title: The study of the influence of surfactant charge on alkaline hydrolysis reactions of acetylsalicylic acid (ASA) and triflusal (TFL) using spectrophotometric methods.
abstract: In this research, the effects of micellar systems on alkaline hydrolysis reactions of acetylsalicylic acid (ASA) and triflusal (TFL) were found to be dependant upon the surfactant charge within the micelle. In cationic micelles, there is a catalytic effect at low concentrations of surfactant. However, this reaction is inhibited at higher surfactant concentrations. In anionic micelles, a catalytic effect occurs, while in zwitterionic and non-ionic micelles there is an inhibitory effect. Such reactions are attributable to changes in reactants on the micellar surface, or to the fact that both reactants are found in different microenvironments. The pseudophase (PS) and ion-exchange (PPIE) models were found to be consistent with the experimental result. Furthermore, the association constants for both drugs could be determined together with micellar rate constants in heterogeneous media.
authors.affiliation: Departmant of Physical-Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja s/n, 18071 Granada, Spain. martimm@ugr.es
authors.forename: Mónica
authors.initials: M
authors.lastname: Ferrit
authors.forename: Carmen
authors.initials: C
authors.lastname: del Valle
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez
mesh_terms: D000465:Algorithms; D000468:Alkalies / Q000737:chemistry; D001241:Aspirin / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012459:Salicylates / Q000737:chemistry*; D020156:Salicylic Acid / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D055672:Static Electricity; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000468:Alkalies; D010975:Platelet Aggregation Inhibitors; D000644:Quaternary Ammonium Compounds; D012459:Salicylates; D013501:Surface-Active Agents; D014867:Water; C034730:zwittergent 3-12; C016167:triflusal; C033502:4-trifluoromethylsalicylic acid; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D012972:Sodium Hydroxide; C022806:dodecyltrimethylammonium; C515901:Brij 35; D020156:Salicylic Acid; D001241:Aspirin