Nitroarginine (LNNA), an analog of L-arginine, is a competitive inhibitor of nitric oxide synthase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. The Kd value (k(off)/k(on)) of bovine brain cNOS for LNNA was 15 nM. In contrast to the potent and slow onset of LNNA inhibition of brain cNOS, LNNA inhibition of inducible mouse macrophage NOS (iNOS) was weaker (Ki = 4.4 uM) and rapidly reversible. Thus, LNNA was a 300-fold more potent inhibitor of bovine brain cNOS than mouse macrophage iNOS. By inhibiting nitric oxide synthase LNNA causes the selective reduction of blood flow to tumor cells. Despite the potential of LNNA to function as an adjuvant in cancer therapies, its poor solubility and stability have hindered the development of an injectable formulation of LNNA that is suitable for human administration.

Streptoniazid is a streptomycin derivative patented by Societe des usines chimiques de Rhone-Poulenc as antibiotic effective against tuberculosis.

Coumazoline is a vasoconstrictor developed as a nasal decongestant by a French corporation Labez. Intravenous administration of the compound to dogs lead to a marked and prolonged drop in the temperature of the gingival mucosa. In rats, coumazoline caused slowing of the dye diffusion on the surface of the skin. The compound did not influence the ciliary motility, as was measured on an isolated guinea pig trachea.

Carubicin (also known as Carminomycin) is an anthracycline antineoplastic antibiotic isolated from the bacterium Actinomadura carminata. Carubicin intercalates into DNA and interacts with topoisomerase II, thereby inhibiting DNA replication and repair and RNA and protein synthesis. The drug is active against a variety of experimental tumors. Pharmacology studies in animals revealed that the drug bound largely to serum proteins and that it was widely distributed. In clinical trials The main toxic effect was myelosuppression but gastrointestinal intolerance and alopecia were also reported. Objective partial responses were seen in two of seven previously untreated patients with non-small cell lung cancer and one of three patients with squamous cell carcinoma of the head and neck previously untreated with chemotherapy.

Altanserin is a potent and selective 5-HT2A receptor antagonist. Serotonin (5-HT) system functioning have been proposed for a variety of psychiatric disorders, but a direct method quantitatively assessing 5-HT release capacity in the living human brain is still lacking. It was suggested that the combination of a dexfenfluramine-induced 5-HT release and subsequent assessment of 5-HT(2A) receptor availability with [(18)F]altanserin by positron emission tomography (PET) was suitable to measure cortical 5-HT release capacity in the human brain. Besides human neuroimaging studies altanserin has also been used in the study of rats.

Cemadotin (LU103793) is a cytotoxic water-soluble pentapeptide analogue of dolastatin 15. The dolastatin peptides were originally isolated from the shell-less mollusc Dolabella auricularia. Cemadotin blocks cells at mitosis. It exerts its antitumor activity by suppressing spindle microtubule dynamics through a distinct molecular mechanism by binding at a novel site in tubulin. Cemadotin was in phase II clinical trials as a promising cancer chemotherapeutic agent. However, this agent appears to be inactive in the treatment of advanced non-small-cell lung cancer and other tumors and this research has been discontinued.

Tasidotin (also known as ILX-651), an orally active synthetic microtubule-targeted derivative of the marine depsipeptide dolastatin-15. It was suggested, that tasidotin has a unique mechanism of action. The drug inhibits cell proliferation by suppressing spindle microtubule dynamics through a reduction of the shortening rate, reduction of the switching frequency from growth to shortening, and reduction of the time microtubules grow. Tasidotin was studied in clinical trials phase II in patients with locally advanced or metastatic non-small cell lung carcinoma, in patients with hormone-refractory prostate cancer, and in patients with inoperable locally advanced or metastatic melanoma. However, no new results were published last 5 years. It was suggested that tasidotin is no longer being used as single or even components of multiple agents today.

Omaciclovir (previously known as H2G), a cyclic guanosine analog that is structurally similar to acyclovir and was in clinical development for the treatment of herpesvirus infections. This drug acted against varicella-zoster virus (VZV), by the formation of high concentrations of relatively stable H2G-triphosphate, which is a potent inhibitor of the viral DNA polymerases. However, further development of this drug was discontinued.

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.

Sparfosate (PALA) is a stable transition state analogue for an aspartate transcarbamylase- cartalyzed reaction with antineoplastic activity. PALA is a potent inhibitor of aspartate transcarbamylase (Ki about 10(-8) M for ACTases of various origins), which in whole cells blocks the de novo synthesis of pyrimidines. Thus PALA inhibits de novo pyrimidine biosynthesis and increases the extent to which fluorouracil metabolites are incorporated into RNA. In vivo, low doses of PALA inhibit whole body pyrimidine synthesis. While this action is cytotoxic in vitro, extensive human testing demonstrates that PALA alone is devoid of selective antitumor activity. Interest in the therapeutic action of PALA derives from the demonstration that its action potentiates the cytotoxicity of several cytotoxic drugs, notably 5-fluorouracil (5-FU). Development of Sparfosate for cancer and Hepatitis B treatment is assumed to have been discontinued.