Sustained release of guaifenesin combination drugs

A drug product comprising an immediate release portion comprising a guaifenesin and optionally dextromethorphan wherein guaifenesin becomes bioavailable in the subject's stomach;

• and a sustained release portion comprising guaifenesin and dextromethorphan
• wherein the ratio of the immediate release guaifenesin to the sustained release guaifenesin is about 1:1 to about 1:15, the product provides a guaifenesin Cmax in a human subject equivalent to the Cmax obtained when the first of three doses of a FDA-specified immediate release formulation having one third the amount of guaifenesin is dosed every four hours over a 12 hour period, and the product provides a therapeutically effective bioavailable guaifenesin for at least twelve hours after a single dose in a human subject according to serum analysis and a therapeutically effective amount of the dextromethorphan.

A method of treating a subject in need of temporary relief from bronchial mucus accumulation and coughing comprising administering to said subject a therapeutically effective amount of a modified release drug product comprising guaifenesin and optionally dextromethorphan in an immediate release formulation and wherein the guaifenesin becomes bioavailable in the subject's stomach;

• and a sustained release portion comprising a guaifenesin, dextromethorphan and a release-delaying matrix,
• wherein the release-delaying matrix comprises a hydrophilic polymer and a water-insoluble polymer in a weight ratio of hydrophilic polymer to water-insoluble polymer from about 1:1 to about 9:1,
• wherein the guaifenesin has a Cmax in a human subject equivalent to the Cmax obtained when the first of three doses of a FDA-specified immediate release formulation having one third the amount of guaifenesin is dosed every four hours over a 12 hour period, and releases therapeutically effective bioavailable guaifenesin dose for at least twelve hours after a single dose in a human subject according to serum analysis.

A drug delivery system comprising a sustained release portion comprising guaifenesin, dextromethorphan and a release-delaying matrix comprising a hydrophilic polymer and a water-insoluble polymer;

• and an immediate release portion comprising guaifenesin and dextromethorphan;
• wherein the guaifenesin is bioavailable at a therapeutically effective level for at least twelve hours according to serum analysis following a single dose and wherein a unit dose form demonstrates a Cmax in a human subject above 640 ng/ml with a Tmax within 0.8 hours and maintains a Cmin above 80 ng/ml for a period of 12 or more hours.