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Molecular dynamics of articaine in POPC membranes

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Erica Teixeira Prates
Total Authors: 1
Document type: Master's Dissertation
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
Defense date:
Examining board members:
Munir Salomão Skaf; Hubert Karl Stassen; Celso Aparecido Bertran
Advisor: Munir Salomão Skaf; Monica Andrea Pickholz

We studied the interactions of articaine - a local anesthetic widely used for me- dical and odontological applications - with model membranes of POPC (palmitoyl-oleyl-phosphatidylcholine) at biological relevant conditions. We have employed molecular dynamics technique, which allowed us to investigate the system at molecular level. Firstly, we applied quantum mechanical methods to parametrize articaine molecule based on CHARMM force field. We have done extensive molceular dynamics simulations, taking into account the different ionization states of the drug (neutral and protonated) as well as its optical isomers. From the equilibirum simulations of articaine in POPC membranes, we investigated the conformational behaviour of the drug, its tranversal position and its specific interactions with the lipids and water molecules. Our results show a preferential orientation of the articaine molecule within the membrane. Neutral articaine was mainly found at the lipid head/water interface, in very good agreement with H-RMN experimental results from Prof. Eneida de Paula (IB-UNICAMP) and Prof. Leonardo F. Fraceto (Dpto. de Eng. Ambiental - UNESP, Sorocaba - SP) and from literature (C. Song et al, 2008). By studying properties like electronic density prole and longitudi- nal time relaxation for different regions of the lipid molecules, we discussed the lipossolubility of articaine in comparison to other local anesthetics. We have also performed non-equilibrium simulations, using steered molecular dynamics (SMD) technique. A single articaine molecule was extracted from the membrane to the wa- ter phase, by applying an external force in its mass centre. Coupling the Jarzynski identity to the SMD simulations, we estimated the partition free energy of the neutral drug (the most potent specie) in POPC membranes. (AU)

FAPESP's process: 07/02629-2 - Interactions of local anesthetics with phospholipid bilayers
Grantee:Érica Teixeira Prates
Support type: Scholarships in Brazil - Master