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Dihydroartemisinin (DHA) and piperaquine (PPQ) are two drugs used in an artemisinin‐based combination therapy (ACT). The circulation of counterfeit antimalarial drugs demands the development of simple, point‐of‐care (POC) tests for monitoring drug quality. Here we aimed to design an antibody‐based lateral flow dipstick assay for simultaneous quality control of DHA and PPQ. To obtain a monoclonal antibody (mAb) for PPQ, one structural unit of the symmetric PPQ molecule was used to derive a carboxylic acid for linkage to a carrier protein as immunogen. Screening of hybridoma cells identified an mAb 4D112B2 that reacted with the PPQ‐based immunogen. A highly‐sensitive icELISA was designed based on this mAb, which showed 50% inhibition concentration of PPQ at 1.66 ng/mL and a working range of 0.35 – 7.40 ng/mL. The mAb showed 10.2, 15.9 and 30.4% cross reactivity to hydroxychloroquine sulfate, chloroquine and amodiaquine, respectively. No cross reactivity was observed to lumefantrine, mefloquine artemisinin and its derivatives. Using our previous DHA dipstick design, a lateral flow dipstick for simultaneous analysis of PPQ and DHA was developed. The indicator ranges for PPQ and DHA were 2 – 5 μg/mL and 250 – 500 ng/mL, respectively. The dipstick was used to semi‐quantitatively analyze PPQ and DHA content in commercial ACT drugs, which produced agreeable results to those determined by high‐performance liquid chromatography. This combination dipstick makes it a potential POC device for quality control of the two active ingredients in a commonly used ACT. [ABSTRACT FROM AUTHOR]

Dihydroartemisinin (DHA) is one of the artemisinin derivatives widely used in artemisinin-based combination therapies (ACTs) for malaria treatment. The availability of a point-of-care device for estimation of DHA quantity would allow a quick quality assessment of the DHA-containing drugs. In this study, 9-O-succinylartemisinin was obtained from microbial fermentation of artemisinin, which was hydrogenated to 9-O-succinyldihydroartemisinin as the hapten for DHA. A monoclonal antibody (mAb), designated as 2G 1 1G 4 , was identified after screening the hybridoma library, which showed 52.3% cross reactivity to artemisinin, but low or no cross reactivity to artesunate, artemether, and several ACTs partner drugs. Based on this mAb, a highly-sensitive, indirect competitive enzyme-linked immunosorbent assay was designed, which showed 50% inhibition concentration of DHA at 1.16 ng/mL, a working range of 0.26–4.87 ng/mL, and limit of detection of 0.18 ng/mL. In addition, a colloidal gold-based lateral flow immunoassay (dipstick) was developed with an indicator range (indicating sensitivity) of 50–100 ng/mL. This dipstick was evaluated for determination of DHA contents in commercial drugs and the results were highly agreeable with those determined by high-performance liquid chromatography. [ABSTRACT FROM AUTHOR]