Research Article

Stability of Epidoxorubicin Hydrochloride in Aqueous Solutions: Experimental and Theoretical Studies

Table 1

Catalytic rate constants and thermodynamic parameters for the degradation of EP in aqueous solutions.

Catalytic rate constantTemperature (K)Parameters of regression 
Thermodynamic parameters


(mol−1 L s−1)
333(1.02 ± 0.07) × 10−3 = 118.8 ± 9.4 (kJ mol−1)
343(3.44 ± 0.12) × 10−3 = 116.3 ± 9.4 (kJ mol−1)
353(1.22 ± 0.11) × 10−2 = 54.5 ± 27.0 (J K−1 mol−1)
363(3.43 ± 0.41) × 10−2

(s−1)
333(8.82 ± 8.22) × 10−7 = 104.1 ± 55.4 (kJ mol−1)
343(3.79 ± 2.75) × 10−6 = 101.6 ± 55.4 (kJ mol−1)
353(1.12 ± 0.85) × 10−5 = −46.6 ± 159.5 (J K−1 mol−1)
363(1.91 ± 1.04) × 10−5

(s−1)
333(5.02 ± 0.42) × 10−5 = 80.7 ± 36.7 (kJ mol−1)
343(1.57 ± 0.04) × 10−4 = 78.3 ± 36.7 (kJ mol−1)
353(2.46 ± 0.11) × 10−4 = −84.0 ± 105.7 (J K−1 mol−1)
363(6.28 ± 0.52) × 10−4

(mol−1 L s−1)
333(4.95 ± 0.65) = 66.8 ± 13.1 (kJ mol−1)
343(9.89 ± 1.21) = 64.4 ± 13.1 (kJ mol−1)
353(17.6 ± 8.7) = −30.8 ± 37.8 (J K−1 mol−1)
363(37.6 ± 19.2)

(mol−1 L s−1)
333(0.821 ± 3.110) = 63.8 ± 7.3 (kJ mol−1)
343(1.44 ± 7.17) = 61.4 ± 7.3 (kJ mol−1)
353(3.10 ± 24.78) = −54.8 ± 21.1 (J K−1 mol−1)
363(5.39 ± 99.46)

and were calculated for 293 K. (J mol−1); (J mol−1); (J K−1 mol−1), where is Boltzmann’s constant (1.3807 × 10−23 J K−1), is Planck’s constant (6.626 × 10−34 J s), is the universal gas constant (8.314 J K−1 mol−1), is temperature in K, is the vectorial coefficient of the Arrhenius relationship, and is the frequency coefficient.