Fluorometer for Screening of Doxorubicin in Perfusate Solution and Tissue with Solid-Phase Microextraction Chemical...

The recent development of an in vivo solid-phase microextraction (SPME) method capable of analyzing drugs and metabolic products in biofluids and living tissues holds great promise. The standard in vivo SPME protocol based on mass spectrometry is a very powerful analytical approach, but it is not practical for on-site analysis in many cases. In this paper, we present a fluorescence-based SPME method and a prototype of a portable fluorometer that is capable of quickly quantifying concentrations of the anticancer drug, doxorubicin (DOX). The instrument uses thin coated, biocompatible SPME fibers, which we have previously presented as a chemical biopsy tool for use during in vivo lung perfusion (IVLP) procedures within a hospital setting. In this research, we test SPME fibers with C8-SCX, C18, and HLB coatings with our fluorometer. The mixed-mode C8-SCX fibers showed the best sensitivity of the three and were therefore used to examine DOX extraction from perfusate solution and a homogenized lamb lung tissue. The maximum concentration of free active sites in the C8-SCX fiber and the adsorption equilibrium constant were determined to be (9.1 ± 0.3) × 10^-7 mol m^-2 and 420 ± 30 m³ mol^-1, respectively. Finally, the detection limits for DOX extracted from buffer, perfusate, and lung tissue were 40, 100, and 3700 μg L^-1, respectively.