Simultaneous enantioseparation and simulation studies of atenolol, metoprolol and propranolol on Chiralpak® IG column using supercritical fluid chromatography

Abstract

Enantioseparation of three β-blockers, i.e., atenolol, metoprolol and propranolol, was studied on amylose tris(3-chloro-5-methylphenylcarbamate) immobilized chiral stationary phase using supercritical fluid chromatography (SFC). The effect of organic modifiers (methanol, isopropanol and their mixture), column temperature and back pressure on chiral separation of β-blockers was evaluated. Optimum chromatographic separation with respect to resolution, retention, and analysis time was achieved using a mixture of CO 2 and 0.1% isopropyl amine in isopropanol: methanol (50:50, V/V ), in 75:25 ( V/V ) ratio. Under the optimized conditions, the resolution factors ( R s ) and separation factors (α) were greater than 3.0 and 1.5, respectively. Further, with increase in temperature (25–45 °C) and pressure (100–150 bars) there was corresponding decrease in retention factors ( k ), α and R s . However, a reverse trend (α and R s ) was observed for atenolol with increase in temperature. The thermodynamic data from van't Hoff plots revealed that the enantioseparation was enthalpy driven for metoprolol and propranolol while entropy driven for atenolol. To understand the mechanism of chiral recognition and the elution behavior of the enantiomers, molecular docking studies were performed. The binding energies obtained from simulation studies were in good agreement with the elution order found experimentally and also with the free energy values. The method was validated in the concentration range of 0.5–10 μg/mL for all the enantiomers. The limit of detection and limit of quantitation ranged from 0.126 to 0.137 μg/mL and 0.376–0.414 μg/mL, respectively. The method was used successfully to analyze these drugs in pharmaceutical preparations.

Recent Advances in Separation and Analysis of Chiral Compounds

“…Hayes et al built a microscale SFC-based purification platform via the alteration of fluid channel and introduction of gas–liquid separators for the discovery and analysis of pharmaceuticals on ChiralPak Column (Westchester). More drug racemates of β2-agonist of terbutaline, β-blockers, antidepressant drug of paroxetine hydrochloride, and borneol lipid (candidate drug for cerebrovascular disease) were also efficiently resolved by SFC. − The coupling of different chiral columns can provide great opportunity to increase the separation efficiency of SFC . A two-dimensional chiral SFC based on two different CSPs of amylose tri-(3,5-dimethylphenylcarbamate) and cellulose tris (4-methyl-benzoate) was applied to chiral separation of aliphatic acid derivatives …”

Update on chiral recognition mechanisms in separation science

“…Accordingly, molecular modeling techniques were also applied to illustrate the selector‐selectand interactions in this chromatographic technique. The SFC enantioseparations of the β‐blocker drugs atenolol, metoprolol, and propranolol were studied on amylose tris(3‐chloro‐5‐methylphenylcarbamate) as chiral CSP [84]. Molecular docking revealed higher negative binding energies for the ( R )‐enantiomers of the drugs compared to the ( S )‐enantiomers, which correlated with the enantiomer elution order.…”

Polysaccharide Chiral Stationary Phases for the Achiral and Chiral Separation of Cannabinoids

“…This diversification of selectors allowed for an expansion of selectivity that corresponded with a widening utilization in more application areas. β-blockers [33][34][35] and non-steroidal anti-inflammatory drugs (NSAIDs) [36][37][38] were two of the first classes of compounds to be screened for chiral recognition. Relevant examples included, but were not limited to, acebutolol and propranolol (β-blockers), ibuprofen and naproxen (NSAIDs).…”