Pharmacokinetics of 5-Aminofluorescein-Albumin, a Novel Fluorescence Marker of Brain Tumors During Surgery

In a phase I/II study, the new fluorescence marker 5‐aminofluorescein covalently bound to human serum albumin (AFL‐HSA) was intravenously administered to 10 patients with brain tumor 1 to 4 days before surgery, and AFL‐HSA kinetics were determined to assess the optimum timing of dye administration. AFL‐HSA was determined in serum and brain tissue by size exclusion chromatography with fluorescence detection. AFL‐HSA disposition was quite similar to albumin kinetics with small volumes of distribution (volume of central compartment [Vc] = 2.4 L; volume of distribution [Vdβ] = 6.8 L; volume at steady state [Vss] = 5.9 L), a low clearance (mean Cl = 16.85 mL/h), and a long elimination half‐life (mean T½β = 307 hours). Predicted peak concentrations in the peripheral compartment occurred at 80.9 hours, the time point of optimal fluorescence intensity observed in brain tumors during surgery.