New trans-[Ru(NO)(NO2)(dppb)(o-bdqi)]+ complex as NO donor encapsulated Pluronic F-127 micelles

Abstract

Ruthenium complexes that act as nitric oxide (NO) donors show potential cytotoxicity in tumor models. In this work, we proposed the synthesis of the new nitrosyl ruthenium complex trans-[Ru(NO2)(NO)(dppb)(o-bdqi)]Cl2, containing a non-innocent ligand of the o-phenylenediamine type (o-bdqi). The 31P{1H} NMR spectra confirmed that the trans-[Ru(NO2)(NO)(dppb)(o-bqdi)] is the isomer formed. The complex was characterized by elemental analysis, mass spectrometry, UV–vis and infrared spectroscopy and cyclic voltammetry. Natural transition orbitals (NTOs) for trans-[RuCl2(dppb)(o-bdqi)] and trans-[Ru(NO2)(NO)(dppb)(o-bdqi)]Cl2 complex were obtained with TD-DFT/B3LYP methodology to contribute to the assignment of electronic transition. A micellar system (F-127/Ru) produced with Pluronic F-127 copolymer was used as a drug delivery system, due to the hydrophobicity of the complex. The F-127/Ru system showed NO release in aqueous media. The free complex showed higher cytotoxicity than the F-127/Ru system in the studied tumor cells. However, the F-127/Ru system showed a higher selectivity index for lung cells. This shows that the Pluronic F-127 carrier can be a good alternative in the use of hydrophobic nitrosyl ruthenium compounds in the treatment of some types of cancer.