Racemic phenibut (beta-phenyl-gamma-aminobutyric acid or 4-amino-3-phenylbutyric acid) is a neuropsychotropic drug that was discovered and introduced into clinical practice in Russia in the 1960s. In pharmacological tests of locomotor activity, antidepressant and pain effects, S-phenibut was inactive. In contrast, R-phenibut turned out to be two times more potent than racemic phenibut in most of the tests. Racemic phenibut and R-phenibut demonstrated an affinity for GABAB receptors, in contrast, S-phenibut was not able to bind receptors. Pharmacological activity of racemic phenibut relies on R-phenibut and this correlates to the binding affinity of enantiomers of phenibut to the GABAB receptor. Both S- and R-phenibut bind to the α2-δ subunit of voltage-dependent calcium channels and exert gabapentin-like anti-nociceptive effects. In addition S-isomer was found to be a substrate of gamma-aminobutyric acid aminotransferase, however, the R-isomer is a competitive inhibitor.

Arabinitol is the five-carbon sugar alcohol D-arabinitol (DA). It is a metabolite of the pathogenic Candida species, in vitro as well as in vivo, and can be determined by gas chromatography or enzymatic analysis. Endogenous DA and L-arabinitol (LA) are present in human body fluids. Serum DA and LA increase in renal dysfunction. In prospective clinical studies, elevated DA/LA or DA/creatine ratios in serum or urine have been found in immunocompromised, usually neutropenic, patients with invasive candidiasis. In addition, positive DA results have been obtained several days to weeks before positive blood cultures, and the normalization of DA levels has been correlated with therapeutic response in both humans and animals. Thus, arabinitol has been suggested a marker for invasive candidiasis. A non-invasive, non-culture-based method of determining urinary D-/L-arabinitol (D-/L-ARA) ratios was investigated as a tool for the diagnosis of invasive candidiasis in nosocomial paediatric infection cases in the clinical trial.

(+)-octopamine is an enantiomer of octopamine, a naturally occurring phenolamine acting as a neurotransmitter in invertebrates. Octopamine is considered to be trace amine present in mammalian tissues at very low (nanomolar) concentrations. Generally, the (+)-enantiomers of octopamine are less active than the (-)-enantiomers at adrenergic receptors. However (+)-octopamine is more potent than the (-)-octopamine as an inhibitor of semicarbazide-sensitive amine oxidase.

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 S(−)-NAF were higher than those of R(+)-NAF after intragastric administration. S(−)-NAF reached higher plasma concentrations within shorter times and achieved lower plasma CL within 24 h than R(+)-NAF. S(−)-NAF bioavailability in rats was consistently about two-fold higher than that of R(+)-NAF. The major pathways of S(−)-NAF metabolism in vitro were demethylation and hydroxylation. CYP2C9 played the most important role in the demethylation and hydroxylation of both NAF enantiomers.

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.

(1,1'-Biphenyl)-3,3',4,4'-tetramine (3,3'-Diaminobenzidine, DAB) is an organic benzidine derivative, that used as a precursor to polybenzimidazoles. As its water-soluble tetrahydrochloride, (1,1'-Biphenyl)-3,3',4,4'-tetramine has been used in immunohistochemical staining of nucleic acids and proteins. Diaminobenzidine is oxidized by hydrogen peroxide in the presence of hemoglobin to give a dark-brown color. This color change is used to detect fingerprints in blood. The solubility of (1,1'-Biphenyl)-3,3',4,4'-tetramin in water allows for adaptability compared to other detection solutions which use toxic solvents. In research, this reaction is used to stain cells that were prepared with hydrogen peroxidase enzyme, following common immunocytochemistry protocols. Relevant to Alzheimer's disease, Aβ protein amyloid plaques are targeted by a primary antibody, and subsequently by a secondary antibody, which is conjugated to a peroxidase enzyme. This will bind (1,1'-Biphenyl)-3,3',4,4'-tetramine as a substrate and oxidize it, producing an easily observable brown color. Plaques can then be quantified for further evaluation.