Question

Study of the selfassociation of amoxicillin, thiamine and the heteroassociation with biologically active compound chlorgenic acid

Answer 1

The self-association of amoxicillin (AMX) and its hetero-association with biologically active compound, chlorogenic acid (CGA) were investigated at room temperature (295°K). The dimerization constant of amoxicillin and thiamine (THIA) analyzed using the dimer model at the wavelength of 278 and 256 nm were found to be   1 3 10 2. 3 438. 5    M and 1 2 10 991. 8   M , respectively. The hetero-association constant of amoxicillin and chlorogenic acid analyzed using Benesi-Hildebrand approach were 1 3 10 18. 1   M. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy of dimerization reactions for the self-association and hetero-association of the compounds were also investigated using Vant's Hoff equation at the temperature ranges (295 to 305°K). The change of enthalpy calculated for amoxicillin, thiamine and the complexes of amoxicillin-chlorogenic acid are 34.73±2.17, 54.1±4.585, and 6.988±0.493 1.  mol kJ at the temperature of 305°K, respectively. The values of change in enthalpy and entropy indicate that the hydrophobic interaction play the major role in the interaction between the molecules.