Idazoxan is an alpha2 receptor antagonist which also shows activity at imidazoline I1 and I2 receptors and modulates the release of dopamine. Idazoxan was in phase II development in the US. Later the development of idazoxan for schizophrenia was discontinued. It was also in clinical trials for cognition disorders in United Kingdom, and was also discontinued. Idazoxan is used in scientific research as a tool for the study of alpha 2-adrenoceptors. Idazoxan`s diastereoisomers possess different relative selectivity for alpha2- pre- and postsynaptic receptors: (+)-idazoxan was 7-8 times more potent than (-)-idazoxan in inhibiting p-[3H]aminoclonidine binding, and 40 times more active in antagonizing clonidine at presynaptic level, indicating a better selectivity for alpha2-presynaptic sites. The pre- and postsynaptic alpha2-adrenoceptors have a different affinity for the two enantiomers of idazoxan. Although the stereoisomers are closely related structurally, (+)-idazoxan possesses a stronger affinity for presynaptic sites. This stereoselectivity was less evident for postsynaptic sites. In rats and dogs, both enantiomers antagonized the sympathoinhibitory effects of clonidine. In rats, (+)- idazoxan was 4-7 times more potent than (-)- idazoxan and 3-8 times more than (-)- idazoxan in dogs. A same order of potency was observed against the sedative effects of clonidine and azepexole in chicks, (+)- idazoxan being 8 times more potent than (-)- idazoxan. Although (+)- idazoxan was more potent than (-) idazoxan, binding studies revealed (-)- idazoxan to be more selective than (+)- idazoxan at central sites. It is concluded that (+)- idazoxan antagonizes both alpha-1 and alpha-2 adrenoceptors and (-)- idazoxan is selective for alpha-2 adrenoceptors. In the pithed rat, only (-)- idazoxan possesses both alpha-1 and alpha-2 agonistic effects.

Levovirin is a guanosine nucleoside analog and the L-enantiomer of ribavirin. It is an investigational drug for the treatment of hepatitis C virus-mediated diseases. Levovirin has a similar immunomodulatory potency to ribavirin in vitro without accumulating in red blood cells or causing hemolytic anemia, a known side effect of ribavirin. Levovirin has been shown to stimulate host immune responses (enhanced Th1 and reduced Th2 cytokine expression). Significantly improved oral absorption of levovirin was achieved following administration of a valine ester prodrug of levovirin R1518. Levovirin was found more potent to inhibit Tick-borne encephalitis virus (TBEV) on the basis of robust binding affinity between protein-drug interactions. This finding may help to understand the nature of helicase and development of specific anti-TBEV therapies.

SB-271046 is one of the first selective 5-HT6 receptor antagonists to be discovered. SB-271046 is a potent, selective and orally active 5-HT6 receptor antagonist with a pKi value of 8.9. This compound provides a useful tool for further elucidating the physiological function of 5-HT6 receptors in vivo. SB-271046 was found to increase levels of the excitatory amino acid neurotransmitters glutamate and aspartate, as well as dopamine and noradrenaline in the frontal cortex and hippocampus of rats, and 5-HT6 antagonists have been shown to produce nootropic effects in a variety of animal studies. Suggested applications of SB-271046 included treatment of schizophrenia and other psychiatric disorders. A phase I clinical development of SB-271046 by GlaxoSmithKline (GSK) was discontinued due to a poor BBB permeability.

SB-743921 is a synthetic small molecule with potential antineoplastic properties. SB-743921 selectively inhibits the ATP-binding domain of the kinesin spindle protein (KSP), an important protein involved in the early stages of mitosis that is expressed in proliferating cells. Inhibition of KSP results in inhibition of mitotic spindle assembly and interrupts cell division, thereby causing cell cycle arrest and induction of apoptosis. SB-743921 has greater than 40,000 fold selectivity for KSP over other kinesins. SB-743921 has demonstrated promising anti-cancer activity in a variety of in vivo and in vitro human cancer models in preclinical studies. Furthermore, anti-cancer effect has been demonstrated in taxane-refractory malignancies with SB-743921. Toxicity studies demonstrated predictable neutropenias and gastrointestinal toxicities without clear evidence of neurotoxicity. The recommended phase II dose for SB-743921 as a 1-h infusion every 21 days is 4 mg/m2.

PD-153035 is a potent and selective ATP-competitive inhibitor of the epidermal growth factor receptor tyrosine kinase EGFR. PD 153035 shows a potent and selective inhibitory effect on tyrosine phosphorylation induced by EGF in Swiss 3T3 fibroblast and A-431 human epidermoid carcinoma cells. PD153035 shows dose-dependent growth inhibitory effects in cultures of EGF receptor-overexpressing human cancer cell lines (A431, Difi, DU145, MDA-MB-468, and ME180) and in nasopharyngeal carcinoma (NPC) cell lines (NPC-TW01, NPC-TW04, and HONE1). Pretreatment of EGFR inhibitors by 24 hours significantly enhances the cytotoxic effect of doxorubicin, paclitaxel, cisplatin, and 5-fluorouracil in NPCTW04 cells. PD153035 abolishes COX-2 expression induced by the PAR(2)-activating peptide 2-furoyl-LIGRLO-NH(2) (2fLI) in Caco-2 colon cancer cells. In A431 human epidermoid tumors grown as xenografts in immunodeficient nude mice, PD153035 at 80 mg/kg i.p. inhibit EGF receptor tyrosine kinase activity. PD153035 improves glucose tolerance, insulin sensitivity, and signaling and reduces subclinical inflammation in HFD-fed mice.

Quaternium-15, a preservative, is one of the most used substances and is added to several cosmetics and other industrial products. Quaternium-15 is a mixture of isomers, where the cis-form is the dominant form and where the trans-form is the minor component present as an impurity. Quaternium-15 can be found under a variety of names, most commonly those of the Dow Chemical Company: Dowicil 200 (cis isomer only), Dowicil 75 and Dowicil 100 (both a mix of cis and trans isomers). The isolated cis-compound is used primarily in cosmetic applications, with a maximum permitted concentration in the EU of 0.2%. DOWICIL 200 preservative (cis form) is used primarily as a preservative in a wide variety of personal-care and cosmetic products. It is designed to provide highly effective broad-spectrum antimicrobial activity, especially in water-based formulations. It is used in both leave-on and rinse-off application such as baby-care products, hair-care products, lotions, powders, and creams. The mixed product (cis- and trans-) is used in a wider range of formulations such as: emulsifiable metal-cutting fluids; latex and emulsion paints; liquid floor polishes and floor waxes; glues and adhesives. Recently, the cis-form has been classified as a CMR substance with the classification toxic to reproduction, category 3. This classification only concerns the cis-isomer:

Clove oil is a natural product, derived from the Eugenia caryophyllata tree. Clove oil is 85 to 95% eugenol. Isoeugenol and methyleugenol make up 5 to 15% of the remaining ingredients. Isoeugenol is manufactured from eugenol by a process of isomerization. Isoeugenol have been used in foods and eugenol has been used in animal feeds. Isoeugenol is used as a fish anesthetic. The mechanism of action of isoeugenol in fish has not been determined. It is hypothesised that its effects are mediated via receptors controlling cellular ion channels in a similar way to that described for local anaesthetics. Reports of adverse reactions involving the use of isoeugenol in humans are primarily confined to incidents of contact sensitization or allergy following dermal exposure.

Quaternium-15, a preservative, is one of the most used substances and is added to several cosmetics and other industrial products. Quaternium-15 is a mixture of isomers, where the cis-form is the dominant form and where the trans-form is the minor component present as an impurity. Quaternium-15 can be found under a variety of names, most commonly those of the Dow Chemical Company: Dowicil 200 (cis isomer only), Dowicil 75 and Dowicil 100 (both a mix of cis and trans isomers). The isolated cis-compound is used primarily in cosmetic applications, with a maximum permitted concentration in the EU of 0.2%. DOWICIL 200 preservative (cis form) is used primarily as a preservative in a wide variety of personal-care and cosmetic products. It is designed to provide highly effective broad-spectrum antimicrobial activity, especially in water-based formulations. It is used in both leave-on and rinse-off application such as baby-care products, hair-care products, lotions, powders, and creams. The mixed product (cis- and trans-) is used in a wider range of formulations such as: emulsifiable metal-cutting fluids; latex and emulsion paints; liquid floor polishes and floor waxes; glues and adhesives. Recently, the cis-form has been classified as a CMR substance with the classification toxic to reproduction, category 3. This classification only concerns the cis-isomer:

Propylparaben is a bacteriostatic and fungistatic agent used as a preservative in cosmetic products, food and drugs. As a food additive, it has the E number E216. To increase the activity and reduce its dose propylparaben is used in a mixture with other parabens and in combination with other types of preservatives. Propylparaben is a chemical allergen capable of producing immunologically mediated hypersensitivity reactions. Chemically it is an ester of p-hydroxybenzoic acid.

Omidenepag isopropyl, a prodrug, is hydrolyzed in the eye to the active form (Omidenepag) which functions as a selective, nonprostaglandin, prostanoid EP2 agonist, has been developed by Ube Industries and Santen Pharmaceutical as an ophthalmic solution (EYBELIS®) for the treatment of glaucoma and ocular hypertension. Omidenepag isopropyl increases the outfow of aqueous humor via both the uveoscleral outfow and the trabecular outfow pathways, resulting in potent and stable reduction in intraocular pressure (IOP). In September 2018, omidenepag isopropyl ophthalmic solution 0.002% was approved in Japan for the treatment of glaucoma and ocular hypertension. On September 22, 2022, the FDA approved Santen’s Omlonti (omidenepag isopropyl), for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension.