Acta Pharmaceutica, Vol. 56 No. 3, 2006.
Izvorni znanstveni članak
Pectin/chitosan/Eudragit® RS mixed-film coating for bimodal drug delivery from theophylline pellets: Preparation and evaluation
ALIREZA GHAFFARI
MAHVASH OSKOUI
KAMRAN HELALI
KHOSROW BAYATI
MORTEZA RAFIEE-TEHRANI
Sažetak
Pellets containing theophylline as a model drug and microcrystalline cellulose, in a ratio of 6:4, were prepared by extrusion-spheronization method. The pellets were coated with Eudragit® RS aqueous dispersions, containing various amounts of pectin-chitosan complex and different coating mass gains, using a fluidized-bed apparatus. Twelve formulations were developed, which differed in two factors: coating mass gain (10, 15 and 20%, m/m) and amount of pectin-chitosan complex (5, 10, 15 and 20%, m/m). Drug release studies were conducted using the USP apparatus Ι (basket) in dissolution media, mimicking the conditions pertaining in the stomach, small intestine and colon, respectively. Studies have shown that drug release rate and pattern were dependent on both two mentioned factors. Some formulations showed bimodal and burst drug release, being triggered in the colonic medium by the action of pectinolytic enzymes. In formulations with 15 or 20% (m/m) of coating mass gain and 5 or 10% (m/m) of pectin-chitosan amount, the burst drug release was eliminated and replaced by lag phase of drug release. In viewpoint of burst drug release in the colonic medium, formulations with 20% (m/m) of coating mass gain and 15 or 20% (m/m) of pectin-chitosan amount were found to be better than the other formulations. Studies on the surface SEMs of uncoated and coated pellets show that after coating, coated pellets became smoother and exposure to pectinolytic enzymes in the colonic medium may result in surface erosion.
Ključne riječi
bimodal drug delivery; burst release; chitosan; Eudragit® RS; mixed-film coating; pectin; pellet
Hrčak ID:
4541
URI
Datum izdavanja:
1.9.2006.
Posjeta: 2.739 *