Hydroxypioglitazone (M-IV) is an active metabolite of the peroxisome proliferator-activated receptor γ (PPARγ) agonist pioglitazone. Experiments in vitro have shown that hydroxypioglitazone was more efficient than the parent drug in stimulating lipid synthesis.

Codoxime is a synthetic derivative of an opiate dihydrocodeinone. It differs from dihydrocodeinone by the substitution of a carboxymethyl oxime for the ketonic oxygen at carbon 6 of the dihydrocodeinone molecule. Codoxime has been proposed as an antitussive with prolonged duration of action. In a clinical trial conducted on prisoner volunteers in 1966, it was found that codoxime has a capacity to produce physical dependence of the morphine type.

Elvucitabine (ACH-126443 or beta-L-Fd4C) is a reverse transcriptase inhibitor exerting antiviral properties. Elvucitabine, an L-cytosine nucleoside analog, is intracellularly phosphorylated to its active 5′-triphosphate metabolite, which has an intracellular half-life of at least 20 hours. Elvucitabine triphosphate inhibits the activity of HIV reverse transcriptase by competing with natural substrates and by causing DNA chain termination after incorporation into viral DNA. Elvucitabine has also demonstrated in vitro and in vivo activity against HBV. Achillion, under license from Vion is developing elvucitabine for the potential treatment of HIV and hepatitis B virus (HBV) infection.

Palifosfamide or ZIO-201 (isophosphoramide mustard; IPM), a bi-functional DNA alkylator, is the active metabolite of ifosfamide (IFOS). IFOS and the related drug cyclophosphamide (CPA) are widely used anti-cancer drugs. Both are pro-drugs and need to be metabolized to be active. Their clinical use is limited by the toxicity associated with some of their metabolites. Palifosfamide has shown efficacy in diverse cancer models. ZIOPHARM Oncology Inc, under license from Dekk-Tec Inc, was developing palifosfamide, a formulation of isophosphoramide mustard with tris(hydroxymethyl)aminomethane salt-stabilization (palifosfamide-tris) and previously with lysine-stabilization (palifosfamide-lys). Preclinical studies and phase I and I/II clinical trials demonstrated that palifosfamide-tris had an antitumor efficiency comparable or superior to that of ifosfamide. To date ZIO-201 is not present in ZIOPHARM pipeline.

Atilmotin (also known as BAX-ACC-1638), a motilin receptor agonist, is short acting, with t1/2 less than 10 min. It was shown that at doses of 6, 30 or 60 mg intravenously, it affected esophageal, lower esophageal sphincter (LES), and gastric motility. LES and gastric pressures were increased, whereas there was disruption of esophageal peristalsis characterized by lower amplitude and failed contractions. The drug can have the clinical implementation for stomach motility disorders but is needed further study.