PF-06282999 is an irreversible, mechanism-based inactivator of the enzyme myeloperoxidase (MPO). The inhibitory mechanism involves oxidation of its thiouracil sulfur atom by the MPO compound I intermediate, leading to covalent attachment to the heme moiety and enzyme inactivation. The partition ratio for MPO inactivation is approximately 7.0. [1]

PF-06282999 (Compound 8) is a strong and specific myeloperoxidase inhibitor. The IC50 value of 1.9 μM found in human whole blood testing is in good agreement with the expected EC50 value of 3.8 μM for the total concentration of PF-06282999 in plasma [2].

In humans and preclinical animals, PF-06282999 is moderately bound to plasma proteins. Mice, rats, dogs, monkeys, and humans had blood/plasma ratios of PF-06282999 of 1.1, 1.1, 0.91, 1.2, and 0.94, respectively, suggesting that PF-06282999 is dispersed equally in plasma and red blood cells [1]. More research was done on the in vivo pharmacokinetics of PF-06282999 in mice, rats, dogs, and monkeys. The results showed that it was medium with low CLp in the monkeys (10.3 mL/min/kg), and moderate with the rats (41.8 mL/min/kg). The four species' terminal plasma elimination half-lives (t1/2) varied from 0.75 to 3.3 hours. The urine of rats, dogs, and monkeys excretes about 26-32% of an intravenous dose of PF-06282999 unaltered. It has also been demonstrated to be well dispersed in these animals, with a steady-state volume of distribution (Vdss) in the range of 0.5 - mouse, rat, and 2.1 L/kg in dogs and monkeys. In mice, rats, dogs, and monkeys, oral administration of PF-06282999 results in rapid (Tmax=0.78-1.70 h) and well-absorbed drug with oral bioavailability values of 100%, 86%, 75%, and 76%, respectively [2].

For intravenous (i.v.) pharmacokinetic studies, PF-06282999 was administered at 1 mg/kg to various species: mice (tail vein, in 12% sulfobutylether-β-cyclodextrin ± 1% DMSO, 5 ml/kg), rats (carotid artery, in 12% sulfobutylether-β-cyclodextrin ± 1% DMSO, 2 ml/kg), dogs (saphenous vein, in 30% hydroxypropyl-β-cyclodextrin with 5% DMSO, 0.5 ml/kg), and monkeys (femoral vein, in 30% hydroxypropyl-β-cyclodextrin with 5% DMSO, 1 ml/kg). Serial blood samples were collected up to 24 hours post-dose. [1]
For oral (p.o.) pharmacokinetic and bioavailability studies, PF-06282999 was administered to mice (5 mg/kg in 0.5% methylcellulose, 5 ml/kg), rats (5 mg/kg in 0.5% methylcellulose, 2.5 ml/kg), dogs (3 mg/kg in 0.5% methylcellulose, 3 ml/kg), and monkeys (3 mg/kg in 5% hydroxypropyl methylcellulose in 20 mM Tris/0.5% hydroxypropyl methylcellulose acetate succinate, 5 ml/kg). Blood samples were collected serially up to 24 hours post-dose. Urine was also collected after i.v. administration in all species. [1]
In a human clinical study (first-in-human), PF-06282999 was administered as a single oral solution [formulation: 1% (w/v) methylcellulose, 0.5% (w/v) hydroxypropyl methylcellulose acetate succinate-HF, and 80 mM tromethamine with NaOH] to fasted healthy male subjects at doses of 20, 50, 125, and 200 mg in a crossover design. Blood samples were collected for up to 48 hours, and urine was collected from 0-24 hours post-dose. [1]

PF-06282999 showed moderate plasma protein binding in different species. The free fraction (fu) was: 0.451 in mice, 0.447 in rats, 0.460 in dogs, 0.536 in monkeys, and 0.376 in humans. The blood-to-plasma ratio ranged from 0.91 to 1.2 in different species. [1]
PF-06282999 had strong metabolic resistance. When incubated with liver microsomes or cryopreserved hepatocytes from rats, mice, dogs, monkeys, or humans, no significant depletion was observed even in prolonged relay tests (t1/2 > 2400 min) in human hepatocytes (t1/2 > 120 min in liver microsomes and t1/2 > 240 min in hepatocytes). Only trace amounts of the three oxidative metabolites (M1, M2, M3) were detected. [1]
PF-06282999 showed irreversible inhibition (IC50 > 100 µM) of major human cytochrome P450 isoenzymes (CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4/5) and no time-dependent/NADPH-dependent inhibition (IC50 > 100 µM). [1]
Medium in vitro permeability. At pH 7.4, the apparent apical to basal lateral permeability (Papp, AB) in Caco-2 cells was 2.7 x 10^-6 cm/s. PF-06282999 was identified as a substrate for the efflux transporter MDR1 (P-glycoprotein), with an efflux ratio of 3.8 in Caco-2 cells and 3.3 in MDCKII-MDR1 cells. [1] Very little distribution in the liver and gallbladder. In sandwich-cultured human hepatocytes, PF-06282999 exhibited low total uptake clearance and bile excretion index (approximately 11%). Rifamycin SV (a pan-transporter inhibitor) had minimal effect on its uptake. [1] In transfected HEK-293 cells, PF-06282999 was not a substrate for the major human renal uptake transporters hOAT1, hOAT3, or hOCT2. [1]
Preclinical pharmacokinetic parameters after intravenous administration (1 mg/kg): low plasma clearance (CLp) in mice (10.1 ml/min/kg), dogs (3.39 ml/min/kg), and monkeys (10.3 ml/min/kg), and moderate plasma clearance in rats (41.8 ml/min/kg). Steady-state volume of distribution (Vdss) ranged from 0.5 to 2.1 L/kg. Terminal half-life (t1/2) ranged from 0.75 to 3.3 hours. Oral bioavailability (F) was high at doses of 3–5 mg/kg: >100% (mice), 86% (rats), 75% (dogs), and 76% (monkeys). Following intravenous administration, renal excretion of the unchanged drug ranged from 19.5% (monkeys) to 44.2% (mice) of the administered dose. [1] Following a single oral dose (20–200 mg) in humans, PF-06282999 was rapidly absorbed (median time to peak concentration, Tmax, was 0.5–0.75 hours). The mean elimination half-life was approximately 4.3–4.4 hours. Apparent oral clearance (CL/F) was approximately 186–197 ml/min. Apparent volume of distribution (Vd/F) was approximately 69–74 L. Renal clearance was the primary route of elimination, with 66.7–75.5% of the dose excreted unchanged in the urine over 24 hours in each dose group. The observed free renal clearance (>300 ml/min) exceeded the glomerular filtration rate, suggesting the presence of active tubular secretion. [1]

[1]. Pharmacokinetics and Disposition of the Thiouracil Derivative PF-06282999, an Orally Bioavailable, Irreversible Inactivator of Myeloperoxidase Enzyme, Across Animals and Humans. Drug Metab Dispos. 2016 Feb;44(2):209-19.

[2]. Discovery of 2-(6-(5-Chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide (PF-06282999): A Highly Selective Mechanism-Based Myeloperoxidase Inhibitor for the Treatment of Cardiovascular Diseases. J Med Chem. 20.

PF-06282999 is being investigated in clinical trial NCT01626976 (a study evaluating the safety, tolerability and pharmacokinetics of PF-06282999 administered orally in healthy adult subjects). PF-06282999 (2-(6-(5-chloro-2-methoxyphenyl)-4-oxo-2-thio-3,4-dihydropyrimidin-1(2H)-yl)acetamide) is a low molecular weight (326 Da), hydrophilic, weakly acidic thiouracil derivative that is currently in clinical development and is expected to be a potential treatment for cardiovascular diseases due to its selective and irreversible inhibition of myeloperoxidase (MPO). It is metabolized very little, has a low risk of drug interactions through CYP inhibition, and is mainly excreted by the kidneys in the human body, which is consistent with its physicochemical properties. [1]

C13H12CLN3O3S

325.77

325.028

1435467-37-0

71571306

White to light yellow solid powder

1.5±0.1 g/cm3

1.694

1.31

2

4

4

21

497

0

ICYNYWFGIDGBRD-UHFFFAOYSA-N

InChI=1S/C13H12ClN3O3S/c1-20-10-3-2-7(14)4-8(10)9-5-12(19)16-13(21)17(9)6-11(15)18/h2-5H,6H2,1H3,(H2,15,18)(H,16,19,21)

2-[6-(5-chloro-2-methoxyphenyl)-4-oxo-2-sulfanylidenepyrimidin-1-yl]acetamide

PF-06282999; PF 06282999; PF06282999

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~306.97 mM)

Solubility in Formulation 1: 2.5 mg/mL (7.67 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 2.5 mg/mL (7.67 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: 2.5 mg/mL (7.67 mM) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)