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BETA
Bergqvist, Yngve
Alternative names
Publications (4 of 4) Show all publications
Blessborn, D., Römsing, S., Annerberg, A., Sundquist, D., Björkman, A., Lindegårdh, N. & Bergqvist, Y. (2007). Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper. Journal of Pharmaceutical and Biomedical Analysis, 45(2), 282-287
Open this publication in new window or tab >>Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper
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2007 (English)In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 45, no 2, p. 282-287Article in journal (Refereed) Published
Abstract [en]

A bioanalytical method for the determination of lumefantrine in 100 μl 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 solid-phase extraction and finally quantified with HPLC. The between-day variation was below 10% over the range 0.4-25 μM. The lower limit of quantification was 0.25 μM in 100 μl capillary blood. No decrease in lumefantrine concentration in dried blood spot is seen after 4 months storage at 22 °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 day 7 (i.e. 4 days after the last dose) after a standard regimen with the lumefantrine/artemether combination.

Keywords
Lumefantrine, Sampling paper, Dried blood spots, Capillary blood, Antimalarial drugs, Solid-phase extraction, Liquid chromatography
National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-11919 (URN)10.1016/j.jpba.2007.07.015 (DOI)000250888700014 ()17719735 (PubMedID)
Available from: 2007-11-06 Created: 2007-11-06 Last updated: 2018-01-12Bibliographically approved
Tarning, J., Bergqvist, Y., Day, N., Bergquist, J., Arvidsson, B., White, N., . . . Lindegårdh, N. (2006). Characterization of Human Urinary Metabolites of the Antimalarial Piperaquine. Drug Metabolism And Disposition, 34(12), 2011-2019
Open this publication in new window or tab >>Characterization of Human Urinary Metabolites of the Antimalarial Piperaquine
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2006 (English)In: Drug Metabolism And Disposition, ISSN 0090-9556, E-ISSN 1521-009X, Vol. 34, no 12, p. 2011-2019Article in journal (Refereed) Published
Abstract [en]

Five metabolites of the antimalarial piperaquine (PQ) (1,3-bis-[4-(7chloroquinolyl-4)-piperazinyl-1]-propane) have been identified and their molecular structures characterized. After a p.o. dose of dihydroartemisinin-piperaquine, urine collected over 16 h from two healthy subjects was analyzed using liquid chromatography (LC)/UV, LC/tandem mass spectrometry (MS/MS), Fourier transform ion cyclotron resonance (FTICR)/MS, and H NMR. Five different peaks were recognized as possible metabolites [M1, 320 m/z; M2, M3, and M4, 551 m/z (PQ + 16 m/z); and M5, 567 m/z (PQ + 32 m/z)] using LC/MS/MS with gradient elution. The proposed carboxylic M1 has a theoretical monoisotopic molecular mass of 320.1166 m/z, which is in accordance with the FTICR/MS (320.1168 m/z) findings. The LC/MS/MS results also showed a 551 m/z metabolite (M2) with a distinct difference both in polarity and fragmentation pattern compared with PQ, 7-hydroxypiperaquine, and the other 551 m/z metabolites. We suggest that this is caused by N-oxidation of PQ. The results showed two metabolites (M3 and M4) with a molecular ion at 551 m/z and similar fragmentation pattern as both PQ and 7-hydroxypiperaquine; therefore, they are likely to be hydroxylated PQ metabolites. The molecular structures of M1 and M2 were also confirmed using H NMR. Urinary excretion rate in one subject suggested a terminal elimination half-life of about 53 days for M1. Assuming formation rate-limiting kinetics, this would support recent findings that the terminal elimination half-life of PQ has been underestimated previously.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-21710 (URN)10.1124/dmd.106.011494 (DOI)000242374700010 ()16956956 (PubMedID)
Available from: 2007-01-03 Created: 2007-01-03 Last updated: 2017-12-07Bibliographically approved
Malm, M., Lindegårdh, N. & Bergqvist, Y. (2004). Automated solid-phase extraction method for the determination of piperaquine in capillary blood applied onto sampling paper by liquid chromatography. Journal of Chromatography B (809), 43-49
Open this publication in new window or tab >>Automated solid-phase extraction method for the determination of piperaquine in capillary blood applied onto sampling paper by liquid chromatography
2004 (English)In: Journal of Chromatography B, no 809, p. 43-49Article in journal (Refereed) Published
Abstract [en]

A bioanalytical method for the determination of piperaquine in 100 uL blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Blood spots were cut into small pieces prior to addition of 0.3 M perchloric acid, acetonitrile and phosphate buffer containing an internal standard. The liquid phase was loaded onto a mixed phase cation-exchange (MPC) solid-phase extraction column. Piperaquine and the internal standard were analysed by liquid chromatography and separated on a Chromolith Performance (100 mm x 4.6 mm) column with acetonitrile: phosphate buffer pH 2.5, I = 0.1 (8:92, v/v) at the flow of 3.5 mL/min. The UV detection was performed at 345 nm. the intra-assay precision was 12.0% at 0.150 uM, 7.3% at 1.25 uM and 7.3% at 2.25 uM. The inter-assay precison was 1.8% at 0.150 uM, 5.2% at 1.25 uM and 2.8% at 2.25 uM. The lower limit of quantification (LLOQ) was determined to 0.050 uM where the precison was 14.7%.

Keywords
Piperaquine
Identifiers
urn:nbn:se:uu:diva-70705 (URN)
Available from: 2005-04-27 Created: 2005-04-27 Last updated: 2011-01-12
Jastrebova, J., Nyholm, L., Markides, K. & Bergqvist, Y. (1998). On-Line Deoxygenation for Reductive Electrochemical Detection of Artemisinin and Dihydroartemisinin in Liquid Chromatography. The Analyst, 123, 313
Open this publication in new window or tab >>On-Line Deoxygenation for Reductive Electrochemical Detection of Artemisinin and Dihydroartemisinin in Liquid Chromatography
1998 (English)In: The Analyst, ISSN 0003-2654, Vol. 123, p. 313-Article in journal (Refereed) Published
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-69537 (URN)
Available from: 2005-04-05 Created: 2005-04-05 Last updated: 2011-01-14
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