Effect of Polymethylmethacrylate-Montmorillonite Nanocomposite on the Release of Some Biologically Active 1,2,4-Triazine Derivatives

Methylmethacrylate chloromethylstyrene copolymer-montmorillonite (PMMA-MMT) intercalated nanocomposite was prepared by bulk copolymerization of methylmethacrylate (MMA) and chloromethylstyrene (2 wt%) followed by phosphonium salt formation. The intercalation of polymeric phosphonium salt into montmorillonite was achieved through an ion exchange process between sodium cations in MMT and phosphonium groups attached to the copolymer. Thermogravimetric analysis (TGA) showed improved thermal stability for the intercalated nanocomposite in comparison with the pure PMMA. Biologically active compounds including 4-amino-6-methyl-3-thioxo-3,4-dihydro-2H-[1,2,4]triazin-5-one (I), 4-amino-6-methyl-3,4-dihydro-2H-[1,2,4]triazin-3,5-dithione (II), 4-amino-6-(4-methoxystyryl)-3-thioxo3,4-dihydro-2H-[1,2,4]triazin-5-one (III), and 4-amino-6-styryl-3-thioxo-3,4-dihydro-2H-[1,2,4]triazin-5-one (IV) have been prepared and reacted with PMMA-MMT intercalates and ion exchanged with sodium montmorillonite (MMT) in the presence of HCI. Infrared spectra (IR) show bands characteristic to amide linkage between triazine derivatives and PMMA. These nano-composites have been characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The release of biologically active compounds intercalated layered silicates is controllable and these materials have a great potential as a delivery host in the pharmaceutical field. The effect of temperature and presence of saline solution on the release was studied. POLYM. COMPOS., 30:1190-1198, 2009. (C) 2008 Society of Plastics Engineers