Mazapertine (RWJ-37796) is an arylpiperazine antipsychotic with high affinity to dopamine D2 and D3, serotonin 5-HT1A and alpha 1A-adrenergic receptors. It was being studied in the treatment of schizophrenia.

Etorphine was the first potent opiate agonist employed primarily for use in non-domestic and wild species. Etorphine was 500 times as potent as morphine, with a very rapid onset and short duration of action. In morphine-dependent subjects, etorphine suppressed abstinence but for a shorter period than morphine. Etorphine is a full opiate agonist and binds to multiple opiate sites in the central nervous system. It is believed to produce its clinical effects through binding the µ-, δ-, and κ- opiate sites. It has a potent effect on depressing the respiratory centers of the CNS thus resulting in apnea being commonly seen in immobilized animals. Etorphine revolutionized the ability of biologists and veterinarians to safely capture and restrain many species that previously could not be handled. Etorphine is not currently commercially available due to lack of production by the manufacturer.

LAVOLTIDINE, also known as loxtidine, is a highly potent and selective histamine H2-receptor antagonist. It is a member of triazoles. It produces gastric carcinoid tumors in rodents that is why its clinical development was discontinued.

Dexniguldipine (B8509-035, (-)-(R)-niguldipine) is a new dihydropyridine derivative, that exerts selective antiproliferative activity in a variety of tumor models and, in addition, has a high potency in overcoming multidrug resistance. Dexniguldipine is ( - )-(R)-enantiomer of niguldipine, of which the ( )-(S)-enantiomer shows pronounced cardiovascular hypotensive activity due to its high affinity for the voltage-dependent Ca2 channel. As compared with the (S)-enantiomer, the (R)-enantiomer has a 40-fold lower affinity for the Ca 2 channel and, accordingly, only minimal hypotensive activity in animal pharmacology models. Dexniguldipine have shown antiproliferative activity in several tumor cell lines, but the concentrations necessary to inhibit growth have varied by several orders of magnitude between cell lines. Initial results of preclinical investigations for the evaluation of the mechanism of its antiproliferative activity demonstrate that dexniguldipine interferes with intracellular signal transduction by affecting phosphoinositol pathways, protein kinase C expression, and intracellular Ca 2 metabolism. In a series of human tumor xenografts in vitro, dexniguldipine demonstrated selective antiproliferative activity against several tumor types, e.g., melanoma and renal-cell carcinoma. Striking results were obtained in a hamster model, in which neuroendocrine lung tumors could be completely eradicated by 20 weeks of oral treatment with 32.5mg/kg dexniguldipine, whereas Clara-cell-type lung tumors were not affected. In in vitro studies, dexniguldipine has been found to bind to P-glycoprotein (P-gp) and to enhance the cytotoxicity of chemotherapeutic agents such as doxorubicin and etoposide in several cell lines The synergistic effect may well be associated with the reversal of multidrug resistance (MDR) related to the activity of P-gp. In the clinical therapy of cancer, resistance to many cytostatic drugs is a major cause of treatment failure. However, the high potency of dexniguldipine (about 10-fold as compared with that of verapamil in vitro) and its low cardiovascular activity provide the opportunity to achieve blood or tumor concentrations that might be high enough to overcome Mdr 1 resistance in patients without producing dose-limiting cardiovascular effects.

Liarozole is an imidazole-containing compound that inhibits the cytochrome P-450-dependent metabolism of all-trans-retinoic acid (RA). Liarozole, a retinoic acid (RA) metabolism-blocking agent (RAMBA) in clinical development, has been granted orphan drug designation for congenital ichthyosis by the European Commission and the U.S. Food and Drug Administration. Later, based on the mixed results from a phase II/III trial of liarozole for the treatment of ichthyosis, Barrier decided to discontinue the development of liarozole. Liarozole displays antitumor activity against androgen-dependent and independent rat prostate carcinomas.A large phase III international study was completed comparing liarozole 300 mg twice daily with cyproterone acetate (CPA) 100 mg twice daily in a total of 321 patients with metastatic prostate cancer in relapse after first-line endocrine therapy. The results indicate that liarozole might be a possible treatment option for prostate cancer (PCA) following failure of first-line endocrine therapy.

Emilium is an antiarrhythmic agent and cardiac depressant.

m-Chlorophenylpiperazine (meta-chlorophenylpiperazine or mCPP) is a psychoactive substance, which is illegal in many countries but can be found on the black market. It induces endocrine, neurological and psychiatric effects. mCPP is a partial agonist at the 5-HT2C receptor but antagonized the 5-HT2B and 5-HT3 receptors. mCPP is also an active metabolite of the drug trazodone, which is used as an effective antidepressant drug with a broad therapeutic spectrum, including anxiolytic efficacy. It is known, that mCPP induces migraine attacks and that the decrease of food intake induced by the mCPP depends on its ability to act as a serotonin agonist is a brain.

Fenobam is a selective and potent metabotropic glutamate (mGlu)5 receptor antagonist with inverse agonist activity. Fenobam was previously investigated as an anxiolytic in a number of phase II studies in the early 1980s. These studies revealed a mixed picture of anxiolytic efficacy, with double blind, placebo controlled trials variously reporting the compound as active or inactive. This discrepancy was not easily reconciled based on patient numbers, dose level, duration of treatment, or outcome measures. The positive effects seen in animal models of fragile X syndrome (FXS) treated with fenobam or other mGluR5 antagonists, the apparent lack of clinically significant adverse effects, and the potential beneficial clinical effects seen in this pilot trial support further study of the compound in adults with FXS.

Doxpicomine is the hydrochloride salt of l-3[(dimethylamino)-(m-dioxan-5-yl)methyl]pyridine, a derivative of substituted 1,3 dioxanes. Its analgesic effect appears to be mediated centrally through opiate-like receptors. Preclinical animal studies revealed analgesic activity and duration of action of the same order as that of meperidine and codeine when administered subcutaneously and of codeine but of shorter duration when administered orally. The analgesic effects were reversed by naloxone. The drug did not reduce or antagonize the analgesic effect of morphine. Drowsiness is an expected response to effective analgesics. It was the foremost side effect observed but was of short duration and minimal intensity and did not interfere with the postoperative regimen of coughing, deep breathing, and early ambulation. Nausea and vomiting were not reported after doxpicomine.

Fenobam is a selective and potent metabotropic glutamate (mGlu)5 receptor antagonist with inverse agonist activity. Fenobam was previously investigated as an anxiolytic in a number of phase II studies in the early 1980s. These studies revealed a mixed picture of anxiolytic efficacy, with double blind, placebo controlled trials variously reporting the compound as active or inactive. This discrepancy was not easily reconciled based on patient numbers, dose level, duration of treatment, or outcome measures. The positive effects seen in animal models of fragile X syndrome (FXS) treated with fenobam or other mGluR5 antagonists, the apparent lack of clinically significant adverse effects, and the potential beneficial clinical effects seen in this pilot trial support further study of the compound in adults with FXS.