Arbaclofen (STX209, R-baclofen), a selective agonist of GABA-B receptors, has been investigated in clinical trials for the treatment of autism spectrum disorder ASD, phase II and for the treatment of patients with fragile X syndrome in phase III. As a result, the drug did not meet the primary outcome of improved social avoidance in FXS in either study. In spite of positive results in some children with ASD, further study will be needed to replicate and extend these initial findings. Arbaclofen has also been investigated in phase III clinical trials as a treatment for spasticity due to multiple sclerosis.

Amustaline (S-303) is a quinacrine mustard compound with potential antineoplastic activity. Amustaline binds to, intercalates and crosslinks DNA and RNA. This agent is mainly used for ex vivo purposes, specifically for the inactivation of pathogens such as viruses, protozoa and bacteria in red blood cells (RBCs). When S-303 is added to red blood cells, the compound rapidly passes through membranes, including those of cells and viral envelopes, due to its amphipathic character, and intercalates into helical regions of the nucleic acids of pathogens and white blood cells. TERCEPTTMBlood System usingamustaline (S-303) and glutathione (GSH) was able to inactivate high levels of DENV and ZIKV in RBCs. S-303 system has been shown to effectively inactivate a broad spectrum of pathogens, while maintaining RBC quality.

Sepazonium was studied as a topical anti-infective drug. However, information about the current use of this agent is not available.

Sergliflozin, a novel oral selective low-affinity sodium glucose cotransporter (SGLT2) inhibitor, improves hyperglycemia by suppressing renal glucose reabsorption, in which SGLT2 participates as a dominant transporter. Its prodrug form, sergliflozin etabonate, is orally available and is converted to sergiflozin upon absorption. Development of sergliflozin has been discontinued in favor of remogliflozin.

Puromycin dihydrochloride belongs to the aminonucleoside family of antibiotics and is isolated from Streptomyces alboniger. Since the partial structure of this antibiotic showed it to be a purine derivative, puromycin was assigned as its generic name. Puromycin is a broad spectrum antibiotic and antibacterial agent. It is active against Gram-positive microorganisms, less active against acid-fast bacilli, and weakly active against Gram-negative microorganisms. It acts very quickly and can kill 99% of the cells within 2 days. It also exhibits antitumor activity in studies on brain tumor cells. Puromycin is a protein synthesis inhibitor that causes premature chain termination by acting as an analog of the 3’-terminal end of aminoacyl-tRNA. It has been used to study transcriptional regulatory mechanisms that control the sequential and coordinate expression of genes during cell differentiation.

Inocoterone acetate (USAN) (also known as RU-38882, RU-882) is the acetate ester of inocoterone a steroid-like nonsteroidal antiandrogen (NSAA) that was developed for topical administration to treat acne but was never marketed. Inocoterone acetate is actually not a silent antagonist of the androgen receptor but rather a weak partial agonist, similarly to steroidal antiandrogens like cyproterone acetate. In this double-blind study of 126 male subjects with acne, a topical solution of the antiandrogen inocoterone produced a modest but statistically significant reduction in the number of inflammatory acne lesions.

Taribavirin, an oral prodrug of ribavirin that was developed as nucleoside antimetabolite, which interferes with duplication of viral genetic material. Taribavirin was studied in phase III clinical trial for the treatment of chronic hepatitis C patients. However, this drug not yet approved for pharmaceutical use.

Celgosivir is a butanoyl ester derivative of castanospermine, a compound derived from the Australian chestnut with activity against hepatitis C virus. Celgosivir rapidly converts to castanospermine in the body, where it is a potent inhibitor of alpha-glucosidase I, a host enzyme required for viral assembly, release, and infectivity.

Enadoline (CI-977) is a potent and selective agonist at the kappa-opioid receptor. Enadoline is a potent antinociceptive agent. Clinical use of enadoline was associated with dose-limiting neuropsychiatric adverse events. Enadoline may yet find some application against ischaemic stroke and severe head injury, presumably in comatose patients.

Naflocort (SQ 26,490) is a topical anti-inflammatory adrenocortical steroid. It was a moderately potent inhibitor of edema formation in the rat. After extended topical application, SQ 26,490 totally inhibited edema formation without appreciable production of skin atrophy, measured under identical conditions. SQ 26,490 possesses the property for a greater separation of anti-inflammatory and atrophogenic activities than comparative corticoids.