Immersion coating of pellets with calcium pectinate and chitosan.
This study has investigated the potential of immersion coating calcium containing pellet cores first with pectin, and then with two different cross-linkers, calcium or chitosan. The interaction between pectin and calcium, and between pectin and chitosan, are believed to slow down the drug release, and thereby, the coated pellets might possibly be used for colon specific drug delivery. Both the calcium coated pellets and the chitosan coated pellets had a reduced drug release compared to uncoated pellets in 0.1M HCl (1 h) and phosphate buffer pH 6.8 (4 h). The most successful combination had a drug release of only 17% during the entire test period in comparison to the uncoated pellets that had a drug release of 80%. When chitosan was used as a cross-linker, a higher reduction in drug release was obtained than by using calcium as the cross-linker. For the pellets coated with pectin in combination with chitosan, the type of pectin with a degree of methoxylation (DM) of 35 was superior to the pectin type with DM 17. The drug release was further slowed down by choosing a type of chitosan with a high degree of deacetylation (Dda) 89% and by coating at low concentrations (0.1%) in the immersion solution.
Hiorth
Marianne
M
Department of Pharmaceutics, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway. marianne.hiorth@farmasi.uio.no
Versland
Therese
T
Heikkilä
Juha
J
Tho
Ingunn
I
Sande
Sverre Arne
SA
D002118:Calcium / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D005765:Gastrointestinal Agents / Q000737:chemistry; D010368:Pectins / Q000737:chemistry*; D012995:Solubility; D013997:Time Factors
D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005765:Gastrointestinal Agents; D010368:Pectins; D048271:Chitosan; D002118:Calcium; C003181:polygalacturonic acid