Phase II trial of piroxantrone in metastatic breast cancer. A Southwest Oncology Group study

Indazole as a Privileged Scaffold: The Derivatives and their Therapeutic Applications

BACKGROUND

Heterocyclic compounds, also called heterocycles, are a major class of organic chemical compound that plays a vital role in the metabolism of all living cells. The heterocyclic compound, indazole, has attracted more attention in recent years and is widely present in numerous commercially available drugs. Indazole-containing derivatives, representing one of the most important heterocycles in drug molecules, are endowed with a broad range of biological properties.

METHODS

A literature search was conducted in PubMed, Google Scholar and Web of Science regarding articles related to indazole and its therapeutic application.

RESULTS

The mechanism and structure-activity relationship of indazole and its derivatives were described. Based on their versatile biological activities, the compounds were divided into six groups: anti-inflammatory, antibacterial, anti-HIV, antiarrhythmic, antifungal and antitumour. At least 43 indazole-based therapeutic agents were found to be used in clinical application or clinical trials.

CONCLUSION

This review is a guide for pharmacologists who are in search of valid preclinical/clinical drug compounds where the progress of approved marketed drugs containing indazole scaffold is examined from 1966 to the present day. Future direction involves more diverse bioactive moieties with indazole scaffold and greater insights into its mechanism.

Comparison of the chronic toxicity of piroxantrone, losoxantrone and doxorubicin in spontaneously hypertensive rats

Comparisons were made of the toxic effects produced in the heart, kidney and small intestine of spontaneously hypertensive rats (SHR) by the administration of 12 consecutive weekly doses of doxorubicin (1 mg/kg), and high, intermediate and low doses of piroxantrone (3, 1.5 and 0.75 mg/kg) and losoxantrone (1, 0.5 and 0.25 mg/kg). Animals receiving saline were used as controls. The toxicities of the three drugs were evaluated by clinical chemistry and hematological determinations, light microscopy and transmission electron microscopy. The severity of the histologic alterations in heart, kidney and small intestine was assessed semiquantitatively. Biochemical and molecular modeling studies were made to evaluate the formation of complexes of Fe(III) with piroxantrone and losoxantrone. The cardiac (myofibrillar loss and dilatation of the sarcoplasmic reticulum) and renal (glomerular vacuolization, tubular damage and laboratory evidence of a nephrotic syndrome) lesions induced by all three agents had similar features. However, the cardiac lesions induced by losoxantrone and doxorubicin were significantly more severe (Billingham scores) than those produced by piroxantrone. The renal lesions induced by piroxantrone and losoxantrone were less severe than those produced by doxorubicin. Similarly losoxantrone and piroxantrone-induced intestinal alterations (denudation of epithelial layer and inflammatory cellular infiltration) were less severe than those occurring after treatment with doxorubicin. Both losoxantrone and piroxantrone were shown to form Fe(III): drug complexes that may cause oxidative damage to various tissues.