Journal of Chemical Thermodynamics, Vol.107, 37-41, 2017
Comprehensive thermodynamic study of methylprednisolone
In the present work the temperature dependence of heat capacity for methylprednisolone has been measured for the first time over the temperature range from 6 to 350 K using by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the methylprednisolone, namely, the heat capacity, enthalpy H degrees(T) - H degrees(0), entropy S degrees(T) - S degrees(0) and Gibbs function G degrees(T) - H degrees(0) have been evaluated from the experimental values for the range from T -> 0 to 350 K. Standard molar enthalpy of combustion (-11898.9 +/- 6.7) kJ center dot mol(-1) of the methylprednisolone was measured for the first time using high-precision combustion calorimeter. The standard molar enthalpy of formation in the crystalline state (-1045.8 +/- 7.3) kJ center dot mol(-1) of compound at 298.15 K was derived from the combustion experiments. The standard molar enthalpy of sublimation at 298.15 K (194.5 +/- 2.2) kJ center dot mol(-1) was measured by using the quartz-crystal microbalance (QCM). Using combination of the adiabatic and combustion calorimetry with the result from QCM, the thermodynamic functions of the methylprednisolone at T = 298.15 K and p = 0.1 MPa have been calculated. (c) 2016 Elsevier Ltd.
Keywords:Steroid hormone;Methylprednisolone;Heat capacity;Combustion calorimetry;Vapor pressure;Thermodynamic functions