title: Quantum dot as a drug tracer in vivo.
abstract: Quantum dots (QDs) have been applied to a wide range of biological studies by taking advantage of their fluorescence properties. There is almost no method to trace small molecules including medicine. Here, we used QDs for fluorescent tracers for medicine and analyzed their kinetics and dynamics. We conjugated QDs with captopril, anti-hypertensive medicine, by an exchange reaction while retaining the medicinal properties. We investigated the medicinal effect of QD-conjugated captopril (QD-cap) in vitro and in vivo. We also evaluated the concentration and the distribution of the QD-cap in the blood and the organs with their fluorescence. We demonstrate that the QD-cap inhibits the activity of ACE in vitro. The QD-cap reduced the blood pressure of hypertensive model rats. The concentration of the QD-cap in the blood was measured by using the standard curve of the fluorescence intensity. The blood concentration of the QD-cap decrease exponentially and QD-cap has approximately the same half-life as that of captopril. In addition, the fluorescence of the QDs revealed that QD-cap accumulates in the liver, lungs, and spleen. We succeeded in analyzing the dynamics and kinetics of small molecules using fluorescence of QDs.
authors.affiliation: International Clinical Research Center, Research Institute, International Medical Center of Japan, Tokyo 162-8655, Japan.
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Manabe
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Hoshino
authors.forename: Yi-qiang
authors.initials: YQ
authors.lastname: Liang
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Goto
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kato
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D002216:Captopril / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D006973:Hypertension / Q000188:drug therapy* / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D045663:Quantum Dots; D051381:Rats; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013194:Staining and Labeling / Q000379:methods; D014018:Tissue Distribution
chemical_list: D000959:Antihypertensive Agents; D002216:Captopril