Identification of N-octylnortadalafil and its Stereoisomers in Dietary Supplements with Chiral Liquid Chromatography-Circular Dichroism

• Published in: Chirality (New York, N.Y.) N.Y.), 2016-03, Vol.28 (3), p.204-208
• Main Authors: Sakamoto, Miho, Kishimoto, Kiyoko, Saito, Yuri, Suzuki, Ikuo, Moriyasu, Takako
• Format: Article
• Language: English
• Subjects: Acetonitrile; Carbolines - chemistry; chiral column; chiral LC-CD; Chirality; Chromatography; Chromatography, Liquid; Circular Dichroism; diastereoisomers; Dichroism; Dietary Supplements; enantiomers; Flow rate; Formic acid; Indicators and Reagents - chemistry; Liquids; Methyl alcohol; PDE assay; Stereoisomerism
• ISSN: 0899-0042; 1520-636X
• DOI: 10.1002/chir.22570

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. Chirality 28:204–208, 2016. © 2016 Wiley Periodicals, Inc.