S. Kaewvichit et Ig. Tucker, THE RELEASE OF MACROMOLECULES FROM FATTY-ACID MATRICES - COMPLETE FACTORIAL STUDY OF FACTORS AFFECTING RELEASE, Journal of Pharmacy and Pharmacology, 46(9), 1994, pp. 708-713
A replicated complete factorial design to study the main effects and i
nteractions of four factors: bovine serum albumin (BSA) particle size
(Factor A); stearic acid particle size (Factor B); BSA loading (Factor
C); and compression force (Factor D), on the release of BSA from comp
ressed stearic acid pellets was performed in isotonic phosphate buffer
pH 7.4 at 37 degrees C. Samples were withdrawn over 64 h. Analysis of
variance of the percentage released at 64 h showed that A, B, and C,
but not D, affected the release and the interactions AB, BC, ABC were
highly significant. At low loading (5%), the surface release depended
on BSA particle size. The release increased when BSA particle size was
large. At high loading (20%), more release was shown when stearic aci
d particle size was large. More release with Increasing BSA particle s
ize occurred only when stearic acid particle size was small. It is pro
posed that release is due to the interconnected pore networks created,
not only by BSA particles, but also by the void space between stearic
acid particles. These void spaces vary according to particle size-dep
endent arrangements of stearic acid and BSA particles. An increase in
the pellet thickness was observed probably due to the relaxation of co
mpacted stearic acid particles.