We present the results of theoretical modeling of supermassive black hole binary (SMBHB) mergers using direct 2 -body simulations with a Hermite integration scheme. The BH’s gravitational interaction is described based on the post-Newtonian (𝒫𝒩 terms) approximation up to the 3.5𝒫𝒩 terms. We carry out a large set of runs using a parametric description of SMBHB orbits. The final time of the SMBHs gravitational coalescence is parametrized as a function of initial eccentricity and mass ratio q of the binary. We carry out detailed tests of our coding. We tested our PN terms against the analytic prescription described at the theoretical works in middle 60th. The gravitational radiation polarization amplitudes and from the SMBHBs merging process are also analyzed. Based on our numerical work we estimate the expected merging time for a list of selected potential SDSS SMBHBs. Our results show that the merging time is a strong function of the assumed initial eccentricities and fall within the range of thousands years.