Colterol is a beta-2 adrenoreceptor agonist. Bitolterol, a diester prodrug of colterol, was marketed by Elan Pharmaceuticals for the treatment of reversible bronchospasm associated with asthma or chronic obstructive pulmonary diseases.

Fuzlocillin is a penicillin antibiotic. This semisynthetic acylureidopenicillin with antibacterial activity binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. Fuzlocillin (furazlocillin), has been shown to be highly specific for the FtsI gene. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This interrupts bacterial cell wall synthesis and results in the weakening of the bacterial cell wall, eventually causing the cell to break down (cell lysis). Among the acylureidopenicillins, furaclocillin exerts increased activity against Escherischia coli, Klebsiella, Proteus and Pseudomonas aeruginosa.

Linogliride is a substituted guanidine structurally unrelated to the sulphonylureas but with a similar mechanism of action. Linogliride potentiates insulin release in isolated islets and in the perfused pancreas. In islets, linogliride is reported to stimulate insulin secretion in the presence of glucose but not in its absence. Linogliride and the sulphonylureas act via closely related mechanisms. Possible extrapancreatic effects of the agent have also been suggested. Linogliride produces hypoglycaemic effects in various non-diabetic and diabetic animals. In normal rats and dogs, it improves glucose tolerance and in fasted rats or mice, linogliride lowers blood glucose. Linogliride showed modest effects in the db/db mice but significantly lowered fasting blood glucose in neonatal streptozotocin-treated rats. Clinical studies with non-insulin-dependent diabetes patients have shown linogliride to be effective at lowering fasting and postprandial plasma glucose levels in non-insulin-dependent diabetes patients. linogliride leads to a decrease in the activity of ATP-sensitive K+ channels.

Merimepodib has immunosuppressive activity. It targets hepatitis C indirectly through the inhibition of inositol monophosphate dehydrogenase, which exerts an acute antiproliferative effect on lymphocyte proliferation due to their almost exclusive dependence on the de novo pathway for synthesis of guanosine. Phase II clinical trial study of merimepodib for the treatment of HCV infection and psoriasis were completed. The poor pharmacokinetic-pharmacodynamic results have resulted in discontinuation of clinical trials.

Phenadoxone hydrochloride is one of some forty amino-ketones and amino-esters related to amidone. The compound is a very potent analgesic for the rat; by the subcutaneous route it is more active than either morphine or amidone. In spite of this its acute toxicity to mice is lower than that of amidone and its therapeutic index is therefore correspondingly higher, giving a wider margin of safety. Side effects in dogs, such as narcosis, sedation, and general depression, were much less with phenadoxone than with amidone or morphine. Nausea and vomiting did not occur after phenadoxone in non-tolerant dogs. Clinical results show that for relieving certain types of pain in human subjects it is a potent analgesic that compares favorably with morphine and amidone. At therapeutic dose levels undesirable pharmacological effects, such as cardiac depression and vasomotor disturbance, are absent, and it is only at extremely high dose levels that untoward effects occur. However, the drug has a strong respiratory depressant action when given in high doses; it should be used with special caution if injected intravenously.

Moquizone is quinazolinone derivative with choleretic and antifibrillatory activity. Oral toxic doses of Moquizone exerted depressant effects, whereas parenteral toxic doses exerted stimulant effects on the central nervous system.

Mitozolomide is an antineoplastic agent patented by May and Baker Ltd for cancer treatment. Development of mitozolomide was discontinued during Phase II clinical trials after it was found to cause severe and unpredictable bone marrow suppression.

Metostilenol was developed as an antidepressant. However, it has never been marketed.

Mitoquidone is pentacyclic pyrroloquinone derivative developed for clinical evaluation as a potential anticancer agent. Mitoquidone demonstrated good activity in a range of experimental solid tumour models, but was weakly active against standard prescreens such as the P388 murine leukaemia. Bone marrow suppression or other significant toxicity was not observed in preclinical studies. In clinical trials patients were treated with Mitoquidone given as a 4-h infusion either once every 21 days, once a week, or as 5 daily doses repeated every 28 days. The major adverse events encountered included nausea and vomiting (in virtually all patients), dyspnoea, tumour-related pain, and thrombocytopenia in several patients with pretreatment bone-marrow impairment. Phase I studies were suspended without a maximum tolerated dose being reached because of formulation difficulties. There were no major responses, although stable disease was observed in a number of patients with gastrointestinal malignancies.

Mipimazole was developed as a thyroid inhibitor. However, information about the further development of the drug is not available.