Manipulation of powder characteristics by interactions at the solid-liquidinterface: 1-sulphadiazine

A solvent-treatment technique aiming at manipulating the properties of powd ered materials is reported. Potentials of the technique were assessed using sulphadiazine (SD). A suspension of the drug in a preselected solvent (5% aqueous ammonia solution) was stirred under controlled conditions. The solv ent was subsequently removed and the material dried. The effect of experime ntal variables such as stirring speed and time, powder/solvent ratio and in clusion of additives (Tween 80, sodium chloride and PVP) on the properties of solvent treated SD was assessed. Data obtained were compared with those for SD recrystallized under identical conditions. Solvent treatment of SD i n the absence of additives resulted in a limited change in crystal morpholo gy as indicated by SEM. This was associated with improved flowability and a limited reduction in dissolution rate relative to untreated SD. On the oth er hand, recrystallized SD exhibited superior flowability but a considerabl y low dissolution rate. Solvent treatment of SD in the presence of 2% PVP p roduced a microgranular directly compressible material. (C) 1999 Elsevier S cience B.V. All rights reserved.