Enhancement of dissolution and stability of candesartan cilexetil–loaded silica polymers

Abstract

Objective: To prepare stable amorphous solid dispersions of candesartan cilexetil (CAN) with different types of silica, including non-porous (aerosil 200) and porous silica (sylysia 350) using the spray-drying method. Methods: various ratios of candesartan cilexetil (CAN) were spray dried with aerosil and sylysia. Powder x-ray diffraction (x-ray) differential scanning calorimetry (DSC), SEM were used to characterize the spray dried powders in addition to dissolution and stability studies. Results: X-ray results showed that the spray–dried (CAN) in the prepared solid dispersion were in amorphous form irrespective of the used silica. In (DSC) analysis, the melting peak of spray-dried (CAN-silica) solid dispersion disappeared. Dissolution property of (CAN) was remarkably improved by formulating with silica particles. In comparing the effect of the type of the silica particles, the dissolution rate of (CAN) from the spray-dried (CAN-sylysia) was faster than that (CAN-aerosil 200) irrespective of the drug content. It was also shown that the spray-dried formulation with silica did not recrystallize when storing at severe storage conditions (40 °C, 75% RH) for three months, while spray-dried (CAN) without silica easily re-crystallized under the same conditions. Conclusion: Spray drying of (CAN) with sylysia 350 is an efficient method to enhance the dissolution and stability of the drug.