Čes. slov. farm. 2010, 59(4):163-171

Drug controlled release from dosage forms coated with aqueous cellulose and acrylic polymer dispersions

D. Vetchý^1,*, H. Leštinová²

¹ Veterinární a farmaceutická univerzita Brno, Farmaceutická fakulta, Ústav technologie léků

² Lékárna Na Předměstí, Třeboň

Current scientific papers concerning aqueous cellulose and acrylic polymer dispersions for controlled drug delivery are focused on stability studies and the search for suitable coated formulations for drug release at a specific time and site of the gastrointestinal tract. It can be achieved especially by preparing polymer blends or using other additives. The permeability of the ethylcellulose membranes can be increased by the addition of water-soluble polymers (drug release modifiers). If there is no independence of solubility of the drug on pH, a poly(vinyl alcohol)-poly(ethylene glycol) graft copolymer is frequently used, because it simultaneously hinders further polymer particle coalescence during long term storage. With respect to a low glass transition temperature and consequently high tackiness of polymer films, Eudragit NE should be blended with high glass transition temperature polymers which are miscible with the functional coating, for example Eudragit L or Eudragit RS. Eudragit L 30 D-55 coatings take over 2 hours to dissolve in vivo in the human small intestine. This fact can cause delayed drug release and bioavailability reduction of those drugs which are to be absorbed in proximal small intestine. Accelerated coating disintegration can be achieved by preparation of double-coating enteric systems or leaky enteric coatings.

Keywords: controlled release; ethylcellulose; Eudragit RS; Eudragit NE; Eudragit L-55

Received: June 29, 2010; Accepted: July 7, 2010; Published: April 1, 2010  Show citation