Pharmacokinetics and metabolism of H3B-6545, a selective estrogen receptor covalent antagonist, in dog plasma by liquid chromatography combined with electrospray ionization tandem mass spectrometry

Optimization of small molecule degraders and antagonists for targeting estrogen receptor based on breast cancer: current status and future

The estrogen receptor (ER) is a classical receptor protein that plays a crucial role in mediating multiple signaling pathways in various target organs. It has been shown that ER-targeting therapies inhibit breast cancer cell proliferation, enhance neuronal protection, and promote osteoclast formation. Several drugs have been designed to specifically target ER in ER-positive (ER+) breast cancer, including selective estrogen receptor modulators (SERM) such as Tamoxifen. However, the emergence of drug resistance in ER+ breast cancer and the potential side effects on the endometrium which has high ER expression has posed significant challenges in clinical practice. Recently, novel ER-targeted drugs, namely, selective estrogen receptor degrader (SERD) and selective estrogen receptor covalent antagonist (SERCA) have shown promise in addressing these concerns. This paper provides a comprehensive review of the structural functions of ER and highlights recent advancements in SERD and SERCA-related small molecule drugs, especially focusing on their structural optimization strategies and future optimization directions. Additionally, the therapeutic potential and challenges of novel SERDs and SERCAs in breast cancer and other ER-related diseases have been discussed.

A review on synthetic strategy, molecular pharmacology of indazole derivatives, and their future perspective

With different nitrogen-containing heterocyclic moieties, Indazoles earn one of the places among the top investigated molecules in medicinal research. Indazole, an important fused aromatic heterocyclic system containing benzene and pyrazole ring with a chemical formula of C₇ H₆ N₂ , is also called benzopyrazole. Indazoles consist of three tautomeric forms in which 1H-tautomers (indazoles) and 2H-tautomers (isoindazoles) exist in all phases. The tautomerism in indazoles greatly influences synthesis, reactivity, physical and even the biological properties of indazoles. The thermodynamic internal energy calculation of these tautomers points view 1H-indazole as the predominant and stable form over 2H-indazole. The natural source of indazole is limited and exists in alkaloidal nature (i.e., nigellidine, nigeglanine, nigellicine, etc.) found from Nigella plants. Some of the FDA-approved drugs like Axitinib, Entrectinib, Niraparib, Benzydamine, and Granisetron are being used to treat renal cell cancer, non-small cell lung cancer (NSCLC), epithelial ovarian cancer, chronic inflammation, chemotherapy-induced nausea, vomiting, and many more uses. Besides all these advantages regarding its biological activity, the main issue about indazoles is the less abundance in plant sources, and their synthetic derivatives also often face problems with low yield. In this review article, we discuss its chemistry, tautomerism along with their effects, different schematics for the synthesis of indazole derivatives, and their different biological activities.

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.

Characterization of the metabolites of H3B-6545 in vitro and in vivo by using ultra-high performance liquid chromatography combined with electrospray ionization linear ion trap-orbitrap tandem mass spectrometry

H3B-6545 is a selective ERα covalent antagonist, which has been demonstrated to be effective in anti-tumor. To fully understand its mechanism of action, it is necessary to investigate the in vitro and in vivo metabolic profiles. For in vitro metabolism, H3B-6545 (50 μM) was incubated with the hepatocytes of rat and human for 2 h. For in vivo metabolism H3B-6545 was orally administered to rats at a single dose of 10 mg/kg, and plasma, urine and fecal samples were then collected. All samples were analyzed by using ultra-high performance liquid chromatography combined with linear ion trap-orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MS) operated in positive ion mode. The structures of the metabolites were elucidated by comparing their MS and MS² spectra with those of parent drug. A total of 11 metabolites, including a GSH adduct, were detected and structurally identified. M2, M7 and M8 were further unambiguously identified by using reference standards. Among these metabolites, M1, M5, M7 and M10 were newly found and reported for the first time. The metabolic pathways of H3B-6545 included deamination (M8 and M9), dealkylation (M2, M3 and M10), N-hydroxylation (M6), hydroxylation (M1 and M4), formation of amide derivatives (M5 and M7) and GSH conjugation (G1).