تفاصيل الرسالة العلمية

The interaction between cyclodextrins with etoricoxib (ETR) , have been investigated in different pH aqueous media and we notice that spectral properties of ETR changes with pH of the solution. Absorption and fluorescence studies , show that etoricoxib (ETR) could forms ground state inclusion complexes with different cyclodextrins ( Beta, Hydroxypropyl beta, gamma and alpha CD) In the ground state, ETR have pKa1 = 5.87, however, in the excited state, ETR have pKa1*= 11.44 and pKa2*= 3.71 which means that ETR becomes more basic in the excited state, Steady state experiments detect the kind of etoricoxib-CD (ETR-CD) complex, Time resolved measurements were also performed to study the type of the inclusion and calculate the association constant. This study showed that ETR can only form 1:1 complexes with ?-CD, ?-CD, ?-CD and HP?-CD at pH2, pH6, and pH10, and the largest association constants were found for neutral ETR (at pH10) with ?-CD and ?-CD,