Tomoxiprole belongs to the class of 3-alkyl-2-aryl-3H-naphth (1,2-d)imidazoles. It is a nonsteroidal anti-inflammatory compound that was reported to have low ulcerogenic potential. Tomoxiprole inhibition of cyclooxygenase-2 but not cyclooxygenase-1 is time-dependent. It has anti-inflammatory activity in various anti-inflammatory models such as carrageenin and nystatin oedemas, cotton pellet granuloma and adjuvant arthritis. The anti-inflammatory potency of tomoxiprole is greater than that of acetylsalicylic acid and phenylbutazone, but lower than that of indomethacin. Tomoxiprole reduced PGE2 and 6-keto-PGF1 alpha levels more effectively in inflamed tissue than in gastric mucosa when assayed in in vivo experiments, whereas indomethacin and other non-steroidal anti-inflammatory drugs are equally effective in both systems.

Folitixorin, a thymidylate synthase inhibitor is a substrate used by the enzyme methylenetetrahydrofolate reductase (MTHFR) to generate 5-methyltetrahydrofolate. Folitixorin was studied in clinical trials for the treatment of breast cancer, metastatic colorectal cancer and for the treatment of advanced pancreatic cancer. Folitixorin had been granted orphan drug status for the treatment of pancreatic cancer in both the U.S. and EU. However, further development of this drug was discontinued.

Velusetrag (TD-5108) is a potent, selective high intrinsic activity serotonin 5-HT(4) receptor agonist. Velusetrag has achieved proof-of-concept in patients with chronic idiopathic constipation and was on phase II of clinical trial for the treatment of Alzheimer's disease and constipation, when studies were discontinued. In addition, velusetrag is on the phase II of clinical trial for the treatment of gastroparesis.

Clibucaine is a piperidine derivative possessing local anesthetic properties and used in the clinic as a local anesthetic in the 1980s.

Clantifen is an aminothiophene derivative invented by Hoersht AG. The compound is claimed to have antiphlogistic and antipyretic properties.

Clinpirin is an investigational compound developed by CIBA and Schering as an acaricide, used for controlling spider mites. The compound possesses ovicidal and adulticidal efficacy and is active in the cattle tick resistant to organophosphorus pesticides.

Clanfenur is a benzoylphenyl urea derivative, developed as an anticancer drug, developed by Solvay. In preclinical studies, clanfenur exhibited anti-tumor activity in mice. A phase I study was initiated to establish the maximum tolerable dose (MTD) and safety of clanfenur. The study had to be discontinued because of intolerance to the vehicle and because the target plasma concentration of 1 ug/mL could not be reached due to very poor solubility of clanfenur.

Citenazone (Hoe 105) is an antiviral compound, developed in the 1970s by Hoechst. It is claimed to have activity for vaccinia infection in mice, baby rats, and rabbits, and for variola infection in baby mice.

Cinoxopazide is a compound disclosed in the patent application by Delalande S.A. The compounds of the series are claimed to have applications for stimulating intellectual efficiency in normal subjects, for preserving the cerebral function in aged subjects and for treating trouble of vigilance and/or memorization consequent on different pathologies.

Sitalidone (HOE-708) is a potent thiazide-like diuretic and antihypertensive drug.