Pentabamate was developed as an anxiolytic agent and was studied as a minor tranquilizer by Bayer. Information about the current use of this drug is not available.

Zaprinast is (M&B 22,948; 2-o-propoxy-phenyl-8-azapurin-6-one) is a selective inhibitor of cyclic GMP (cGMP)-dependent phosphodiesterases, with vasodilation activity in a variety of species and tissues. The potency of zaprinast as a vasorelaxant varies with the species, the tissue, and the presence and absence of endothelium. Zaprinast apparently loses all or most of its vasorelaxant capacity when arteries have been denuded of the endothelial cell layer. Alternatively, the vasorelaxant effects of zaprinast can be attenuated using methylene blue, an inhibitor of soluble guanylate cyclase and hemoglobin inhibitor of nitric oxide synthesis. Therefore, zaprinast-induced relaxations appear to be endothelium-dependent. In human platelets zaprinast, at a dose of 10 mkM, caused a modest (20%) inhibition of aggregation as well as a small increase in cGMP content. In anesthetized rats, zaprinast dose-dependently lowered mean arterial blood pressure (MAP), an effect that correlated well with increased levels of plasma cGMP. Zaprinast decreased mean arterial pressure, the reduction being inversely related to zaprinast concentration. Zaprinast had no effect on heart rate, but increased cardiac output, urinary output, urinary sodium excretion, as well as renal blood flow. Oral administration of zaprinast to spontaneously hypertensive rats at a dose of 200 mg/kg/day normalized blood pressure. In normotensive rats, however, no changes in blood pressure were observed with the same treatment. In an initial placebo-controlled, double-blind crossover trial, 10 mg of zaprinast was effective in reducing exercise-, but not histamine-induced bronchoconstriction in adult asthmatics. However, in a similar study with asthmatic children, zaprinast was ineffective in preventing exercise-induced bronchoconstriction. Since then the clinical development of zaprinast has been discontinued.

Clinafloxacin is a broad-spectrum fluoroquinolone antibiotic that was originally developed and subsequently abandoned in the late 1990s as a human health antibiotic for respiratory diseases. Clinafloxacin displays broad-spectrum antibacterial activity against Gram-positive, Gram-negative, and anaerobic pathogens by inhibiting the bacterial regulatory enzyme DNA gyrase (IC50 = 0.92 ug/ml) as well as topoisomerase IV (IC50 = 1.62 ug/ml).

Antineoplaston (Phenylacetylglutamine) is the amino acid acetylation product of phenylacetate (or phenylbutyrate after beta-oxidation). The chemical structure of Antineoplaston AS2-5 corresponds to phenylacetylglutamine. Two synthetic derivatives of Antineoplaston A10 were named Antineoplaston AS2-1 and AS2-5. All antineoplaston formulations were submitted for Phase I clinical studies in advanced cancer patients. The treatment was free from significant side-effects and resulted in objective response in a number of advanced cancer cases. Antineoplastons are an experimental cancer therapy developed by S.R. Burzynski, MD, PhD. Chemically, antineoplastons are a mixture of amino acid derivatives, peptides, and amino acids found in human blood and urine. The developer originally isolated antineoplastons from human blood and later found the same peptides in urine. Urine was subsequently used because it was less expensive and easier to obtain. Since 1980, antineoplastons have been synthesized from commercially available chemicals at the Burzynski Research Institute. According to the developer, antineoplastons are part of a biochemical surveillance system in the body and work as "molecular switches." For the developer, cell differentiation is the key to cancer therapy. At the molecular level, abnormal cells that are potential cancer cells need to be "switched" to normal mode. Antineoplastons are the surveillance system that directs cancer cells into normal channels of differentiation. According to statements published by the developer, people with cancer lack this surveillance system because they do not have an adequate supply of antineoplastons.

Glycovir (SC-49483) is an ester produg (a biologically inactive compound that can be metabolized in the body to produce a drug) of SC 48334, an α-glycosidase 1 inhibitor that has anti-HIV activity. Glycovir was thus studied for treatment in HIV. It is targeted against viral glycoprotein processing in host cell endoplasmic reticulum. Bioavailability of the pharmacologically active SC-48334 observed after glycovir administration was found to be very different between species, but monkeys are a good animal model for prediction of bioavailability of SC-48334 in humans. A phase II trial was conducted to determine the safety and anti-HIV activity of a combination treatment of glycovir with zidovudine (AZT).

Opaviraline (also known as GW 420867), a nonnucleoside reverse transcriptase inhibitor that was studied for the treatment of HIV infections. The drug participated in clinical trials phase II in Germany, in South Africa, and in the United Kingdom, however, these studies were discontinued.

Omigapil (CGP 3466 or TCH346) is a structurally related analog of R-(-)-deprenyl that exhibits virtually no monoamine oxidase type B inhibiting activity but is neuroprotective in the picomolar concentration range. It binds to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and at subnanomolar concentrations prevent the S-nitrosylation of GAPDH, inhibit GAPDH-Siah binding and prevent the nuclear translocation of GAPDH. Omigapil demonstrated promising potential in the treatment of Parkinson's disease and motoneuron disease in animal models, however, it did not show efficacy in clinical trials. Omigapil is in development for the treatment of congenital muscular dystrophy.

Ipragratine is azabicyclo[3.3.1]nonyl derivative patented by German pharmaceutical company Boehringer Ingelheim G.m.b.H. as central anticholinergics and spasmolytics.

OXAZIDIONE was developed as an anticoagulant that could prevent the formation of clots in thromboembolic disease. However, this drug has never been marketed.

Sedecamycin (also known as lankacidin A), a 17-membered macrolide antibiotic that showed potent activity against Treponema hyodysenteriae. This compound was used in veterinary for treating swine dysentery.