Title: Darifenacin
CAS Registry Number: 133099-04-4
CAS Name: (3S)-1-[2-(2,3-Dihydro-5-benzofuranyl)ethyl]-a,a-diphenyl-3-pyrrolidineacetamide
Additional Names: 3-(S)-(-)-(1-carbamoyl-1,1-diphenylmethyl)-1-[2-(2,3-dihydrobenzofuran-5-yl)ethyl]pyrrolidine; (S)-2-[1-[2-(2,3,-dihydrobenzfuran-5-yl)ethyl]-3-pyrrolidinyl]-2,2-diphenylacetamide
Manufacturers' Codes: UK-88525
Molecular Formula: C28H30N2O2
Molecular Weight: 426.55
Percent Composition: C 78.84%, H 7.09%, N 6.57%, O 7.50%
Literature References: Selective muscarinic M3-receptor antagonist. Prepn: P. E. Cross, A. R. MacKenzie, EP 388054; eidem, US 5096890 (1990, 1992 both to Pfizer). HPLC/MS determn in plasma: B. Kaye et al., Anal. Chem. 68, 1658 (1996). Binding profile for receptor subtypes: C. M. Smith, R. W. Wallis, J. Recept. Signal Transduction Res. 17, 177 (1997); and pharmacology: R. M. Wallis, C. M. Napier, Life Sci. 64, 395 (1999). Pharmacokinetics and metabolism: K. C. Beaumont et al., Xenobiotica 28, 63 (1998). Clinical trial in overactive bladder: F. Haab et al., Eur. Urol. 45, 420 (2004). Review of clinical experience: C. R. Chapple, Expert Opin. Invest. Drugs 13, 1493-1500 (2004).
Properties: Foam or colorless glass. [a]25D -20.6° (c = 1.0 in methylene chloride). pKa (25°): 9.2.
pKa: pKa (25°): 9.2
Optical Rotation: [a]25D -20.6° (c = 1.0 in methylene chloride)
Derivative Type: Hydrobromide
CAS Registry Number: 133099-07-7
Trademarks: Emselex (Novartis); Enablex (Novartis)
Molecular Formula: C28H31N2O2Br
Molecular Weight: 507.46
Percent Composition: C 66.27%, H 6.16%, N 5.52%, O 6.31%, Br 15.75%
Properties: mp 229°. [a]25D -30.3° (c = 1.0 in methylene chloride). Soly at 37° (mg/ml): water 6.03.
Melting point: mp 229°
Optical Rotation: [a]25D -30.3° (c = 1.0 in methylene chloride)
Therap-Cat: Antispasmodic; in treatment of urinary incontinence.
Keywords: Antispasmodic; Antimuscarinic.
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Systematic (IUPAC) name
(S)-2-[1-[2-(2,3-dihydrobenzofuran-5-yl)ethyl] pyrrolidin-3-yl] -2,2-diphenyl-acetamide
Clinical data
Trade names Enablex
AHFS/Drugs.com monograph
MedlinePlus a605039
Pregnancy cat. B3 (AU) C (US)
Legal status POM (UK) -only (US)
Routes Oral
Pharmacokinetic data
Bioavailability 15 to 19% (dose-dependent)
Protein binding 98%
Metabolism Hepatic (CYP2D6- and CYP3A4-mediated)
Half-life 13 to 19 hours
Excretion Renal (60%) and biliary (40%)
CAS number 133099-04-4 YesY
ATC code G04BD10
PubChem CID 444031
DrugBank DB00496
ChemSpider 392054 YesY
KEGG D01699 N
ChEBI CHEBI:391960 YesY
Chemical data
Formula C28H30N2O2 
Mol. mass 426.55 g/mol
 N (what is this?)  (verify)

Darifenacin (trade name Enablex in US and Canada, Emselex in Europe) is a medication used to treat urinary incontinence. It was discovered by scientists at the Pfizer research site in Sandwich, UK under the identifier UK-88,525 and previously was marketed by Novartis; however in 2010 US rights for were sold to Warner Chilcott for 400 million US$.