Enantioseparation and determination of orphenadrine in rat plasma and its application to a stereoselective pharmacokinetic study

Abstract

A simple, sensitive, and enantioselective HPLC-MS/MS method has been developed for the determination of orphenadrine (ORP) enantiomers in rat plasma for the first time. The method used diphenhydramine as...

Solid–Liquid–Liquid Equilibria of the System Water, Acetonitrile, and Ammonium Bicarbonate in Multiphase Reacting Systems

“…Because acetonitrile itself acts as an extractor for many organic molecules from water, the addition of inorganic salts is a widespread tool in many protocols: − the analytes are brought in the light phase, whereas the ionic species remains with the water and does not interfere in the downstream steps. Although the general procedure is consolidated, newer particular systems are continuously devised and tested. , In this context, phase-splitting substances that can also affect the pH are of interest where proteins or other pH-sensitive molecules are involved. ,− For this reason, adding ammonium bicarbonate to acetonitrile–water eluents is foreseen in several HPLC and extraction procedures, even when a phase separation is not foreseen, because other salts could adjust the ionic strength without granting a buffering effect. − Selected reactions can be carried out in the homogeneous phase, achieving phase separation when needed through salting out. In this way, the reactor is dealt as a solid–liquid–liquid multiphase one, needing the computing of phase equilibria to model its output.…”