Pleuromulin (pleuromulitin) is a natural antibiotic isolated from Basidiomycete Pleurotus. Pleuromulitin exhibits activity mainly against gram-positive bacteria including S. aureus, Klebasiella pneumoniae and Bacillus Subtilis. Pleuromulin is an organic compound which is not reported to be used in as a drug however its derivatives have been used in treatment of infections. The first pleuromulitin that was approved in 1979 for use in veterinary medicine was semi-synthetic derivative tiamulin. Semisynthetic pleuromutilin retapamulin (ALTABAX, GlaxoSmithKline) was the first approved for topical use in humans in 2007. Another derivative of pleuromulin, Lefamulin has been successfully tested in phase 1 clinical trial for systemic use in patients (Nabriva Therapeutics AG).

The natural tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP also known as Goralatide) is generated from the N-terminus of thymosin-β4 through enzymatic cleavage by prolyl oligopeptidase (POP). AcSDKP regulation of proliferation of different cells is implicated in hematopoiesis and angiogenesis. This tetrapeptide present in almost all cells was recently detected at elevated concentrations in neoplastic diseases. However, previously reported in vitro and in vivo studies indicate that AcSDKP does not contribute to the pathogenesis of cancers. AcSDKP was in the phase II clinical trial for development of a new non-radioactive test for measuring glomerular filtration rate in patient with Chronic Kidney Disease. In addition, using mice models was concluded ,that AcSDKP might be an oral antifibrotic peptide drug that would be relevant to combating fibroproliferative kidney diseases such as diabetic nephropathy.

Ronipamil was developed as a verapamil analogue with a longer duration of action. However, it has much less calcium antagonist action than verapamil. Ronipamil has been tested for its ability to reduce ischaemia-induced arrhythmias in conscious rats. Compared to similar compounds, ronipamil was less effective and produced no statistically significant antiarrhythmic effects in rats. It had limited haemodynamic effects and no marked actions on blood pressure and heart rate. In another study, ronipamil prolonged survival time after traumatic shock and was shown to possess anti-shock potential. No information on current development of this drug is available.

Benzmalecene, an inhibitor of cholesterol biosynthesis, was studied for patients with hypercholesterolemia. Unfortunately, treatment was associated with undesirable side effects that prevented further using this drug in clinical.

Atropine-N-oxide hydrochloride is an alkaloid of the belladonna plants. It is the major metabolite of atropine. It is a competitive nonselective antagonist at central and peripheral muscarinic acetylcholine receptors.

Climazolam is a benzodiazepine derivative, developed by Hoffman-LaRoche. It was used in veterinary for anesthetizing animals.

FEPROSIDNINE, also known as Sidnofen, is a psychostimulant and monoamine oxidase inhibitor developed in USSR.

Bromerguride is an ergot derivative with dopamine antagonistic activity. Bromerguride has been claimed to bind to 5-HT1A receptors and to have 5-HT agonist properties. The neuropharmacological effects caused by the drug in animals were characterized by a central depressant neuroleptic-like symptomatology; the neuroleptic activity of the Bromerguride being at least in the same order of magnitude as haloperidol.

Ertiprotafib was originally developed as an inhibitor of PTP1B. Multiple targets of ertiprotafib, in addition to PTP1B inhibition, have been suggested including dual PPARalpha/PPARgamma agonism and IKK-beta inhibition. It normalized the plasma glucose and insulin levels in diabetic animal models and progressed to a phase II clinical trial for the treatment of Type 2 diabetes mellitus. Ertiprotafib development has been discontinued.