Kinetic and thermodynamic analysis of degradation of doripenem in the solid state |
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Authors: | Judyta Cielecka‐Piontek Anna JelińSka Agnieszka Dołhań Przemysław Zalewski |
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Affiliation: | Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Poznan University of Medical Sciences, 60‐780 Poznań, Poland |
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Abstract: | The kinetic and thermodynamic parameters of degradation of doripenem were studied using a high‐performance liquid chromatography method. In dry air, the degradation of doripenem was a first‐order reaction depending on the substrate concentration. At increased relative air humidity, doripenem was degraded according to the autocatalysis kinetic model. The dependence ln k = f1/T) was described by the equations ln k = 5.10 ± 13.06 ? (7576 ± 4939)(1/T) in dry air and ln k = 46.70 ± 22.44 ? (19,959 ± 8031)(1/T) at 76.4% relative humidity (RH). The thermodynamic parameters Ea, ΔH≠a, and ΔS≠a of the degradation of doripenem were calculated. The dependence ln k = f (RH%) was described by the equation ln k = (0.155 ± 0.077) × 10?1 (RH%) ? (3.45 ± 21.8) × 10?10. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 722–728, 2012 |
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