Abstract
Dissolution profiles of sulfamonomethoxine (SMM)/18-crown-6 (1, 4, 7, 10, 13, 16-hexaoxacyclooctadecane) complex, SMM anhydrate and SMM hydrate were investigated by dispersed amount method and stationary disk method, and also in vivo absorption study of these compounds in dogs was carried out in comparison with the data of the dissolution behaviors. According to the dispersed amount method, the concentration of SMM rose quickly and then decreased gradually when the complex was dispersed. On the other hand, a characteristic convex dissolution curve was observed in the case of the anhydrate. This result indicated that the dissolution rate of complex was extremely large, but its decomplexation accompanying the change to the hydrate form in water was also rapid compared with that of the anhydrate. The rate constant of phase change for the complex to the hydrate form, which was calculated by stationary disk method, was extremely large compared with that for the anhydrate. It was observed that the plasma levels of SMM increased extremely by the administration of the anhydrate form. An increase of plasma levels was also observed in the case of the complex.
