Preparation and adhesive characterization of colon adhesive pellets of sodium 4-amino salicylate

Aim ：To develop a new preparation consisting of colon adhesive pellets of sodium 4-amino salicylate for the treatment of ulcerative colitis，and to characterize the adhesive of the prepared pellets. Methods ：Centrifugation-granulation was used to prepare sodium 4-amino salicylate pellets into which HPMC K4M and Carbomer 934P as matrix were incorporated.The pellets were coated with Surlease，and filled into enteric-coated capsules.The release of sodium 4-amino salicylate from the pellets was evaluated in the pH 7.4 buffer.The adhesive property of the pellets was characterized by evaluating the transit rate of the pellets in the rat intestine in vivo，and by determing the remaining（%） of the pellets in the isolated rat colonic segment in vitro.The adhesive of the pellets in vivo was also verified by X-rays. Results ：It was shown that the resultant pellets of round shape，good uniformity in size，and favorable rigidity possessed the colon-adhesive and sustained-release properties. Conclusion ：The simple，economical and practical approach was sucessfully utilized in the preparation of sodium 4-amino salicylate pellets with the remarked colonic adhesion and targeting.