Novel oral controlled-release microspheres using polyglycerol esters of fatty acids

Abstract

A novel oral controlled-release drug delivery system which consists of microspheres of 75–500 μm in diameter has been designed and developed. A drug is dispersed in a spherical micromatrix of poly-glycerol esters of fatty acids (PGEFs). The microspheres were prepared by a spray-chilling method using a rotating disc and had a narrow particle size distribution. A required size could easily be obtained by altering the spray conditions. In the in vitro dissolution tests, drug release was found to be affected by the size of the microspheres and the drug content in the microspheres. However, release of the drug could be regulated by selecting an appropriate hydrophile-lipophile balance value of PGEF. PGEF-based micromatrix system could provide stable controlled release, i.e., the surface morphology and the release profiles did not change during a long storage period at 40°C while the surface morphology and the release profiles changed after only one-day storage at 40°C when hydrogenated cotton seed oil (HSCS) was used as the matrix base.