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  Subjects -> PHARMACY AND PHARMACOLOGY (Total: 575 journals)
Showing 401 - 253 of 253 Journals sorted alphabetically
Microbial Drug Resistance     Hybrid Journal   (Followers: 3)
Molecular Informatics     Hybrid Journal   (Followers: 5)
Molecular Pharmacology     Hybrid Journal   (Followers: 2)
Molekul     Open Access   (Followers: 1)
Natural Product Communications     Open Access  
Nature Reviews Drug Discovery     Full-text available via subscription   (Followers: 310)
Naunyn-Schmiedeberg's Archives of Pharmacology     Hybrid Journal  
NeuroMolecular Medicine     Hybrid Journal  
Neuropharmacology     Hybrid Journal   (Followers: 5)
Neuropsychopharmacology     Hybrid Journal   (Followers: 17)
Neuropsychopharmacology Reports     Open Access  
Nigerian Journal of Natural Products and Medicine     Full-text available via subscription  
OA Drug Design & Delivery     Open Access  
OA Medical Hypothesis     Open Access  
Obesity Facts     Open Access   (Followers: 8)
Open Pharmacoeconomics & Health Economics Journal     Open Access   (Followers: 1)
Open Pharmacology Journal     Open Access  
OpenNano     Open Access   (Followers: 1)
Orbital - The Electronic Journal of Chemistry     Open Access   (Followers: 1)
Oriental Pharmacy and Experimental Medicine     Partially Free   (Followers: 2)
Pain and Therapy     Open Access   (Followers: 3)
Particulate Science and Technology: An International Journal     Hybrid Journal   (Followers: 1)
PDA Journal of Pharmaceutical Science and Technology     Full-text available via subscription   (Followers: 33)
Pediatric Drugs     Full-text available via subscription   (Followers: 3)
Pediatric Pharmacology     Open Access   (Followers: 1)
Pharmaceutica Analytica Acta     Open Access  
Pharmaceutical Biology     Open Access  
Pharmaceutical Care-La Farmacoterapia     Open Access  
Pharmaceutical Chemistry Journal     Hybrid Journal  
Pharmaceutical Development and Technology     Hybrid Journal   (Followers: 19)
Pharmaceutical Executive     Full-text available via subscription   (Followers: 2)
Pharmaceutical Fronts     Open Access   (Followers: 9)
Pharmaceutical Historian     Open Access  
Pharmaceutical Journal     Free   (Followers: 8)
Pharmaceutical Journal of Sri Lanka     Open Access  
Pharmaceutical Medicine     Full-text available via subscription   (Followers: 4)
Pharmaceutical Nanotechnology     Hybrid Journal  
Pharmaceutical Patent Analyst     Full-text available via subscription   (Followers: 3)
Pharmaceutical Research     Hybrid Journal   (Followers: 93)
Pharmaceutical Statistics     Hybrid Journal   (Followers: 15)
Pharmaceutical Technology     Full-text available via subscription   (Followers: 6)
Pharmaceuticals     Open Access   (Followers: 4)
Pharmacia     Open Access  
Pharmaciana     Open Access  
PharmacoEconomics     Full-text available via subscription   (Followers: 25)
PharmacoEconomics & Outcomes News     Full-text available via subscription   (Followers: 2)
PharmacoEconomics German Research Articles     Full-text available via subscription  
PharmacoEconomics Spanish Research Articles     Hybrid Journal   (Followers: 1)
Pharmacoepidemiology and Drug Safety     Hybrid Journal   (Followers: 33)
Pharmacogenetics and Genomics     Hybrid Journal   (Followers: 1)
Pharmacogenomics     Hybrid Journal   (Followers: 7)
Pharmacogenomics and Personalized Medicine     Open Access   (Followers: 2)
Pharmacogenomics Journal     Hybrid Journal   (Followers: 5)
Pharmacognosy Communications     Partially Free  
Pharmacognosy Magazine     Open Access   (Followers: 2)
Pharmacognosy Research     Open Access   (Followers: 2)
Pharmacological Reports     Hybrid Journal  
Pharmacological Research     Hybrid Journal   (Followers: 1)
Pharmacological Research - Modern Chinese Medicine     Open Access  
Pharmacological Reviews     Hybrid Journal   (Followers: 2)
Pharmacology     Full-text available via subscription  
Pharmacology & Therapeutics     Hybrid Journal   (Followers: 3)
Pharmacology & Pharmacy     Open Access   (Followers: 1)
Pharmacology Biochemistry and Behavior     Hybrid Journal   (Followers: 2)
Pharmacology Research & Perspectives     Open Access  
Pharmacon : Jurnal Farmasi Indonesia     Open Access  
Pharmacopsychiatry     Hybrid Journal   (Followers: 3)
Pharmacotherapy The Journal of Human Pharmacology and Drug Therapy     Hybrid Journal   (Followers: 37)
Pharmactuel     Open Access   (Followers: 1)
Pharmacy     Open Access   (Followers: 4)
Pharmacy & Pharmacology     Open Access   (Followers: 1)
Pharmacy Education     Full-text available via subscription   (Followers: 11)
Pharmacy Practice (Internet)     Open Access   (Followers: 8)
Pharmakon : Arzneimittel in Wissenschaft und Praxis     Full-text available via subscription   (Followers: 1)
PharmaNutrition     Hybrid Journal   (Followers: 3)
PharmaTutor     Open Access  
Pharmazeutische Industrie     Full-text available via subscription   (Followers: 9)
Pharmazeutische Zeitung     Full-text available via subscription   (Followers: 11)
Pharmazie in Unserer Zeit (Pharmuz)     Hybrid Journal   (Followers: 11)
Physiology International     Full-text available via subscription   (Followers: 3)
Plant Products Research Journal     Full-text available via subscription  
Planta Medica     Hybrid Journal   (Followers: 4)
Planta Medica International Open     Open Access  
Prescriber     Hybrid Journal   (Followers: 9)
Progress in Neuro-Psychopharmacology and Biological Psychiatry     Hybrid Journal   (Followers: 8)
Psychiatry and Clinical Psychopharmacology     Open Access   (Followers: 1)
Psychopharmacology     Hybrid Journal   (Followers: 15)
Pulmonary Pharmacology & Therapeutics     Hybrid Journal   (Followers: 2)
PZ Prisma : Materialien zur Fort- und Weiterbildung     Full-text available via subscription  
Redox Report     Open Access  
Regulatory Mechanisms in Biosystems     Open Access   (Followers: 1)
Regulatory Toxicology and Pharmacology     Hybrid Journal   (Followers: 41)
Research & Reviews : A Journal of Drug Design & Discovery     Full-text available via subscription  
Research & Reviews : A Journal of Pharmaceutical Science     Full-text available via subscription  
Research & Reviews : A Journal of Pharmacognosy     Full-text available via subscription  
Research & Reviews : A Journal of Pharmacology     Full-text available via subscription   (Followers: 1)
Research in Pharmaceutical Sciences     Open Access   (Followers: 3)
Research in Social and Administrative Pharmacy     Hybrid Journal   (Followers: 3)
Research Journal of Pharmacognosy     Open Access  
Research Results in Pharmacology     Open Access  
Reviews of Physiology, Biochemistry and Pharmacology     Hybrid Journal   (Followers: 4)
Reviews on Clinical Pharmacology and Drug Therapy     Full-text available via subscription  
Revista Colombiana de Ciencias Químico-Farmacéuticas     Open Access  
Revista Cubana de Plantas Medicinales     Open Access   (Followers: 1)
Revista de Ciências Farmacêuticas Básica e Aplicada     Open Access  
Revista Mexicana de Ciencias Farmaceuticas     Open Access  
Revue de Médecine et de Pharmacie     Full-text available via subscription  
Safety and Risk of Pharmacotherapy     Open Access   (Followers: 1)
Saudi Pharmaceutical Journal     Open Access  
Scandinavian Journal of Clinical and Laboratory Investigation     Hybrid Journal   (Followers: 7)
Scientia Pharmaceutica     Open Access  
Seminars in Hematology     Hybrid Journal   (Followers: 12)
Seminars in Oncology Nursing     Full-text available via subscription   (Followers: 10)
Separation Science plus (SSC plus)     Hybrid Journal  
Side Effects of Drugs Annual     Full-text available via subscription   (Followers: 2)
Skin Pharmacology and Physiology     Full-text available via subscription   (Followers: 6)
Substance Abuse : Research and Treatment     Open Access   (Followers: 5)
Suchttherapie     Hybrid Journal   (Followers: 1)
Sustainable Chemistry and Pharmacy     Full-text available via subscription   (Followers: 1)
Synfacts     Hybrid Journal   (Followers: 5)
SynOpen     Open Access  
The Botulinum J.     Hybrid Journal  
The Brown University Psychopharmacology Update     Hybrid Journal   (Followers: 2)
The Medical Letter     Full-text available via subscription   (Followers: 18)
The Pink Sheet     Full-text available via subscription   (Followers: 12)
The Pink Sheet Daily     Full-text available via subscription   (Followers: 4)
Therapeutic Advances in Drug Safety     Open Access   (Followers: 3)
Therapeutic Advances in Psychopharmacology     Open Access   (Followers: 4)
Therapeutic Advances in Vaccines     Hybrid Journal   (Followers: 1)
Therapeutic Drug Monitoring     Hybrid Journal   (Followers: 3)
Therapeutic Innovation & Regulatory Science     Hybrid Journal   (Followers: 7)
Thérapie     Full-text available via subscription   (Followers: 1)
TheScientist     Free   (Followers: 5)
Toxicological & Environmental Chemistry     Hybrid Journal   (Followers: 2)
Toxicological Research     Hybrid Journal  
Toxicological Sciences     Hybrid Journal   (Followers: 11)
Toxicology     Hybrid Journal   (Followers: 18)
Toxicology and Applied Pharmacology     Hybrid Journal   (Followers: 24)
Toxicology and Industrial Health     Hybrid Journal   (Followers: 6)
Toxicology in Vitro     Hybrid Journal   (Followers: 11)
Toxicology International     Full-text available via subscription   (Followers: 5)
Toxicology Letters     Hybrid Journal   (Followers: 15)
Toxicology Mechanisms and Methods     Hybrid Journal   (Followers: 7)
Toxicology Research     Partially Free   (Followers: 8)
Toxicon     Hybrid Journal   (Followers: 5)
Toxicon : X     Open Access  
Toxin Reviews     Hybrid Journal  
Translational Psychiatry     Open Access   (Followers: 14)
Trends in Peptide and Protein Sciences     Open Access  
Trends in Pharmacological Sciences     Full-text available via subscription   (Followers: 19)
Tropical Journal of Pharmaceutical Research     Open Access  
Ukrainian Biopharmaceutical Journal     Open Access  
Vascular Pharmacology     Hybrid Journal   (Followers: 2)
World Mycotoxin Journal     Hybrid Journal   (Followers: 3)
Yakugaku Zasshi     Open Access   (Followers: 1)
Zeitschrift für Phytotherapie     Hybrid Journal   (Followers: 1)
Актуальні питання фармацевтичної та медичної науки та практики     Open Access  
Фармацевтичний часопис     Open Access  

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Journal Cover
Journal of Pharmacokinetics and Pharmacodynamics
Journal Prestige (SJR): 0.784
Citation Impact (citeScore): 2
Number of Followers: 22  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1573-8744 - ISSN (Online) 1567-567X
Published by Springer-Verlag Homepage  [2469 journals]
  • Should patients skip late doses of medication' A pharmacokinetic
           perspective

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      Abstract: Abstract Missed doses, late doses, and other dosing irregularities are major barriers to effective pharmacotherapy, especially for the treatment of chronic conditions. What should a patient do if they did not take their last dose at the prescribed time' Should they take it late or skip it' In this paper, we investigate the pharmacokinetic effects of taking a late dose. We consider a single compartment model with linear absorption and elimination for a patient instructed to take doses at regular time intervals. We suppose that the patient forgets to take a dose and then realizes some time later and must decide what remedial steps to take. Using mathematical analysis, we derive several metrics which quantify the effects of taking the dose late. The metrics involve the difference between the drug concentration time courses for the case that the dose is taken late and the case that the dose is taken on time. In particular, the metrics are the integral of the absolute difference over all time, the maximum of the difference, and the maximum of the integral of the difference over any single dosing interval. We apply these general mathematical formulas to levothyroxine, atorvastatin, and immediate release and extended release formulations of lamotrigine. We further show how population variability can be immediately incorporated into these results. Finally, we use this analysis to propose general principles and strategies for dealing with dosing irregularities.
      PubDate: 2022-06-20
       
  • Towards a translational physiologically-based pharmacokinetic (PBPK) model
           for receptor-mediated transcytosis of anti-transferrin receptor monoclonal
           antibodies in the central nervous system

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      Abstract: Abstract In this manuscript, we present a translational physiologically-based pharmacokinetic (PBPK) model to characterize receptor-mediated transcytosis (RMT) of anti-transferrin receptor (TfR) monoclonal antibodies (mAbs) in the central nervous system (CNS). The model accounts for the state-of-the-art knowledge of the brain's anatomy and physiology, and physiological parameters were fixed according to different species. By estimating a few parameters associated with the TfR concentration, the TfR turnover, and the internalization rate, the model simultaneously characterizes plasma, whole brain, interstitial fluid (ISF), and cerebrospinal fluid (CSF) PK of unbound and bound anti-TfR mAbs with different binding affinities in mice, rats, and monkeys obtained from various literature sources within a threefold prediction error. The final PBPK model was validated using external anti-TfR mAb PK data in mice and monkeys with different affinities and doses. The simulation reasonably predicted plasma and brain PK of monovalent/bivalent anti-TfR mAbs within a threefold prediction error and characterized a bell-shaped relationship between the brain ISF/plasma AUC ratio and the KD value. Although further refinements of the PBPK model and clinical validation are required, this PBPK model may provide physiologically-based translation of CNS disposition of anti-TfR mAbs by accounting for the physiological difference of the endogenous RMT system among different species. The PBPK model may also guide selection of other endogenous receptors, lead optimization, and clinical development of novel CNS-targeted mAbs.
      PubDate: 2022-06-01
       
  • Improving categorical endpoint longitudinal exposure–response modeling
           through the joint modeling with a related endpoint

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      Abstract: Abstract Exposure–response modeling is important to optimize dose and dosing regimens in clinical drug development. While primary clinical trial endpoints often have few categories and thus provide only limited information, sometimes there may be additional, more informative endpoints. Benefits of fully incorporating relevant information in longitudinal exposure–response modeling through joint modeling have recently been shown. This manuscript aims to further investigate the benefit of joint modeling of an ordered categorical primary endpoint with a related near-continuous endpoint, through the sharing of model parameters in the latent variable indirect response (IDR) modeling framework. This is illustrated by analyzing the data collected through up to 116 weeks from a phase 3b response-adaptive trial of ustekinumab in patients with psoriasis. The primary endpoint was based on the 6-point physician’s global assessment (PGA) score. The Psoriasis area and severity Index (PASI) data, ranging from 0 to 72 with 0.1 increments, were also available. Separate and joint latent variable Type I IDR models of PGA and PASI scores were developed and compared. The results showed that the separate PGA model had a substantial structural bias, which was corrected by the joint modeling of PGA and PASI scores.
      PubDate: 2022-06-01
       
  • Physiologically-based pharmacokinetic model for 2,4-dinitrophenol

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      Abstract: Abstract New approaches in drug development are needed to address the growing epidemic of obesity as the prevalence of obesity increases worldwide. 2,4-Dinitrophenol (DNP) is an oxidative phosphorylation uncoupling agent that was widely used in the early 1930s for weight loss but was quickly banned by the FDA due to the severe toxicities associated with the compound. One of the limitations leading to the demise of DNP as a pharmaceutical was a lack of understanding about the pharmacokinetic–pharmacodynamic relationship. The purpose of this study was to investigate whole body disposition of DNP in order to understand the relationship between the pharmacokinetics, efficacy and toxicity in the C57BL/6J diet induced obese mouse model. Following intravenous administration of 1 mg/kg, and intraperitoneal administration of 5 mg/kg and 15 mg/kg of DNP, we found limited DNP distribution to tissues. Experimentally measured partition coefficients were found to be less than 1 for all analyzed tissues. In addition, DNP exhibits significant nonlinear pharmacokinetics, which we have attributed to nonlinear plasma protein binding and nonlinear partitioning into liver and kidney. By enhancing our understanding of the PK–PD relationship, we can develop new approaches to leverage oxidative phosphorylation uncoupling as a weight loss strategy.
      PubDate: 2022-06-01
       
  • R-praziquantel integrated population pharmacokinetics in preschool- and
           school-aged African children infected with Schistosoma mansoni and
           S. haematobium and Lao adults infected with Opisthorchis viverrini

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      Abstract: Abstract Racemic praziquantel (PZQ) is the standard treatment for schistosomiasis and liver fluke infections (opisthorchiasis and clonorchiasis). The development of an optimal pediatric formulation and dose selection would benefit from a population pharmacokinetic (popPK) model. A popPK model was developed for R-PZQ, the active enantiomer of PZQ, in 664 subjects, 493 African children (2–15 years) infected with Schistosoma mansoni and S. haematobium, and 171 Lao adults (15–78 years) infected with Opisthorchis viverrini. Racemate tablets were administered as single doses of 20, 40 and 60 mg/kg in children and 30, 40 and 50 mg/kg in 129 adults, and as 3 × 25 mg/kg apart in 42 adults. Samples collected by the dried-blood-spot technique were assayed by LC-MS/MS. A two-compartment disposition model, with allometric scaling and dual first-order and transit absorption, was developed using Phoenix™ software. Inversely parallel functions of age described the apparent oral bioavailability (BA) and clearance maturation in children and ageing in adults. BA decreased slightly in children with dose increase, and by 35% in adults with multiple dosing. Crushing tablets for preschool-aged children increased the first-order absorption rate by 64%. The mean transit absorption time was 70% higher in children. A popPK model for R-PZQ integrated African children over 2 years of age with schistosomiasis and Lao adults with opisthorchiasis, and should be useful to support dose optimization in children. In vitro hepatic and intestinal metabolism data would help refining and validating the model in younger children as well as in target ethnic pediatric and adult groups.
      PubDate: 2022-06-01
       
  • Prediction of CYP-mediated silybin A-losartan
           pharmacokinetic interactions using physiological based pharmacokinetic
           modeling

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      Abstract: Abstract The concomitant use of herbal products and synthetic drugs necessitates the assessment of their interaction potentials. The herbal hepatoprotective medicine, silybin A inhibits cytochrome P450 (CYP) 2C9 and 3A4 enzymes, thus, may interact with the drugs that are substrates of CYP2C9 and 3A4, such as losartan. The three most prominent genotypes, expressed by CYP2C9 are the CYP2C9*1/*1, CYP2C9*1/*2 and CYP2C9*1/*3. This study aimed to assess silybin A-losartan interaction in different CYP2C9 genotypes using physiological-based pharmacokinetic (PBPK) model approach. The individual PBPK models for silybin A and losartan were developed using PK-Sim®. Losartan pharmacokinetics was predicted with or without co-administration of silybin A in individuals of different CYP2C9 genotypes to find herbal-drug interaction. The predicted drug plasma curves and pharmacokinetic parameters were optimized using parameter identification tool and were compared with reported pharmacokinetic parameters from the published clinical studies for model validation. The silybin-losartan interactions were predicted by change in area under the curve (AUC) and peak systemic concentration (Cmax). The co-treatment of silybin A, 420 mg/24 h (140 mg/8 h) with losartan 50 mg/24 h, exhibited a genotype-dependent change in the losartan’s AUC and Cmax. In CYP 2C9*1/*1 genotype, AUC and Cmax of losartan were increased 1.16 and 1.37 folds, respectively falling in a range stipulated for negligible interaction. Increase in AUC and Cmax by 0.873 and 0.294 folds, respectively in CYP2C9*1/*3 after co-administration of silybin A exhibited a minor interaction with losartan. However, in individuals with CYP2C9*1/*2 genotype, the losartan’s AUC and Cmax were decreased by 0.01 folds, manifesting a moderate interaction. Hence, in CYP2C9*1/*1 and CYP2C9*1/*3 genotypes, silybin A is a weak CYP inhibitor for losartan while in CYP2C9*1/*2 genotype, the co-administration of silybin consequents into a moderate pharmacokinetic interaction with losartan.
      PubDate: 2022-06-01
       
  • Semi-empirical anticoagulation model (SAM): INR monitoring during Warfarin
           therapy

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      Abstract: The International Normalized Ratio (INR) monitoring is an essential component to manage thrombotic disease therapy. This study presents a semi-empirical model of INR as a function of time and assigned therapy (Warfarin, k-vitamin). With respect to other methodologies, this model is able to describe the INR using a limited number of parameters and is able to describe the time variation of INR described in the literature. The presented methodology showed great accuracy in model calibration [(trueness (precision)]: 0.2% (0.1%) to 1.2% (0.3%) for coagulation factors, from 5% (9%) to 9.7% (12%) for Warfarin-related parameters and 38% (40%) for K-vitamin-related parameters. The latter value was considered acceptable given the assumptions made in the model. It has two other important results: the first is that it was able to correctly estimate INR with respect to daily therapy doses taken from the literature. The second is that it introduces a single numeric semi-empirical parameter that is able to correlate INR/dose response to physiological and environmental condition of patients. Graphic abstract
      PubDate: 2022-06-01
       
  • Global sensitivity analysis in physiologically-based
           pharmacokinetic/pharmacodynamic models of inhaled and opioids anesthetics
           and its application to generate virtual populations

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      Abstract: Abstract The integration between physiologically-based pharmacokinetics (PBPK) models and pharmacodynamics (PD) models makes it possible to describe the absorption, distribution, metabolism and excretion processes of drugs, together with the concentration–response relationship, being a fundamental framework with wide applications in pharmacology. Nevertheless, the enormous complexity of PBPK models and the large number of parameters that define them leads to the need to study and understand how the uncertainty of the parameters affects the variability of the models output. To study this issue, this paper proposes a global sensitivity analysis (GSA) to identify the parameters that have the greatest influence on the response of the model. It has been selected as study cases the PBPK models of an inhaled anesthetic and an analgesic, along with two PD interaction models that describe two relevant clinical effects, hypnosis and analgesia during general anesthesia. The subset of the most relevant parameters found adequately with the GSA method has been optimized for the generation of a virtual population that represents the theoretical output variability of various model responses. The generated virtual population has the potential to be used for the design, development and evaluation of physiological closed-loop control systems.
      PubDate: 2022-05-26
       
  • Knowledge dissemination and central indexing of resources in
           pharmacometrics: an ISOP education working group initiative

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      Abstract: Abstract Pharmacometrics is a constantly evolving field that plays a major role in decision making in drug development and clinical monitoring. Scientists in Pharmacometrics, especially in their early phases of career, are often faced with the challenge of identifying adequate resources for self-training and education. Hence, the ISoP Education Committee through its working group dedicated to Central Indexing and knowledge Dissemination has built a database of worldwide educational programs and most common references in Pharmacometrics.
      PubDate: 2022-04-26
       
  • Population pharmacokinetic model selection assisted by machine learning

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      Abstract: Abstract A fit-for-purpose structural and statistical model is the first major requirement in population pharmacometric model development. In this manuscript we discuss how this complex and computationally intensive task could benefit from supervised machine learning algorithms. We compared the classical pharmacometric approach with two machine learning methods, genetic algorithm and neural networks, in different scenarios based on simulated pharmacokinetic data. Genetic algorithm performance was assessed using a fitness function based on log-likelihood, whilst neural networks were trained using mean square error or binary cross-entropy loss. Machine learning provided a selection based only on statistical rules and achieved accurate selection. The minimization process of genetic algorithm was successful at allowing the algorithm to select plausible models. Neural network classification tasks achieved the most accurate results. Neural network regression tasks were less precise than neural network classification and genetic algorithm methods. The computational gain obtained by using machine learning was substantial, especially in the case of neural networks. We demonstrated that machine learning methods can greatly increase the efficiency of pharmacokinetic population model selection in case of large datasets or complex models requiring long run-times. Our results suggest that machine learning approaches can achieve a first fast selection of models which can be followed by more conventional pharmacometric approaches.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09793-6
       
  • A longitudinal model for the Mayo Clinical Score and its sub-components in
           patients with ulcerative colitis

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      Abstract: Abstract Clinical trials in patients with ulcerative colitis (UC) face the challenge of high and variable placebo response rates. The Mayo Clinical Score (MCS) is used widely as the primary endpoint in clinical trials to describe the clinical status of patients with UC. The MCS is comprised of four subscores, each scored 0, 1, 2 and 3: rectal bleeding (RB), stool frequency (SF), physician’s global assessment (PGA), and endoscopy (ENDO) subscore. Excluding the PGA subscore gives the modified MCS. Quantitative insight on the placebo response, and its impact on the components of the MCS over time, can better inform clinical trial design and interpretation. Longitudinal modeling of the MCS, and the modified MCS, can be challenging due to complex clinical trial design, population heterogeneity, and limited assessments for the ENDO subscore. The current study pooled patient-level placebo/standard of care (SoC) arm data from five clinical trials in the TransCelerate database to develop a longitudinal placebo response model that describes the MCS over time in patients with UC. MCS subscores were modeled using proportional odds models, and the removal of patients from the placebo/SoC arm, or “dropout”, was modeled using logistic regression models. The subscore and dropout models were linked to allow for the prediction of the MCS and the modified MCS. Stepwise covariate modeling identified prior exposure to TNF-α antagonists as a statistically significant predictor on the RB + SF subscore. Patients with prior exposure to TNF-α antagonists had higher post-baseline RB + SF subscores than naive patients.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09789-2
       
  • Exposure-response modeling improves selection of radiation and
           radiosensitizer combinations

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      Abstract: Abstract A central question in drug discovery is how to select drug candidates from a large number of available compounds. This analysis presents a model-based approach for comparing and ranking combinations of radiation and radiosensitizers. The approach is quantitative and based on the previously-derived Tumor Static Exposure (TSE) concept. Combinations of radiation and radiosensitizers are evaluated based on their ability to induce tumor regression relative to toxicity and other potential costs. The approach is presented in the form of a case study where the objective is to find the most promising candidate out of three radiosensitizing agents. Data from a xenograft study is described using a nonlinear mixed-effects modeling approach and a previously-published tumor model for radiation and radiosensitizing agents. First, the most promising candidate is chosen under the assumption that all compounds are equally toxic. The impact of toxicity in compound selection is then illustrated by assuming that one compound is more toxic than the others, leading to a different choice of candidate.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09784-7
       
  • Statistical analysis of one-compartment pharmacokinetic models with drug
           adherence

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      Abstract: Abstract Pharmacokinetics is a scientific branch of pharmacology that describes the time course of drug concentration within a living organism and helps the scientific decision-making of potential drug candidates. However, the classical pharmacokinetic models with the eliminations of zero-order, first-order and saturated Michaelis–Menten processes, assume that patients perfectly follow drug regimens during drug treatment, and the significant factor of patients’ drug adherence is not taken into account. In this study, therefore, considering the random change of dosage at the fixed dosing time interval, we reformulate the classical deterministic one-compartment pharmacokinetic models to the framework of stochastic, and analyze their qualitative properties including the expectation and variance of the drug concentration, existence of limit drug distribution, and the stochastic properties such as transience and recurrence. In addition, we carry out sensitivity analysis of drug adherence-related parameters to the key values like expectation and variance, especially for the impact on the lowest and highest steady state drug concentrations (i.e. the therapeutic window). Our findings can provide an important theoretical guidance for the variability of drug concentration and help the optimal design of medication regimens. Moreover, The developed models in this paper can support for the potential study of the impact of drug adherence on long-term treatment for chronic diseases like HIV, by integrating disease models and the stochastic PK models.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09794-5
       
  • Development of a genetic algorithm and NONMEM workbench for automating and
           improving population pharmacokinetic/pharmacodynamic model selection

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      Abstract: Abstract The current approach to selection of a population PK/PD model is inherently flawed as it fails to account for interactions between structural, covariate, and statistical parameters. Further, the current approach requires significant manual and redundant model modifications that heavily lend themselves to automation. Within the discipline of numerical optimization it falls into the “local search” category. Genetic algorithms are a class of algorithms inspired by the mathematics of evolution. GAs are general, powerful, robust algorithms and can be used to find global optimal solutions for difficult problems even in the presence of non-differentiable functions, as is the case in the discrete nature of including/excluding model components in search of the best performing mixed-effects PK/PD model. A genetic algorithm implemented in an R-based NONMEM workbench for identification of near optimal models is presented. In addition to the GA capabilities, the workbench supports modeling efforts by: (1) Organizing and displaying models in tabular format, allowing the user to sort, filter, edit, create, and delete models seamlessly, (2) displaying run results, parameter estimates and precisions, (3) integrating xpose4 and PsN to facilitate generation of model diagnostic plots and run PsN scripts, (4) running regression models between post-hoc parameter estimates and covariates. This approach will further facilitate the scientist to shift efforts to focus on model evaluation, hypotheses generation, and interpretation and applications of resulting models.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09782-9
       
  • Inferring pulmonary exposure based on clinical PK data: accuracy and
           precision of model-based deconvolution methods

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      Abstract: Abstract Determining and understanding the target-site exposure in clinical studies remains challenging. This is especially true for oral drug inhalation for local treatment, where the target-site is identical to the site of drug absorption, i.e., the lungs. Modeling and simulation based on clinical pharmacokinetic (PK) data may be a valid approach to infer the pulmonary fate of orally inhaled drugs, even without local measurements. In this work, a simulation-estimation study was systematically applied to investigate five published model structures for pulmonary drug absorption. First, these models were compared for structural identifiability and how choosing an inadequate model impacts the inference on pulmonary exposure. Second, in the context of the population approach both sequential and simultaneous parameter estimation methods after intravenous administration and oral inhalation were evaluated with typically applied models. With an adequate model structure and a well-characterized systemic PK after intravenous dosing, the error in inferring pulmonary exposure and retention times was less than twofold in the majority of evaluations. Whether a sequential or simultaneous parameter estimation was applied did not affect the inferred pulmonary PK to a relevant degree. One scenario in the population PK analysis demonstrated biased pulmonary exposure metrics caused by inadequate estimation of systemic PK parameters. Overall, it was demonstrated that empirical modeling of intravenous and inhalation PK datasets provided robust estimates regarding accuracy and bias for the pulmonary exposure and pulmonary retention, even in presence of the high variability after drug inhalation.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09780-x
       
  • Wide size dispersion and use of body composition and maturation improves
           the reliability of allometric exponent estimates

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      Abstract: Abstract To evaluate study designs and the influence of dispersion of body size, body composition and maturation of clearance or reliable estimation of allometric exponents. Non-linear mixed effects modeling and parametric bootstrap were employed to assess how the study sample size, number of observations per subject, between subject variability (BSV) and dispersion of size distribution affected estimation bias and uncertainty of allometric exponents. The role of covariate model misspecification was investigated using a large data set ranging from neonates to adults. A decrease in study sample size, number of observations per subject, an increase in BSV and a decrease in dispersion of size distribution, increased the uncertainty of allometric exponent estimates. Studies conducted only in adults with drugs exhibiting normal (30%) BSV in clearance may need to include at least 1000 subjects to be able to distinguish between allometric exponents of 2/3 and 1. Nevertheless, studies including both children and adults can distinguish these exponents with only 100 subjects. A marked bias of 45% (95%CI 41–49%) in the estimate of the allometric exponent of clearance was obtained when maturation and body composition were ignored in infants. A wide dispersion of body size (e.g. infants, children and adults) is required to reliably estimate allometric exponents. Ignoring differences in body composition and maturation of clearance may bias the exponent for clearance. Therefore, pharmacometricians should avoid estimating allometric exponent parameters without suitable designs and covariate models. Instead, they are encouraged to rely on the well-developed theory and evidence that clearance and volume parameters in humans scale with theory-based exponents.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09788-3
       
  • Experimental and computational assessment of the synergistic
           pharmacodynamic drug–drug interactions of a triple combination therapy
           in refractory HER2-positive breast cancer cells

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      Abstract: Abstract The development of innate and/or acquired resistance to human epidermal growth factor receptor type-2 (HER2)-targeted therapy in HER2-positive breast cancer (HER2 + BC) is a major clinical challenge that needs to be addressed. One of the main mechanisms of resistance includes aberrant activation of the HER2 and phosphatidylinositol 3-kinase/AKT8 virus oncogene cellular homolog/mammalian target of rapamycin (PI3K/Akt/mTOR) pathways. In the present work, we propose to use a triple combination therapy to combat this resistance phenomenon. Our strategy involves evaluation of two targeted small molecule agents, everolimus and dasatinib, with complementary inhibitory circuitries in the PI3K/Akt/mTOR pathway, along with a standard cytotoxic agent, paclitaxel. Everolimus inhibits mTOR, while dasatinib inhibits Src, which is a protein upstream of Akt. An over-activation of these two proteins has been implicated in approximately 50% of HER2 + BC cases. Hence, we hypothesize that their simultaneous inhibition may lead to enhanced cell-growth inhibition. Moreover, the potent apoptotic effects of paclitaxel may help augment the overall cytotoxicity of the proposed triple combination in HER2 + BC cells. To this end, we investigated experimentally and assessed computationally the in vitro pharmacodynamic drug–drug interactions of the various dual and triple combinations to assess their subsequent combinatorial effects (synergistic/additive/antagonistic) in a HER2-therapy resistant BC cell line, JIMT-1. Our proposed triple combination therapy demonstrated synergism in JIMT-1 cells, thus corroborating our hypothesis. This effort may form the basis for further investigation of the triple combination therapy in vivo at a mechanistic level in HER2-therapy resistant BC cells.
      PubDate: 2022-04-01
      DOI: 10.1007/s10928-021-09795-4
       
  • Integrated multiple analytes and semi-mechanistic population
           pharmacokinetic model of tusamitamab ravtansine, a DM4 anti-CEACAM5
           antibody-drug conjugate

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      Abstract: Abstract Tusamitamab ravtansine (SAR408701) is an antibody-drug conjugate (ADC), combining a humanized monoclonal antibody (IgG1) targeting carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) and a potent cytotoxic maytansinoid derivative, DM4, inhibiting microtubule assembly. SAR408701 is currently in clinical development for the treatment of advanced solid tumors expressing CEACAM5. It is administered intravenously as a conjugated antibody with an average Drug Antibody Ratio (DAR) of 3.8. During SAR408701 clinical development, four entities were measured in plasma: conjugated antibody (SAR408701), naked antibody (NAB), DM4 and its methylated metabolite (MeDM4), both being active. Average DAR and proportions of individual DAR species were also assessed in a subset of patients. An integrated and semi-mechanistic population pharmacokinetic model describing the time-course of all entities in plasma and DAR measurements has been developed. All DAR moieties were assumed to share the same drug disposition parameters, excepted for clearance which differed for DAR0 (i.e. NAB entity). The conversion of higher DAR to lower DAR resulted in a DAR-dependent ADC deconjugation and was represented as an irreversible first-order process. Each conjugated antibody was assumed to contribute to DM4 formation. All data were fitted simultaneously and the model developed was successful in describing the pharmacokinetic profile of each entity. Such a structural model could be translated to other ADCs and gives insight of mechanistic processes governing ADC disposition. This framework will further be expanded to evaluate covariates impact on SAR408701 pharmacokinetics and its derivatives, and thus can help identifying sources of pharmacokinetic variability and potential efficacy and safety pharmacokinetic drivers.
      PubDate: 2022-02-15
      DOI: 10.1007/s10928-021-09799-0
       
  • A pharmacokinetic and pharmacodynamic analysis of drug forgiveness

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      Abstract: Abstract Nonadherence to medication is a major public health problem. To combat nonadherence, some clinicians have suggested using “forgiving” drugs, which maintain efficacy in spite of delayed or missed doses. What pharmacokinetic (PK) and pharmacodynamic (PD) factors make a drug forgiving' In this paper, we address this question by analyzing a linear PK/PD model for a patient with imperfect adherence. We assume that the drug effect is far from maximal and consider direct effect, effect compartment (biophase), and indirect response PD models. We prove that the average drug effect relative to the clinically desired effect is simply the fraction of prescribed doses actually taken by the patient. Hence, under these assumptions, drug forgiveness cannot be defined in terms of the average effect. We argue that forgiveness should instead be understood in terms of effect fluctuations. We prove that the rates of PK absorption, PK elimination, and PD elimination are exactly equivalent for determining effect fluctuations. We prove all the aforementioned results for any pattern of nonadherence, including late doses, missed doses, drug holidays, extra doses, etc. To obtain quantitative estimates of effect fluctuations, we consider a simple statistical pattern of nonadherence and analytically calculate the coefficient of variation of effect. We further show how effect fluctuations can be reduced by taking an extra “make up” dose following a missed dose if any one of the aforementioned PK/PD rates is sufficiently slow. We illustrate some of our results for a nonlinear indirect response model of metformin.
      PubDate: 2022-02-13
      DOI: 10.1007/s10928-022-09808-w
       
  • Correction to: R-praziquantel integrated population pharmacokinetics in
           preschool- and school-aged African children infected with
           Schistosoma mansoni and S. haematobium and Lao adults infected with
           Opisthorchis viverrini

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      PubDate: 2022-02-04
      DOI: 10.1007/s10928-022-09807-x
       
 
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