Isolation of 6-mercaptopurine in human plasma by aluminum ion complexation for high-performance liquid chromatographic analysis.
A sample preparation technique and a high-performance liquid chromatographic method for 6-mercaptopurine (6-MP) that is simple, sensitive and without interference from its metabolites is described. 6-Thioguanine (6-TG) is added as an internal standard to the plasma sample, which is then treated with an aqueous solution of aluminum perchlorate to denature the plasma proteins and form complexes with 6-TG, 6-MP and its major metabolite, 6-thiouric acid (6-TUA). These complexes coprecipitate with proteins on centrifugation. 6-MP and its analogues are then extracted from the precipitate with perchloric acid containing sodium hydrosulfite and the extract is chromatographed on an Ultrasphere ODS column eluted with 0.1 M phosphoric acid and 0.001 M dithiothreitol in deionized water. The eluate is monitored at 340 nm. No interfering peak was encountered in over 300 clinical plasma samples. 6-TUA was separated from 6-MP and was found to be present in much higher concentration than 6-MP itself throughout the sampling time (6 h) following oral administration of the drug.
Lin
K T
KT
Centre de Recherche, Hopital Ste-Justine, Montreal, Quebec, Canada.
Varin
F
F
Rivard
G E
GE
Leclerc
J M
JM
D000535:Aluminum / Q000737:chemistry*; D002412:Cations; D002614:Chelating Agents; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D015122:Mercaptopurine / Q000097:blood* / Q000493:pharmacokinetics; D013056:Spectrophotometry, Ultraviolet; D013866:Thioguanine / Q000097:blood; D014527:Uric Acid / Q000031:analogs & derivatives / Q000097:blood
D002412:Cations; D002614:Chelating Agents; D014527:Uric Acid; C010352:6-thiouric acid; D000535:Aluminum; D015122:Mercaptopurine; D013866:Thioguanine