Study of competitive interactions in poly(methacrylic acid)-poly(ethylene oxide)-2-chloro-10-(3-dimethylaminopropyl)phenothiazine hydrochloride triple systems

The triple system composed of poly(methacrylic acid), poly(ethylene oxide), and 2-chloro-10-(3-dimethylaminopropyl)phenothiazine hydrochloride (known as aminazin or the drug Aminazine) was studied by the potentiometric and turbidimetric titration, viscometry, high-rate sedimentation, and IR spectroscopy. At a low aminazin content, its cations interact with defects of the polyacid-poly(ethylene oxide) interpolymer complex by means of electrostatic forces with an formation of the aminazin-polyacid-poly(ethylene oxide) triple complex. As the content of aminazin in the mixture increases, its ability to form bonds with the polymer complex due to hydrophobic interactions becomes more pronounced. In this case, conformations of the polymer complex particles vary, nonpolar contacts between polyacid and poly(ethylene oxide) tend to break, and aminazin displaces poly(ethylene oxide) from the polymer complex moiety with the formation of a poly(methacrylic acid)-aminazin water-soluble complex.