Salclobuzate sodium was developed as an oral absorption promoter. This compound had to “chaperone” poorly permeable payloads across the intestine. Information about the current use of this compound is not available.

Tetrabarbital is a barbituric acid derivative patented by Eli Lilly and Co. as a central nervous system depressant. In chloralosed dogs, intravenous Tetrabarbital 2.5-10 mg/kg, accelerated the heartbeat and lowered the carotid pressure.

Pumitepa is a purine derivative patented by All-Union Scientific-Research Chemical-Pharmaceutical Institute as cancerolytic. Although the exact mechanism of action of pumitepa has yet to be fully elucidated, this agent appears to work through alkylation, thereby causing DNA damage and cell cycle arrest. In in vitro studies, Pumitepa prolonged the mitotic cycle in human embryo fibroblasts by 2.5-3 hr, primarily by prolonging the start of phase G1. Pumitepa induced similar types of chromosomal aberrations in cells of all phases of the mitotic cycle. Chromosomes in phase S were the most sensitive for Pumitepa, followed by chromosomes in phases G1 and G2.

AstraZeneca R&D Charnwood (formerly Astra Charnwood, a subsidiary of AstraZeneca) was developing sibenadet (Viozan, AR-C68397AA) for the potential treatment of chronic obstructive pulmonary disease and asthma. Sibenadet is a dual D2 dopamine receptor, beta2-adrenoceptor agonist that combines bronchodilator activity with the sensory afferent modulating effects associated with D2-receptor agonism. Development of sibenadet has been discontinued due to disappointing efficacy findings.

Pumaprazole is imidazopyridine derivative patented by Byk Gulden Lomberg Chemische Fabrik GmbH for the treatment of gastrointestinal diseases. Pumaprazole acts as a reversibly binding acid pump antagonist. Pumaprazole differs from covalently binding proton pump inhibitors (PPIs), such as omeprazole, both with respect to chemical structure and mode of interaction with the gastric H(+)/K(+)-ATPase. In preclinical models, the single dose of Pumaprazole is able to elevate intragastric pH in the dog with gastric fistula under pentagastrin or carbachol stimulation from pH 1 to about pH 7 while still displaying a dose-dependent, well-controllable duration of action of a few hours.

Eritoran (E-5564) is a synthetic lipid A analog that has been designed to antagonize the effects of lipopolysaccharide (LPS) and has been found to do this by interacting with Toll-like receptor 4, the cell surface receptor for LPS. Preclinical in vitro and in vivo studies of eritoran tetrasodium indicate it can limit excessive inflammatory mediator release associated with LPS and improve survival in sepsis models. Clinically, eritoran was being investigated for the treatment of severe sepsis, septic shock, and other endotoxin-mediated indications. Eritoran development has been discontinued.

Edonentan (BMS 207940) is a highly selective biphenylsulfonamide endothelin A receptor antagonist. (11)C- and (18)F-labeled analogs of edonentan were evaluated of novel PET radioligands for imaging the endothelin-A receptor. Edonentan was in clinical trials for the treatment of heart failure however its development has been discontinued.

AstraZeneca developed disufenton (NXY-059), a free radical trapping agent, for the treatment of ischaemic stroke and other brain injuries. Nevertheless, large clinical trial (3306 versus 1722 patients) was neutral, providing no evidence for the efficacy of disufenton sodium in patients with stroke. One study using rat cortical brain slices concluded that NXY-059 improved neuronal survival. However, another study in mouse neuroblastoma cells reported no effect. Another study reported that NXY-059 restored endothelial blood-brain. Histological analyses revealed several therapeutic advantages associated with disufenton sodium treatment following acute acoustic trauma, including reductions in inner and outer hair cell loss; reductions in acute acoustic trauma-induced loss of calretinin-positive afferent nerve fibers in the spiral lamina; and reductions in fibrocyte loss within the spiral ligament. However, AstraZeneca terminated the development program.