The present study included the use of the approximate semi-experimental method, the time-independent density function theory (unrestricted), the time-dependent density function theory, and Hartree-Fock method to calculate the reaction pathway of the anti-inflammatory drug diclofenac with its common ionic carriers (sodium and potassium). The basis sets used were STO-3G, 3-21G, 6-31G, and 6-311G. The drug was studied with two new proposed carrier ions (lithium and calcium) which were compared with common carriers. The calculations included the optimized geometrical structure and some physical properties such as standard heat of formation, dipole moment, total energies, and analytical spectra of IR, UV-VIS and 1H NMR. The biological and toxicological activities and the nonlinear optical (NLO) properties were also studied theoretically for the drug and for its proposed and common carriers. All calculations were performed using Gaussian-09 program. The results of the proposed carriers were compared with the common carriers in terms of activation energies, transition states, and products. This study is considered as a step to develop diclofenac prodrugs and find new carriers for diclofenac. The proposed lithium showed a good result and a potential for use as a drug carrier. The results also showed the convergence of the values of the common carriers (Na, K) and those of the proposed carrier (Ca), with their preference over it.
