title: Identification of N-octylnortadalafil and its Stereoisomers in Dietary Supplements with Chiral Liquid Chromatography-Circular Dichroism.
abstract: A direct chiral liquid chromatography-circular dichroism (LC-CD) method was developed for the simple and rapid identification of N-octylnortadalafil [(6R, 12aR)-6-(1,3-benzodioxol-5-yl)-2-octyl-2,3,6,7,12,12a-hexahydropyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4-dione; RR-OTDF] and its stereoisomers in dietary supplements. Samples were extracted with methanol. Compounds were then separated by chiral LC-CD using Chiralcel OD-RH (4.6 × 150 mm, 5 µm) with 5 mM ammonium formate (pH 3)/0.1% formic acid in acetonitrile (95:5, v/v) mixture solution (mobile phase A) and 0.1% formic acid in acetonitrile (mobile phase B). The isocratic elution used was mobile phase A / mobile phase B (3:7, v/v) at a flow rate of 1 ml/min. The column temperature was held at 30°C. RR-OTDF and its stereoisomers were separated within 20 min with the resolution factors being over 2.0. Using this method, RR-OTDF and (6R, 12aS)-6-(1,3-benzodioxol-5-yl)-2-octyl-2,3,6,7,12,12a-hexahydropyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4-dione were detected in a dietary supplement.
authors.affiliation: Tokyo Metropolitan Institute of Public Health, Department of Pharmaceutical Sciences, Tokyo, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Sakamoto
authors.affiliation: Tokyo Metropolitan Institute of Public Health, Department of Pharmaceutical Sciences, Tokyo, Japan.
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Kishimoto
authors.affiliation: Tokyo Metropolitan Institute of Public Health, Department of Pharmaceutical Sciences, Tokyo, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Tokyo Metropolitan Institute of Public Health, Department of Pharmaceutical Sciences, Tokyo, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Suzuki
authors.affiliation: Tokyo Metropolitan Institute of Public Health, Department of Pharmaceutical Sciences, Tokyo, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Moriyasu
mesh_terms: D002243:Carbolines / Q000737:chemistry*; D002853:Chromatography, Liquid; D002942:Circular Dichroism; D019587:Dietary Supplements; D007202:Indicators and Reagents / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D002243:Carbolines; D007202:Indicators and Reagents; C539047:N-octylnortadalafil
keywords: PDE assay; chiral LC-CD; chiral column; diastereoisomers; enantiomers