Guaifenesin-d₃is intended for use as an internal standard for the quantification of guaifenesin by GC- or LC-MS. Guaifenesin is an expectorant.¹It inhibits production of mucin 5AC (MUC5AC), reduces mucus viscosity and elasticity, and increases the mucociliary transport rate of endogenous particles in primary human tracheobronchial epithelial cells in a concentration-dependent manner.²Guaifenesin (50 mg/kg, p.o.) increases phenol red secretion, a marker of expectorant activity, in rats.³Formulations containing guaifenesin have been used as expectorants in the treatment of the common cold and chronic bronchitis.

1.Seagrave, J., Albrecht, H.H., Hill, D.B., et al.Effects of guaifenesin, N-acetylcysteine, and ambroxol on MUC5AC and mucociliary transport in primary differentiated human tracheal-bronchial cellsRespir. Res.13(1)98(2012) 2.Seagrave, J., Albrecht, H., Park, Y.S., et al.Effect of guaifenesin on mucin production, rheology, and mucociliary transport in differentiated human airway epithelial cellsExp. Lung Res.37(10)606-614(2011) 3.Kagan, L., Lavy, E., and Hoffman, A.Effect of mode of administration on guaifenesin pharmacokinetics and expectorant action in the rat modelPulm. Pharmacol. Ther.22(3)260-265(2009)