Novel inhibition of cis/trans retinoic acid interconversion in biological fluids - An accurate method for determination of trans and 13-cis retinoic acid in biological fluids

Chao Jih Wang, Li Heng Pao, Cheng Huei Hsiong, Chih Yuan Wu, Jacqueline Jia Kang Whang-Peng, Oliver Yoa Pu Hu

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All-trans retinoic acid (tRA, or tretinoin) can be metabolized through stereoisomerzation to 13-cis retinoic acid (13-cRA) in vivo. We have developed a simple, sensitive and accurate method for analyzing tRA and 13-cRA in plasma with the addition of N-ethylmaleimide (NEM) and Vitamin C (Vit. C) to prevent the interconversion of cis/trans retinoic acid. All-trans RA, 9-cRA, and 13-cRA were well separated from each other in plasma by using a C18 precolumn and a column with a gradient solvent system of mobile phases A and B at a flow rate of 1.0ml/min. In addition, thermal stability of tRA and cRA in plasma during the sample preparation under the temperature of 0 and 25°C were studied. Our results showed that (1) the interconversion ratios (%) (cRA/tRA and tRA/cRA) were decreased with the addition of NEM and Vit. C and the minimum concentrations of NEM and Vit. C to inhibit the interconversion were 50 and 150μM, respectively, (2) higher concentrations of NEM and Vit. C were required to prevent the interconversion at higher temperature, (3) the precision and accuracy of calibration curve with various concentration of tRA (1-1000ng/ml) and 13-cRA (5-800ng/ml) in plasma showed good linearity (r 2=0.9992 and 0.9994), and between-day errors expressed by coefficient of variation (CV, %) for tRA and 13-cRA which were both less than 5.6%, (4) the mean recovery of the analytes were 78-94% for tRA and 80-92% for 13-cRA at concentration range from 1 to 1000ng/ml and 5 to 800ng/ml, respectively, and (5) the limit of quantitation of tRA and 13-cRA were 1 and 5ng/ml, respectively. In addition, the HPLC method had been successfully applied to the tRA pharmacokinetic study in two hepatoma patients after receiving 45mg/m2 per day orally. Thus, our results suggest that the HPLC method for analyzing tRA and 13-cRA in plasma with the addition of NEM and Vit. C is a simple, sensitive and accurate method.

Original languageEnglish
Pages (from-to)283-291
Number of pages9
JournalJournal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
Issue number2
Publication statusPublished - Nov 5 2003
Externally publishedYes



  • Interconversion
  • Pharmacokinetics
  • Retinoic acid

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry
  • Cell Biology

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