Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2017, 9(5):371-376 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 371 Antioxidant Activity Assay In vitro of Polysorbate 80 and Dimethyl Sulfoxide (DMSO) through DPPH Method Rafaelly Maria Pinheiro Siqueira 1* , Nicácio Tântalo Pinheiro Araújo 1 , Maria Janaína Paula Gomes 1 , Ana Virgínia Timbó Paiva Mororó 1 , André Luiz Cunha Cavalcante 2 , Francisco Eduardo Aragão Catunda 3 and Suzana Barbosa Bezerra 4 1 Pharmaceutical, Faculty INTA of Sobral, Brazil 2 University of Fortaleza, Brazil 3 Doctor in Chemistry, State University of the Tocantina Region of Maranhão, Brazil 4 Pharmaceutical, Professor Metropolitan Faculty of Fortaleza, Brazil _____________________________________________________________________________ ABSTRACT Excipients are components that help preparing a formulation and are classified according to their purpose. Among the different classes there are the tensoactive ones which are important in various areas of industry for having a capability of generating emulsions. Polysorbate 80 and dimethyl sulfoxide (DMSO) are important tensoactives widely used by industry in different segments to favor the homogenization of immiscible substances. Thus, the aim of this study is to evaluate the antioxidant activity of polysorbate 80 and DMSO through the ability to neutralize free radical DPPH The results were analyzed by logarithmic regression curve to obtain the curve of the function and the curve of the coefficient of determination. Statistical analysis was obtained using the GraphPad Prism® software version 7.0 for Windows®. The different concentrations of polysorbate 80 and DMSO showed significant antioxidant activity in a dose-dependent manner. In this experiment, both substances exhibited antioxidant activity by scavenging free radicals by DPPH, even when used in low concentrations. These results raise concerns in the indiscriminate use of these substances in laboratory research involving antioxidant activity, since the activity can be obtained from use in experiments, DMSO or polysorbate 80. However, it has been emphasized the need for deeper studies that have higher concentrations of the substance, or using different methodologies of antioxidant analysis in vitro and in vivo, in order to establish the performance of these excipients that have a large usability in the pharmaceutical field. Keywords: Antioxidants activity; Polysorbate 80; Dimethyl sulfoxide (DMSO); 2,2-diphenyl-1-picrylhydrazyl (DPPH) _____________________________________________________________________________ INTRODUCTION Excipients are components that help preparing a formulation and are classified according to their purpose. Among the different classes there are the tensoactive ones which are important in various areas of industry for having a capability of generating emulsions. By acting on the reduction of the superficial tension of two imiscible liquids, the tensoactives enable their own dilution [1]. As an example, there is polysorbate 80, and dimethylsulfoxide (DMSO) [2-4]. Polysorbate 80, also known as Tween 80® is used in the food industry, dermocosmetic and medicine as an emulsifier, solubilizer, dispersant, defoamer, wetting agent and surfactant [5]. It has already been reported for introducing toxic characteristics, proved to be a toxicant agent for various vias of administration [6], like in the topical via, causing irritation; and at the oral one diarrhea [7]. In vivo tests in mice and rats using the intraperitoneal via, the substance promoted depression in the central nervous system reduced locomotor activity and rectal temperature, ataxia, paralytic activity and potentiation of sleep time induced by phenobarbital. In tests using intravenous via, it was observed an hipotensive efect when administered in dogs, antagonism of the activity of acetylcholine, histamine and barium when administered to rats and myocardial depression when