Pfizer was developing PF-4995274, an orally administered serotonin 4 receptor (5HT-4) agonist for the treatment of Alzheimer's disease. In 2011, the company discontinued the development of the compound.

Pterostilbene is a naturally derived compound found primarily in blueberries and Pterocarpus marsupium heartwood. The multiple benefits of pterostilbene in the treatment and prevention of human disease have been attributed to its antioxidant, anti-inflammatory, and anti-carcinogenic properties leading to improved function of normal cells and inhibition of malignant cells. The antioxidant activity of pterostilbene has been implicated in anti-carcinogenesis, modulation of neurological disease, anti-inflammation, attenuation of vascular disease, and amelioration of diabetes. Pterostilbene increases LDL and reduces blood pressure in adults. Low doses of pterostilbene seem to hold some benefit for cognition.

Puerarin (7, 4’-dihydroxyisolavone-8-β-glucopyranoside) is an active isoflavone extracted from the roots of Pueraria lobata (Willd.) Ohwi. Puerarin is widely used in traditional Chinese medicine, and is clinically used in China for the treatment of coronary artery disease, heart failure, hypertension and myocardial infarction. It has been reported that puerarin had therapeutic effects on diabetes mellitus, arteriosclerosis and myocardial ischemia in animals. Puerarin demonstrated beta-adrenergic receptor blocking effect. On the other hand, puerarin stimulated alpha1-adrenoreceptor to increase glucose uptake into cultured C2C12 cells of mice. Puerarin has been investigated for the treatment (phase II clinical trials) of Alcohol Abuse, Rheumatoid Arthritis and Hypertension.

AstraZeneca was developing AZD-2066, a metabotropic glutamate receptor 5 (mGLUR5) antagonist, for the oral treatment of pain indications (e.g. chronic neuropathic pain and painful diabetic neuropathies), depressive disorders and gastro-oesophageal reflux disease. AZD-2066 had been in phase II clinical trials by AstraZeneca for the treatment of diabetic neuropathic pain and phase I for the treatment of gastrooesophageal reflux disease (GERD). However, this reasearch had being discontinued.

Bioresmethrin is a synthetic pyrethroid insecticide. It is the (+)-trans isomer of resmethrin which itself contains a minimum of 30% bioresmethrin. Bioresmethrin is the [1R, trans] isomer of resmethrin and has greater insecticidal activity than the racemic mixture. Bioresmethrin is a potent contact insecticide effective against a wide range of household insects, plant pests, grain pests and insects found in animal housing. It exhibits a high order of insecticidal activity, which when coupled with its excellent toxicological properties, makes it potentially one of the safest and most useful insecticides now being produced.

Pfizer was developing PF-4455242, a selective, short-acting (non-"inactivating") antagonist of the κ-opioid receptor. PF-4455242 was pursued in phase I clinical trial for the treatment of the bipolar disorder and was also investigated as a treatment for depression and substance abuse. In September 2010 Pfizer discontinued the development of the compound.

Dihydromyricetin is a flavonoid component from the Ampelopsis species japonica, megalophylla, and grossedentata; Cercidiphyllum japonicum; Hovenia dulcis; Rhododendron cinnabarinum; some Pinus species; and some Cedrus species, as well as Salix sachalinensis. Dihydromyricetin exerts a more rapid antidepressant-like effect than does a typical antidepressant, in association with enhancement of BDNF expression and inhibition of neuroinflammation. Dihydromyricetin inhibited the proliferative potential of fibroblasts in the lung cancer cells through targeting the activation of Erk1/2 and Akt. Therefore, there is scope for dihydromyricetin to be evaluated further for the treatment of lung cancer. Dihydromyricetin supplementation improves glucose and lipid metabolism as well as various biochemical parameters in patients with nonalcoholic fatty liver disease, and the therapeutic effects of dihydromyricetin are likely attributable to improved insulin resistance and decreases in the serum levels of tumor necrosis factor-alpha, cytokeratin-18, and fibroblast growth factor 21.

Quisinostat is an orally bioavailable potent histone deacetylase inhibitor, specifically selected due to its sustained inhibition of HDAC1 in solid tumor tissues and prolonged period of half-elimination from tissues. Phase 2 clinical trials are ongoing in patients with platinum-resistant ovarian cancer and non-small cell lung cancer (NSCLC). Quisinostat is active in the treatment of patients with relapsed or refractory Sézary syndrome. The most common drug-related adverse events reported in this trial were: nausea, diarrhea, asthenia. Grade 3 adverse events were also reported: hypertension, lethargy and pruritus.

Encenicline (EVP-6124; MT-4666) acts as a potent partial and selective agonist at alpha-7 nicotinic acetylcholine receptor. Encenicline significantly improved memory function in animal models. FORUM Pharmaceuticals (formerly EnVivo Pharmaceuticals) is developing encenicline for the treatment of cognition disorders such as schizophrenia and for Alzheimer's disease.

Mephedrone (4-methylmethcathinone) is a β-ketoamphetamine belonging to the family of synthetic cathinones, an emerging class of designer drugs known for their hallucinogenic and psychostimulant properties as well as for their abuse potential. Mephedrone is a stimulant of dopamine (DA) release and blocks its reuptake through its interaction with the dopamine transporter. Furthermore, it has some affinity for various 5-hydroxytryptamine (5-HT) receptor subtypes. Neurotoxic effect of mephedrone on 5-HT and DA systems remains controversial. Although some studies in animal models reported no damage to DA nerve endings in the striatum and no significant changes in brain monoamine levels, some others suggested a rapid reduction in 5-HT and DA transporter function. Persistent serotonergic deficits were observed after binge like treatment in a warm environment and in both serotonergic and dopaminergic nerve endings at high ambient temperature. Oxidative stress cytotoxicity and an increase in frontal cortex lipid peroxidation were also reported. Despite the re-classification of mephedrone as a Class B restricted substance by the United Kingdom and restrictive legislation by the United States, international policy regarding mephedrone control is still developing and interest in synthetic amphetamine-like drugs could drive the development of future mephedrone analogues.