibitory concentration (MIC) ≥ 2 mg/L, a high daily dose of polymyxin B might be possible for bacterial eradication, but the risk of nephrotoxicity is increased. CONCLUSIONS: Renal function plays a significant role in polymyxin B PK, and the dose of polymyxin B should be adjusted according to CrCL in patients with renal insufficiency.