Sodium aceneuramate is a sodium salt of aceneuramic acid (sialic acid). It is an effective inhalant expectorant. Inhalation of sodium aceneuramate repaired inflammation in the airway, and caused bronchitic rabbits to produce sputa with a low viscosity, similar to normal air-way secretions. Sodium aceneuramate protected the mucociliary transport impaired bycigarette smoke in a dose-dependent manner. The results suggest that sodium aceneuramate may participate in the defense mechanism in the airway against irritant gases. Sodium aceneuramate inhibited bronchial anaphylaxis and the release of histamine into bronchoalveolar lavages. Sodium aceneuramate has an action which elevates the viscoelasticity of secretions in the respiratory tract.

Morphine-6-glucuronide is a pharmacologically active metabolite of morphine that is being developed by CeNeS Pharmaceuticals as an alternative to morphine for the management of postoperative pain. Compared to morphine, Morphine-6-glucuronide has been reported to have6 and 86 times lower affinity for the human mu and kappa opioid receptors, respectively, and similar affinity for the delta opioid receptor. Morphine-6-glucuronide is was studied in phase III clinical trials for postoperative pain management. Unfortunately, Morphine-6-glucuronide failed to demonstrate superior safety compared to Morphine and further development was discontinued. Morphine-6-glucuronide accumulates after administration of morphine to patients with renal insufficiency, and analgesia can be obtained with lower doses of morphine compared to patients with normal renal function. More importantly, the dose should be reduced to avoid serious side-effects, although the simulations in this review did not account for side-effects.

(1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) is a β-carboline indole alkaloid naturally occurring in plants, foods, insects, and endogenously in mammals and humans. It exerts antioxidant and antithrombotic properties. MTCA is thought to be a possible causative substance of eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan.