Subcutaneous microdialysis in rats correlates with carbamazepine concentrations in plasma and brain

Microdialysis simplifies the measurement of pharmacokinetics in pharmacodyn amically relevant tissues. Microdialysis permits serial measurements of unb ound drug concentration. The objective of the present work was to study rat s to correlate plasma carbamazepine pharmacokinetics with subcutaneous and brain tissues. Microdialysis probes were inserted into the jugular vein, th e brain, and subcutaneous tissue in Sprague-Dawley rats. After receiving si ngle doses of carbamazepine, 12 mg/kg i.p., pharmacokinetic sampling occurr ed simultaneously from three microdialysis sites. Microdialysis sampled unb ound carbamazepine and carbamazepine-10,11-epoxide concentrations. Concentr ations measured in brain, subcutaneous, and plasma correlated with each oth er. Except where differences were anticipated, pharmacokinetic parameters, including half-life and time to maximum concentration, were the same regard less of measurement site. The present study suggests microdialysis may allo w pharmacokinetic measurements in peripheral physiological spaces that are surrogates for the pharmacologically relevant tissue. (C) 2000 Elsevier Sci ence B.V. All rights reserved.