A new series of 5-(pyridinon-1-yl)indazoles with MCH-1 antagonist activity were synthesized. Potential cardiovascular risk for these compounds was assessed based upon their interaction with the hERG potassium channel in a mini-patch clamp assay. Selected compounds were studied in a 5-day diet-induced obese mouse model to evaluate their potential use as weight loss agents. Structural modification of the 5-(pyridinon-1-yl)indazoles to give 5-(furopyridinon-5-yl)indazoles provided compounds with enhanced pharmacokinetic properties and improved efficacy.

A new series of 4-aryl-1-(indazol-5-yl)pyridin-2(1H)ones possessing MCH-1 receptor antagonism is presented. Suzuki coupling of boronic acids with key triflate 6 allowed rapid generation of a range of analogs. The SAR of the MCH-1 receptor was explored with a variety of aryl and heterocyclic moieties. Selected compounds were studied in a five-day diet induced obese mouse model to evaluate their potential use as weight loss agents.

A new series of tetrahydrocarbolines with potent MCH-1 antagonist activity were synthesized, using a conformationally constrained design approach towards optimizing pharmacokinetic properties. Two compounds from this series were progressed to a 5-day diet-induced obesity mouse screening model to evaluate their potential as weight loss agents. Both compounds produced a highly significant reduction in weight, which was attributed to their improved pharmacokinetic profile.

This study was designed to investigate whether brain unbound concentration (C(u,brain)) is a better predictor of dopamine D(2) receptor occupancy than total brain concentration, cerebrospinal fluid concentration (C(CSF)), or blood unbound concentration (C(u,blood)). The ex vivo D(2) receptor occupancy and concentration-time profiles in cerebrospinal fluid, blood, and brain of six marketed antipsychotic drugs were determined after oral administration in rats at a range of dose levels. The C(u,brain) was estimated from the product of total brain concentration and unbound fraction, which was determined using a brain homogenate method. In conclusion, the C(u,brain) of selected antipsychotic agents is a good predictor of D(2) receptor occupancy in rats. Furthermore, C(u,brain) seems to provide a better prediction of D(2) receptor occupancy than C(CSF) or C(u,blood) for those compounds whose mechanism of entry into brain tissue is influenced by factors other than simple passive diffusion.

Melanin-concentrating hormone (MCH) is a cyclic, 19 amino acid neuropeptide. In mammals, MCH is highly expressed in the zona incerta and lateral hypothalamus and regulates food intake and energy homeostasis through interaction with the MCH1 receptor (Collins, et al., 2003; Skofitsch et al., 1985). Antagonists of the MCH1 receptor have been shown to be a promising new approach for the treatment of obesity (Collins, et al., 2003; McBriar, 2006).