Prediction of the Impact of CYP2C19 Polymorphism on Drug-Drug Interaction between Voriconazole and Tacrolimus Using Physiologically-Based Pharmacokinetic Modelling

Abstract Voriconazole increases tacrolimus blood concentration significantly when coadministrated. The recommendation of reducing tacrolimus to 1/3 in voriconazole package insert seems not to be satisfactory in clinical practice. In vitro studies demonstrated that the magnitude of inhibition depends on the concentration of voriconazole, while voriconazole exposure is determined by the genotype status of CYP2C19. CYP2C19 gene polymorphism challenges the management of drug-drug interactions(DDIs) between voriconazole and tacrolimus. This work aimed to predict the impact of CYP2C19 polymorphism on the DDIs by using physiologically based pharmacokinetics (PBPK) models. The precision of the developed voriconazole and tacrolimus models was reasonable by evaluating the pharmacokinetic parameters fold error, such as AUC0-24, Cmax and tmax. Voriconazole increased tacrolimus concentration immediately in all population. The simulated duration of DDIs disappearance after voriconazole withdrawal were 146h, 90h and 66h in poor metabolizers (PMs), intermediate metabolizers (IMs) and extensive metabolizers(EMs), respectively. The developed and optimized PBPK models in this study can be applied to assit the dose adjustment for tacrolimus with and without voriconazole.

Development of Physiologically Based Pharmacokinetic Model and Assessment of the Impact of Renal Underdevelopment in Preterm Infants on the Pharmacokinetics of Aminophylline

Objective:To develop a physiologically based pharmacokinetic (PBPK) model for individualization of the dosing regimen considering the physiological requirements of these preterm neonates. Methods: The study comprised preterm newborns with fewer than 34 weeks of gestation and six apneic episodes in 24 h. A PBPK model was created using PK-SIM (version 9, update 1, GitHub, San Francisco, CA, USA). A PBPK model is built using a typical loading dosage of 5 mg/kg and a maintenance dose of 1.5 mg/kg. Based on the verified base model, a PBPK model representing renal underdevelopment based on nRIFLE/pRIFLE categorization was developed. Results: The PK parameters of Aminophylline were computed using the PBPK model. As per the model prediction, T1/2 and area under the curve reduced as postnatal age increased, and in the event of renal underdevelopment, even while Cmax for patients under R (RISK), I (injury) was within the therapeutic range; it was greater compared to preterm without any renal complications. Mean Cmax (mol/L) was 59.53 and for R, I, and F (FAILURE) categories the values were 83.04, 99.69, and 126.98, respectively. Conclusion: The model was created using appropriate drug, study subject, and dosage protocol inputs. The established PBPK model could help in individualizing aminophylline dose in preterm babies.

Prediction of the bioequivalence of different crystal forms of rifampicin based on physiologically based pharmacokinetic model / 中国药科大学学报

@#The physiologically based pharmacokinetic (PBPK) modeling strategy was adopted to predict the pharmacokinetic behavior of crystal forms I and II of rifampicin in humans, which was used to determine whether the two were bioequivalent.After conducting studies in vitro of the two crystal forms, a rat PBPK model was established based on the pharmacokinetic data of intravenous administration in rats.The model was optimized by the pharmacokinetic data of oral administration in rats.Species were extrapolated to healthy humans, and the extrapolation model was used to predict such pharmacokinetic behaviors as the drug-time curve, absorption site, and absorption amount of the two crystal forms of rifampicin in healthy humans.The prediction results of the healthy human model showed that the cmax of form I and form II rifampicin were 8.42 and 10.35 μg/mL, tmax were 0.40 and 0.32 h,and AUC0-t were both 62.90 μg·h/mL.According to the prediction results of absorption, neither crystal form I nor crystal form II rifampicin was absorbed in the stomach, yet both were completely absorbed in the intestinal tract, with both the absorption site and the absorption amount were basically the same.The pharmacokinetic parameters of both crystal forms I and II of rifampicin were very close, which could indicate bioequivalence.

A Comparative Study of PBPK Model and Allometric Growth Model of Azithromycin in Extrapolation of Adult Pharmacokinetic Data to Pediatric Population / 中国药学杂志

OBJECTIVE: To establish an adult-pediatric transformation model of azithromycin to provide guiding recommendations for clinical using of pediatrics, reduce the risk of medicationfor children, and achieve clinical personalized medication for children. METHODS: The relevant literature was reviewed. The physiological parameters of the azithromycin oral administration test in adults combined with the drug-specific parameters of azithromycin were used to establish an allometric growth model, PBPK model. According to the clinical data of oral azithromycin extracted from individual children, the correctness of the parameter scaling formulas of these two models was verified. These two models were further used to simulate the pharmacokinetic parameters of children and calculate the relative deviation and relative standard error of these parameters. RESULTS: Through simulation, it is found that the pharmacokinetic parameters cmax, tmax, AUC0-∞ obtained by the two models are close to the measured values, which are all within the scope of the literature. It can be considered that the parameter conversion formulas of the two models are correct. Further, the relative deviation and relative standard error of the parameters are calculated, and the relative deviation and relative standard error of the adult-pediatric PBPK prediction model are smaller than those of the allometric growth model. CONCLUSION: The azithromycin PBPK model predicts that children's pharmacokinetic parameters are better than the allometric growth model. The scaling formula for the specific parameters of the oral-dose adult-child model used in this article, which was successfully verified by azithromycin, can be extrapolated to other drugs to facilitate the conversion of other oral-adulterated adult-pediatric models.

Current development of physiologically based pharmacokinetic model and its application in drug clinical study / 中国临床药理学与治疗学

The physiologically based pharmacokinetic (PBPK) model, as a physiological mechanism-based model, can simulate the absorption, distribution, metabolism and excretion of drugs in the body. In recent years, it has been widely used in drug-drug interaction study, special population extrapolation, clinical trial dose selection, individualized medication and impact of different factors on the pharmacokinetic course. This review briefly describes the history and current development of PBPK model, introduces the work flow of PBPK model, and reviews its application in drug clinical study in recent years. We hope this review could provide a reference for researchers who are interested in this field.

Dose selection of chloroquine phosphate for treatment of COVID-19 based on a physiologically based pharmacokinetic model

Chloroquine (CQ) phosphate has been suggested to be clinically effective in the treatment of coronavirus disease 2019 (COVID-19). To develop a physiologically-based pharmacokinetic (PBPK) model for predicting tissue distribution of CQ and apply it to optimize dosage regimens, a PBPK model, with parameterization of drug distribution extrapolated from animal data, was developed to predict human tissue distribution of CQ. The physiological characteristics of time-dependent accumulation was mimicked through an active transport mechanism. Several dosing regimens were proposed based on PBPK simulation combined with known clinical exposure-response relationships. The model was also validated by clinical data from Chinese patients with COVID-19. The novel PBPK model allows in-depth description of the pharmacokinetics of CQ in several key organs (lung, heart, liver, and kidney), and was applied to design dosing strategies in patients with acute COVID-19 (Day 1: 750 mg BID, Days 2-5: 500 mg BID, CQ phosphate), patients with moderate COVID-19 (Day 1: 750 mg and 500 mg, Days 2-3: 500 mg BID, Days 4-5: 250 mg BID, CQ phosphate), and other vulnerable populations (.., renal and hepatic impairment and elderly patients, Days 1-5: 250 mg BID, CQ phosphate). A PBPK model of CQ was successfully developed to optimize dosage regimens for patients with COVID-19.

Development of a physiologically-based pharmacokinetic model for cyclosporine in Asian children with renal impairment

This study aimed to assess the pharmacokinetics of cyclosporine A (CsA) in Asian children with renal impairment (RI) by developing a physiologically-based pharmacokinetic (PBPK) model with Simcyp Simulator. The PBPK model of Asian children with RI was developed by modifying the physiological parameters of the built-in population libraries in Simcyp Simulator. The ratio of healthy and RI populations was obtained for each parameter showing a difference between the populations. Each ratio was multiplied by the corresponding parameter in healthy Asian children. The model verification was performed with published data of Korean children with kidney disease given multiple CsA administrations. Simulations were performed with different combinations of ethnicity, age, and renal function to identify the net impact of each factor. The simulated results suggested that the effect of RI was higher in children than adults for both Caucasian and Asian. In conclusion, the constructed model adequately characterized CsA pharmacokinetics in Korean children with RI. Simulations with populations categorized by ethnicity, age, and renal function enabled to assess the net impact of each factor on specific populations.

PBPK modeling and simulation in drug research and development

Physiologically based pharmacokinetic (PBPK) modeling and simulation can be used to predict the pharmacokinetic behavior of drugs in humans using preclinical data. It can also explore the effects of various physiologic parameters such as age, ethnicity, or disease status on human pharmacokinetics, as well as guide dose and dose regiment selection and aid drug-drug interaction risk assessment. PBPK modeling has developed rapidly in the last decade within both the field of academia and the pharmaceutical industry, and has become an integral tool in drug discovery and development. In this mini-review, the concept and methodology of PBPK modeling are briefly introduced. Several case studies were discussed on how PBPK modeling and simulation can be utilized through various stages of drug discovery and development. These case studies are from our own work and the literature for better understanding of the absorption, distribution, metabolism and excretion (ADME) of a drug candidate, and the applications to increase efficiency, reduce the need for animal studies, and perhaps to replace clinical trials. The regulatory acceptance and industrial practices around PBPK modeling and simulation is also discussed.

Establishment of Physiological Pharmacokinetic Model of Cefdinir in Healthy Volunteers and Its Application / 中国药房

OBJECTIVE:To establish physiological pharmacokinetic (PBPK) model of cefdinir in healthy volunteers,and to predict pharmacokinetic process of cefdinir in volunteers after oral administration. METHODS:Using“toubao dini”“cefdinir”“logP”“pKa”as keywords,related literatures about physico-chemical constants of cefdinir were retrieved from CNKI,ScienceDi-rect,PubMed and other databases;according to related guidelines and preliminary clinical trial plan of FDA,GastroPlusTM 8.6 soft-ware was used to establish PBPK model of oral administration of cefdinir;the effectiveness of the model was evaluated by multiple error. The model was used to simulate the absorption of cefdinir in the gastrointestinal tracts. The bioequivalence of test preparation and reference preparation were evaluated through single and population(n=500)simulation tests using cmax and AUC0-∞ of cefdinir reference preparation (capsule and granular formulation) as factors when release rate t85%=15 min (i.e. accumulatively released 85% within 15 min). RESULTS:The blood concentration-time curves of cefdinir predicted by PBPK model fitted well with mea-sured value(R2≥0.95);the pharmacokinetic parameters(cmax,tmax,AUC0-∞)were close to measured results,and the multiple er-rors were less than 2. After oral administration,cefdinir was mainly absorbed by the intestinal tract (45.6%),especially by seg-ment 1 of jejunum(14.8%);the absorption amount was significantly lower than the release amount of absorption site,and reached the maximal value(about 40%)within 4 h. The results of single simulation test showed that there was no statistical significance in cmax and AUC0-∞ between cefdinir test and reference preparations (P>0.05). The results of population simulation test showed that the relative bioavailability of cefdinir test particle and test capsule respectively were 99.01%-102.99% and 97.60%-105.90%;90%CI of cmax and AUC0-∞ values were within 80%-125% of reference preparation. CONCLUSIONS:The PBPK model is accurate and reliable in this study,can provide reference for pharmacokinetic study and bioequivalence evaluation of cefdinir preparations. Test preparation and reference preparation are equivalent.

Prediction of Pharmacokinetics and Penetration of Moxifloxacin in Human with Intra-Abdominal Infection Based on Extrapolated PBPK Model

The aim of this study is to develop a physiologically based pharmacokinetic (PBPK) model in intraabdominal infected rats, and extrapolate it to human to predict moxifloxacin pharmacokinetics profiles in various tissues in intra-abdominal infected human. 12 male rats with intra- abdominal infections, induced by Escherichia coli, received a single dose of 40 mg/kg body weight of moxifloxacin. Blood plasma was collected at 5, 10, 20, 30, 60, 120, 240, 480, 1440 min after drug injection. A PBPK model was developed in rats and extrapolated to human using GastroPlus software. The predictions were assessed by comparing predictions and observations. In the plasma concentration versus time profile of moxifloxcinin rats, Cmax was 11.151 microg/mL at 5 min after the intravenous injection and t1/2 was 2.936 h. Plasma concentration and kinetics in human were predicted and compared with observed datas. Moxifloxacin penetrated and accumulated with high concentrations in redmarrow, lung, skin, heart, liver, kidney, spleen, muscle tissues in human with intra-abdominal infection. The predicted tissue to plasma concentration ratios in abdominal viscera were between 1.1 and 2.2. When rat plasma concentrations were known, extrapolation of a PBPK model was a method to predict drug pharmacokinetics and penetration in human. Moxifloxacin has a good penetration into liver, kidney, spleen, as well as other tissues in intra-abdominal infected human. Close monitoring are necessary when using moxifloxacin due to its high concentration distribution. This pathological model extrapolation may provide reference to the PK/PD study of antibacterial agents.

Variability in systemic pharmacokinetics of amitriptyline by blood pressure alterations in patients of depression: A PD based PK analysis model.

Physiology of vascular system in designing therapeutics is yet in its infancy. Co–Morbid conditions like depression and hypertension are complex physiological and pathological situations where PBPK drug interactions are highly probable due to change in systemic blood pressure resulting in organ perfusion that is an important determinant of drug dispersion. To generate evidence in support of this probability, a single 100 mg dose of Amitriptyline an object drug was administered with 10 mg of Amlodipine as a precipitating drug in an open label, randomized parallel group, controlled clinical study based on PK/PD analysis model. Hypertensive patients with depression test group (TI), Hypertensive patients with out depression, test group (TII), Normotensive patients with depression, control group (CI) and Normal healthy volunteers, control group (CII), having 25 participants each were enrolled in this study. Plasma samples after single dose Amitriptyline at 0, 1, 2, 4, 8, 12, 24 hours were drawn along with measurement of heart rate, respiratory rate and blood pressure. A wash out period of 7 days for the two test groups (TI and TII) was given. Amlodipine 10 mg was administered which lowered the DBP by nearly 5 to 10 mm Hg, when the Amitriptyline was administered orally and the plasma samples were drawn for PK analysis along with PD parameters in a designed time event profile. Estimation of Amitriptyline and its metabolite Nortriptyline was performed by HPLC. Pharmacokinetic parameters were calculated using a non-compartmental model. After Amlodipine induced fall in DBP in both test groups, T1/2, C max, T max, CLT, AUC of Amitriptyline and Nortriptyline changed in both the test groups (TI and TII).

Urinary, Circulating, and Tissue Biomonitoring Studies Indicate Widespread Exposure to Bisphenol A / Estudos de biomonitoração do sistema urinário, circulatório e tecidos indicam grande exposição ao Bisfenol A

Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Thus, there are concerns that the amount of BPA to which humans are exposed may cause adverse health effects. We examined many possibilities for why biomonitoring and toxicokinetic studies could come to seemingly conflicting conclusions. More than 80 published human biomonitoring studies that measured BPA concentrations in human tissues, urine, blood, and other fluids, along with two toxicokinetic studies of human BPA metabolism were examined. Unconjugated BPA was routinely detected in blood (in the nanograms per milliliter range), and conjugated BPA was routinely detected in the vast majority of urine samples (also in the nanograms per milliliter range). In stark contrast, toxicokinetic studies proposed that humans are not internally exposed to BPA. Available data from biomonitoring studies clearly indicate that the general population is exposed to BPA and is at risk from internal exposure to unconjugated BPA. The two toxicokinetic studies that suggested human BPA exposure is negligible have significant deficiencies, are directly contradicted by hypothesis-driven studies, and are therefore not reliable for risk assessment purposes.

Bisfenol A (BPA) é um dos produtos químicos mais produzido em todo o mundo, e a exposição humana a ele é considerada onipresente. Assim, há preocupações de que a quantidade de BPA para o qual os seres humanos estão expostos podem causar efeitos adversos à saúde. Nós examinamos muitas possibilidades sobre o porquê estudos de biomonitorização e toxicocinética podem chegar a conclusões aparentemente conflitantes. Mais de 80 estudos publicados de biomonitorização humana que mediram a concentração de BPA em tecidos humanos, urina, sangue e outros fluidos, juntamente com dois estudos de toxicocinética do metabolismo humano BPA foram examinados. BPA não conjugado foi detectado no sangue (nonanogramas por mililitro gama), e BPA conjugado foi detectado na grande maioria das amostras de urina. Em contraste, estudos de toxico-cinética propuseram que os seres humanos não são internamente expostos ao BPA. Dados disponíveis de estudos de biomonitorização indicam que a população em geral está exposta ao BPA e em risco de exposição interna ao BPA não conjugado. Os dois estudos de toxicocinética, que sugeriram a exposição humana ao BPA é insignificante, têm deficiências significativas e estão diretamente refutados por outros estudos e, portanto não são confiáveis para fins de avaliação de risco.

Development of Physiologically Based Pharmacokinetic Model for Several Volatile Organic Compounds / 대한산업의학회지

Recently physiologically based pharmacokinetic (PB-PK) model has important role in industrial and environmental health. One of problem in application of PB-PK models is that they have uncertainties that is due to different input parameters according to authors. In order to develope a PB-PK model that hag good validity, the effect of several input parameters on simulation results was studies. Chemicals studied were perchloroethylene, toluene and styrene. Simulation of alveolar concentration, blood concentration and urinary metabolites was performed for three solvents, respectively. Input parameters discusses were physiological parameters, metabolic parameters and partition coefficient of chemicals. By comparing simulation results according to several pairs of parameters with experimental data, input parameters that showed best fit were decided.