chemical engineering research and design 1 0 4 ( 2 0 1 5 ) 453–456 Contents lists available at ScienceDirect Chemical Engineering Research and Design j ourna l h omepage: www.elsevier.com/locate/cherd Replacing microemulsion formulations experimental solubility studies with in-silico methods comprising molecular dynamics and docking experiments Abdelkader A. Metwally a,1 , Rania M. Hathout a,b,*,1 a Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt b Bioinformatics Program, Faculty of Computer and Information Sciences, Ain Shams University, Cairo, Egypt a r t i c l e i n f o Article history: Received 3 December 2014 Received in revised form 2 May 2015 Accepted 9 September 2015 Available online 14 September 2015 Keywords: In-silico Microemulsions Solubility Molecular dynamics Docking a b s t r a c t Usually, formulating hydrophobic drugs in microemulsions starts with screening the sol- ubility of the active pharmaceutical ingredients in different oils and thereby selecting the best candidate according to its solubilising power. We hypothesise that in-silico methods such as molecular dynamics to simulate the oils domains together with docking of the investigated drug(s) on these simulated domains can offer extremely valuable tools saving researches long experimentation time in the laboratories and incalculable efforts exerted in developing sensitive and accurate methods of analysing drugs in oils. © 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction Microemulsions are excellent candidates for the delivery of hydrophobic drugs. They have been especially shown to overcome the hurdles that face the formulation of many weakly water-soluble drugs (Hathout and Woodman, 2012). One of the most important factors in developing microemul- sion systems is the type of the solubilising oil used, and many microemulsion-based studies start with experiment- ing the solubility in different oil carriers (Patel and Vavia, 2007; Sharma and Kumar, 2012; Mehta et al., 2007; Zhao et al., 2005, 2006). This is usually performed prior to formulating a lipophilic drug such as testosterone in a microemulsion system to select the best oily carrier that can accommo- date the drug (Hathout, 2010). The work in this study utilises ∗ Corresponding author. Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, African Union St., 11566 Cairo, Egypt. Tel.: +20 100 5252919/+20 2 22912685; fax: +20 2 24011507. E-mail address: r hathout@yahoo.com (R.M. Hathout). 1 The authors have equally contributed in this manuscript. molecular dynamics and docking studies in order to predict the best solubilising oil for a model drug viz. testosterone hormone as an alternative to adopting exhausting solubil- ity studies that need complicated and sensitive methods and instruments of analysis. Recently, a similar study was performed where modeling of mixed micelles was adopted using computer simulations in order to record the pos- sible interactions between mixed micelles and drugs (Xie et al., 2014). In another recent study, molecular simula- tions were utilised to gain deep insights about the inter- and the intramolecular interactions between a hydropho- bic drug viz. Vinpocetine and different hydrophilic excipients such as: hydroxyl propyl methyl cellulose, polyvinyl alcohol and lactose to select the suitable candidates for nanopar- ticles preparation (Li et al., 2014). Comparing the potential http://dx.doi.org/10.1016/j.cherd.2015.09.003 0263-8762/© 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.