FLEZELASTINE, a phthalazinone derivative, an anti-asthmatic/anti-allergic agent. It exhibits inhibition of histamine release and 5-lipoxygenase, calcium antagonistic properties and antagonism at the histamine H1 receptor. FLEZELASTINE is a racemate consisting of (+)- and (-)-enantiomers. Both enantiomers contribute to the pharmacodynamic efficacy of racemic flezelastine.

FLOSATIDIL is an antihypertensive drug discontinued in Phase II for angina pectoris.

Fluquazone, a proquazone derivative, was studied as an anti-inflammatory agent. However, information about the further development of this compound is not available.

Cingestol is a steroidal progestin, a derivative of 19-nortestosterone, developed in the 1970s by Organon as a low-dose progestogen-only contraceptive.

Nalmexone is an opioid partial agonist or mixed agonist-antagonist with both analgesic and narcotic antagonist properties. In preclinical models parenteral nalmexone was a moderately active antagonist and therefore might have low abuse potential. At the same time, early work in man indicated analgesic activity in doses above 20 mg.

Torcitabine is the beta-L-enantiomer of the natural nucleoside D-cytidine. The drug was under development as an antiviral agent for the treatment of chronic hepatitis B virus infection. Torcitabine has poor oral bioavailability, but its 3’,5’-derivative ester (val-L-dC) and the 3’-monovaline ester, valtorcitabine dihydrochloride, have excellent oral bioavailability and consequently the torcitabine prodrug, valtorcitabine, has replaced torcitabine in clinical development. Torcitabine is active against hepadnaviruses, specifically human hepatitis B virus (HBV), duck hepatitis virus (DHBV) and woodchuck hepatitis virus (WHV). Torcitabine triphosphate is a selective inhibitor of the polymerase enzyme of HBV.

Transcainide is a new and very potent analog of lidocaine that has been found effective in the treatment of ventricular arrhythmias. In common with other class I antiarrhythmic drugs its main electrophysiologic effect is a reduction of the upstroke velocity of the action potential (Vmax) suggesting a blockade of the sodium channel. The interaction of transcainide with this receptor is reversible and state-dependent. Transcainide characterized by very slow kinetics of binding and unbinding to the activated "open" Na+ channel. Transcainide had been in phase II clinical trial for the treatment of Arrhythmias. However, this development was discontinued.

Valrocemide is an anticonvulsant agent which was under development by Teva and Acorda as a potential therapeutic for the treatment of epilepsy. Valrocemide is an N-valproyl derivative of GABAand glycine. It was found that 1 mM of valrocemide could drastically inhibit human brain crude homogenate MIP synthase activity. Furthermore, the mechanism of the effect of valrocemide was studied and results showed that valrocemide reduced the enzyme activity by an apparent competitive mode of inhibition. In October 2003, a phase II trial using valrocemide as an adjunct therapy in refractory epilepsy patients had been completed and phase III trials were being planned. Valrocemide was also being investigated for potential utility in the treatment of bipolar disorder and neuropathic pain. This compound was originally discovered by Yissum Research and Development Company of the Hebrew University of Jerusalem, then licensed and developed by Teva in collaboration with Acorda in 2003, then licensed to Shire the worldwide development, production and marketing rights in 2006. However, the development of Valrocemide was discontinued by Shire in 2009.

Piriqualone is the noncompetitive AMPA receptors antagonist. It was developed as an anticonvulsant, hypnotic and muscle relaxant agent.