The Enteric-coated Multi-unit Drug Delivery Systems For Small Intestinal Or Colonic Targeting

Abstract: BACKGROUND The present study is within the scheme of oralcontrolled-release drug delivery systems, which is focused on industrial pharmacy research.AIM The main objective of the present study was to develop the enteric-coated multi-unitdrug delivery systems for small intestinal or colonic targeting, respectively.The furtherobjective of the present study was to compress Eudragit FS 30 D-coated meloxicam pelletsinto divisible rapidly disintegrating tablets. METHODS Metformin hydrochloride ormeloxicam-loaded pellets were prepared by layering the drug-binder solution ontononpareils using a fluidized bed coater with the Wurster insert and then coated withEudragit LI 00-55 or Eudragit FS 30 D to achieve a specific drug release in small intestineor colon, respectively. To prevent the interaction between drugs and enteric polymers,drug-loaded pellets were also seal coated with 3% w/w HPMC (6cps) prior to enteric coating.Consequently, their in vitro and in vivo performances were evaluated, respectively. Finaly,compression of Eudragit FS 30 D-coated meloxicam pellets were investigated using singlepunch press. RESULTS The diffusion of highly water-soluble metformin hydrochloridefrom the drug-loaded cores to the aqueous enteric film occurred during the polymer coatingprocess. 3% HPMC-sealed coat could prevent this phenomenon effectively, β-cyclodextrincould evidently improve the aqueous solubility of meloxicam and most importantly make thesolubility pH-independent. The critical dissolution pH of Eudragit FS 30 D was 7.2 orabove in 0.2 M phosphate buffer. Buffer capacity of phosphate buffer influenced thedissolution of enteric coating, and increasing the ionic strength or buffer capacity increasedmeloxicam release form Eudragit FS 30 D-coated pellets. 15% coating level of EudragitFS 30 D allowed sufficient gastric resistance (no release for 2 hours at pH 1.2) and the totalrelease of meloxicam at pH 7.4 within 30 minutes. In vivo, the onset of meloxicam...