Delivery systems for some biologically active 1,2,4‐triazine derivatives: synthesis and release

Triazine‐loaded polymer microparticles composed of cross‐linked polymethylmethacrylate (PMMA) have been prepared. A series of PMMA cross‐linked polymers were prepared from methylmethacrylate (MMA) and divinylbenzene (DVB) by suspension polymerization using different percentages of solvents and cross‐linkers. Biologically active compounds including 4‐amino‐6‐substituted‐3‐thioxo‐3,4‐dihydro‐2H‐5‐oxo (or thioxo)‐1,2,4‐triazines (I–IV) were prepared and reacted with PMMA. Since optimization of the polymer delivery system is required to improve clinical applications, the effect of surface area, cross‐linker percentage on the loading, and release of triazines were studied. Alkaline conditions seem to favorably affect triazine release. Triazine hydrochlorides were ion exchanged with sodium montmorillonite (Na‐MMT). X‐ray diffraction (XRD) analysis confirms the intercalation of triazines between the layers of MMT. The presence of mineral domains with an average size of 33 nm was observed by transmission electron microscopy (TEM). The release of triazine compounds is more controllable in intercalated layered silicates. Copyright © 2008 John Wiley & Sons, Ltd.