Preparation and evaluation of colon targeted drug delivery systems for albendazole using kneading, extrusion and compaction technology

Albendazole is an orally administered broad-spectrum benzimidazole anthelmintic used against helminthiasis, hydatid cyst disease and neurocysticercosis.  The objectives of this investigation are to develop a sustained release drug delivery system for albendazole, and to target its delivery to colon.  Albendazole matrix tablets containing varying proportions of single and binary blends of four polymers; polyacrylic acid (carbopol 971), ethylcellulose (Etcell), eudragit L100-55 (EUD), and sodium carboxymethyl cellulose (CMC) were prepared by a modified wet granulation technique of kneading, extrusion and compaction.  In vitro release profiles of  albendazole was sequentially determined in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) without enzymes and in rat caecal content medium (RCCM) at 37 ℃.  The in vitro drug release from matrix tablets  containing CMC and Etcell as single polymers showed initial burst effect in the first 2 h (>20% and 50%     respectively), followed by a slow release in SIF.  However, matrix tablets containing polymer blends showed that no appreciable drug release occurred up to 5 h.  Drug release from tablets containing polymer blends in the dissolution medium containing rat caecal material suddenly increased to ≥30% after 5 h (RCCM), and reaching up to 90% in 24 h.  Albendazole matrix tablets containing carbopol 971, Etcell, EUD, and CMC as single polymers and as blends were formulated for oral use.  Drug release from the tablet matrices containing carbopol alone, binary blends of carbopol/Etcell, and CMC/EUD were found to be very slow and dependent on polymer  concentration.  Matrix tablets containing blends of these polymers formulated using kneading, extrusion  and compaction technique could provide sustained drug release and can be utilized in the colonic delivery of   albendazole.