The influence of nicotine on pioglitazone encapsulation into carbon nanotube: the investigation of molecular dynamic and density functional theory

In this work, molecular dynamics simulations of the insertion of pioglitazone into the nanotube with chirality (10, 10) at 400 K and 1 bar in the presence and absence of nicotine molecules and in different drug concentrations have been studied. The main aim is consideration of the effect of nicotine in the drug encapsulation process. The results indicate that encapsulation of pioglitazone could be attributed to the water flow via van der Waals and hydrophilic interactions. Because of the existence of the partial π–π interactions between aromatic rings of pioglitazone and the conjugated aromatic rings of nanotube, pioglitazone molecule can enter inside the nanotube. Some physical properties such as hydrogen bonding, number of contacts, also, the diffusion coefficient of the pioglitazone and water molecules, and variation of the center of mass have been calculated during the simulation. Furthermore, computing the electronic structure has also been done on model systems for quantitative determination of the adsorption energy (E_ads). The B3LYP/6-31G* level calculations on four different configurations of pioglitazone/carbon nanotube (CNT) and nicotine/CNT show that the interaction of drug with the inside of the nanotube is stronger than the other forms.