Ambroxol-d5 is intended for use as an internal standard for the quantification of ambroxol by GC- or LC-MS. Ambroxol is an expectorant and active metabolite of bromhexine. It decreases short-circuit currents in electrically stimulated isolated canine tracheal epithelial cells when applied submucosally. Ambroxol decreases IL-13-induced production of mucin 5AC (MUC5AC) in primary human airway epithelial cells and inhibits IL-13-induced decreases in the mucociliary transport rate of endogenous particles in the same cells. Ambroxol increases phenol red secretion, a marker of expectorant activity, in mice when administered at doses of 30, 60, or 120 mg kg. Formulations containing ambroxol have been used in the treatment of acute or chronic respiratory conditions.
Fenspiride-d5 is intended for use as an internal standard for the quantification of fenspiride by GC- or LC-MS. Fenspiride is an antagonist of histamine H1 receptors and a non-steroidal anti-inflammatory drug (NSAID). It inhibits histamine-induced contraction of isolated guinea pig trachea but not histamine-induced inotropy of isolated guinea pig heart. It also inhibits phosphodiesterase 4 (PDE4), PDE5, and PDE3 (IC50s = 69, ~158, and 363 µM, respectively, in isolated human bronchi derived from patients with lung cancer). It is selective for these phosphodiesterases over PDE1 and PDE2, where it provides less than 25% inhibition. Fenspiride potentiates the airway relaxant effects of isoproterenol and sodium nitroprusside indicating an effect on cAMP and cGMP phosphodiesterases, respectively. Aerosolized fenspiride (1 mg ml) reverses bronchoconstriction induced by capsaicin and, when used at aerosolized concentrations ranging from 1-10 mg ml, reduces cough induced by citric aci......