Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper

A bioanalytical method for the determination of lumefantrine in 100 mu 1 blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Whatman 31 ET Chr sampling paper was pre-treated with 0.75 M tartaric acid before sampling capillary blood to enable a high recovery of lumefantrine. Lumefantrine was extracted from the sampling paper, then further purified using solidphase extraction and finally quantified with HPLC. The between-day variation was below 10% over the range 0.4-25 mu M. The lower limit of quantification was 0.25 mu M in 100 mu 1 capillary blood. No decrease in lumefantrine concentration in dried blood spot is seen after 4 months storage at 22 degrees C. The method was also evaluated in field samples from patients in Tanzania after treatment with lumefantrine/artemether. Lumefantrine could be estimated accurately enough to assess bioavailability and treatment compliance on clay 7 (i.e. 4 days after the last dose) after a standard regimen with the lumefantrine/artemether combination. (c) 2007 Elsevier B.V. All rights reserved.