Determination of rosmarinic acid and its N-substituted analog A1 in rat plasma by high-performance liquid chromatography-tandem mass spectrometry and its application in pharmacokinetics

The researcher will introduce the way of effective liquid chromatography tandem mass spectrometric method (HPLC-MS) which is quick, sensitive, and alternative to determine the (E)-3-(3,4-dihydroxyphenyl) -2-(3-(3,4-dihydroxyphenyl)acrylamido)propanoic acid (A1) and rosmarinic acid (RA) of the plasma in rats. The analyses were divided into a C18 column (1.9 μm, 2.1 mm × 100 mm) with a security guard C18 column (5 μm, 2.1 mm × 10 mm) and a triple-quadrupole mass spectrometry with an electrospray ionization (ESI) ion-source generates ions. With Pseudoephedrine hydrochloride being a standard, the sample pretreatment is relevant to the one-step protein precipitation with isopropanol: ethyl acetate (v/v, 20:80). This method presented a linear relationship within ranges of the concentration of 5–750 ng/ml for RA and A1. Relative standard deviations (RSD) in daily courses stood less than 15% and the relative errors (RE) registered within 15%. The means adopted in this research makes the RA’s and A1’s unambiguous quantification and identification and in vivo possible. And this study can be the first one to focus on determining the A1 and RA of rat plasma with administration orally. The results served as a significant basis to evaluate the medicine’s applications in the clinic.