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Characterizing Pt-Derived Anticancer Drugs from First Principles: The Case of Oxaliplatin in Aqueous Solution

✍ Scribed by Elizabeth C. Beret; Rafael R. Pappalardo; Dominik Marx; Enrique Sánchez Marcos


Publisher
John Wiley and Sons
Year
2009
Tongue
English
Weight
505 KB
Volume
10
Category
Article
ISSN
1439-4235

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✦ Synopsis


Abstract

Anionic hydration: Ab initio molecular dynamics simulations help to obtain a microscopic description of the behavior of oxaliplatin anticancer drug in bulk water (see picture). Its hydration structure is closely related to that previously found for Pt^II^ aqua ion and derives from the presence of a square‐planar motif around the metal center.magnified image

The molecular compound ethyldiamine‐oxalatoplatinum(II), EDO–Pt, is used as a model to study the oxaliplatin anticancer drug in aqueous solution by means of ab initio computer simulation. Gas‐phase structure optimizations have been performed for both oxaliplatin and its EDO–Pt mimic along with Car–Parrinello molecular dynamics simulations of EDO–Pt in gas phase and in aqueous solution. The coordination of Pt^II^ is square‐planar on average, with PtN and PtO~I~ distances of 2.04 Å in solution. The diamine ligand has a bent structure, while the oxalate ligand is planar on average. The complex features a very rigid structure during the simulation and the charge distribution describes a dipole with its negative pole on the oxalate ligand and the positive pole on the Ptdiamine side. The solvation pattern of EDO–Pt is most well‐defined around the amine and oxalate groups and is quantified by means of radial and spatial distribution functions of water molecules around the complex. Decomposition of radial distribution functions into their contributions from different regions (axial and equatorial) reveals an “anionic hydration” pattern of the metal cation by the solvent, which is analogous in nature to the bare Pt^II^ aqua ion. A qualitative prediction on the kinetics of ligand exchange in oxaliplatin is derived based on its axial hydration pattern.