Hydrophilic interaction chromatography: A promising alternative to reversed‐phase liquid chromatography systems for the purification of small protonated bases

Abstract

The overloaded band profiles of the protonated species of propranolol and amitriptyline were recorded under acidic conditions on four classes of stationary phases including a conventional silica/organic hybrid material in reversed-phase liquid chromatography mode (BEH-C18), an electrostatic repulsion reversed-phase liquid chromatography C18 column (BEH-C18+), a poly(styrene-divinylbenzene) monolithic column, and a hydrophilic interaction chromatography stationary phase (underivatized BEH). The same amounts of protonated bases per unit volume of stationary phase were injected in each column (16, 47, and 141 μg/cm(3)). The performance of the propranolol/amitriptyline purification was assessed on the basis of the asymmetry of the recorded band profiles and on the selectivity factor achieved. The results show that the separation performed under reversed-phase liquid chromatography like conditions (with BEH-C18, BEH-C18+, and polymer monolith materials) provide the largest selectivity factors due to the difference in the hydrophobic character of the two compounds. However, they also provide the most distorted overloaded band profiles due to a too small loading capacity. Remarkably, symmetric band profiles were observed with the hydrophilic interaction chromatography column. The larger loading capacity of the hydrophilic interaction chromatography column is due to the accumulation of the protonated bases into the diffuse water layer formed at the surface of the polar adsorbent. This work encourages purifying ionizable compounds on hydrophilic interaction chromatography columns rather than on reversed-phase liquid chromatography columns.

Static vs. Dynamic Electrostatic Repulsion Reversed Phase Liquid Chromatography: Solutions for Pharmaceutical and Biopharmaceutical Basic Compounds

“…Finally, the chromatographic method was compared to the official methods described in the USP 39 and BP 2013 monographs, which were more selective. As a corollary, we noted that the dynamic ERRP approach begins to be efficiently applied even in the analytical control of peptides and related impurities as an alternative to the ERLIC [46,49]. However, the interest in this field mainly concerns purification, as reported in the following section.…”

“…The chromatographic strategies described up to now have been mainly applied to the separation of small basic charged molecules. However, peptides and proteins, given their structures (namely, molecules of various lengths made up of charged units based on As a corollary, we noted that the dynamic ERRP approach begins to be efficiently applied even in the analytical control of peptides and related impurities as an alternative to the ERLIC [46,49]. However, the interest in this field mainly concerns purification, as reported in the following section.…”

Overloading behavior of fenoprofen and naproxen as two model compounds on a non-porous silicon pillar array column

“…The adsorption isotherm at equilibrium between the amounts adsorbed in the stationary phase and the concentration in the mobile phase determines the direction of the band asymmetry, either as a fronting or tailing shape. The overload band profiles and related the adsorption isotherms in reverse phase liquid chromatography (RP-LC) conditions using packed [8,9] and monolithic [10,11] columns have been studied to understand of retention and overloading mechanisms.…”

Ultra‐high performance separation of basic compounds on reversed‐phase columns packed with fully/superficially porous silica and hybrid particles by using ultraviolet transparent hydrophobic cationic additives

“…This makes them ideal to be included in the routine method development and to be used in analytical platforms where the pH of mobile phase is frequently changed [28]. Gritti and Guichon have published many papers concerning the use of CSH supports and the theoretical investigation of their interaction mechanism [31–33]. In particular, in a paper dated 2014, the authors introduced the term electrostatic repulsion interactions RPLC to describe this new version of mixed‐mode mechanism [34–38].…”