Clodanolene is a skeletal muscle contraction antagonist, closely related to dantrolene sodium. The drug has no measurable direct effect on the peripheral or central nervous systems. In a mouse of muscle spasticity (Straub-tail mouse), clodanolene induced skeletal muscle relaxation more effectively than neuromuscular blocking agents, local anesthetics, or centrally-acting muscle relaxants. Indirect evidence indicates clodanolene acts on caffeine-sensitive calcium stores in the muscle cells.

Tigemonam is a dialkylazetidinone derivative patented by E. R. Squibb and Sons, Inc. as a beta-lactam agent useful for the treatment of bacterial infections. Of the orally active beta-lactams, tigemonam is one of the most potent, with a spectrum of activity similar to that of aztreonam and highly resistant to hydrolysis by the beta-lactamase enzymes. Tigemonam inhibits 90% of Escherichia coli, Klebsiella spp., Proteus spp., Salmonella spp., Haemophilus influenzae and Branhamella catarrhalis tested. In localized infections, tigemonam also demonstrated excellent in vivo activity. In acute pyelonephritis in mice caused by Escherichia coli or Proteus sp., tigemonam was very effective. In a rat lung model with Klebsiella pneumoniae, tigemonam was active with a median effective dose of 46 mg/kg compared with 160 mg/kg for cefaclor and over 200 mg/kg for amoxicillin.

Azaspirium was studied as a spasmolytic and antihypertensive agent.

Darbufelone mesylate is a dual inhibitor of cellular prostaglandin and leukotriene production. Darbufelone potently inhibits PGHS-2 (IC50 = 0.19 uM) but is much less potent with PGHS-1 (IC50= 20 uM). Darbufelone is a dual inhibitor of cellular PGF2R and LTB4 production. Darbufelone is orally active and nonulcerogenic in animal models of inflammation and arthritis. Darbufelone mesylate was in phase III clinical trials by Pfizer and Zhuhai United Laboratories for the treatment of rheumatoid arthritis.

Pirazmonam is a potent anti-gram-negative monobactam that is differentiated from aztreonam by its high intrinsic activity against Ps. aeruginosa and good activity against Pseudomonas species. Pirazmonam has generally poor activity against gram-positive aerobic bacteria and anaerobic bacteria. Pirazmonam is a Trojan Horse molecule containing a b-lactam antibiotic that has been developed based on bacterial iron uptake systems. It features high structural similarity to aztreonam attached to a 3-hydroxy-4-pyridinone iron chelating group. Pirazmonam exhibited strong affinity to penicillin-binding protein 3 (PBP3) of Escherichia coli and moderate to negligible affinity to the other E. coli PBPs.

BLI 489 was developed by Wyeth as a 6-methylidene-penem β-lactamase inhibitor for the treatment of bacterial infections and urinary tract infections. BLI-489 has shown the promising clinical data, however, development of this drug, was discontinued.

Xorphanol (also known as TR5379M) is a full κ-opioid receptor agonist and is a partial agonist at μ opioid receptor. Clinically, xorphanol was studied as an orally active analgesic that provided effective pain relief but showed low physical dependence liability. Further development of this drug was discontinued.

Bendacalol (also known as CGS 10078B) is an alpha- and beta-adrenergic receptor inhibitor with calcium entry blocking effect was studied for the treatment of hypertension. Animal experiments have sown some positive results. However, information about further studies is not available.

Elzasonan (CP 448187) is a serotonin 1B/1D receptor antagonist. Elzasonan was primarily metabolized via oxidative N‐demethylation, N‐oxidation, and aryl hydroxylation. Pfizer was developing elzasonan for the treatment of anxiety and affective disorders however development has been discontinued.

Obatoclax (GX15-070) is a novel BH3 mimetic pan Bcl- 2 inhibitor. The clinically studied formulation is as obatoclax mesylate (Box 1), a salt. It is only under study as an intravenous preparation. It functions to block BH3-mediated binding of Bcl-2, Bcl-XL, Mcl-1 and A1 to Bax and Bak. Bax and Bak thus are unopposed and able to dimerize to allow initiation of intrinsic apoptosis. Preclinically, obatoclax has been shown to reverse inhibition of Bax or Bak by Bcl-2, Bcl-XL, Bcl-w and Mcl-1. Obatoclax was discovered by Gemin X, which was acquired by Cephalon, which has since been acquired by Teva Pharmaceuticals. Obatoclax had been in phase III clinical trials by Gemin X Biotechnologies (subsidiary of Teva) for the treatment of non-small lung cancer (NSCLC). The compound received orphan drug designation in the U.S. in 2004 for the treatment of chronic lymphocytic leukemia (CLL). However, Teva discontinued the development of obatoclax in 2013.