title: Effect of surfactant mixing on partitioning of model hydrophobic drug, naproxen, between aqueous and micellar phases.
abstract: Mixed surfactants may improve the performance of surfactant-enhanced solubilization of drugs and thus can serve as the tool for increased bioavalaibility, controlled drug release, and targeted delivery. Solubilization of Naproxen by micellar solutions at 25 degrees C using single and mixed surfactant systems was measured and compared. Solubilization capacity determined with spectrophotometry and tensiometry has been quantified in terms of molar solubilization ratio, micelle-water partition coefficient, and locus of solubilization. Cationic surfactants exhibited higher solubilization capacity than nonionics and anionics, the efficiency increasing with chain length. Mixing effect of surfactants on mixed micelle formation and solubilization efficiency has been discussed in light of regular solution approximation (RSA). Equimolar cationic-nonionic surfactant combinations showed better solubilization capacity than pure cationics or nonionics, which, in general, increased with increase in hydrophobic chain length. Equimolar cationic-nonionic-nonionic ternary surfactant systems exhibited intermediate solubilization efficiency between their single and binary counterparts. Use of RSA has been extended, with fair success, to predict the partition coefficient of ternary surfactant systems using data from binary mixtures. The theoretical micelle-water partition coefficients calculated from the geometric mean equation compared well with experimental values. Locus of solubilization of NAP in different micellar solutions was probed by UV-visible spectroscopy.
authors.affiliation: Department of Chemistry, University of Kashmir, Srinagar-190006, J&K, India.
authors.forename: Parvaiz Ahmad
authors.initials: PA
authors.lastname: Bhat
authors.forename: Ghulam Mohammad
authors.initials: GM
authors.lastname: Rather
authors.forename: Aijaz Ahmad
authors.initials: AA
authors.lastname: Dar
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry; D000077286:Cetrimonium; D002593:Cetrimonium Compounds; D008823:Micelles; D008958:Models, Molecular; D008968:Molecular Conformation; D009288:Naproxen / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds; D012995:Solubility; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002593:Cetrimonium Compounds; D008823:Micelles; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014867:Water; C013912:decyltrimethylammonium; D009288:Naproxen; D000077286:Cetrimonium