ALTERNATIVE SOLVENT-FREE PREPARATION METHODS FOR FELODIPINE SURFACE SOLID DISPERSIONS

Surface solid dispersions were prepared via physical mixture and were either heated in a vacuum dryer or in a microwave oven for different p eriods of rime. The physical state of felodipine in solid dispersions was studied using differential scanning calorimetry and x-ray powder d iffractometry. USP paddle method was used for felodipine dissolution s tudies. The use of vacuum or microwave energy led to a significant imp rovement of felodipine dissolution which was caused partly by the amor phous state of felodipine and a large surface area of amorphous silico n dioxide.