Determination of Artemether and Dihydroartemisinin in Human Plasma with A New Hydrogen Peroxide Stabilization Method

Abstract

Background: Numerous methods have been reported for the determination of artemether (ARM) and its metabolite dihydroartemisinin (DHA) in plasma. However, stability issues in patient plasma have not received enough attention. Results: An LC–MS/MS method for simultaneous determination of ARM and DHA in human plasma (K₃EDTA) turned out to be problematic: ARM and DHA were degraded partially or completely in some patient plasma samples as indicated by the stable isotope-labeled internal standards. We postulated iron II (Fe²⁺) in hemoglobin or its derived products from malaria patients causes degradation of the drugs, and found that hydrogen peroxide (H₂O₂) protected the drugs from degradation. Acidifying plasma increased recovery of ARM significantly. Using only 50 µl of plasma sample, the method has a LLOQ at 0.5 ng/ml for both ARM and DHA. Conclusion: H₂O₂ is a stabilizing agent for artemisinin derivatives. The modified method is reliable and sensitive.

Supplementary Data

Financial & competing interests disclosure

This work was supported by NIH (R01 HD068174). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

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Funding

This work was supported by NIH (R01 HD068174). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.