NOVEL ORAL CONTROLLED-RELEASE MICROSPHERES USING POLYGLYCEROL ESTERS OF FATTY-ACIDS

A novel oral controlled-release drug delivery system which consists of microspheres of 75-500 mum in diameter has been designed and develope d. A drug is dispersed in a spherical micromatrix of polyglycerol este rs of fatty acids (PGEFs). The microspheres were prepared by a spray-c hilling method using a rotating disc and had a narrow particle size di stribution. A required size could easily be obtained by altering the s pray conditions. In the in vitro dissolution tests, drug release was f ound to be affected by the size of the microspheres and the drug conte nt in the microspheres. However, release of the drug could be regulate d by selecting an appropriate hydrophile-lipophile balance value of PG EF. PGEF-based micromatrix system could provide stable controlled rele ase, i.e., the surface morphology and the release profiles did not cha nge during a long storage period at 40-degrees-C while the surface mor phology and the release profiles changed after only one-day storage at 40-degrees-C when hydrogenated cotton seed oil (HSCS) was used as the matrix base.