Pharmacokinetics of guaifenesin, pseudoephedrine and hydrocodone in a combination oral liquid formulation, administered as single and multiple doses in healthy Chinese volunteers, and comparison with data for individual compounds formulated as Antuss®

1. A new oral liquid formulation combining guaifenesin, pseudoephedrine and hydrocodone is effective in improving the symptoms of common cold. The pharmacokinetic properties of the individual components were evaluated in a randomized, open-label, four-period study in 12 healthy Chinese volunteers following single and multiple doses. The data were compared with data for the individual ingredients in Antuss (R). 2. In the single-dose period, exposure levels (AUC and C-max) for guaifenesin, pseudoephedrine and hydrocodone increased directly as the dose of the oral liquid formulation increased from 5 to 15mL. Only minor amounts of guaifenesin and hydrocodone were excreted in urine (approximate to 0.10% and 4.66%, respectively). Pseudoephedrine was mainly excreted unchanged, with 44.95% of the dose excreted in urine within 24h. After multiple dosing, there was no obvious accumulation of any drug, as assessed by AUC. When considering C-max, there was a trend toward accumulation of hydrocodone and pseudoephedrine. The pharmacokinetic profiles of guaifenesin and pseudoephedrine in the oral liquid formulation were similar to those in the branded preparation, Antuss (R). 3. The newly developed oral liquid formulation combining guaifenesin, pseudoephedrine and hydrocodone was safe and well tolerated and might provide a reliable alternative to the branded formulation for patients with common colds.