The invention relates to a novel pharmaceutical sustained release formulation of guaifenesin and pseudoephedrine. The formulation may comprise a hydrophilic polymer, preferably a hydroxypropyl methylcellulose, and a water-insoluble polymer, preferably an acrylic resin, in a ratio range of about one-to-one...http://www.google.se/patents/US7985420?utm_source=gb-gplus-sharePatent US7985420 - Sustained release of guaifenesin combination drugs
