title: Fluorescence detection of the anticancer drug topotecan in plasma and whole blood by two-photon excitation.
abstract: The anticancer drug topotecan was detected in human plasma and whole blood using two-photon excitation at 730 or 820 nm. These wavelengths are longer than the main absorption bands of hemoglobin. Two-photon excitation of topotecan was demonstrated by a quadratic dependence of the emission intensity on the incident power, compared to a linear dependence for one-photon excitation at 410 nm. The observed emission centered at 525 nm was shown to be topotecan from the similarity of the emission spectrum and decay times observed for one-photon and two-photon excitation. Topotecan was detected at concentrations as low as 0.05 and 1 microM in plasma and whole blood, respectively. Since skin blood and tissues are translucent at long wavelengths, these results suggest the possibility of homogeneous or noninvasive clinical sensing with two-photon excitation.
authors.affiliation: Division of Medicinal Chemistry and Pharmaceutics, College of Pharmacy, University of Kentucky, Lexington 40506-0286, USA.
authors.forename: T G
authors.initials: TG
authors.lastname: Burke
authors.forename: H
authors.initials: H
authors.lastname: Malak
authors.forename: I
authors.initials: I
authors.lastname: Gryczynski
authors.forename: Z
authors.initials: Z
authors.lastname: Mi
authors.forename: J R
authors.initials: JR
authors.lastname: Lakowicz
mesh_terms: D000970:Antineoplastic Agents / Q000097:blood* / Q000737:chemistry; D001774:Blood Chemical Analysis / Q000379:methods*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000379:methods; D006801:Humans; D007259:Infrared Rays; D007834:Lasers; D008297:Male; D017785:Photons; D010949:Plasma / Q000737:chemistry; D012867:Skin / Q000098:blood supply; D013050:Spectrometry, Fluorescence / Q000379:methods*; D019772:Topotecan
chemical_list: D000970:Antineoplastic Agents; D019772:Topotecan; D002166:Camptothecin