Enantioselective analysis of primaquine and its impurity quinocide by capillary electrophoresis

Abstract

A capillary electrophoretic (CE) method for the baseline separation of the enantiomers of primaquine diphosphate (PQ) and quinocide (QC) (a major contaminant) in pharmaceutical formulations is proposed. Both components were separated under the following conditions: 50 mm tris phosphate buffer (pH 3.0) containing 15 mm hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as background electrolyte; applied voltage, 16 kV; capillary temperature, 25 degrees C; detection wavelength, 254 nm; hydrostatic injection, 10 s. The separations were conducted using a 35 cm length and 50 microm i.d. uncoated fused silica capillary column. Under the optimized conditions, the components were successfully separated in about 5 min. Intraday precision of migration time and corrected peak areas when expressed as relative standard deviation ranged from 0.17 to 0.45 and 2.60 to 3.94%, respectively, while the interday precision ranged from 2.59 to 4.20 and 3.15 to 4.21%, respectively. After the validation exercise, the proposed method was applied for the determination of QC impurity in PQ formulations.

Analytical Methods in the Quality Control of Scientific Publications Part V: The Fraud of Pseudoscientists Based on False Measurements and Method Development

“…The presence of quinocide in primaquine was well known to Elbashir et al [27]. Despite this, Elbashir et al [28] published "Spectrophotometric Method for Determination of Primaquine in Pharmaceutical Formulations via Derivatization with 1, 2-Naphthoquinone-4-Sulfonate" by Aida Makram Nouralla Altigani, Abdalla Ahmed Elbashir in Austin Journal of Analytical and Pharmaceutical Chemistry.…”

“…This publication is a shameful fraud, but it is not the first fraud published by Elbashir et al His series of shameful fraudulent publications were criticized in [29]. In connection with publication [27], the corrupt nature of acceptance for publication of this paper was discussed in [29]. The Editor in Chief of Current Chromatography, Pavel N. Nesterenko, was contacted (Figure 1) to give his evaluation of the disclosure presented in [29].…”

“…Chromatographic or capillary electrophoretic methods must be used [3] [7] [8] [17]- [26]. In publication [28], the authors were well aware of the presence of isomers in their analytical procedure, because they previously published papers [2] [27]. Publication [28] should be considered as a direct service to the pharmaceutical industry to conceal the fact of the presence of contaminants.…”

“…All this information was presented over a significant period of time at international meetings, and in technical and scientific international journals and could not be missed by any serious scientist. In Biomedical Chromatography, Elbashir et al published a paper [27] "Determination of Quinocide as Impurity in Primaquine Tablets by Capillary Zone Electrophoresis"; they also mentioned some of the previous publications that described quinocide analyses in primaquine. All this pointed to the good knowledge about the presence of quinocide in primaquine by Elbashir et al Primaquine and quinocide are isomers.…”

High-Performance Liquid-Chromatographic Separation of Ofloxacin Using a Chiral Stationary Phase

“…[2][3][4] A few capillary electrokinetic chromatographic methods were published for the enantiomeric separation of ofloxacin using neutral or charged cyclodextrines (CDs) as chiral selectors. [5][6][7] Nevertheless, a few methods have been reported using a chiral column to separate the ofloxacin enantiomers. In particular, the use of enantioselective stationary phases (CSPs) enables a direct separation of the enantiomers without any preliminary derivation with chiral reagents.…”