ABSTRACT:The absorption, metabolism, and excretion of (1-[[3-hydroxy-1-adamantyl) amino] acetyl]-2-cyano-(S)-pyrrolidine (vildagliptin), an orally active and highly selective dipeptidyl peptidase 4 inhibitor developed for the treatment of type 2 diabetes, were evaluated in four healthy male subjects after a single p.o. 100-mg dose of [ 14 C]vildagliptin. Serial blood and complete urine and feces were collected for 168 h postdose. Vildagliptin was rapidly absorbed, and peak plasma concentrations were attained at 1.1 h postdose. The fraction of drug absorbed was calculated to be at least 85.4%. Unchanged drug and a carboxylic acid metabolite (M20.7) were the major circulating components in plasma, accounting for 25.7% (vildagliptin) and 55% (M20.7) of total plasma radioactivity area under the curve. The terminal half-life of vildagliptin was 2.8 h. Complete recovery of the dose was achieved within 7 days, with 85.4% recovered in urine (22.6% unchanged drug) and the remainder in feces (4.54% unchanged drug). Vildagliptin was extensively metabolized via at least four pathways before excretion, with the major metabolite M20.7 resulting from cyano group hydrolysis, which is not mediated by cytochrome P450 (P450) enzymes. Minor metabolites resulted from amide bond hydrolysis (M15.3), glucuronidation (M20.2), or oxidation on the pyrrolidine moiety of vildagliptin (M20.9 and M21.6). The diverse metabolic pathways combined with a lack of significant P450 metabolism (1.6% of the dose) make vildagliptin less susceptible to potential pharmacokinetic interactions with comedications of P450 inhibitors/inducers. Furthermore, as vildagliptin is not a P450 inhibitor, it is unlikely that vildagliptin would affect the metabolic clearance of comedications metabolized by P450 enzymes.

The absorption, metabolism, and excretion of midostaurin, a potent class III tyrosine protein kinase inhibitor for acute myelogenous leukemia, were evaluated in healthy subjects. A microemulsion formulation was chosen to optimize absorption. After a 50-mg [C]midostaurin dose, oral absorption was high (>90%) and relatively rapid. In plasma, the major circulating components were midostaurin (22%), CGP52421 (32.7%), and CGP62221 (27.7%). Long plasma half-lives were observed for midostaurin (20.3 hours), CGP52421 (495 hours), and CGP62221 (33.4 hours). Through careful mass-balance study design, the recovery achieved was good (81.6%), despite the long radioactivity half-lives. Most of the radioactive dose was recovered in feces (77.6%) mainly as metabolites, because only 3.43% was unchanged, suggesting mainly hepatic metabolism. Renal elimination was minor (4%). Midostaurin metabolism pathways involved hydroxylation, -demethylation, amide hydrolysis, and-demethylation. High plasma CGP52421 and CGP62221 exposures in humans, along with relatively potent cell-based IC for FMS-like tyrosine kinase 3-internal tandem duplications inhibition, suggested that the antileukemic activity in AML patients may also be maintained by the metabolites. Very high plasma protein binding (>99%) required equilibrium gel filtration to identify differences between humans and animals. Because midostaurin, CGP52421, and CGP62221 are metabolized mainly by CYP3A4 and are inhibitors/inducers for CYP3A, potential drug-drug interactions with mainly CYP3A4 modulators/CYP3A substrates could be expected. Given its low aqueous solubility, high oral absorption and extensive metabolism (>90%), midostaurin is a Biopharmaceutics Classification System/Biopharmaceutics Drug Disposition Classification System (BDDCS) class II drug in human, consistent with rat BDDCS in vivo data showing high absorption (>90%) and extensive metabolism (>90%).

ABSTRACT:The pharmacokinetics, absorption, metabolism, and excretion of vildagliptin, a potent and orally active inhibitor of dipeptidyl peptidase 4, were evaluated in male rats and dogs. Vildagliptin was rapidly absorbed with peak plasma concentrations occurring between 0.5 and 1.5 h. Moderate to high bioavailability was observed in both species (45-100%). The distribution and elimination halflives of vildagliptin were short: 0.57 h [82% of area under the plasma drug concentration-time curve (AUC)] and 8.8 h in the rat and 0.05 and 0.89 h (87% of AUC) in the dog, respectively. The volume of distribution was 1.6 and 8.6 l/kg in dogs and rats, respectively, indicating moderate to high tissue distribution. The plasma clearance of vildagliptin was relatively high for the rat (2.9 l/h/kg) and dog (1.3 l/h/kg) compared with their hepatic blood flow.The major circulating components in plasma after an intravenous or oral dose were the parent compound (rat and dog), a carboxylic acid metabolite from the hydrolysis of the amide bond M15.3 (dog), and a carboxylic acid metabolite from the hydrolysis of the cyano moiety M20.7 (rat and dog). After intravenous dosing, urinary excretion of radioactivity (47.6-72.4%) was the major route of elimination for rats and dogs as 18.9 to 21.3% of the dose was excreted into urine as unchanged parent drug. The recovery was good in both species (81-100% of the dose). Vildagliptin was mainly metabolized before excretion in both species. Similar to plasma, the most predominant metabolite in excreta was M20.7 in rats and dogs, and another major metabolite in dogs was M15.3.The administration of dipeptidyl peptidase IV (DPP-4) inhibitors to diabetics has been proven to augment endogenous glucagon-like peptide-1 (GLP-1) activity, which in turn produces a clinically significant lowering of diabetic glycemia comparable with that observed when GLP-1 is administered by direct infusion (Gutniak et al., 1992(Gutniak et al., , 1997Deacon et al., 1995;Mentlein, 1999;Drucker, 2003;Mest and Mentlein, 2005). Vildagliptin (Galvus, LAF237, 1-[[3-hydroxy-1-adamantyl)amino]acetyl]-2-cyano-(S)-pyrrolidine) is a potent, orally active inhibitor of DPP-4, which has been shown to ameliorate hyperglycemia in diabetic patients by preventing the cleavage and inactivation of GLP-1. Vildagliptin is now commercially available in the European market (Villhauer et al., 2003;He et al., 2007).The IC 50 of vildagliptin against the DPP-4 enzyme is 2 nM, based on the in vitro recombinant DPP-4 assay, indicating high potency. In humans, the effect of vildagliptin on DPP-4 inhibition is reflected in an IC 50 of 4.5 nM, a value that suggests higher potency than that reported for another DPP-4 inhibitor, sitagliptin (IC 50 of 26 nM) (Herman et al., 2005;He et al., 2007). To aid in the selection of appropriate species for preclinical testing, the disposition of vildagliptin was evaluated in the rat and dog and compared with that in the human. Results from in vivo absorption, metabolism, and excretion studies in rat and dogs as wel...

Supplemental informationSynthesis of M27.5: In a 400 mL polyethylene cup the reaction buffer [30 mL, 50 mM uridine 5'-diphosphoglucuronic acid trisodium salt, 25 mM magnesium cloride, 250 mM 2-(4-(2-Hydroxyethyl)-1-piperazinyl)-ethansulfonic acid, aq. pH 7.5] was mixed with bovine liver S9 preparation (15 mL; the liver S9 fractions were prepared as described in Kittellmann M. et al 2003). Substrate solution (4 mL, 55 mM asciminib in DMSO) was added. The reaction was incubated on an orbital shaker at 37°C and 230 rpm for 16 hours. The reaction was mixed with two volume equivalents of acetonitrile:methanol mixture (50:50) and stirred at room temperature for 15 minutes. The broth was centrifuged at 8600 g for 40 min and the supernatant was filtered through a paper filter. The filtrate was mixed with 900 mL of aqueous trifluoroacetic acid 0.05 % and pumped directly on the RP18 chromatography column. The conditions for preparative HPLC were: 250 x 21 mm Nucloeodur 100-10 C18 ec column (Macherey-Nagel, Düren, Germany); solvent A: aqueous trifluoroacetic acid 0.05 %; solvent B: acetonitrile; gradient: 0 -5 min 10 % B, 40 min 95 % B, flow rate of 40 mL/min; room temperature; detection at 220 nm; fraction size 40 mL. The product containing fractions were again combined, concentrated to about 50 mL and dried by lyophilization overnight. M27.5, 65 mg (40%), was obtained with > 97 % purity (HPLC/full DAD) as a trifluoroacetic acid salt and analyzed by NMR spectroscopy.