In this work, the interaction between theophylline (TP) and creatinine was studied. A three electrode detection system was used, 2mm diameter glassy carbon electrode as working electrode, 1mm diameter platinum wire as auxillary electrode and Ag/AgCl. saturated KCl as reference electrode. Square wave voltammetric technique (SWV) also used, the voltammogram of theophylline shows a stable well - defined reduction peak at (1.07) V versus Ag/ AgCl Sat. KCl/ in phosphate buffer solution (pH=7) using glassy carbon electrode. The voltammograms were recorded for theophyline with serious addition of creatinine, interaction of theophyline with the sequence addition of creatinine were examined at different temperatures (288, 293, 298, 298, 303, 308 and 310) ºK and the thermodynamics parameters were calculated. The binding constant (K) between theophylene and creatinine was also measured. The results showed that the binding constant (K) decreased with increasing temperature, this is as a result of the negative value of enthalpy change ( -46.6 ) KJ. mol-1 ( exothermic binding ). Negative value of Gibbs energy (-275.338 x 102 _ -36384.961 x102) KJ. mol-1 indicates that the interaction is spontaneous and could be due to van der waals forces or hydrogen bonds effect i. e the low value of Gibbs energy indicates weak interaction between the studied compounds.
Theophylline, Cratinine, Interaction, Modified electrode