29-03-2014, 12:15 PM
Effect of crosslinking agent on atenolol loaded mucoadhesive microspheres
crosslinking agent on atenolol.docx (Size: 12.44 KB / Downloads: 21)
ABSTRACT
The problems of frequent administration and variable low bioavailability (40-50%) after oral administration of conventional dosage forms of atenolol can be attenuated by designing it in the form of mucoadhesive microspheres. Atenolol loaded mucoadhesive microspheres were successfully prepared by emulsification-internal gelation technique with a maximum encapsulation efficiency of 99.54± 0.24%. The order of increasing release rate observed with various microspheres was as follows Sodium alginate < Sodium alginate+ NaCMC < Sodium alginate+ HPMC. The order of increasing release rate observed with various cross linking agents was as follows Aluminium chloride < Barium chloride < Calcium chloride. The release behavior of microspheres, with different cross-linking agents depends upon the valency and size of the cations of the respective cross-linking agent. The dissolution profiles followed zero order kinetics and the mechanism of drug release was governed by peppas model. The n values are found to be more than 0.5 (n>0.5) indicted that the drug release from the microspheres followed the anomalous transport and super case-II transport mechanism controlled by swelling and relaxation of the polymer chains. The wash-off was faster at simulated intestinal fluid (phosphate buffer, pH 7.4) than that at simulated gastric fluid (0.1 M HCl, pH 1.2). The mucoadhesive microspheres formulated with sodium alginate+HPMC and calcium chloride showed a satisfactory sustained release profile for 12hours.