Potential applications of armchair, zigzag, and chiral boron nitride nanotubes as a drug delivery system: Letrozole anticancer drug encapsulation

A density functional theory calculation has been applied to be investigated the ability of (12,12) armchair, (21,0) zigzag, and (18,5) chiral boron nitride nanotubes (BNNT) as the drug nanocarrier in Letrozole delivery. For this purpose, the behavior of drug Letrozole when encapsulated into different chirality of BNNTs with the same diameter was studied. Moreover, the reduced side effects and increasing solubility of Letrozole can be achieved by encapsulation in boron nitride nanotubes. A complete understanding of the encapsulation process of drug molecules into BNNTs is necessary for the development of drug delivery systems. Geometry optimizations of the three types of BNNTs and drug Letrozole have been performed by means of density functional theory calculation, using the functional wb97xd with 6-31G basis set. The results indicate that Letrozole is encapsulated in cavity of the nanotubes. The structural and the electronic properties of encapsulated Letrozole in the studied systems have been also predicted by quantum mechanical descriptors such as equilibrium distances, highest occupied molecular orbital (HOMO)—lowest unoccupied molecular orbital (LUMO) energy gap. The quantum mechanical calculations verify that the armchair and the chiral single-walled boron nitride nanotubes could spontaneously adsorb Letrozole in a chemisorption process while the physisorption process plays a large role in adsorption within the zigzag single-walled boron nitride nanotube.