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Background/objectives: This study aimed to develop a fully validated HPLC-MS/MS method for quantifying total and unbound lenalidomide concentrations in human plasma.
Methods: Unbound concentrations were measured using plasma ultrafiltrate prepared with Amicon Centrifugal Filters. Lenalidomide and lenalidomide-d5 (internal standard) were extracted from 50 μL of human plasma using liquid-liquid extraction. Chromatography was conducted with a Halo C18 column using 0.1% formic acid and methanol (20:80, /) as the mobile phase. The mass spectrometer was operated in a positive ion mode with an electrospray ionization interface and multiple reaction monitoring modes.
Results: Calibration curves were linear over the range of 5 to 1000 ng/mL (r > 0.996) for both the total and unbound lenalidomide. For total lenalidomide concentrations, between-run precision (coefficients of variation) and accuracy were 1.70-7.65% and 94.45-101.10%, respectively. For unbound concentrations, inter-day precision and accuracy were 1.98-10.55% and 93.95-98.48%, respectively.
Conclusions: We developed a highly reproducible, sensitive, and efficient bioanalytical method using a smaller volume of plasma sample (50 μL) with a relatively short run time (2.5 min). The proposed analytical method was successfully applied to measure total and unbound lenalidomide concentrations at various time points in multiple myeloma patients with renal impairment.
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http://dx.doi.org/10.3390/pharmaceutics16101340 | DOI Listing |
J Clin Pharmacol
September 2025
Daiichi Sankyo Inc., Basking Ridge, NJ, USA.
Valemetostat is a dual inhibitor of EZH2/1 approved in Japan for the treatment of relapsed/refractory (R/R) adult T-cell lymphoma/leukemia (ATLL) and R/R peripheral T-cell lymphoma (PTCL). It is administered orally once daily (QD) at 200 mg. Here, we present comprehensive population pharmacokinetic (PPK) and exposure-response (ER) analyses of valemetostat.
View Article and Find Full Text PDFJ Pharmacokinet Pharmacodyn
September 2025
Centre for Applied Pharmacokinetic Research (CAPKR), University of Manchester, Manchester, UK.
Concentration-dependent binding to red blood cells is a characteristic of several drugs, complicating the understanding of how pathophysiological factors influence drug behavior. This study utilized user-friendly, physiologically-based pharmacokinetic (PBPK) models to compare concentration-dependent and independent blood-to-plasma drug concentration ratios (B/P), using tacrolimus as a case study. Two models were developed and validated for tacrolimus using clinical data from healthy volunteers; Model 1 accounted for saturable blood binding, and Model 2 used a constant B/P level.
View Article and Find Full Text PDFJ Pharmacol Exp Ther
June 2025
PET Science Centre, Precision Medicine and Biosamples, Oncology R&D, AstraZeneca, Stockholm, Sweden; Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden. Electronic address:
The receptor tyrosine kinase mesenchymal-epithelial transition factor inhibitor savolitinib is currently being evaluated as a treatment in non-small cell lung cancer (NSCLC) in combination with osimertinib. NSCLC patients with epidermal growth factor receptor/anaplastic lymphoma kinase mutations appear to have a high incidence (50%-60%) of brain metastasis; hence, cancer drugs that can efficiently access the brain hold a critical advantage. In this study, savolitinib blood-brain barrier penetration properties were investigated in nonhuman primates using positron emission tomography and intravenous administration of microdoses of [C]savolitinib either as a bolus or a bolus-constant infusion.
View Article and Find Full Text PDFHeadache
August 2025
Pfizer Inc., Groton, Connecticut, USA.
Objective: The objective of this study was to investigate the pharmacokinetics of rimegepant in participants with mild, moderate, or severe renal impairment compared to healthy adults with normal renal function.
Background: Rimegepant is a calcitonin gene-related peptide receptor antagonist approved in the United States for treatment of acute and preventive treatment of migraine.
Methods: In this Phase 1, open-label, four-group, pharmacokinetic study, 36 participants were grouped by degree of renal impairment according to estimated glomerular filtration rate (eGFR): normal; mild (60-89 mL/min/1.
Clin Microbiol Infect
August 2025
Department of Paediatric Intensive Care, Ghent University Hospital, Belgium; Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Belgium; Department of Pharmacy, Ghent University Hospital, Belgium. Electronic address:
Objectives: Optimal ciprofloxacin dosing in critically ill children is influenced by complex factors affecting drug disposition, including pathophysiological changes and supportive therapies. This study aimed to develop a population pharmacokinetic (PK) model for ciprofloxacin in critically ill children to identify predictors of inter-individual variability, evaluate target attainment for both total and unbound exposure, and provide tailored dosing recommendations.
Methods: A prospective, open-label, multicentric PK study was conducted in 44 critically ill children (< 16 years) receiving intravenous ciprofloxacin.