الفهرس 
Radiographic Contrast MediaOnly 14 pages are availabe for public view
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Abstract
The conformational analysis of iodinated non-ionic contrast agent,
Iobitridol, was carried out using theoretical calculations to explore its
conformational space, and to study different aspects connected with
application of different search techniques. Monte Carlo (MC), random
search (RS) and molecular dynamics (MD) based conformational search
techniques were used to extract a reasonable-size sample that adequately
represents and has an average behavior of the entire conformational
ensemble.
While MC is good for quick search for lowest energy conformer,
RS is better in obtaining conformational sample that cover the whole
conformational space and MD is the best for investigation of isomeric
preferences inside the conformational ensemble at thermal equilibrium.
Conformational analysis of the produced gas phase samples reveals that
RS and MD methods could sufficiently present the 18 distinct isomeric
classes that constitute the total conformational space of the Iobitridol.
RS samples of conformational space of Iobitridol are extensively
studied, as it hypothetically cover the total conformational space. They are
used to test the suitability of different methods (charge distribution
methods, energy calculation methods) for Iobitridol molecular
computations and internal structure forces (steric hindrance, resonance
interaction), as well as dependances among the internal coordinates
(dihedral angles correlations and coincidences).
The atomic partial charge distribution is found to greatly affect the
energy calculation for the molecular mechanics based conformational
energy distributions. Further energy minimization of conformational
sample by the quantum molecular orbital methods is crucial to obtain
charge independent as well as energy balanced conformational sample.