Corn starches as film formers in aqueous-based film coating.
The purpose of this study was to evaluate the film formation ability and mechanical stress-strain properties of aqueous native corn starches, using free films and film coatings applied to tablets. Free films were prepared from high-amylose corn (Hylon VII), corn and waxy corn starches, using sorbitol and glycerol as plasticizers. The tablets and pellets were film-coated using an air-suspension coater, and characterized with respect to the film coating surface topography, cross-sectional structure and thickness (SEM), and dissolution in vitro. The amylose content of the starch film formers affected both the tensile strength and the elongation. The elongations were under 5% for even the plasticized starches, and in most cases, no plasticization effect was seen by either of the plasticizers. Dissolution of native corn starch film-coated tablets (weight gain 1%) did not differ from uncoated ones. A notable delay in dissolution of the drug was found by increasing Hylon VII film coating thickness, suggesting controlled-release characteristics.
Palviainen
P
P
Department of Pharmacy, University of Helsinki, Finland. paivi.palviainen@helsinki.fi
Heinämäki
J
J
Myllärinen
P
P
Lahtinen
R
R
Yliruusi
J
J
Forssell
P
P
D000688:Amylose / Q000737:chemistry / Q000648:ultrastructure; D002626:Chemistry, Pharmaceutical; D008855:Microscopy, Electron, Scanning; D012995:Solubility; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure; D013314:Stress, Mechanical; D013499:Surface Properties; D013607:Tablets; D014867:Water
D013607:Tablets; D014867:Water; D013213:Starch; D000688:Amylose