Tetrahydrobiopterin

Tetrahydrobiopterin
INN: Sapropterin
Clinical data
Trade names	Kuvan, Biopten
Other names	Sapropterin hydrochloride (JAN JP), Sapropterin dihydrochloride (USAN US)
AHFS/Drugs.com	Monograph
MedlinePlus	a608020
License data	EU EMA: by INN; US DailyMed: Sapropterin; US FDA: Sapropterin;
Pregnancy; category	AU: B1;
Routes of; administration	By mouth
ATC code	A16AX07 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); CA: ℞-only; US: ℞-only; EU: Rx-only; In general: ℞ (Prescription only);
Pharmacokinetic data
Elimination half-life	4 hours (healthy adults); 6–7 hours (PKU patients)
Identifiers
	IUPAC name (6R)-2-Amino-6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydropteridin-4(1H)-one;
CAS Number	62989-33-7 ; as salt: 69056-38-8;
PubChem CID	135398654;
IUPHAR/BPS	5276;
DrugBank	DB00360 ; as salt: DBSALT001133;
ChemSpider	40270 ; as salt: 552166;
UNII	EGX657432I;
KEGG	D08505; as salt: D01798;
ChEBI	CHEBI:59560 ; as salt: CHEBI:32120;
ChEMBL	ChEMBL1201774 ; as salt: ChEMBL1201775;
PDB ligand	H4B (PDBe, RCSB PDB);
CompTox Dashboard (EPA)	DTXSID1041138 ;
ECHA InfoCard	100.164.121
Chemical and physical data
Formula	C9H15N5O3
Molar mass	241.251 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES CC(C(C1CNC2=C(N1)C(=O)N=C(N2)N)O)O;
	InChI InChI=1S/C9H15N5O3/c1-3(15)6(16)4-2-11-7-5(12-4)8(17)14-9(10)13-7/h3-4,6,12,15-16H,2H2,1H3,(H4,10,11,13,14,17)/t3-,4+,6-/m0/s1 ; Key:FNKQXYHWGSIFBK-RPDRRWSUSA-N ;
	(what is this?) (verify)

Tetrahydrobiopterin (BH₄, THB), also known as sapropterin (INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the metabolism of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the production of nitric oxide (NO) by the nitric oxide synthases. Chemically, its structure is that of a (dihydropteridine reductase) reduced pteridine derivative (quinonoid dihydrobiopterin).

Tetrahydrobiopterin is available as a tablet for oral administration in the form of sapropterin dihydrochloride (BH4*2HCL). It was approved for use in the United States as a tablet in December 2007 and as a powder in December 2013. It was approved for use in the European Union in December 2008, Canada in April 2010, and Japan in July 2008. It is sold under the brand names Kuvan and Biopten. The typical cost of treating a patient with Kuvan is US$100,000 per year. BioMarin holds the patent for Kuvan until at least 2024, but Par Pharmaceutical has a right to produce a generic version by 2020.