De. Chickering et al., BIOADHESIVE MICROSPHERES .3. AN IN-VIVO TRANSIT AND BIOAVAILABILITY STUDY OF DRUG-LOADED ALGINATE AND POLY(FUMARIC-CO-SEBACIC ANHYDRIDE) MICROSPHERES, Journal of controlled release, 48(1), 1997, pp. 35-46
Bioadhesive drug delivery systems (BDDSs) could improve bioavailabilit
y by protecting bioactive molecules from physical and chemical degrada
tion, enhancing absorption rates by minimizing diffusion barriers, and
increasing the period for absorption by prolonging residence time. Th
e in vivo bioadhesive performance of calcium alginate microspheres and
poly(fumaric-co-sebacic anhydride) 20:80 microspheres were evaluated
in two ways. Firstly, effect on GI transit was measured in rats. P(FA:
SA) 20:80 microspheres showed significantly prolonged retention in the
gut when compared to alginate microspheres. Secondly, the ability of
these polymers to improve relative bioavailability of a model drug, di
cumarol, in rats was assayed. A significant increase was measured in t
he area under the plasma concentration-time curve for dicumarol encaps
ulated in P(FA:SA) 20:80 when compared to its controls. The results of
this study suggest that polymers which have bioadhesive forces in vit
ro and delayed GI transit in vivo may be used to improve oral bioavail
ability of certain drugs. (C) 1997 Elsevier Science B.V.