Abstract

The objective of present investigation was to develop rhubarb matrix tablets intended for colon specific delivery system (CoSDS) using two combined approaches of biodegradable microflora-activated system with a pH-sensitive system. Matrix tablets of rhubarb were prepared by wet granulation method using polysaccharide, that is, pectin (10%) alone and in combination with hydrocolloids, that is, hydroxypropyl methylcellulose (HPMC) and hydroxyethylcellulose (HEC) in different concentration of 5, 10, and 15%. Each formulation was characterized in terms of hardness, friability, drug content, disintegration time and in vitro drug release study. On the basis of release profile in the presence of pectinase enzyme after 6 h, formulation containing 10% pectin with 10% HEC was selected as an optimized formulation which was not able to retard the drug release in stomach and upper intestine environment completely. So, it was further coated with eudragit S-100 (ES 100) as a pH sensitive polymer in different coat weight of 3 and 6% w/w. The results obtained reveal that pectin based matrix formulation containing 10% HEC with 6% coat weight of ES 100 exhibited a promising colon targeting performance. There was no significant variation found during stability studies.

Key words: Rhubarb, colon, pectin, hydrocolloids, eudragit S-100.