15-Epiprostaglandin E1 is a synthetic prostaglandin analogue. The activity of the racemic synthetic prostaglandin is approximately one-half that of the naturally occurring compound. 15-Epiprostaglandin E1 is 4% and 6% as potent as PGE1 in contracting the rat uterus and guinea pig ileum. PGA1 is very potent vasodilator and hypotensive agent, whereas its epimer 15-Epiprostaglandin E1 has a little vasodilator or hypotensive effects in anaesthetized dogs. 15-Epiprostaglandin E1 is a non-competitive inhibitor of 15-hydroxyprostaglandin dehydrogenase from human placenta.

MK-0657, (+)-, a MK 0657 - cis-(+)-isomer, relates to N-substituted nonarylheterocyclic compounds, N-methyl-D-aspartate subunit 2B (NMDA NR2B) antagonists which were developed by Merck as a candidate drugs for the treatment of Parkinson's disease and pain. There are no studies on MK 0657 - cis-(+)-isomer activity.

CL-387785 is irreversible inhibitor of EGF-R kinase

Olmesartan Lactone Impurity (Olmesartan EP Impurity B) is a cyclic ester impurity in commercial preparations of olmesartan medoxomil. Olmesartan medoxomil is an angiotensin II receptor antagonist, which is indicated for the treatment of hypertension.

Naftopidil,(R)- is an enantiomer of Naftopidil (NAF), a specific subtype selective α1-adrenoceptor blocker. Racemic Naftopidil is frequently used for the treatment of lower urinary tract symptoms/benign prostatic hyperplasia. No significant differences in pharmacokinetic parameters were observed between R(+)- and S(−)-NAF after intravenous administration. However, mean plasma concentrations of R(+)-NAF were lower than those of S(-)-NAF after intragastric administration. R(+)-NAF bioavailability in rats was consistently about two-fold lower than that of S(-)-NAF. The fractions of R(+)- NAF reaching the prostate and metabolized in the liver were higher than those of S(−)-NAF. The major pathways of R(+)- NAF metabolism in vitro were demethylation and hydroxylation. CYP2C9 played the most important role in the demethylation and hydroxylation of both NAF enantiomers. CYP2C19 was another CYP isoform that played a major role in R(+)-NAF metabolism.

Ascorbyl laurate or L-ascorbyl-6-laurate is a lipophilic derivative of Vitamin C, a popular antioxidant. It was shown, that L-ascorbyl-6-laurate possessed a "double-faced" effect on free-radical-induced hemolysis of human erythrocytes: antioxidant and prooxidant, that might be useful for the safe use of lipophilic vitamin C.

(6S ,12AR)-Tadalafil is an inactive diastereomer of "Tadalafil" which is the active ingredient in Cialis which is used to treat erectile dysfunction. Tadalafil has 4 isomers [(RR), (SS), (RS), and (SR)], of which (RR) is the name-sake isomer and potent inhibitor of phosphodiesterase-5. The (RS) diastereomer is the only other isomer with some PDE-5 inhibitory activity.

(6R,12AS)-Tadalafil is a diastereomer of "Tadalafil" which is the active ingredient in Cialis which is used to treat erectile dysfunction. Tadalafil has 4 isomers [(RR), (SS), (RS), and (SR)], of which (RR) is the name-sake isomer and potent inhibitor of phosphodiesterase-5. The (RS) diastereomer is the only other isomer with some PDE-5 inhibitory activity.

L-Amoxicillin is an isomer of amoxicillin also known as 'amoxicillin related compound B'. It is considered an impurity.

Trans-Difethialone is an anticoagulant used as a rodenticide. For difenacoum commercial formulations, the cis-isomer is the major form and the trans-isomer is the minor form. Trans-Difethialone inhibit the subunit 1 of the vitamin K epoxide reductase complex this leads to block the formation of the active form of vitamin K, which in turn inhibits the hepatic production of coagulation factors II, VII, IX, and X. Difethialone is not approved for use in Europe but is still used elsewhere.