Preparation and evaluation of floating risedronate sodium Gelucire 39/01 matrices.

Incorporation of bisphosphonates in the lipid reduces gastric irritation. Only gastric retention with sustained release allows the drug to reach the duodenum and jejunum and improves the availability of bisphosphonates. Risedronate sodium and Gelucire 39/01 floating matrices were prepared using melt solidification. The sustained release floating matrices were evaluated for in vitro and in vivo floating ability and in vitro drug release. Ageing of the matrices was studied by differential scanning calorimetry, hot stage polarizing microscopy, scanning electron microscopy and in vitro drug release. Ageing causes changes in the crystal structure of Gelucire, which is responsible for an increase in drug release.