Thermo-acoustical analysis of sodium dodecyl sulfate: Fluconazole (antifungal drug) based micellar system in hydro-ethanol solutions for potential drug topical application Tarun Bhardwaj a , Varun Bhardwaj a , Kundan Sharma b , Abhishek Gupta a , Swaranjit Singh Cameotra c , Poonam Sharma a,⇑ a Department of Biotechnology, Bioinformatics and Pharmacy, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234, India b Department of Chemistry, Himachal Pradesh University, Summer hill, Shimla, Himachal Pradesh 173005, India c Environmental Biotechnology & Microbial Biochemistry, Institute of Microbial Technology, Chandigarh, India article info Article history: Received 19 May 2014 Received in revised form 31 May 2014 Accepted 3 June 2014 Available online 16 June 2014 Keywords: Fluconazole Sodium dodecyl sulfate Micellization Interaction abstract Micellar systems hold excellent drug delivery applications due to their capability to solubilize a large number of hydrophobic and hydrophilic molecules. In this present work, the mixed micelle formation between the anionic surfactant sodium dodecyl sulfate (SDS) and the ‘Azole’ derivative antifungal drug fluconazole (FLZ) have been studied at four temperatures in different hydro-ethanolic solutions. The crit- ical micelle concentration (CMC) was determined by specific conductance techniques and the experimen- tal data was used to calculate several useful thermodynamic parameters, like standard free energy, enthalpy and entropy of micelle formation. Early micellization was found with critical micelle concentra- tion shifting towards lower concentration (CMC) than the standard concentration of SDS in water at 25 °C suggesting that drug and the solvent system facilitates the micellization process. In addition, the trans- port properties were examined by employing controlled approaches likely, apparent molar volume (/ v ), apparent molar adiabatic compression (/ k ), and isentropic compression (j s ) of SDS in presence of FLZ. These parameters revealed the existence of intermolecular interactions within the molecules. Therefore, this study would cast light on utilizing surfactant immobilized FLZ system for better topical biological action. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction An increased number of serious fungal infections caused by opportunistic and pathogenic fungi were reported in early 1990s [1]. However to date, fungal infection poses a continuous and serious threat to human health and life. Healthy individuals are susceptible to a host of superficial, cutaneous, subcutaneous and in certain instances, systemic infections that cause a variety of conditions ranging from foot and nail infections to severe life threatening disseminated diseases [2]. Antifungal drugs are employed worldwide and lend to one fourth of all prescriptions that account for half of the allocated drug budget in infirmaries. Out of the available antifungal drugs for treatment of fungal infections especially caused by Candida species, the azoles, and particularly fluconazole (FLZ), has been most commonly utilized drug candidate [3]. Fluconazole exhibit activity against a wide range of yeasts, moulds, rusts and mushrooms such as Blastomyces dermatitidis, Candida species, Coccidioides immitis, Epidermophyton species, Histoplasma capsulatum, Microsporum species, and Trichophyton species etc. [4]. Rationally, FLZ inhibits the ergosterol which is the main component of fungal cell membrane. It inhibits 14 a-demethylase resulting in a decreased ergosterol synthesis and causes the accumulation of 14 methylated sterols, thus, prevents the 14-a demethylation of lanosterol into ergosterol in the ergosterol synthetic pathway [5]. Unfortunately, the widespread use of FLZ has led to the appearance of resistance among various fungal species, importantly Candida species and also exhibits a decrease susceptibility to other drugs (e.g. Itraconazole) [6]. The hydrophobic nature of FLZ poses problems in a suitable topical dosage form for topical delivery. Hence, for the solubilization of FLZ, micellar system could appear to be an alternative approach. The interactions of drug which could occur throughout formula- tion, storage and pharmacological actions are commonly catego- rized as physico–chemical interactions. The colloidal properties http://dx.doi.org/10.1016/j.jct.2014.06.003 0021-9614/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +91 1792 239389; fax: +91 1792 245362. E-mail addresses: varunmilton@yahoo.com (V. Bhardwaj), drpoonamsharma@r- ediffmail.com (P. Sharma). J. Chem. Thermodynamics 78 (2014) 1–6 Contents lists available at ScienceDirect J. Chem. Thermodynamics journal homepage: www.elsevier.com/locate/jct