The structures of PAMAM G4 dendrimer in different protonation states were initially modeled using the program Hyperchem. After this procedure the structures were inserted in a box of water and simulated with molecular dynamics. Was observed an increase in volume of the dendrimer when degree of protonation was increased. Once known the topologies of PAMAM dendrimer at different pH, the rifampin was included in cavities of dendrimer in Neutral and low pH. Using an algorithm designed for the purpose of optimizing this encapsulation, were encountered 20 molecules inside the cavities of dendrimer. This procedure resulted in a low computational cost for molecular dynamics because the molecules were in a optimal position in the structure of dendrimer. After these couplings of the systems these were simulated with molecular dynamics for observation of capacity in transport of dendrimer these molecules in neutral pH and liberation in low pH. The study of the possible release of the complex molecules of rifampicin (rifampicin / PAMAM G4) showed that the molecules are released gradually of the structures at low pH. The computational results were validated by experimental results on the work developed in collaboration between IQ / UFRJ and IPEC / FIOCRUZ, whose objective was to characterize and determine the tuberculostatic activity of complex.