Morpheridine is a pethidine analog with strong analgesic activity. Morpheridine does not cause convulsions, although it produces the standard opioid side effects such as sedation and respiratory depression. Morpheridine is not currently used in medicine and is a Schedule I drug which is controlled under United Nations drug conventions.

Fananserin is a potential antipsychotic compound with a high affinity for both D4 and 5-HT2A receptors, and negligible affinity for D2 receptors. Fananserin has been researched for the treatment of schizophrenia. Fananserin was the first selective D4/5-HT2A antagonist to undergo clinical trials for schizophrenia. It has a high affinity for D4 (Ki 2.9 nM) and 5-HT2A (Ki 0.37 nM) receptors and is over 100-fold selective versus H1, a1 adrenergic, 5-HT1A and D2 dopamine receptors. Development of this compound was halted following phase II clinical trials due to lack of efficacy.

Normorphine is an opiate analog, specifically the N-demethylated derivative of morphine. It was first described in the 1953 as part of an effort to characterize N-substituted morphine analogs. Normorphine has relatively little opioid activity, but it is a useful intermediate for the production of more potent morphine analogs. It is also a major metabolite of morphine.

Tetraisopropyl 2-(3,5-Di-Tert-Butyl-4-Hydroxyphenyl)Ethyl-1,1-Biphosphonate (also known as SR-9223I and SR 45023A) is a gem-diphosphonate derivative patented by Symphar S. A. as an antihypertensive and anti-inflammatory agent. Tetraisopropyl 2-(3,5-Di-Tert-Butyl-4-Hydroxyphenyl)Ethyl-1,1-Biphosphonate acts as 3-hydroxy-3-methylglutaryl reductase inhibitor, besides that SR-9223I suppresses acyl-CoA: cholesterol acyltransferase activity and prevents the oxidation of plasma lipoproteins. In preclinical studies, SR-9223i reduces blood cholesterol concentrations in mice, hamsters, dogs, and monkeys. SR-9223i inhibits the growth of a wide variety of tumor cell lines in vitro and triggered apoptosis in HL60 cells in less than 2 h. SR-9223i induces caspase-3 activity at concentrations similar to it’s IC(50) values for cell proliferation. Unfortunately, in clinical trials SR-9223I failed to demonstrate efficacy in patients with refractory melanoma and further development was discontinued.

Marimastat is a broad spectrum matrix metalloprotease (MMP) inhibitor. It is an angiogenesis and metastasis inhibitor. It mimics the peptide structure of natural MMP substrates and binds to matrix metalloproteases, thereby preventing the degradation of the basement membrane by these proteases. This antiprotease action prevents the migration of endothelial cells needed to form new blood vessels. Inhibition of MMPs also prevents the entry and exit of tumor cells into existing blood cells, thereby preventing metastasis. Marimastat has been in pivotal phase III trials in glioblastoma, breast, ovarian and small and non-small cell lung cancer, but these trials have all been discontinued because marimastat failed to show superior efficacy over either standard chemotherapy or placebo.

Tiotidine is a controversial histamine H2 receptor ligand with negligible activity against H1- and H3- receptors. It was found that tiotidine behaves as an inverse agonist in U-937 cells, diminishing basal cAMP levels. Tiotidine showed two binding sites, one with high affinity and low capacity and the other with low affinity and high capacity. Tiotidine is currently in use as a radioligand in histamine H2-receptor binding studies. Compared to cimetidine, tiotidine appears to be approximately eight times more potent on a molar basis than cimetidine as an inhibitor of acid secretion, and the tiotidine effect is more prolonged. It was developed for the treatment of peptic ulcer.

Ocaperidone [R 79598] is an equipotent antagonist of central dopamine D2 and serotonin2 receptors being investigated as a potential antipsychotic agent. Ocaperidone is a benzisoxazol piperidine antipsychotic primarily binds and with high affinity to 5-HT2 (serotonin) receptors, alpha1 and alpha 2 adrenergic receptors, dopamine D2 receptors and histamine H1 receptors. Ocaperidone is an antagonist primarily at the 5HT and D2 receptors. A proposed mechanism of action is the central D2 receptor blockade which is common to all neuroleptics that are used to treat positive symptoms of schizophrenia.

MK-0767 is a potent hypoglycaemic insulin sensitizer being evaluated by Kyorin with potential as an antidiabetic agent. MK-0767 acts as a dual agonist of the peroxisome proliferator-activated receptors alpha and gamma, induced high-affinity interactions of PPARα and PPARγ with the transcriptional coactivator CBP in vitro. In ob/ob mice, MK-0767 normalized hyperglycemia and hyperinsulinemia with equal or greater potency and efficacy than pioglitazone. Treatment of hamsters with MK-0767 produced substantial reductions in blood cholesterol and triglycerides. In dogs, MK-0767 reduced serum cholesterol levels with a potency more than 10-fold greater than simvastatin. The efficacies of MK-0767 and simvastatin were additive when given together.