[Application of polyethylene glycol (PEG) to the control of permeability of poly(meth)acrylate coatings]

Pellets with pholedrine sulphate are coated by means of a fluid-bed process with poly(meth)acrylate materials (Eudragit RS, Eudragit E 30 D, Scopacryl D 340) and varying portions of PEG 6000. In addition to influencing drug release by change of the thickness it was studied the admixture of PEG to the films. Figure logarithm permeability coefficient vs. the portion of PEG can be used to select a coating composition with wished permeability. By application of aqueous latex dispersions (Eudragit E 30 D, Scopacryl D 340) PEG dissolves completely very fast from the coatings. On the other hand if organic lac solution (Eudragit RS) is used a stagnation of the dissolution process after some min is observed. By leaching out the PEG the structure of the resulting films is loosened and therefore its permeability is increased.