The research included a study of the kinetic reactions for the colored produced complexes derived from two different electron-donating drugs (Salicylic acid and Paracetamol) with a diazotized reagent (2,4-dinitroaniline) that accepts these electrons at different pH functions and a constant temperature (298°K).

The optimal conditions were determined for each complex formed as well as the optimal ratios (stoichiometry) of its components, which were (1:10) for (drug: reagent) respectively. Then, the kinetics of the formation for the above complexes was followed spectroscopically, and it was found that these interactions was proved that drug complex formation followed a Pseudo-first-order kinetic with respect to Salicylic acid or Paracetamol drug.

We were able to calculate the rate constant(k1) for the formation of the two produced drug compounds. The highest value(k1) for the drug complex (SADDNA: Salicylic Acid Drug + Diazotized 2,4-Dinitroaniline) is (0.0457 at pH7), and for the drug complex (PDDNA: Paracetamol Drug + Diazotized 2,4-Dinitroaniline) is (0.0314 at pH9). We also calculated the half-life-time(t1/2) for each of them, and it was (15.17min.) and (22.08min.), respectively, which is completely opposite to the values of their rate constants under the same conditions.