The absorption, distribution, metabolism, and excretion of fasiglifam were investigated in rats, dogs, and humans. The absolute oral bioavailability of fasiglifam was high in all species (>76.0%). After oral administration of [C]fasiglifam, the administered radioactivity was quantitatively recovered and the major route of excretion of radioactivity was via feces in all species. Fasiglifam was a major component in the plasma and feces in all species. Its oxidative metabolite (M-I) was observed as a minor metabolite in rat and human plasma (<10% of plasma radioactivity). In human plasma, hydroxylated fasiglifam (T-1676427), the glucuronide of fasiglifam (fasiglifam-G), and the glucuronide of M-I were detected as additional minor metabolites (<2% of plasma radioactivity). None of these metabolites were specific to humans. Fasiglifam-G was the major component in the rat and dog bile. In vitro cytochrome P450 (CYP) and uridine diphosphate glucuronosyltransferase (UGT) reaction phenotyping indicated that oxidation (to form M-I and T-1676427) and glucuronidation of fasiglifam are mainly mediated by CYP3A4/5 and UGT1A3, respectively. Fasiglifam and fasiglifam-G are substrates of BCRP and Mrp2/MRP2, respectively. Glucuronidation of fasiglifam-G was found to be the predominant elimination pathway of fasiglifam in all species tested, including humans.

ABSTRACT:Animal pharmacokinetic studies of sipoglitazar, a novel antidiabetic agent, showed that the deethylated metabolite (M-I) and the glucuronide conjugate of sipoglitazar (sipoglitazar-G) appeared to be the key metabolites in the elimination process. M-I was also measured as the main metabolite in the plasma of humans administered sipoglitazar. In vitro metabolic studies were performed to investigate the metabolic pathways from sipoglitazar to M-I in humans. The metabolic profile with human hepatocytes and hepatic microsomes indicated that M-I was not formed directly from sipoglitazar and that sipoglitazar-G was involved in the metabolism from sipoglitazar to M-I. Further studies of the metabolism of sipoglitazar-G revealed that the properties of the glucuronide conjugate and its metabolism are as follows: high-performance liquid chromatography, liquid chromatography-tandem mass spectrometry, and NMR analyses showed that sipoglitazar-G was composed of two glucuronides, sipoglitazar-G1, a ␤-1-O-acyl glucuronide, and sipoglitazar-G2, an ␣-2-O-acyl glucuronide. The stability study of these glucuronides suggested that sipoglitazar-G1 could be converted to sipoglitazar-G2 and sipoglitazar, but sipoglitazar-G2 could not be converted to sipoglitazar-G1. The oxidative metabolic study of sipoglitazar-G1 and -G2 with human hepatic microsomes and cytochrome P450-expressing microsomes revealed that M-I was formed only from sipoglitazar-G1, not from sipoglitazar-G2, and that CYP2C8 was mainly involved in this process. From these results, it is shown that the metabolic pathway from sipoglitazar to M-I is an unusual one, in which sipoglitazar is initially metabolized to sipoglitazar-G1 by UDP-glucuronosyltransferase and then sipoglitazar-G1 is metabolized to M-I by O-dealkylation by CYP2C8 and deconjugation. Sipoglitazar-G2 is sequentially formed by the migration of the ␤-site of sipoglitazar-G1.

Sipoglitazar is a novel anti-diabetic agent with triple agonistic activities on the human peroxisome proliferator-activated receptors, hPPAR-γ, -α, and -δ. The bioavailability for sipoglitazar was 95.0% and 72.6% in rats and monkeys respectively and sipoglitazar is hardly subject to first pass metabolism in either species. Following oral administration of [¹⁴C]sipoglitazar to rats, sipoglitazar and its metabolites were distributed to the rat tissues with relatively high concentrations in the liver and also to the target tissue, the adipose tissue. The major component was sipoglitazar in the plasma of rats and monkeys. In rats, sipoglitazar was mainly excreted into the feces via biliary excretion as sipoglitazar-G, while the major component was M-I-G in the urine and M-I in the feces of monkeys. In hepatocytes, the metabolism was not extensively advanced in rats and the main metabolites were M-I and sipoglitazar-G in humans, similar to the metabolic profile in monkeys. There was no metabolite specific for humans in vitro. In conclusion, the formation of M-I, M-I-G and sipoglitazar-G is considered to be crucial and sipoglitazar is presumed to be cleared primarily by oxidation and glucuronidation in humans, when examined in vivo and in vitro.

We evaluated the long-term stability of hepatocytes stored in the vapor phase of liquid nitrogen for their viability, cytochrome P450 (CYP) 1A2 activity, CYP3A4/5 activity, uridine diphosphate-glucuronosyl transferase (UGT) activity, sulfotransferase (SULT) activity, and CYP3A4/5 induction during 14 years of preservation. No substantial degradation of viability, CYP1A2 activity, UGT activity, or CYP3A4/5 induction was observed. CYP3A4/5 activity showed a slight decrease after 7 years of storage, and SULT activity gradually decreased during storage, although substantial activities remained even after 14 years. These results indicate that cryopreserved human hepatocytes can be stored stably for more than a decade with little or no change in viability, activity of drug-metabolizing enzymes, or CYP3A4/5 induction, and can be widely applicable to qualitative research in drug metabolism.

TAK-063 is currently being developed to treat schizophrenia. In this study, we investigated the absorption, distribution, metabolism and excretion (ADME) properties of TAK-063 using several paradigms. Following oral administration of TAK-063 at 0.3 mg/kg, bioavailability of TAK-063 was 27.4% in rats and 49.5% in dogs with elimination half-lives of 3.1 hr in rats and 3.7 hr in dogs. TAK-063 is a highly permeable compound without P-glycoprotein (P-gp) or breast cancer resistance protein substrate liability and can be readily absorbed into systemic circulation via the intestine. TAK-063 can also cross the blood-brain barrier. TAK-063 was metabolized mainly by CYP2C8 and CYP3A4/5, while incubation with human liver microsomes produced the major human metabolite, M-I as well as several unknown minor metabolites. Metabolism of TAK-063 to M-I occurs through hydroxylation of the mono-substituted pyrazole moiety. In vitro, TAK-063 was observed to inhibit CYP2C8, CYP2C19 and Pgp with IC 50 values of 8.4, 12 and 7.13 lM, respectively. TAK-063 was primarily excreted in the faeces in rats and dogs with M-I as a predominant component. The pre-clinical data from these ADME studies demonstrate a favourable pharmacokinetic profile for TAK-063 with good brain distribution supporting the feasibility of targeting central nervous system regions involved in schizophrenia pathophysiology. TAK-063 has recently been investigated in a phase 2 clinical trial (NCT02477020).Phosphodiesterase 10A (PDE10A) acts as an important regulator of signal transduction by degrading the second messengers cyclic adenosine monophosphate and cyclic guanosine monophosphate [1,2]. PDE10A is preferentially expressed in the medium spiny neurons of the striatum, a region of critical importance for domains that are disrupted in patients with schizophrenia [3][4][5].Current treatments often do not adequately address the multifaceted clinical symptomatology of schizophrenia [6]. In addition, antipsychotics are associated with cardiometabolic disturbances and cardiovascular morbidity that worsen longterm outcomes [7]. Because of the shortcomings in current treatment options for schizophrenia, PDE10A inhibition by TAK-063 is being evaluated as a new therapeutic strategy.TAK-063 is a potent and highly selective PDE10A inhibitor [8,9]. Furthermore, TAK-063 has demonstrated pre-clinical efficacy in animal models of schizophrenia. TAK-063 produced dose-dependent antipsychotic-like effects in rodent models of induced psychosis [10]. In rodents, PDE10A inhibition by TAK-063 also improved cognitive functions impaired in schizophrenia [11]. TAK-063 exhibits a favourable safety profile in a rodent study [12]. To understand the mechanism of these efficacy and safety profiles of TAK-063, the absorption, distribution, metabolism and excretion (ADME) properties of TAK-063 were investigated.In general, ADME properties using radiolabelled materials in animals and human beings are required for inclusion in the New Drug Application for new molecular entities. This report he...