HSG4112, a racemic drug, is a new anti-obesity agent. In this study, the stereoselective pharmacokinetics of HSG4112 were investigated in rats and dogs, and the underlying mechanism was investigated. The plasma concentrations of HSG4112(S) and HSG4112(R) were quantitated in plasma from rats and beagle dogs after IV and/or oral administration of racemic HSG4112. The concentration of HSG4112(S) was significantly higher than that of HSG4112(R) in rat plasma. Contrarily, the concentration of HSG4112(R) was significantly higher than HSG4112(S) in dog plasma. A metabolic stability test with liver microsomes showed that HSG4112(S) was more stable than HSG4112(R) in rat liver microsomes, but the difference between stereoisomers did not appear in dog liver microsomes. However, the stereoselectivity was observed in dog liver and intestinal microsomes after uridine 5’-diphospho-glucuronic acid was added. Thus, stereoselective metabolism by uridine 5’-diphospho-glucuronosyltransferases is mainly responsible for the stereoselective pharmacokinetics in dogs. These results suggest that the species difference in the stereoselective plasma pharmacokinetics of HSG4112 is due to the stereoselective metabolism.

Drug solubility limits intravenous dosing for poorly water-soluble medicines, which misrepresents their bioavailability estimation. The current study explored a method using a stable isotope tracer to assess the bioavailability of drugs that are poorly water-soluble. HGR4113 and its deuterated analog, HGR4113-d7, were tested as model drugs. To determine the level of HGR4113 and HGR4113-d7 in rat plasma, a bioanalytical method using LC-MS/MS was developed. The HGR4113-d7 was intravenously administered to rats that were orally pre-administered HGR4113 at different doses; subsequently, the plasma samples were collected. HGR4113 and HGR4113-d7 were simultaneously determined in the plasma samples, and bioavailability was calculated using plasma drug concentration values. The bioavailability of HGR4113 was 53.3% ± 19.5%, 56.9% ± 14.0%, and 67.8% ± 16.7% after oral dosages of 40, 80, and 160 mg/kg, respectively. By eliminating the differences in clearance between intravenous and oral dosages at different levels, acquired data showed that the current method reduced measurement errors in bioavailability when compared to the conventional approach. The present study suggests a prominent method for evaluating the bioavailability of drugs with poor aqueous solubility in preclinical studies.

Vutiglabridin, which affects the pharmacokinetics (PKs) of food, is currently under clinical development for the treatment of obesity. This study aimed to evaluate the effects of low‐ and high‐fat meals on PKs of vutiglabridin in healthy male subjects. A randomized, open‐label, single‐dose, three‐period, six‐sequence crossover study was conducted. The subjects received a single oral dose of vutiglabridin 480 mg in a fasted state, 30 min after the intake of a low‐fat meal (total 500–600 kcal, fat content 100–125 kcal) and high‐fat meal (total 800–1000 kcal, fat content 500–600 kcal), with a 21‐day washout period. Geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for maximum plasma concentration (C_max) and area under the plasma concentration‐time curve to the last measurable timepoint (AUC_last) were calculated. After intake of low‐ and high‐fat meals, systemic exposure to vutiglabridin was increased, and the time to reach C_max (T_max) was delayed compared to that in the fasted state. The GMRs (90% CIs) of low‐fat meal to fasted state for C_max and AUC_last were 2.14 (1.76–2.60) and 2.15 (1.92–2.42), respectively, and those of high‐fat meal to fasted state were 3.07 (2.53–3.72) and 3.00 (2.67–3.37), respectively. The median T_max was delayed by 1.5 h in both fed states compared with that in the fasted state. The study drug was well‐tolerated after administration in both the fed and fasted states. Food ingestion substantially increased the extent of oral vutiglabridin absorption in healthy subjects, and this enhancement increased with the fat content of the meal.

Current anti-obesity therapies that suppress appetite often cause undesirable reductions in lean mass by indirectly depleting systemic energy store. In this study, we developed a novel anti-obesity drug, Vutiglabridin (VUTI), designed to selectively reduce fat mass while preserving lean mass. We evaluated its efficacy in high-fat diet-induced obese (DIO) mice and investigated its underlying mechanism in in vitro adipocyte models. VUTI dose-dependently and selectively decreased fat mass, resulting in normalization of body weight within 3 weeks while preserving lean mass. Pharmacokinetic and mechanistic analyses revealed that VUTI targets white adipose tissue (WAT), where it enhances lipid degradation through AMPK-mediated lipophagy in both mouse and human adipocytes. The lipid degradation-enhancing effect of VUTI was shown to be dependent on paraoxonase 2 (PON2). Multi-omics analyses, including proteomic and transcriptomic profiling of epididymal WAT in DIO-mice, further confirmed this mechanism. Collectively, these findings demonstrate that VUTI represents a promising therapeutic strategy for obesity by inducing fat-selective reduction via AMPK-mediated lipophagy.

Although glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are highly effective for body weight reduction, there remains a critical unmet need for complementary strategies that drive selective fat loss and sustain long-term weight reduction. This study aimed to investigate whether Vutiglabridin, a novel oral small-molecule anti-obesity drug, complements GLP-1 RAs to enhance therapeutic efficacy by selectively reducing fat mass and achieving normal body composition. 6-week-old mice were fed a high-fat diet (60 kcal% fat) for 11 weeks to generate mice with diet-induced obesity (DIO) and then treated with GLP-1 RAs (Semaglutide, Liraglutide, or Exenatide) either alone or in combination with Vutiglabridin for 3-4 weeks. Body weight, food intake, fat mass, and lean mass were evaluated during treatment. For the drug discontinuation study, mice were administered Vutiglabridin, Semaglutide, or the combination for 4 weeks, after which treatment was withdrawn on Day 28 and body weight regain was monitored for 21 days. In DIO mice treated with Semaglutide, weight loss attenuated, and body weight was maintained at a constant level after 2 weeks. In contrast, co-administration of Vutiglabridin overcame this attenuation of efficacy, enabling continuous weight reduction and achieving normal body composition. Vutiglabridin also resolved the diminishing weight-loss effect when combined with comparatively less potent appetite-suppressing GLP-1 RAs, including liraglutide and exenatide. In addition to normalizing body composition, Vutiglabridin mitigated the body weight and fat-mass regain that occurs following Semaglutide discontinuation. These findings demonstrate that Vutiglabridin can normalize body composition in combination with multiple GLP-1 RAs, highlighting its potential as a novel therapeutic option for obesity treatment.