A sensitive LC/MS/MS bioanalysis assay of orally administered lipoic acid in rat blood and brain tissue.
A sensitive liquid chromatography tandem mass spectrometry (LC/MS/MS) bioanalytical method was developed and validated to analyze lipoic acid (LA) in rat blood and brain samples. Ten mobile phase combinations were investigated during method development. Mobile phase combination of 0.1% acetic acid (pH 4 adjusted with ammonia solution)/acetonitrile was most optimum in terms of sensitivity and peak shape of LA and the internal standard, valproic acid. Sample extraction method was explored using liquid-liquid extraction and protein precipitation methods. Protein precipitation yielded the highest recovery of the analytes from blood and brain ranging from 92 to 115%. The lower limit of quantitation (LLOQ) of LA was 0.1ng/mL (0.485nM) in both blood and brain while on-column lower limit of detection (LLOD) was 0.03pg. The precision (% R.S.D.) ranged from 1.49 to 26.39% and 1.49 to 10.89% for intra- and inter-day assays, respectively. The accuracy ranged from 91.2 to 116.17% for intra-day assay and 102.68 to 114.33% for inter-day assay.
Chng
Hui Ting
HT
Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
New
Lee Sun
LS
Neo
Aveline H
AH
Goh
Catherine W
CW
Browne
Edward R
ER
Chan
Eric C Y
EC
D000284:Administration, Oral; D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D002853:Chromatography, Liquid / Q000379:methods; D051381:Rats; D053719:Tandem Mass Spectrometry / Q000379:methods*; D008063:Thioctic Acid / Q000008:administration & dosage* / Q000032:analysis* / Q000737:chemistry; D014018:Tissue Distribution / Q000502:physiology
D008063:Thioctic Acid