"In this dose range-finding study of tapinarof in the rat, tapinarof and its metabolite need to be determined when administered by oral gavage to rats to characterize the toxicity and toxicokinetics. In this study, tapinarof was administered at a low dose and the plasma volume collected at each time point is small. Based on the previous research data, the linear range of tapinarof and its metabolite were designed to be 0.500-250ng/mL and 0.200-100ng/mL, respectively. Tapinarof and its metabolite have different chemical properties from the performance of method development, under alkaline condition, metabolite obtained a high response, but significantly inhibited tapinarof signaling. In order to obtain the best compound response with reducing the sample volume used, difference LC-MS/MS methods for tapinarof and its metabolite were established respectively. After extraction with 10 μL plasma sample by protein precipitation , part of the supernatant was directly used for tapinarof method injection, and the other part of the supernatant was diluted with deionized water for metabolite analysis injection. AS qualified by the methods, the results showed that the interference between tapinarof and its metabolite, endogenous interference and matrix effect were not observed. A good linear relationship was achieved over the concentration ranges of 0.500-250 ng/mL for tapinarof and 0.200-100 ng/mL for metabolite. In contrast to published Tapinarof LC–MS/MS assay methods, the present methods showed higher sensitivity of tapinaorf and its metabolite with a small volume of plasma using a simple and rapid protein precipitation. The ability to analyze small samples could eliminate the need for satellite animals and allow comparisons of links between exposure and toxicity in individual animals, as is generally the case in non-rodent studies. "