Crystallization and dissolution of pharmaceutical compounds An experimental approach

摘要

In pharmaceutical industry grwoth and dissolution areimportant stages for different reasons. In industrial processes crysallization is an important operation which controls the physical poperties of thematerial such as the crystal habit, crysal size distriubtion and polymoprhism. For economic and echnqical reasons before paenting a drug it is important to search all the possible polymorphs. IOn the caseof organic drugs which are slightly soluble in gastrointestinal fluids, the dissolution rate of the solid dosage form is an imporant factor determining the rate of absorption. The kientics of solubilization will depend mainly on the crystal habit, crysttal sizek distribution and on thepolymorphs. This paper presents a laboratory study of the dissolution of crystals of an organic drug in a crytallizer equipped with an in situ conductivity probe and an UV analyzer on-.line. The rate of dissoluton and evoltuion of the crystal size distribution are measured. A solution mediatedphase transtion of the drug isobserved. The final objective is to model the dissolution process from kinetic daa and determine the infleunce on the dssoution of under-saturaitonm, temperature, crystal habit and crystal size distribution.