Biological membrane in presence of alcohol and anti-asthma drugs: a molecular dynamics study
This thesis is dealing with drug delivery systems for anti-asthma drugs. We have investigated about the effect of different components in a drug delivery system where liposomes are drug carriers. These components include alcohol, which is used as a solvent in the system and the drug itself. In order to gain a better understanding of the effect of alcohol and anti-asthma drugs on phospholipid bilayer a series of atomistic molecular dynamics (MD) have been carried out. Although alcohol is widely used as a solvent in drug delivery systems, it is known that it can affect a lipid bilayer. The effect of two different alcohol molecules (ethanol and methanol) on lipid bilayer has been compared taking into account different concentrations of ethanol and methanol (0\%-30\%) in the third chapter of this thesis. In the fourth chapter the effect of three hydrophobic anti-asthma drugs including Beclomethasone Dipropionate, Fluticasone Propionate and Prednisone on lipid bilayer is investigated. The behaviour of these three anti-asthma drugs in various positions with respect to the bilayer as well as their preferred position in the bilayer and alcohol role in penetration of drug inside the bilayer is studied in this chapter. Studying the effect of alcohol on DMPC lipid bilayer has shown that ethanol and methanol have destructive effect on lipid bilayer such as causing lipids expansion (increasing the area per lipid), interdigitation and changing the deuterium order parameter of lipid molecules. It is also shown that ethanol effect on DMPC lipid bilayer is more in comparison with methanol. The MD studies on three anti-asthma drugs have shown that the drugs are stable inside the lipid bilayer. It is also observed that drug molecules preferable position inside the bilayer is close to the lipid head groups according to the hydrogen bonds and electrostatic interactions between the drug molecule and lipids head groups. It is also shown that presence of ethanol as a solvent, enhance the penetration of drug molecule inside the lipid bilayer.
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