Colloids and Surfaces B: Biointerfaces 82 (2011) 333–339 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces journal homepage: www.elsevier.com/locate/colsurfb Voltammetric behaviour of drotaverine hydrochloride in surfactant media and its enhancement determination in Tween-20 Rajeev Jain ∗ , Vikas, Jahangir Ahmad Rather School of Studies in Chemistry, Jiwaji University, Gwalior 474011, India article info Article history: Received 27 March 2010 Received in revised form 3 September 2010 Accepted 5 September 2010 Available online 15 September 2010 Keywords: Drotaverine hydrochloride (DRO) Surfactants HMDE Pharmaceutical dosage forms abstract Simple, sensitive and rapid adsorptive voltammetric behaviour of drotaverine hydrochloride onto the HMDE has been explored and validated in surfactant media by using cyclic, differential pulse and square-wave voltammetry. Addition of Tween-20 to the drotaverine hydrochloride containing electrolyte enhances the reduction current signal. The voltammograms of the drug with Tween-20 in phosphate buffers of pH 2.5–11.0 exhibit a single well defined reduction peak which may be due to the reduction of –C C– group. The cyclic voltammetric studies indicated the reduction of drotaverine hydrochloride at the electrode surface through two electron irreversible step and diffusion-controlled. The peak current showed a linear dependence with the drug concentration over the range 0.8–7.2 g mL -1 . The calculated LOD and LOQ are 1.8 and 6.0 ng mL -1 by SWCAdSV and 8.1 and 27.2 ng mL -1 by DPCAdSV, respectively. The procedure was applied to the assay of the drug in tablet form with mean percentage recoveries of 100.2% with SWCAdSV and 99.7% with DPCAdSV. The validity of the proposed methods was further assessed by applying a standard addition technique. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Drotaverine [A] is widely used in medicine as an effective spasmolytic agent [1–3]. This drug is capable of relieving spasms of various organs, regardless of their function and innervation. Drotaverine hydrochloride has been proved to be superior in its efficiency to papaverine hydrochloride and its absorption after oral administration is more reliable [4]. It is used as an antispasmodic in the treatment of various conditions, e.g., gastrointestinal dis- eases, biliary dyskinesia, nephrolithiasis, gynaecological diseases and vasomotor diseases associated with smooth muscle spasms [5,6]. It can also be used as an adjuvant to hypotensive agents in acute disturbances of blood pressure in hypertensive disease, angina pectoris and coronary spasms [7]. ∗ Corresponding author at: School of Studies in Chemistry, Jiwaji University, 54, Krishna Vihar, Gwalior 474011, India. Tel.: +91 0751 2346209; fax: +91 0751 244276. E-mail address: rajeevjain54@yahoo.co.in (R. Jain). There are few reports in the literature for the determination of drotaverine by, spectrophotometry [8–11], high performance liquid chromatography [12–15], differential spectrophotometry [16,17], computer-aided spectrophotometry [18], potentiometric flow injection analysis [19], spectrofluorometric [20], ion selective electrode [21–23] and voltammetry [24–26]. Surfactants influence the electrochemical processes of elec- troactive species [27–29] and thus are widely used in electroana- lytical chemistry to improve the sensitivity and selectivity [30–33]. Contrary to the extensive applications of surfactants in the electro- analytical chemistry, little work has been carried out to explore the nature of surfactant adsorption on electrode surfaces. Adsorption of surfactant aggregates on the electrode surface might signifi- cantly facilitate the electron transfer, change the redox potentials or charge transfer coefficients or diffusion coefficients and alter the stability of electrogenerated intermediates or electrochemi- cal products [34–38]. The main objective of the present work is to develop an electrochemical method for the determination of drotaverine hydrochloride utilizing enhancement effect of surfac- tant. 2. Experimental 2.1. Instrumentation Electrochemical measurements were performed with Metrohm Computrace Voltammetric Analyzer -AUTOLAB TYPE III Poten- 0927-7765/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2010.09.005