Abstract
Targeting of drugs to colon via oral route can be achieved by different approaches controlled by pH conditions, gastrointestinal transit time and colonic microbial flora. Modified Pulsincaps and compression coated tablets of aceclofenac, a non steroidal anti-inflammatory drug used for the treatment of rheumatoid arthritis were developed to target drug release in the colon. Pulsincaps were formulated by treating bodies of hard gelatin capsules with formaldehyde and caps were untreated. Aceclofenac was incorporated into these specialized capsule bodies which were plugged with hydrogels like guar gum, acacia, gelatin and sodium alginate separately and in combination. Pulsincaps were evaluated for lag time, qualitative test for free formaldehyde and in vitro drug release studies. Compression coated tablets of aceclofenac were developed using Guar gum to deliver drug to colon due to its release retarding property and susceptibility to microbial degradation by colonic bacteria like Bacteroides species. These tablets were evaluated for various parameters like hardness, friability, drug content, in vitro drug release studies in simulated colonic fluid containing Male Wistar Rats colonic contents.The findings of the present study conclusively state that developed dosage forms are promising for colon targeting of aceclofenac to synchronize the chronobiological symptoms for effective treatment of rheumatoid arthritis.

Key words: Chronobiological, Compression coated, Guar gum, Hydrogel, Pulsincaps, Rheumatoid arthritis