High-performance liquid chromatographic analysis of cyclosporin A in rat blood and liver using a commercially available internal standard

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2002-05, Vol.772 (1), p.107-114
• Main Authors: Chimalakonda, Anjaneya P., Shah, Rakhi B., Mehvar, Reza
• Format: Article
• Language: English
• Subjects: Acetonitrile; Animals; Biochemistry; Chromatography, High Pressure Liquid - methods; Cyclosporin A; Cyclosporine - analysis; Cyclosporine - blood; Evaporation; High performance liquid chromatography; Liver - chemistry; Methanol; Rats; Reference Standards; Reproducibility of Results; Separation
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/S1570-0232(02)00062-4

All the available HPLC assays of cyclosporin A (CyA) use internal standards that are not commercially available. Our purpose was to develop an HPLC assay for measurements of CyA in rat blood and liver using a commercially available internal standard (I.S.). After the addition of tamoxifen (I.S.), blood (0.25 ml) or the liver homogenate (1 ml) samples were extracted into a mixture of ether:methanol (95:5). The residue after evaporation of the organic layer was dissolved in 200 μl of an injection solution and washed with 1 ml of hexane before analysis. The separation was achieved using an LC-1 column (70 °C) with a mobile phase of methanol–acetonitrile–0.01 M KH 2PO 4 (50:25:25, v/v) and a flow-rate of 1 ml/min. Detection was at 205 nm. Cyclosporin A and I.S. eluted at 5 and 7 min, respectively, free from endogenous peaks. Linear relationships ( r>0.98) were observed between the CyA:I.S. peak area ratios and the CyA concentrations within the range of 0.2–10 μg/ml for blood and 0.1–4 μg/ml for the liver homogenates. The intra- and inter-run C.V.s and errors for both the blood and liver samples were