(2'S)-Nicotine-1-oxide, a nicotine metabolite, arises from the liver's metabolism of nicotine via the cytochrome P450 (CYP) isoform CYP2A6. It has been identified in human sperm and semen.

γ-CEHC, a metabolite of γ-tocopherol, is predominantly excreted through urine, primarily in its conjugated form as glucuronide [1], rather than through bile.

4-epiMinocycline, recognized as a primary degradation product and a probable impurity in minocycline commercial formulations, is derived from minocycline, a broad-spectrum tetracycline antibiotic notable for its extended serum half-life. Besides treating acne, especially in older patients, minocylvania exhibits significant anti-inflammatory and neuroprotective effects.

m-Nifedipine, an impurity of Nifedipine, serves as a potent calcium channel blocker and the preferred treatment option for cardiac insufficiencies.

ω-Hydroxy-DEET, a significant metabolite of the insect repellent N-N-diethyl-meta-toluamide (DEET), exhibits anti-proliferative properties. DEET, renowned for being a spatial repellent and irritant, is frequently employed to deter mosquito contact.

cPrPMEDAP, an intermediate metabolite of GS-9219, acts as a prodrug for the guanine nucleotide analog PMEG, demonstrating antiproliferative activity. It is negatively charged at physiological pH, resulting in poor skin permeability.