Pretreatment and analysis techniques development of TKIs in biological samples for pharmacokinetic studies and therapeutic drug monitoring

Tyrosine kinase inhibitors(TKIs)have emerged as the first-line small molecule drugs in many cancer therapies,exerting their effects by impeding aberrant cell growth and proliferation through the modulation of tyrosine kinase-mediated signaling pathways.However,there exists a substantial inter-individual variability in the concentrations of certain TKIs and their metabolites,which may render patients with compromised immune function susceptible to diverse infections despite receiving theoretically efficacious anticancer treatments,alongside other potential side effects or adverse reactions.Therefore,an urgent need exists for an up-to-date review concerning the biological matrices relevant to bioanalysis and the sampling methods,clinical pharmacokinetics,and therapeutic drug monitoring of different TKIs.This paper provides a comprehensive overview of the advancements in pretreatment methods,such as protein precipitation(PPT),liquid-liquid extraction(LLE),solid-phase extraction(SPE),micro-SPE(μ-SPE),magnetic SPE(MSPE),and vortex-assisted dispersive SPE(VA-DSPE)achieved since 2017.It also highlights the latest analysis techniques such as newly developed high performance liquid chromatography(HPLC)and high-resolution mass spectrometry(HRMS)methods,capillary electrophoresis(CE),gas chromatography(GC),supercritical fluid chromatography(SFC)procedures,surface plasmon resonance(SPR)assays as well as novel nanoprobes-based biosensing techniques.In addition,a comparison is made between the advantages and disadvantages of different approaches while presenting critical challenges and prospects in pharmacokinetic studies and therapeutic drug monitoring.

Evidence of voriconazole pharmacokinetic variability in children and adolescents with haematological disease: proposal for therapeutic drug monitoring optimisation

Objective:Voriconazole(VCZ)is a triazole antifungal agent widely used in immunocompromised patients with suspected or proven invasive fungal infections.The achievement of therapeutic range(1-5 mg/L)is essential to maximize VCZ efficacy,as its pharmacokinetics is characterized by a wide inter-and intra-individual variability.This study aims to quantify the variability of VCZ trough concentrations in children and adolescents with haematological diseases and optimize therapeutic drug monitoring in clinical practice.Methods:We analysed the monitoring concentrations of all children(<18 years old)treated with VCZ in the Haematology Department of Robert DebréHospital between January 2014 and December 2016.Demographic,clinical data,and VCZ dosing and monitoring concentrations measured by high-performance liquid chromatography with ultraviolet detection(HPLC-UV)were analysed.Non-parametric tests were performed using SPSS IBM 24.0.Results:380 trough VCZ concentrations at steady-state(Ctrough,ss)were available in 79 children:45.6%had first Ctrough,ss in the therapeutic range at first monitoring,46.8%had Ctrough,ss below 1 mg/L and 7.6%had Ctrough,ss over 5 mg/L.Forty-one patients were treated with recommended doses but only 53%of them reached the therapeutic range.There was no impact of age,sex,biological parameters,or indication of VCZ on Ctrough,ss values.The number of Ctrough,ss in the therapeutic range increases with the number of monitoring per patient following dosage adaptations.Conclusion:The wide inter-and intra-individual variability of VCZ trough concentrations at recommended doses confirm the need to standardize VCZ monitoring and identify factors to be considered to prospectively adapt treatment for each patient.

A Study on the Multi-Compartment Linear Circulation Pharmacokinetic Model for the Targeting Drug Delivery System

By analyzing the observed phenomena and the data collected in the study, a multi-compartment linear circulation model for targeting drug delivery system was developed and the function formulas of the drug concentration-time in blood and target organ by computing were figured out. The drug concentration-time curve for target organ can be plotted with reference to the data of drug concentration in blood according to the model. The pharmacokinetic parameters of the drug in target organ could also be obtained. The practicability of the model was further checked by the curves of drug concentration-time in blood and target organ(liver) of liver-targeting nanoparticles in animal tests. Based on the liver drug concentration-time curves calculated by the function formula of the drug in target organ, the pharmacokinetic behavior of the drug in target organ(liver) was analyzed by statistical moment, and its pharmacokinetic parameters in liver were obtained. It is suggested that the (relative targeting index( can be used for quantitative evaluation of the targeting drug delivery systems.

Capillary electrophoresis with electrochemiluminescence detection for the analysis of quinolone drugs and pharmacokinetics study

A novel method for the determination of two quinolone drugs norfloxacin （NOR） and levofloxacin （LVX） was described by capillary electrophoresis with electrochemiluminescence detection. The good relationship （r ≥ 0.9991） between peak area and concentration of analytes was established over two orders of magnitude. The limits of detection （LOD, S/N = 3） in standard solution are 4.8 × 10^-7 mol/L for NOR and 6.4 × 10^-7 mol/L for LVX, respectively. The limits of quantitation （LOQ, S/N = 10） in real human urine samples are 1.2 × 10^-6 mol/L for NOR and 1.4 × 10^-6 mol/L for LVX, respectively. The present method was successfully applied to the determination of NOR and LVX in human urine and the studv of oharmacokinetics of NOR.

A simulation study of sampling time point designing for therapeutic drug monitoring based on a population pharmacokinetic model

Aim To develop a method to estimate population pharmacokinetic parameters with the limited sampling time points provided clinically during therapeutic drug monitoring. Methods Various simulations were attempted using a one-compartment open model with the first order absorption to determine PK parameter estimates with different sampling strategies as a validation of the method. The estimated parameters were further verified by comparing to the observed values. Results The samples collected at the single time point close to the non-informative sampling time point designed by this method led to bias and inaccurate parameter estimations. Furthermore, the relationship between the estimated non-informative sampling time points and the values of the parameter was examined. The non-informative sampling time points have been developed under some typical occasions and the results were plotted to show the tendency. As a result, one non-informative time point was demonstrated to be appropriate for clearance and two for both volume of distribution and constant of absorption in the present study. It was found that the estimates of the non-informative sampling time points developed in the method increase with increases of volume of distribution and the decrease of clearance and constant of absorption. Conclusion A rational sampling strategy during therapeutic drug monitoring can be established using the method present in the study.

Psychotropic drugs and liver disease:A critical review of pharmacokinetics and liver toxicity

The liver is the organ by which the majority of sub-stances are metabolized, including psychotropic drugs. There are several pharmacokinetic changes in end-stage liver disease that can interfere with the metabolization of psychotropic drugs. This fact is particularly true in drugs with extensive first--pass metabolism, highly protein bound drugs and drugs depending on phase I hepatic metabolic reactions. Psychopharmacological agents are also associated with a risk of hepatotoxicity. The evidence is insufficient for definite conclusions regarding the prevalence and severity of psychiatric drug-induced liver injury. High-risk psychotropics are not advised when there is pre-existing liver disease, and after starting a psychotropic agent in a patient with hepatic impairment, frequent liver function/lesion monitoring is advised. The authors carefully review the pharmacokinetic disturbances induced by end-stage liver disease and the potential of psychopharmacological agents for liver toxicity.

Effects of tomato juice on the pharmacokinetics of CYP3A4-substrate drugs

We previously demonstrated that tomato juice(TJ) contains potent mechanism-based inhibitor(s) of CYP3A4. In this study, we investigated the effects of TJ and grapefruit juice(GFJ)on the pharmacokinetics of the CYP3A4-substrate drugs, nifedipine(NFP) and midazolam(MDZ), in male Wistar rats. Oral administration of GFJ 90 min before the intraduodenal administration of NFP or MDZ increased the area under the concentration–time curves(AUCs)of NFP and MDZ by 32.4% and 89.4%, respectively. TJ increased MDZ blood concentrations and AUC after intraduodenal MDZ administration;however, it had no effect on NFP. When MDZ and NFP were intravenously administered, GFJ significantly increased the AUC of MDZ,but only slightly increased that of NFP. In contrast, TJ only slightly increased the AUC of MDZ.These results suggest that, similar to GFJ, TJ influences the pharmacokinetics of CYP3A4-substrate drugs;however, it may be a drug-dependent partial effect.

Body Composition as A Determinant of Pharmacokinetics and Toxicity of Anticancer Drugs

Chemotherapy-induced toxicity,resulting from inter-individual variability in pharmacokinetics is emerging as a highly active area of investigation.Body composition analysis,primarily concerning the amount of fat mass(FM)and lean body mass(LBM),has provided a proof-concept that the inter-individual variability in pharmacokinetics and toxicity profiles may be partially explained by the discrepancies of FM and LBM in patients.Recent research suggests a close relationship among body composition,pharmacokinetics and toxicity of anticancer drugs.Because LBM and FM,significantly influence the exposure to drugs,they are considered as the promising predictors of chemotherapy-induced toxicity and a potential basis for optimizing the dosing of oncology drugs and the outcomes.Our review summarizes the recent studies rendering the aforementioned correlations to highlight that a critical evaluation of body composition has initiated a new era for dose standardization.

Preface for special issue on new analytical techniques and methods in drug metabolism and pharmacokinetics

Analytical technologies and approaches for drug metabolism and pharmacokinetics(DMPK)research in the pharmaceutical industry and academic research institutes have evolved rapidly over the past decade.On one hand,the discovery and development of small molecule drug candidates requires earlier and better understanding of their absorption,distribution,metabolism and excretion(ADME)in human as well as their interactions with metabolizing enzymes.

The Presence of Phases and the Inability of the Classical Compartment Models to Provide Pharmacokinetic Parameters of Physiological Significance for Lipophilic Drugs

The first biphasic open one-compartment pharmacokinetic model is described. Its analytical solutions to drug concentration were developed from parameters of an open two-compartment pharmacokinetic model. The model is used to explain the unusually large compartment volumes and apparent volumes of distribution of lipophilic drugs, as well as to identify which of the pharmacokinetic parameters of the classical compartment models are biologically relevant.

Characteristics of the anti-dementia drug system of Zisu Fang preparations based on pharmacokinetic and pharmacodynamic analysis

Objectives:To investigate the pharmacokinetics (PK) and pharmacodynamics (PD)of index components of Zisu Fang preparations and additionally analysis the anti-dementia drug system characteristics.Methods:A PK-PD-drug interaction (DI) method was applied to determine the characteristics of index components of Zisu Fong preparations in vivo.Results:In the PK study,maximum plasma concentration,area under the plasma concentration-time curve,and mean residence time of index components of Zisu Fang preparations were higher in the memory-deficit model group than in the control group.This suggested that the index components of Zisu Fang preparations had an affinity for the state of dementia in this model.In the PD study,at the peak time points of anti-dementia efficacy (0.17 h and 1 h),the plasma concentrations of index components of Zisu Fang preparations reached the first or second largest plasma concentration peak or were close to the plasma concentration peak,and showed positive correlation between these two peaks,indicating that the index components of Zisu Fang synergistically exerted an anti-dementia effect.According to the association analysis of PK-PD-DI,baicalin,rosmarinic acid,salvianolic acid B,matrine,and tanshinone ⅡA were the main active ingredients of the anti-dementia drug system of Zisu Fang preparations in vivo,but were only efficacious against dementia when all five components were present at a specific concentration and proportion.Conclusions:Based on the PK and PD correlation analysis,baicalin,rosmarinic acid,salvianolic acid B,matrine,and tanshinone ⅡA are the main active ingredients of Zisu Fang preparations with regard to its anti-dementia effects,and represent the basic characteristics of drug system:natures,synergy,and affinity.

Single-dose and multiple-dose pharmacokinetics of zaltoprofen after oral administration in healthy Chinese volunteers

Zaltoprofen, a propionic acid derivative of non-steroidal anti-inflammatory drugs, has strong inhibitory effects on actue and chronic inflammation. A randomized, dose-escalating study was conducted to evaluate the pharma-cokinetics of single and multiple oral doses of zaltoprofen in 12 healthy Chinese volunteers. Pharmacokinetics was determined from serial blood samples obtained up to 24 h after administration of a single dose of zaltoprofen at 80, 160 or 240 mg and after multiple doses of zaltqorofen at 80 mg 3 times daily. The C max and AUC 0-24 of zaltoprofen were found to be proportional to drug dose. Zaltoprofen was rapidly absorbed （t max =1.46±0.83 h） and cleared （t 1/2 =4.96±2.97 h）. Pharmacokinetic parameters after multiple doses were similar to those after single doses. Zaltoprofen was well tolerated. These results support a tid regimen of zaltoprofen for the management of acute and chronic inflammation.

Succinylated whey protein isolate as a sustained-release excipient of puerarin derivative oral tablets:Preparation,optimization and pharmacokinetics

This work was done to investigate succinylated commercial whey protein isolate(S-WPI)as an oral sustained-release delivery carrier for puerarin 5(PR-5). The succinylation condi-tions were established for S-WPIs by optimization of single factor study and Box–Beehnkendesign. The effect of succinylation degree on S-WPIs solubility was evaluated. Physicochem-ical properties of S-WPIs dried by different three methods on their flow ability, particle size,morphology and in vitro release behavior were studied. After preparing PR-5 sustained re-lease protein tablets with S-WPIs as the carrier by direct powder compression method, thedrug release were studied in vitro and the oral pharmacokinetics and bioavailability wasevaluated using in vivo dog model. It was observed that concentration of substrate has asignificant effect on succinylation. Release behavior in vitro showed spry dried S-WPIs with100% succinylation rate and 30% drug loading would be applied to the preparation of PR-5 sustained-release protein tablets based on the swelling mechanism(protein loss). Comparedwith PR-5 conventional tablet with oral administration, T max value of PR-5 sustained-releaseprotein tablets was approximately 1.58 fold greater than those of the conventional tablets asfurther evidenced by the significantly prolonged MRT and T 1/2. The findings demonstratedthat spray-dried S-WPIs has potential as a promising functional excipient for the design of PR-5 oral sustained-release tablets which can fully improve sustained-release effect and oral bioavailability.

Comparative study on pharmacokinetics and toxicity of intravitreal and sub-Tenon injection of triamcinolone acetonide in ocular tissues

AIM:To compare the differences in kinetics,distribution,and toxicity of triamcinolone acetonide(TA)between the injection methods,sub-Tenon and intravitreal injections in rabbit ocular tissues.METHODS:TA was injected into the vitreous or the sub-Tenon in rabbits.For pharmacokinetic study,rabbits were sacrificed periodically and then TA in blood and ocular tissues(retina/choroids,vitreous,and aqueous humor)were measured over 91 d.For toxicological study,clinical signs,slit-lamp microscopic examination,ophthalmological test were performed.The eyeballs and surrounding tissues were collected and fixed with glutaraldehyde-formalin solution,and then paraffin embedded for histological investigation.RESULTS:Higher levels of TA were distributed in the intraocular tissues when injected into the vitreous compared to the sub-Tenon.Conversely,TA level was remarkably lower in the rabbits which received intravitreal TA injections than those treated with sub-Tenon injection throughout the study period in plasma.Optical discharge probably caused by systemic circulation of TA was observed by receiving sub-Tenon TA injection.Meanwhile,technicassociated toxicological ocular symptoms and findings were more frequently observed in intravitreal injection than in sub-Tenon injection.CONCLUSION:There are significant differences in kinetics and distribution of TA in vitreous body,aqueous humor and plasma,between the two injection methods.Although further study is needed to explain the species difference between human and rabbit,it is assumed that the difference in the frequency of intraocular pressure elevation and cataract formation by TA between the two injection methods are directly related to the TA concentrations in aqueous humor and vitreous body in each injection methods.Systemic toxicity and technic-associated toxicity are also closely related to kinetics of TA in plasma and each injection method itself,respectively.

Impact of Azithromycin on Forsythiaside Pharmacokinetics in Rats:A Population Modeling Method

Objective:Lianhuaqingwen and Shuanghuanglian are drug treatment options for Corona Virus Disease 2019(COVID-19).In China,use of traditional Chinese medicine with Shuanghuanglian or Lianhuaqingwen(for them,forsythiaside is the active antiviral and antibacterial component)in combination with azithromycin is common for the treatment of pediatric pneumonia.It is important to understand the reason why the combination of these compounds is better than a single drug treatment.This study aimed to explore the pharmacokinetic interaction between forsythiaside and azithromycin.Methods:Twelve male Sprague-Dawley rats were randomly divided into an experimental group(Forsythia suspensa extract and azithromycin)and a control group(a single dose of Forsythia suspensa extract in 5%glucose solution).Plasma samples were collected at scheduled time points,and the high-performance liquid chromatography combined with ultraviolet method was used to determine the plasma forsythiaside concentration.Non-compartmental analysis and population pharmacokinetic methods were used to investigate the forsythiaside pharmacokinetic difference between the experimental and control group.Results:Compared with a single administration,the area under the curve and half-life of forsythiaside increased,and forsythiaside clearance decreased significantly after co-administration with azithromycin.The in vivo behavior of forsythiaside could be described by the one compartment model.The forsythiaside clearance decreased when combined with azithromycin.Visual evaluation and bootstrap results suggested that the final model was precise and stable.Conclusion:Co-administration of azithromycin can significantly decrease the forsythiaside clearance and increase drug exposure.A lower dose of azithromycin can obtain sufficient forsythiaside concentration to provide antiviral and antibacterial activity.

Pharmacokinetics of gene recombined angiogenesis inhibitor Kringle 5 in vivo using 131I specific markers and SPECT/CT

The previous pharmacokinetic methods can be only limited to drug analysis in vitro, which provide less information on the distribution and metabolismof drugs, and limit the interpretation and assessment of pharmacokinetics, the determination of metabolic principles, and evaluation of treatment effect. The objective of the study was to investigate the pharmacokinetic characteristics of gene recombination angiogenesis inhibitor Kringle 5 in vivo. The SPECT/CT and specific^(131)I-Kringle 5 marked by Iodogen method were both applied to explore the pharmacokinetic characteristics of^(131)I-Kringle 5 in vivo, and to investigate the dynamic distributions of^(131)I-Kringle 5 in target organs. Labeling recombinant angiogenesis inhibitor Kringle 5 using131 I with longer half-life and imaging in vivo using SPECT instead of PET,could overcome the limitations of previous methods. When the doses of^(131)I-Kringle 5 were 10.0, 7.5 and5.0 g/kg, respectively, the two-compartment open models can be determined within all the metabolic process in vivo. There were no significant differences in t1/2α, t1/2β, apparent volume of distribution and CL between those three levels. The ratio of AUC(0 1)among three different groups of 10.0, 7.5 and 5.0 g/kg was 2.56:1.44:1.0, which was close to the ratio(2:1.5:1.0). It could be clear that in the range of 5.0–10.0 g/kg, Kringle 5 was characterized by the first-order pharmacokinetics. Approximately 30 min after^(131)I-Kringle 5 was injected,^(131)I-Kringle 5 could be observed to concentrate in the heart, kidneys, liver and other organs by means of planar imaging and tomography. After 1 h of being injected, more radionuclide retained in the bladder, but not in intestinal. It could be concluded that^(131)I-Kringle 5 is mainly excreted through the kidneys. About 2 h after the injection of^(131)I-Kringle 5, the radionuclide in the heart, kidneys,liver and other organs was gradually reduced, while more radionuclide was concentrated in the bladder.The radionuclide was completely metabolized within 24 h, and the distribution of radioactivity in rats was similar to normal levels. In our study, the specific marker^(131)I-Kringle 5 and SPECT/CT were successfully used to explore pharmacokinetic characteristics of Kringle 5 in rats. The study could provide a new evaluation platform of the specific, in vivo and real-time functional imaging and pharmacokinetics for the clinical application of^(131)I-Kringle 5.

Research on pharmacokinetics of high-dose tamoxifen in non-small cell lung cancer patients

Objective To study the pharmacokinetics of tamoxifen at a high dosage, which will offer a theoretical support for an appropriate clinical use of the medicine in non-small cell lung cancer (NSCLC) patients. Methods Three qualified NSCLC patients are selected and given tamoxifen (TAM) 160 mg per Os. Blood samples were collected at different times and then analyzed by high-performance liguid chromatography. The PK-GRAPH program was used to obtain the parameters. Results The concentration-time courses of the TAM 160 mg were fitted to one-compartment model. The pharmacokinetic parameters were estimated as follows: Tmax (6.35±1.24)h, Cmax (217.39±7.71)ng/mL, AUC (12 127.39±636.16)ng·h/mL and T1/2ke (34.13±2.97)h. Conclusion TAM 160mg one day per Os cannot reach the effective maintenance concentration in vivo required for reversing MDR in vitro. Loading-maintenance dose strategy is recommended to study the pharmacodynamics of tamoxifen at a high dosage in NSCLC patients.

Mechanism Based Pharmacokinetic Pharmacodynamic Modeling of Vildagliptin as an Add-on to Metformin for Subjects with Type 2 Diabetes

Various drugs are used to maintain normoglycemia in subjects with type 2 diabetes mellitus.The combination of the drugs from different classes in one single tablet may enhance the effectiveness of the anti-diabetic drugs.To investigate the impact of combining drugs on the glucose regulation of subjects with type 2 diabetes,we propose a pharmacokinetic/pharmacodynamics(PK/PD)mathematical modeling approach for a combination of metformin and vildagliptin drugs.In the proposed modeling approach,two separate PK models representing oral administration of metformin and vildagliptin for diabetic subjects are interconnected to a PD model comprising a detailed compartmental physiological model representing the regulatory effect of insulin,incretins and glucagon hormones on glucose concentration in a human body.The impact of doses of individual drugs and their combination on the blood glucose concentration of a group of type 2 diabetic subjects is investigated.It is indicated that while administration of individual drugs reduces the blood glucose levels,since they have separate mechanisms of action,combining them synergizes lowering the blood glucose levels.

In Silico Pharmacokinetics Studies for Quinazolines Proposed as EGFR Inhibitors

In silico pharmacokinetics studies can aid the search for molecules with potential ability to be drug candidates. In this paper, a number of quinazoline candidates for epidermal growth factor receptor inhibitors—EGFR, important targets for the treatment of cancer, are computationally analyzed. The literature described that 69 quinazoline molecules were synthesized and the respective half maximum inhibitory concentrations (IC50) were obtained. A bilinear parabolic model was built to investigate the druglikeness by correlating the corresponding lipophilicities, which can be represented by the ideal Log P , with the optimal biological activity in terms of pIC50 values. Structural characteristics leading to improved pharmacokinetics parameters were then analyzed. Compound 56 exhibited the lowest IC50 and, therefore, it had the highest ability to inhibit the EGFR. In the present work, the most potent inhibitor 56 is not calculated to be the most promising drug candidate, since it’s out of the parabolic model obtained due to a Log P above 5, which is not within the expected optimum range. Finally, this work is an example of computational prediction that an experimentally, highly active EGFR inhibitor can be unsuccessful as drug candidate because of pitfalls in pharmacokinetics parameters.

COVID-19 infection in a kidney transplant recipient—special emphasis on pharmacokinetic interactions:A case report

BACKGROUND Solid organ transplant recipients are considered to be at high-risk of developing coronavirus disease 2019(COVID-19)-related complications.The optimal treatment for this patient group is unknown.Consequently,the treatment of COVID-19 in kidney transplant recipients should be determined individually,considering patient age and comorbidities,as well as graft function,time of transplant,and immunosuppressive treatment.Immunosuppressive treatments may give rise to severe COVID-19.On the contrary,they may also lead to a milder and atypical presentation by diminishing the immune system overdrive.CASE SUMMARY A 50-year old female kidney transplant recipient presented to the transplant clinic with a progressive dry cough and fever that started three days ago.Although the COVID-19 test was found to be negative,chest computed tomography images showed consolidation typical of the disease;thus,following hospital admission,anti-bacterial and COVID-19 treatments were initiated.However,despite clinical improvement of the lung consolidation,her creatinine levels continued to increase.Ultrasound of the graft showed no pathology.The tacrolimus blood level was determined and the elevation in creatinine was found to be related to an interaction between tacrolimus and azithromycin.CONCLUSION During the COVID-19 pandemic,various single or combination drugs have been utilized to find an effective treatment regimen.This has increased the possibility of drug interactions.A limited number of studies published in the literature have highlighted some of these pharmacokinetic interactions.Treatments used for COVID-19 therapy;azithromycin,atazanavir,lopinavir/ritonavir,remdesivir,favipiravir,chloroquine,hydroxychloroquine,nitazoxanide,ribavirin,and tocilizumab,interact with immunosuppressive treatments,most importantly with calcineurin inhibitors.Thus,their levels should be frequently monitored to prevent toxicity.