Population pharmacokinetics and bioavailability of motexafin gadolinium (Xcytrin®) in CD1 mice following intravenous and intraperitoneal injection

  • Boswell GW
  • DR Miles
  • PA Thiemann
  • M Mesfin
Preclinical Studies


Motexafin gadolinium (Xcytrin®) is an expanded porphyrin macrocyclic compound under development for the treatment of several types of cancer. Currently clinical trials and non-clinical pharmacology and toxicology studies are ongoing. The goals of this open label, four arm, non-crossover bioavailability study were to explore motexafin gadolinium pharmacokinetics, determine the IP bioavailability, and define a pharmacokinetic model suitable for descriptive and predictive use. Mice received one or seven daily IV or IP injections (40 mg/kg) then blood samples were collected and analyzed. Plasma concentration data were modelled using population pharmacokinetic methods and a two compartment model was the most appropriate model. The stability and predictive performance of the model were evaluated using bootstrap procedures. The accuracy of the predicted concentrations was 8.3%. Motexafin gadolinium was rapidly cleared from the plasma and although T1/2β was 12.9 h there was no accumulation following seven doses. The IP bioavailability was 87.4% and higher plasma concentrations were sustainable for a longer period with IP dosing. V c was larger than the blood volume and the tissue compartment volume was 38% of V c, suggesting motexafin gadolinium was not widely distributed into less well perfused tissues. The pharmacokinetic profile in this study was similar to that in oncology patients administered multiple doses of motexafin gadolinium. The unbiased model yields reliable parameter estimates and insight into the pharmacokinetics of motexafin gadolinium in mice, is suitable for both descriptive and predictive purposes, and is a valuable tool in the planning, analysis, and interpretation of pharmacology and toxicology studies in mice.


Motexafin Gadolinium Population pharmacokinetics Mouse pharmacokinetics Intraperitoneal dose Intravenous dose Bioavailability 


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Copyright information

© Springer Science + Business Media, LLC 2006

Authors and Affiliations

  1. 1.Pharmacyclics, Inc
  2. 2.Pharmacyclics, Inc 995 E. Aruques Ave Sunnyvale

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