Sudexanox is a xanthone derivative patented by French pharmaceutical company Roussel-UCLAF for the treatment of allergy, allergic asthma, and asthmatic bronchitis. In preclinical studies, Sudexanox possesses potent activity in the IgE-induced rat passive cutaneous anaphylaxis model.

Ruboxistaurin is an orally bioavailable, selective, potent inhibitor of protein kinase C β developed for treating diabetic retinopathy. In vitro and in vivo non-clinical models have demonstrated that Ruboxistaurin decreases PKC β activity and ameliorates many of the effects of PKC β on pathologic processes in the retina. Ruboxistaurin prevents the slowing of retinal blood flow that is observed by fluorescein video angiography in the eyes of diabetic rats. It is also reported to cause regression of retinal neovascularization produced by laser-induced major branch vein occlusions in a porcine model. Ruboxistaurin positively affected the diabetes-induced retinal blood flow abnormalities in a Phase Ib study in diabetic patients. Ruboxistaurin is in phase III clinical trials for the treatment of diabetic nephropathy and diabetic macular edema. Eli Lilly had submitted Ruboxistaurin for approval in the US and the EU; however, the company subsequently discontinued development as it was unable to demonstrate sufficient efficacy

Amikhellin (AK), an antimitotic drug, is a synthetic water-soluble derivative of khellin, an alkaloid extracted from seeds of Ammi Visnaga. Amikhellin has been used so far mostly as a vasodiator. Amikhellin binds to double-stranded DNA by an intercalation process. It inhibits the DNA-polymerase from murine sarcoma leukemia virus.

Rose Bengal lactone is a polyhalogenated derivative of Fluorescein. Rose Bengal lactone is a dye compound described to produce cell membrane damage. Rose Bengal lactone and other Fluorescein derivatives are also described to modulate the function of ATP-sensitive K+ channels. Rose bengal lactone reacts readily with bases so treatment with triethylamine immediately yields the Rose Bengal salt.

Clopipazan (SKF-69634) is an antipsychotic drug related to thioxanthenes. Quantitative pharmaco-EEG analyses showed systematic effects on human brain function with doses as low as 10 mg. In the early phase 2 clinical studies on chronic schizophrenic patients, however, the drug appeared to have a slow onset of action and weak neuroleptic potency.

Hycanthone is a thioxanthene derivative of lucanthone with anti-schistosomal activity and potential antineoplastic activity. It was clinically available for the treatment of human schistosomiasis. Anti-helmintic action relies on its ability to inhibit worm monoamine oxidase and cholinesterases. Hycanthone produced immediate side effects such as hepatotoxicity and gastrointestinal disturbances, and was consequently withdrawn. Hycanthone inhibits apurinic endonuclease-1 (APE1) by direct protein binding. Hycanthone was used in the 1980s as antitumor agents, it was pulled out of Phase II trials.

FENPRINAST is a cromotyn-like bronchodilator used for the treatment of allergy and exercise-induced asthma.

FENPRINAST is a cromotyn-like bronchodilator used for the treatment of allergy and exercise-induced asthma.

Piquindone is an antipsychotic pyrroloisoquinoline derivative that binds to dopamine D2 receptors. It is a potent D-2 antagonist. It has a low potential for extrapyramidal effects and tardive dyskinesia. Piquindone exhibited relatively weaker cataleptogenic and antistereotypic activity than haloperidol, and had minimal activity in a rat chronic stereotypy model of receptor supersensitivity. Piquindone almost as potent as haloperidol, with fewer or less intense extrapyramidal effects and low potential for tardive dyskinesia. Piquindone led to moderate but significant improvements in the positive symptoms of schizophrenia and to improvements in negative symptoms just below the level of statistical significance. Therapeutic efficacy of a piquindone antagonist in Tourette Syndrome can be achieved without production of disabling extrapyramidal-side effects.