Bitopertin (Paliflutine; RG1678; RO4917838; RG-1678; RO-4917838) is a novel, potent and non-competitive glycine reuptake inhibitor that inhibits human GlyT1 with an IC50 of 25 nM. GlyT1 is a key membrane transporter required to supply developing red blood cells with sufficient glycine to support erythropoiesis. It is under development as an adjunct to antipsychotics for the treatment of persistent negative symptoms or suboptimally-controlled positive symptoms associated with schizophrenia. Bitopertin-mediated glycine reuptake inhibition may represent a novel treatment option for schizophrenia, with the potential to address negative symptoms.

Physicochemical Properties

Molecular Formula	C21H20F7N3O4S
Molecular Weight	543.4550
Exact Mass	543.106
CAS #	845614-11-1
Related CAS #	Bitopertin (R enantiomer);845614-12-2
PubChem CID	24946690
Appearance	White to off-white solid powder
LogP	5.018
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	13
Rotatable Bond Count	5
Heavy Atom Count	36
Complexity	872
Defined Atom Stereocenter Count	1
SMILES	C[C@@H](C(F)(F)F)OC1=C(C=C(C=C1)S(=O)(=O)C)C(=O)N2CCN(CC2)C3=C(C=C(C=N3)C(F)(F)F)F
InChi Key	YUUGYIUSCYNSQR-LBPRGKRZSA-N
InChi Code	InChI=1S/C21H20F7N3O4S/c1-12(20(23,24)25)35-17-4-3-14(36(2,33)34)10-15(17)19(32)31-7-5-30(6-8-31)18-16(22)9-13(11-29-18)21(26,27)28/h3-4,9-12H,5-8H2,1-2H3/t12-/m0/s1
Chemical Name	[4-[3-fluoro-5-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl]-[5-methylsulfonyl-2-[(2S)-1,1,1-trifluoropropan-2-yl]oxyphenyl]methanone
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	In the membrane of Chinese hamster ovary cells, bitopertin (RG1678) competitively blocks the [3H]ORG24598 binding site on human GlyT1b. Cells stably expressing hGlyT1b and mGlyT1b are efficiently inhibited from uptaking [3H]glycine by bitopertin, with IC50 values of 25±2 nM and 22±5 nM (n=6), respectively. Conversely, at doses as high as 30 μM, bitopertin exhibited no influence on hGlyT2-mediated glycine absorption. Bitopertin binds to the recombinant hGlyT1b transporter with a strong affinity. Bitopertin dispenses with [3H]ORG24598 binding under equilibrium conditions (one hour at room temperature) with a Ki of 8.1 nM. Bitopertin improved NMDA-dependent long-term potentiation in hippocampal CA1 pyramidal cells at 100 nM, but not at 300 nM [1]. Further investigation revealed that Bitopertin (RG1678) possesses exceptional selectivity for a panel of 86 targets, which includes soluble and transmembrane receptors, enzymes, ion channels, and monoamine transporters (IC50>30 μM) (Measurements for all targets are 10 μM) [2].
ln Vivo	Bitopertin (RG1678) elevates glycine levels in rat striatum and cerebrospinal fluid in a dose-dependent manner as determined by microdialysis. Furthermore, in mice stimulated with D-amphetamine or the NMDA receptor glycine site antagonist L-687,414, Bitopertin can reduce excessive movement. In rats receiving long-term phencyclidine treatment—an NMDA receptor open channel blocker—bitopertin also inhibits hyperresponsiveness to D-amphetamine stimulation. The extracellular levels of striatal glycine were unaffected by the vehicle and stayed unchanged during the experiment. Extracellular glycine levels, on the other hand, increased in a dose-dependent manner upon oral administration of Bitopertin (1–30 mg/kg). Glycine levels were 2.5 times greater after 30 mg/kg of biseptertin than they were before treatment. When comparing the CSF of rats given oral bitopertin (1–10 mg/kg) three hours after dosage to rats given a vehicle, a similar dose-dependent rise in glycine concentration was seen. Remarkably, the rise in glycine levels in the cerebrospinal fluid three hours following the administration of bitopertin was strikingly similar to the rise observed at the same time in microdialysis trials [1]. Bitopertin (RG1678) has been shown in in vivo pharmacokinetic tests conducted in rats and monkeys to exhibit low plasma clearance, a moderate distribution volume, and good oral bioavailability in both species (78% in rats and 56% in monkeys). Its terminal half-life (5.8 hours in rats and 6.4 hours in monkeys) is really good. In humans, 98%, and two preclinical species, 97%, plasma protein binding was observed. Rats (brain/plasma=0.7) have a higher rate of intrathecal penetration of betapertin than mice (brain/plasma=0.5) [2].
References	[1]. Glycine reuptake inhibitor RG1678: A pharmacologic characterization of an investigational agent for the treatment of schizophrenia. Neuropharmacology. 2012 Feb;62(2):1152-61. [2]. Selective GlyT1 Inhibitors: Discovery of [4-(3-Fluoro-5-trifluoromethylpyridin-2-yl)piperazin-1-yl][5-methanesulfonyl-2-((S)-2,2,2-trifluoro-1-methylethoxy)phenyl]methanone (RG1678), a Promising Novel Medicine To Treat Schizophrenia. J Me.
Additional Infomation	Bitopertin has been used in trials studying the treatment of Schizophrenia and Obsessive-Compulsive Disorder. Drug Indication Treatment of schizophrenia

Solubility Data

Solubility (In Vitro)

DMSO : ≥ 50 mg/mL (~92.00 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.60 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. 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. Solubility in Formulation 2: ≥ 2.5 mg/mL (4.60 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.8401 mL	9.2003 mL	18.4006 mL
	5 mM	0.3680 mL	1.8401 mL	3.6801 mL
	10 mM	0.1840 mL	0.9200 mL	1.8401 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.