Analysis of Cyclosporin A and Main Degradation Impurities by Cyclodextrin–Modified Micellar Electrokinetic Chromatography

Abstract

Separation of the immunosuppressive drug cyclosporin A (CyA) from the closely related degradation impurities cyclosporin H (CyH, a CyA diastereomer) and isocyclosporin A (IsoCyA) was accomplished by means of cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). Heptakis (2,3,6-tri-O-methyl)-b-cyclodextrin (TM-bCD) showed to be an effective modifiers of the sodium dodecyl sulfate (SDS) micellar system, allowing for the CD-MEKC separation of CyA from CyH and IsoCyA. By means of electric current measurements carried out using the capillary electrophoretic apparatus, the critical micelle concentration of SDS in the presence of different neutral cyclodextrins was estimated. Interestingly, it was found that TM-bCD strongly inhibited the micellization of SDS compared to b-, and hydroxypropyl-b-cyclodextrin. This unusual behavior was considered to be a key factor of the specific ability of the methylated cyclodextrin in providing CD-MEKC separation of hydrophobic cyclosporins. The optimized method consisted of: 50 mM sodium dodecyl sulfate (SDS) in 50 mM tetraborate buffer (pH 9.2) supplemented with 15 mM TM-bCD. The electrophoretic runs were performed at 30 C under the application of 22 kV in a fused-silica capillary (50 lm id, 64.5 cm total length, 56 cm length to the detector). The method was validated for linearity of CyA (within 0.25-5.00 mg/mL) and CyH and IsoCyA (within 0.25-5.0%, w/w with respect to CyA), sensitivity (LOQ 5.0 lg/mL), accuracy, and precision. The applicability of the method was proved by analysis of a commercially available pharmaceutical (gelatin capsules).

Doubly Protonated Species Collision Induced Dissociation for Identification of Isocyclosporins

“…The enormous importance of CsA as a drug stipulated the development of a number of analytical methods for its detection, identification, and quantificaton. These include HPLC, immunoassay and HPLC-mass spectrometry approaches [7][8][9][10][11][12][13][14][15]. Methods for analysis of cyclosporins in natural sources also draw significant attention.…”

Recent developments in capillary and microchip electroseparations of peptides (2011–2013)

“…Analysis of the immunosuppressive drug cyclosporine A (CyA), cyclic oligopeptide consisting of 11 AAs, and its closely related degradation impurities, cyclosporine H (CyH, a CyA diastereomer) and isocyclosporin A (IsoCyA) was performed by CD modified MEKC (CD‐MEKC) using 15 mM heptakis (2,3,6‐tri‐ O ‐methyl)‐β‐CD as an effective modifier of the 50 mM SDS micellar pseudophase in the 50 mM sodium tetraborate BGE . The analyses were carried out in 50 μm id, 64.5/56 cm total/effective length FS capillary at 30°C, 22 kV separation voltage, and UV‐absorption detection at 200 nm.…”

Development and validation of a micellar electrokinetic capillary chromatography method for the determination of goserelin and related substances

“…CE is a powerful tool for the quality control of peptide drugs [9][10][11][12][13][14][15] because it has its own advantages including high separation efficiency, high peak capacity, low sample and reagent consumption, high speed in analysis, instrumentation simplicity, and use of various separation modes. Previously, we developed a CZE method to determine the purity of exenatide and conducted a preliminary study on its stability.…”