High sensitivity determination of the remoxipride hydroquinone metabolite NCQ-344 in plasma by coupled column reversed-phase liquid chromatography and electrochemical detection
✍ Scribed by Lars B Nilsson
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 66 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0269-3879
No coin nor oath required. For personal study only.
✦ Synopsis
An HPLC method for the determination of NCQ-344, a remoxipride metabolite with a hydroquinone structure, in human plasma is described. Special precautions for the sampling were necessary as the compound rapidly decomposes. An efficient clean-up of the plasma samples was necessary to make use of the inherent sensitivity of the electrochemical detector. This was accomplished by a fast and simple liquid-liquid extraction at pH 7.05 combined with further cleaning on-line by using a short cyanopropyl column as the first column in a column switching system. A heart-cut from the cyanopropyl column containing the NCQ-344 fraction was then injected onto the analytical octadecyl silica column and NCQ-344 was detected at an oxidation potential of 0.70 V. The absolute recovery was > 95% and concentrations down to 0.10 nM could be determined with acceptable precision. The NCQ-344 levels in a limited number of samples from patients given remoxipride were found to be between 0.10 and 1 nM. The remoxipride concentrations in the same samples were 5 000-20,000 nM.