Combined Use of Polymers and Porous Materials to Enhance Cinnarizine Dissolution

Loading of poorly water-soluble drugs on the porous materials has attracted great interest as an effective approach for enhancement of dissolution rate of drugs. The Aerosil (Ae) with porous structure is expected to facilitate the dissolution of drugs which is generally associated with precipitation. Thus, the purpose of this investigation was thus to develop a formulation which combines a precipitation inhibitor and a poorly soluble drug loaded Ae.

A poorly water-soluble drug, Cinnarizine (CNZ) was used as a model, and Eudragit L100 (Eu) was used as a precipitation inhibitor. Formulations were produced by solvent evaporation and characterized by FT-IR and differential scanning calorimetry (DSC). Dissolution experiments were carried out in phosphate buffer (pH 6.8) under nonsink conditions.

DSC thermograms revealed that no crystalline structure of CNZ was present in CNZ-loaded Ae formulations and no long-range order was arranged upon loading of CNZ into Ae. In dissolution test, the CNZ-loaded Ae physically blended with Eu achieved a remarkedly higher CNZ concentration over the plain CNZ and over the CNZ-Eu co-loaded Ae. The dissolution rate of CNZ from the CNZ-loaded Ae was enhanced with increasing Ae amount and the dissolution was maximum when the ratio of CNZ: Ae was 1:10 CNZ: Ae. In addition, the precipitation inhibition was increased when the amount of Eu was high.

The results of this work revealed that the dissolution behaviour of CNZloaded Ae is enhanced by physically blending of Eu as a suitable precipitation inhibitor.