Determination of lumefantrine in small-volume human plasma by LC–MS/MS: using a deuterated lumefantrine to overcome matrix effect and ionization saturation

Background: To support pediatric study, a method to determine lumefantrine (LF) with small sample volume is needed. Matrix effect (ME) is a daunting issue in LF quantification in human plasma with LC–MS/MS. Results: Here we report an LC–MS/MS method with a deuterated LF as the internal standard (IS). Plasma sample (25 µl) was acidified with 5% formic acid prior to extraction with ethyl acetate. The recovery was over 80%. The absolute ME was within the range of 100 ± 8% for both LF and the IS, but cumulative ME was observed via large variation of IS signal. The cumulative ME...