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DESCRIPTION OF THE TEST CHEMICAL Butachlor was developed by Monsanto Company (USA) and introduced in 1968 for the pre-emergence control of undesirable grasses and broadleaf weeds in transplanted, direct seeded rice and barley fields. Butachlor was first introduced in Japan in 1973 and has been used for the control of grass weeds and broadleaf weeds in transplanted rice paddies. Butachlor is a member of the chloroacetanilide class of chemistry and is the herbicidal active ingredient in MACHETE(R) EC. This report summarizes the results of laboratory toxicology studies conducted with butachlor. The physical and chemical properties of butachlor are given below: Common name: Butachlor Chemical name: 2-chloro-2', 6'-diethyl-N-(butoxymethyl)acetanilide Chemical structure:

Two different recombinant antibodies, a single-chain variable fragment (scFv) and an antigen-binding fragment (Fab), were prepared against artemisinin (AM) and artesunate (AS) and were developed for use in an enzyme-linked immunosorbent assay (ELISA). The recombinant antibodies, which were derived from a single monoclonal antibody against AM and AS (mAb 1C1) prepared by us, were expressed by Escherichia coli cells and their reactivity and specificity were characterized. As a result, to obtain sufficient signal in indirect ELISA, a much greater amount of a first antibody was needed in the use of scFv due to the differences of the secondary antibody and conformational stability. Therefore, we focused on the development of the recombinant Fab antibodies and applied it to indirect competitive ELISA. The specificity of the Fab was similar to that of mAb 1C1 in that it showed specific reactivity toward AM and AS only. The sensitivity of the icELISA (0.16 μg/mL to 40 μg/mL for AM and 8.0 ng/mL to 60 ng/mL for AS) was sufficient for analysis of antimalarial drugs, and its utility for quality control of analysis of Artemisia spp. was validated. The Fab expression and refolding systems provided a good yield of high-quality antibodies. The recombinant antibody against AM and AS provides an essential component of an economically attractive immunoassay and will be useful in other immunochemical applications for the analysis and purification of antimalarial drugs.

Abstract:We prepared a monoclonal antibody (mAb 1C1) showing specificity for artemisinin (AM) and artesunate (AS), and we developed an indirect competitive enzymelinked immunosorbent assay (icELISA) using this novel mAb. Moreover, we prepared a recombinant antibody derived from mAb 1C1 in order to overcome insufficient mAb production by hybridoma culture. A recombinant antigen-binding fragment (Fab) was easily constructed using antibody manipulation technologies and was produced by microorganisms in high yield. We herein review immunochemical approaches for analysis of the antimalarial drugs AM and AS that were able to yield analysis results for multiple samples in a short period of time using simple and reliable protocols.

The Health and Environmental Sciences Institute (HESI) is a non-profit scientific research organization based in Washington, D.C., U.S.A. HESI was established in 1989 as a global branch of the International Life Sciences Institute (ILSI) to provide an international forum to advance the understanding of scientific issues related to human health, toxicology, risk assessment and the environment. For the last 25 years, HESI has been the global leader to advance application of new science and technologies in the areas of human health, toxicology, risk assessment and environment. The core principle of “tripartite approach” and the multi-sector operational model have successfully supported HESI’s scientific programs to create science-based solutions for a sustainable and healthier world. HESI’s achievements include the dataset to guide the selection of appropriate supporting assays for carcinogenicity testing, a new testing framework for agricultural chemicals with enhanced efficacy, predictivity, and reduced animal usage, novel biomarkers of nephrotoxicity which provide data on the location of timing of drug effects in the kidney allowing for enhanced drug development, etc.