Computational modeling of inclusion complex of r/s-omeprazole with β-cyclodextrin using oniom2 method

Host-guest inclusion complexes between R/S-omeprazole and β-cyclodextrin has been modeled using ONIOM2 (B3LYP/6-31g(d):PM3) method. Based on the value of binding energy obtained from the computational modeling, it was found that inclusion complex of R-omeprazole with β-cyclodextrin is more stable than the inclusion complex of S-omeprazole with β-cyclodextrin, moreover R/S-omeprazole can form stable inclusion complex with β-siklodekstrin by ratio of host : guest equal to 2 : 1. Based on the value of thermodynamic parameters, the formation of inclusion complex between R/S-omeprazole with β-cyclodextrin is an enthalpy driven process.