title: Theoretical prediction of the complexation behaviors of antitumor platinum drugs with cucurbiturils.
abstract: The inclusion complex formation ability between CB[n] (n = 6-9) and Pt-drugs (oxaliplatin, nedaplatin, carboplatin, and cisplatin) in gas phase as well as water phases has been investigated using the using density functional theory. The results reveal the existence of several stable inclusion complexes in aqueous solution with high solvation energies compared to the guest and host molecule. It has been shown that the formation of complexes between CB[6] and Pt-drugs resulted in structural change in the CB[6], with the calculated deformation energies being higher for the inclusion complexes. The inclusion complexes are stabilized by the hydrogen bonding and the charge transfer between the Pt-drugs and the CB[n] host. Calculated enthalpy and Gibbs free energy of formation in aqueous solution revels that the formation of CB[7]-oxaliplatin is spontaneous, and hence its experimental synthesis is feasible. Among the CB's studied, CB[8]-Pt-drug inclusion complexes have exothermic enthalpy and low Gibbs free energy of formation. Computed (1)NMR spectra in CB[7]-oxaliplatin showed high chemical shielding for the cyclohexane ring, indicating the existence of charge transfer in the inclusion complex. The amine protons in the guest Pt-drugs are shielded due to the hydrogen bonding interaction with CB's oxygen portal.
authors.affiliation: Institute for Materials Research, Tohoku University, Katahira, Aoba-Ku, Sendai, Japan. ramanan@imr.tohoku.ac.jp
authors.forename: Natarajan Sathiyamoorthy
authors.initials: NS
authors.lastname: Venkataramanan
authors.forename: Suvitha
authors.initials: S
authors.lastname: Ambigapathy
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mizuseki
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kawazoe
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000737:chemistry*; D016190:Carboplatin / Q000008:administration & dosage / Q000737:chemistry; D002945:Cisplatin / Q000008:administration & dosage / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D006860:Hydrogen Bonding; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009944:Organoplatinum Compounds / Q000008:administration & dosage* / Q000737:chemistry*; D000077150:Oxaliplatin; D013816:Thermodynamics; D000099246:Cucurbit(n)urils
chemical_list: D000970:Antineoplastic Agents; D016190:Carboplatin; D002945:Cisplatin; D004337:Drug Carriers; D047028:Macrocyclic Compounds; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D000099246:Cucurbit(n)urils; C053989:nedaplatin