Impurity profiling of l-aspartic acid and glycine using high-performance liquid chromatography coupled with charged aerosol and ultraviolet detection

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 183; p. 113149
• Main Authors: Pawellek, Ruben, Schilling, Klaus, Holzgrabe, Ulrike
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 10-05-2020
• Subjects: Aerosols - chemistry; Amino Acids - chemistry; Aspartic acid (Asp); Aspartic Acid - chemistry; Charged aerosol detector (CAD); Chromatography, High Pressure Liquid - methods; Chromatography, Reverse-Phase - methods; Drug Contamination; Glycine (Gly); Glycine - chemistry; High-performance liquid chromatography (HPLC); Impurity profiling; Sensitivity and Specificity; Temperature; Ultraviolet detector (UV); Ultraviolet Rays; R2; RSD; CAD; High-performance liquid chromatography (HPLC); Glycine (Gly); ICH; LOQ; Aspartic acid (Asp); S/N; Ultraviolet detector (UV); Impurity profiling; Charged aerosol detector (CAD); Ph. Eur; i.d; RP
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/j.jpba.2020.113149

•2 separate HPLC methods for the impurity analysis of l-aspartic acid and glycine.•Charged aerosol and UV detectors were coupled to extend the detection range.•The methods were validated according to ICH guideline Q2(R1).•Batch analysis of l-aspartic acid and glycine revealed high purity of the samples.
For the compendial related substances test of l-aspartic acid (Asp) and glycine (Gly), two separate reversed-phase ion-pair high-performance liquid chromatography methods coupled with charged aerosol and ultraviolet detection were developed. Separation of all putative impurities, in particular of the related carboxylic and amino acids, was achieved using volatile perfluorocarboxylic acids as ion-pairing reagents on a polar embedded C18 stationary phase. It was shown that an adjustment of the evaporation temperature of the charged aerosol detector (CAD) was an efficient strategy for meeting the required quantitation limits, when dealing with non-volatile analytes. It was also demonstrated that the usage of a two detector setup can be beneficial for extending the detection range and providing accurate quantitation of low level impurities (LOQs from 5 to 50 ng on column). Both methods were validated with accordance to ICH guideline Q2(R1) assessing specificity, linearity, accuracy, precision, and robustness. Several batches of Asp and Gly were tested for related substances using the developed methods. The purity of each sample was higher than 99.7 %. Coupled charged aerosol and UV detection proved to be a more simple, robust and selective alternative to established derivatization procedures such as the Amino-Acid-Analyser (AAA) for the impurity profiling of amino acids, and should thus be considered for implementation into pharmacopoeial monographs in the future.