Determination of Amino Acid Composition of Ganirelix Acetate in an Injectable Formulation by Pre-column Derivatization with 6-Aminoquinolyl-N-hydroxysuccinimidyl Carbamate

Ganirelix is a synthetic decapeptide linked with nine different amino acids. To understand the peptide amino acid sequence or primary structure, the first step is to determine the amino acid composition of the peptide which can be a determining factor for the peptide immunogenicity. Edman degradation is not a suitable analytical technique to identify amino acid sequence present in Ganirelix due to the absence of uncharged N-terminal amino group. To address this challenge, a pre-column derivatization method was developed with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent. In the present work, the Ganirelix active pharmaceutical ingredient present in the injectable formulation was isolated by fraction collection and further purified by flash chromatography. The amino acid composition of Ganirelix is assayed by carrying out acid hydrolysis with 6 mol L−1 hydrochloric acid solution containing 1% phenol at 100°C for 24 h and derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent solution, followed by determination of individual amino acids by reverse-phase chromatography using a C18 column. High resolution was achieved for the nine amino acid mixture. The amino acid composition results of temperature-stressed Ganirelix generic product and reference listed drug are in good agreement with the theoretical molar ratio of label information.

Retention mechanism of high-performance liquid chromatographic enantioseparation on macrocyclic glycopeptide-based chiral stationary phases

The development of methods for the separation of enantiomers has attracted great interest in the past 20 years, since it became evident that the potential biological or pharmacological applications are mostly restricted to one of the enantiomers. In the past decade, macrocyclic antibiotics have proved to be an exceptionally useful class of chiral selectors for the separation of enantiomers of biological and pharmacological importance by means of high-performance liquid chromatography (HPLC), thin-layer chromatography and electrophoresis. The glycopeptides avoparcin, teicoplanin, ristocetin A and vancomycin have been extensively used as chiral selectors in the form of chiral bonded phases in HPLC, and HPLC stationary phases based on these glycopeptides have been commercialized. In fact, the macrocyclic glycopeptides are to some extent complementary to one another: where partial enantioresolution is obtained with one glycopeptide, there is a high probability that baseline or better separation can be obtained with another. This review sets out to characterize the physicochemical properties of these macrocyclic glycopeptide antibiotics and, through their application, endeavors to demonstrate the mechanism of separation on macrocyclic glycopeptides. The sequence of elution of the stereoisomers and the relation to the absolute configuration are also discussed.

HPLC separation of amino acid enantiomers and small peptides on macrocyclic antibiotic-based chiral stationary phases: a review

The search for new and effective chiral selectors capable of separating a wide variety of enantiomeric compounds is an ongoing process. In the past decade, macrocyclic antibiotics have proved to be an exceptionally useful class of chiral selectors for the separation of enantiomers of biological and pharmacological importance by means of HPLC, TLC and electrophoresis. More chiral analytes have been resolved through the use of glycopeptides than with all the other macrocyclic antibiotics combined (ansamycins, thiostrepton, aminoglycosides, etc.). The glycopeptides avoparcin, teicoplanin, ristocetin A and vancomycin have been extensively used as chiral selectors in the form of chiral bonded phases in HPLC, and HPLC stationary phases based on these glycopeptides have been commercialized. Teicoplanin, vancomycin, their analogs and ristocetin A seem to be the most useful glycopeptide HPLC bonded phases for the enantioseparation of proteins and unusal native and derivatized amino acids. In fact, the macrocyclic glycopeptides are to some extent complementary to one another: where partial enantioresolution is obtained with one glycopeptide, there is a high probability that baseline or better separation can be obtained with another. This review sets out to characterize the physicochemical properties of these antibiotics and their application in the enantioseparations of amino acids. The mechanism of separation, the sequence of elution of the stereoisomers and the relation to the absolute configuration are also discussed.