Article Interaction of antipsychotic drug with novel surfactants: Micellization and binding studies Naved Azum ⁎, Malik Abdul Rub, Abdullah M. Asiri Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia abstract article info Article history: Received 3 May 2017 Received in revised form 24 July 2017 Accepted 14 September 2017 Available online 28 September 2017 The interaction of cationic gemini surfactants (alkanediyl-α,ω-bis(alkyl dimethylammonium bromide)) with an antipsychotic drug (chlorpromazine hydrochloride (CPZ)) has been investigated. Various micellar and interfacial parameters have been deliberated by surface tension measurement to report the nature of interactions between drug and novel surfactant mixtures. The behavior of mixed systems, their compositions and activities of compo- nents have been analyzed in the light of Rubingh's theory. The results indicate synergism in the binary mixtures. The binding study between CPZ and surfactants has been done by spectroscopic techniques such as UV–visible and fluorescence. The results are discussed in the light of the use of gemini surfactants as promising drug delivery agents for phenothiazine drugs, and hence, improve their bioavailability. © 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved. Keywords: Gemini surfactants Antipsychotic drug Chlorpromazine hydrochloride Mixed micellization 1. Introduction Amphiphiles or surface active compounds have both hydrophilic and hydrophobic properties. The amphiphiles have the unique capabil- ity of making nano size clusters in solutions, known as micelles. The mi- celles formed by amphiphiles are capable of solubilizing the sparingly soluble substances. They are able to modify the interfacial properties of the liquid (non-aqueous or aqueous) in which they are present. Am- phiphiles are ubiquitous materials, which exhibit a fascinating range of applications in chemical processes, industries, in the formulation of pharmaceuticals, in mineral processing technologies, and in the food processing industries [1–5]. When amphiphiles are present in low con- centration, they act much as normal electrolytes but deviate at higher concentrations. The solubility of surfactants in water is low because of the presence of the hydrophobic hydrocarbon tail. When these com- pounds are dissolved in a solvent, the hydrophobic portion segregates from the solvent by self-aggregation leading to the formation of mi- celles. This phenomenon, known as the hydrophobic effect, spontane- ously minimizes the unfavorable hydrocarbon–water contacts and increases the entropy of the system. Two or more types of amphiphiles are mixed together, to make a mixed micelle. The mixed micelle is a re- sult of the self-assembly of different amphiphile monomers present in a solution. Many applications from household to industrial are associated with mixed micelles because of it having great properties of a mixed system in comparison to single micelle [6–17]. In recent times, a new generation of surfactants has been evolved named as gemini or novel surfactants [18–24]. In these novel surfac- tants, the two conventional surfactants are chemically bonded together by a spacer group (Fig. 1). The spacer may be a flexible or rigid structure [25]. The gemini surfactants (contain ester or amide group) have glob- ally concern to solve the environmental problems. These surfactants are used in carbon steel pipelines in the acidic medium as corrosion in- hibitor [26–28]. Noteworthy among these gemini surfactants, the cationic alkanediyl- α,ω-bis(alkyldimethylammonium bromide) type, designated m-s-m, where the length of the alkyl tails designated by “m” and s refers to the number of methylene units that make up the alkyl spacer, has received more attention because of its low critical micelle concentration (cmc) values, superior surface activity, higher solubilizing capacity, biodegrad- ability, and non-toxic nature. The hydrophobic interactions in surfactants are driven by the micellization, while the repulsion of charged head groups and hydration are the voluntary. In gemini surfactants two amphiphilic moieties are joined by a spacer group, when the spacer is short, these moieties are closed to each other. Due to chemical bond connection, the hydrophobic chain interactions are enhanced; on the other hand, repulsion between the hydrophilic groups is re- duced. That's why gemini surfactants are more readily to form aggregates. Chlorpromazine (CPZ) is an amphiphilic drug [29,30], marketed with the name Thorazine. It is an antipsychotic drug used to treat psychotic disorders such as schizophrenia. It is also used to treat bipolar disorder, nausea, vomiting, and anxiety before surgery. CPZ is a tricyclic amphi- philic compound, which contains a hydrophobic part as an amino group Chinese Journal of Chemical Engineering 26 (2018) 566–573 ⁎ Corresponding author. E-mail addresses: navedazum@gmail.com, nhassan2@kau.edu.sa (N. Azum). https://doi.org/10.1016/j.cjche.2017.09.009 1004-9541/© 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved. 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