title: Determination of rhynchophylline and hirsutine in rat plasma by UPLC-MS/MS after oral administration of Uncaria rhynchophylla extract.
abstract: An ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to concurrently determine rhynchophylline and hirsutine in rat plasma. The sample preparation of rat plasma was achieved by alkalization and liquid-liquid extraction. The mass transition of precursor ion → product ion pairs were monitored at m/z 385.2 → 160.0 for rhynchophylline, m/z 369.3 → 144.0 for hirsutine and m/z 414.0 → 220.0 for noscapine (internal standard). This method revealed linear relationships from 2.5 to 50 ng/mL (r(2)  > 0.997) for rhynchophylline and from 2.5 to 50 ng/mL (r(2)  > 0.998) for hirsutine. The limit of quantification values for rhynchophylline and hirsutine in rat plasma were both 2.5 ng/mL. Intra-day and inter-day precisions were within 10.6% and 12.5%, respectively, for rhynchophylline and hirsutine, and the accuracy (bias) was <10%. Liquid-liquid extraction of rat plasma samples resulted in insignificant matrix effect, and the extraction recoveries were >83.6% for rhynchophylline, 73.4% for hirsutine and 90.7% for the internal standard. This method was applied successfully to a pharmacokinetic study of rhynchophylline and hirsutine in rats after oral administration.
authors.affiliation: School of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yu-Tse
authors.initials: YT
authors.lastname: Wu
authors.forename: Lie-Chwen
authors.initials: LC
authors.lastname: Lin
authors.forename: Tung-Hu
authors.initials: TH
authors.lastname: Tsai
mesh_terms: D000284:Administration, Oral; D000470:Alkaloids / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D026121:Indole Alkaloids / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D016014:Linear Models; D008297:Male; D000078183:Oxindoles; D010936:Plant Extracts / Q000008:administration & dosage* / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D032070:Uncaria / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D026121:Indole Alkaloids; D000078183:Oxindoles; D010936:Plant Extracts; C052714:rhyncophylline; C038369:hirsutine
keywords: UPLC-MS/MS; hirsutine; pharmcokinetics; rhynchophylline