A microparticulate system consisting of non-enzymatically degrading
poly(dl-lactide-co-glycolide) (PLGA) core and delivering
budesonide site specifically to distal ileum and colon was developed.
Budesonide-loaded microparticles were fabricated using
solvent evaporation technique and formulation variables studied included different molecular weight grades of PLGA
polymer as well as concentration of
polymer,
surfactant and
drug.
Eudragit S-100, an enteric
polymer, was then used to form a coating on the surface of
budesonide-loaded PLGA microparticles for site specific delivery to the distal ileum and colon.
Budesonide-loaded PLGA microparticles prepared from various formulation parameters showed mean encapsulation efficiencies ranging between 50% and 85% and mean particle size ranging between 10 and 35mum. In vitro release kinetics studies showed a biphasic release pattern with an initial higher release followed by a slower drug release. Increasing
polymer and
surfactant concentrations exhibited sharply contrasting drug release profiles, with increasing
polymer concentrations resulting in a lower drug release and vice versa. The
budesonide-loaded PLGA microparticles coated with
Eudragit S-100 coating showed a decrease in entrapment efficiency with an accelerated in vitro drug release. Moreover, complete retardation of drug release in an acidic pH, and, once the coating layer of enteric
polymer was dissolved at higher pH (7.4 and 6.8), a controlled release of the
drug from the microparticles were observed. From the results of this investigation, the application of double microencapsulation technique employing PLGA matrix and
Eudragit S-100 coating shows promise for site specific and controlled delivery of
budesonide in
Crohn's disease.