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For the majority of children with acute lymphoblastic leukemia (ALL), treatment consists in part of a triple intrathecal (Triple IT) therapy, i.e. a combination of cytarabine (CB), methotrexate (MTX) and methylprednisolone sodium succinate (MPSS) [1]. This combination product is prepared ex-tempore. However, no in-use shelf-life under defined storage conditions has yet been established. During stability studies, a large number of samples are generated, thus creating the need for a fast, accurate and selective analytical method. In this study, a fused-core HPLC method was developed. This hybrid technology, consisting of a 0.5 µm thick porous shell fused to a 1.7 µm inert core, enables faster chromatographic separation with sufficiently high resolution. During method development, both stressed and unstressed solutions containing both single Triple IT components and the mixture thereof, were analyzed using different linear gradient times, ranging from 5 to 30 min. The mobile phase composition was fixed (A: 0.1% glacial acid in H2O; B: 0.1% glacial acid in ACN), starting with A:B (90:10, V/V) and ending with A:B (10:90, V/V). Method selectivity was evaluated based on the observed peaks in stressed CB, MTX and MPSS solutions, i.e. incubation at 40°C and 80°C. A balance between fast separation and sufficient resolution between the Triple IT components and related degradants, was found by setting the gradient time at 15 min. The Triple IT related degradation peaks were chromatographically separated from the remaining Triple IT components. Moreover, selectivity was supported by a peak purity analysis on the observed peaks. Linearity was demonstrated (R² > 0.999) for the three Triple IT components. Repeatability was evaluated by triplicate injections of 100% reference assay: relative standard deviation varied between 0.155% (MPSS), 0.464% (CB) and 1.352% (MTX) [2]. References [1] A. Ruggiero, V. Conter, M. Milani, E. Biagi, I. Lazzareschi, P. Sparano, R. Riccardi. Intrathecal chemotherapy with antineoplastic agents in children. Paediatric drugs 3(4) (2001) 237-246. [2] M. D’Hondt, E. Vangheluwe, S. Van Dorpe, J. Boonen, T. Bauters, B. Pelfrene, J. Vandenbroucke, H. Robays, B. De Spiegeleer. Stability of ex-tempore prepared Triple intrathecal solution consisting of cytarabine, methotrexate and methylprednisolone sodium succinate. American Journal of Health-System Pharmacy, submitted for publication. |
