LEACHING OF PECTIN FROM MIXED PECTIN INSOLUBLE POLYMER-FILMS INTENDEDFOR COLONIC DRUG-DELIVERY

Investigations intended to combine pectin HM oi calcium pectinates wit h commercially available aqueous polymer dispersions for colon-specifi c drug delivery have been conducted on isolated films. The mixed films were prepared from Aquacoat(R) ECD 30, Surelease(R) clear, Eudragit(R ) RS30D or Eudragit(R) NE30D containing 5, 10 or 15% w/w (related to i nsoluble polymer content) of pectin HM or 10% w/w of calcium pectinate s. The kinetics of pectin leaching from the mixed films, incubated in 0.05 M acetate-phosphate buffer (pH 4.5, 37 degrees C) in the absence of pectinolytic enzymes, showed that pectin HM or calcium pectinates w ere quickly released from the different films except from the mixed pe ctin/Eudragit(R) RS films. Moreover, in these cases, the leaching of p ectin from Eudragit(R) RS films containing up to 10% w/w (related to E udragit(R) RS polymer content) of pectin HM or pectin LM, was signific antly faster in the presence of enzymes than in absence. These results indicate that the associations of pectin HM or LM and Eudragit RS are likely to give more suitable coating materials for colon-specific dru g delivery than the other combinations. (C) 1998 Elsevier Science B.V. All rights reserved.