Y. Akiyama et al., NOVEL ORAL CONTROLLED-RELEASE MICROSPHERES USING POLYGLYCEROL ESTERS OF FATTY-ACIDS, Journal of controlled release, 26(1), 1993, pp. 1-10
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.