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.

Levofuraltadone is the nitrofurane used for the treatment of trypanosomiasis. It has been shown to be effective in mice and polyneuritis, a serious side effect of nitrofurazone therapy, is less frequent with levofuraltadone. Nevertheless, levofuraltadone is a very toxic agent and it has never been commercially produced.

Oxdralazine is a peripheral vasodilator that was studied for patients with severe essential hypertension. The clinical trial has shown that at the end of the third month 25 patients on the triple regimen (chlorthalidone plus oxdralazine plus propranolol) achieved a stable diastolic blood pressure of 90 mm Hg or less. However, information about the further development of this drug is not available.

Davasaicin is a synthetic derivative of capsaicin, developed at the Korea Research Institute of Chemical Technology. Davasaicin possesses very potent analgesic activity, demonstrated in several animal models, such as phenylbenzoquinone-induced writhing test, tail-flick test in mice and adjuvant arthritic flexion test in rats. When administered topically, davasaicin has an antipruritic effect in the mouse model.

Darglitazone is a member of the thiazolidinedione class of drugs and an agonist of peroxisome proliferator-activated receptor-γ (PPAR-γ), an orphan member of the nuclear receptor superfamily of transcription factors. It has a variety of insulin-sensitizing effects, such as improving glycemic and lipidemic control, and is used in the treatment of metabolic disorders such as type II diabetes. Darglitazone sodium had been in phase I clinical trials by Pfizer for the treatment of type 2 diabetes. However, this study has been discontinued.

Crolibulin is a tubulin-disrupting agent, interacting at the colchicine-binding site, developed by EpiCept Corporation (which was later acquired by Immune Pharmaceuticals). The compound exhibits anti-cancer effect by vascular disruption and inhibition of apoptosis. In preclinical animal tumor models, combination therapy with crolibulin has demonstrated the synergistic activity with cytotoxic drugs as well as anti-angiogenic drugs, such as Avastin. The drug was investigated in clinical trials for the treatment of anaplastic thyroid cancer and has demonstrated a positive effect.

Cormethasone is a topical antiinflammatory corticosteroid discovered by Du Pont.

Cloquinozine is a quinazoline derivative discovered by Japanese company Chugai Pharmaceutical in the 1960s. Cloquinozine has oxytocic properties and induces uterine contractions when administered to rabbits intravenously at 1 mg/kg.

Clonazoline is an imidazoline sympathomimetic, an alpha-adrenoreceptor agonist. It was used as a nasal decongestant and vasoconstrictor. The drug was marketed in Italy in combination with Fluocinolone under tradename Localyn.