PREPARATION OF THE DISPERSE SYSTEMS OF SULFATHIAZOLE-POLYVINYLPYRROLIDONE BY MECHANICAL ACTIVATION

The potential value of solid-state dispersions of insoluble drugs in water-soluble matrices is known to bring about enhancement of solubility, dissolution rate and bioavailability of the drugs. The conventional methods of preparation of solid dispersions such as fusion or solvent technique are somewhat limited. The method of mechanical activation analogous to that which is employed in the mechanical alloying method may be used in preparation of dispersions of organic solids. In this paper, the method of mechanical activation is applied to obtain a solid-state dispersion of sulfathiazole in polyvinylpyrrolidone. The mechanical treatment of sulfathiazole with polyvinylpyrrolidone in a planetary ball mill transfers crystalline drug into amorphous state, the process being accompanied by formation of hydrogen bonds of sulfathiazole with matrice. The apparent solubility and rate of solvation of sulfathiazole were greatly increased if it was previously mechanically treated with polyvinylpyrrolidone. The release of sulfathiazole from solid dispersions with polymer to drug ratio of 1:3, 1:1, 3:1 was examined, a polymer to drug ratio of 3:1 gave the highest solubility.