title: The interaction of a model active pharmaceutical with cationic surfactant and the subsequent design of drug based ionic liquid surfactants.
abstract: Interactions of active pharmaceutical ingredients (API) with surfactants remain an important research area due to the need to improve drug delivery systems. In this study, UV-Visible spectrophotometry was used to investigate the interactions between a model low molecular weight hydrophilic drug sodium valproate (SV) and cationic surfactant cetyltrimethylammonium bromide (CTAB). Changes in the spectra of SV were observed in pre- and post-micellar concentrations of CTAB. The binding constant (Kb) values and the number of drug molecules encapsulated per micelle were calculated, which posed the possibility of mixed micelle formation and strong complexation between SV and CTAB. These results were compared to those of a novel room temperature surface active ionic liquid, which was synthesized by the removal of inorganic counterions from a 1:1 mixture of CTAB and SV. In this new compound the drug now constitutes a building block of the carrier and, as such, has considerably different surfactant properties to its building blocks. In addition, enhanced solubility in a range of solvents, including simulated gastric fluid, was observed. The study provides valuable experimental evidence concerning the performance of drug based surfactant ionic liquids and how their chemical manipulation, without altering the architecture of the API, leads to control of surfactant behavior and physicochemical properties. In turn, this should feed through to improved and controlled drug release rates and delivery mechanisms, and the prevention of precipitation or formation of polymorphs typical of crystalline form APIs.
authors.affiliation: Department of Chemistry, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan.
authors.forename: Sara
authors.initials: S
authors.lastname: Qamar
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Brown
authors.affiliation: Department of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Steven
authors.initials: S
authors.lastname: Ferguson
authors.affiliation: Department of Chemistry, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan.
authors.forename: Rafaqat Ali
authors.initials: RA
authors.lastname: Khan
authors.affiliation: Department of Chemistry, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan.
authors.forename: Bushra
authors.initials: B
authors.lastname: Ismail
authors.affiliation: Department of Chemistry, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan.
authors.forename: Abdur Rahman
authors.initials: AR
authors.lastname: Khan
authors.affiliation: Department of Chemistry, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan.
authors.forename: Murtaza
authors.initials: M
authors.lastname: Sayed
authors.affiliation: Department of Chemistry, COMSATS Institute of Information Technology, 22060 Abbottabad, Pakistan. Electronic address: amk.qau@gmail.com.
authors.forename: Asad Muhammad
authors.initials: AM
authors.lastname: Khan
mesh_terms: D002412:Cations / Q000737:chemistry; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D015195:Drug Design; D052578:Ionic Liquids / Q000737:chemistry*; D008956:Models, Chemical; D011789:Quantum Theory; D013501:Surface-Active Agents / Q000737:chemistry*; D014635:Valproic Acid / Q000737:chemistry*
chemical_list: D002412:Cations; D002593:Cetrimonium Compounds; D052578:Ionic Liquids; D013501:Surface-Active Agents; D014635:Valproic Acid; D000077286:Cetrimonium
keywords: Drug delivery; Encapsulation; Hydrophilic drugs; Ionic liquid; Ionic surfactant; Micelles; UV–Vis spectroscopy