Preparation and pharmacokinetic and pharmacodynamic evaluation of hydroxy propyl cellulose-ethyl cellulose microcapsules containing piretanide.

Hydroxy propyl cellulose (HPC)-ethyl cellulose (EC) microcapsules containing piretanide were newly by a solvent evaporation technique and their slow-release properties were evaluated on dissolution properties in vitro and pharmacokinetic and pharmacodynamic parameters in beagle dogs. The dissolution behavior of piretanide from the microcapsules in dissolution media of pH 1.2-6.8 and the plasma piretanide level in beagle dogs varied dependently on the contents of HPC and EC. As compared with ordinary piretanide tablet on the market, the HPC-EC10 (5:3) microcapsule showed the controlled dissolution behavior, sustained plasma piretanide level, almost same AUC (area under curve), slow urinary piretanide excretion, decreased urine excretion maximum rate, and no difference in the cumulative urine volume and cumulative urinary electrolytes (Na+, K+, Cl-) excretion. HPC-EC microcapsules containing piretanide sufficiently satisfied the conditions which slow-release preparations must have.