First principles calculations of the adsorption of fluorouracil and nitrosourea on CTF-0; organic frameworks as drug delivery systems for cancer treatment

2D sheet like materials such graphene are superior drug delivery systems compared to the conventional macro systems due to good adsorption and reasonable bioavailability. The adsorption and bioavailability can be further improved with periodic cavity containing 2D materials which can bind with drug molecules with moderate binding energies. Therefore, we have studied for the first time the potential of 2-dimensional porous covalent triazine framework (CTF-0) for the delivery of anticancer drugs fluorouracil (FU) and nitrosourea (NU). Adsorption energy analysis shows that the drug molecules bind with CTF-0 with moderate interaction energies which is prime requirement of a good drug delivery system. However, FU@CTF-0 complex (-17.45 kcal/mol) is more stable than NU@CTF-0 (-14.83 kcal/mol), and that the dipole moment of surface increases after adsorption of drugs. The increase in dipole moment after complex formation helps to improve the solubility, which is necessary for drug delivery in biological systems. Symmetry adapted perturbation theory confirms the stability of drug-loaded complexes, where the contribution from dispersion interactions is the highest. The HOMO-LUMO energy gap (EH-L) of CTF-0 decreases from 4.5 eV to 4.1 eV and 4.0 eV after loading of FU and NU respectively. The pH in cancerous tissues is typically low, which can lead to protonation of a drug and hence aid its delivery to target cells. The nature of the attraction between the CTF-0 surface and different drugs has been evaluated on the bases of noncovalent interactions (NCI) and also the quantum theory of atoms in molecules (QTAIM). QTAIM results confirm that FU has a stronger affinity towards CTF-0 than NU. Based on all our calculated results, CTF-0 appears to be a viable candidate for the delivery of the anticancer drug FU. Previously reported surface for FU and NU drugs has much higher interaction energy which is problematic for the release of drug from the carrier in the biological system. This study provides useful information that may assist the experimental formulation of a CTF-0-based DDS for FU. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the potential of a two-dimensional porous covalent triazine framework (CTF-0) as a drug delivery system. The results show that CTF-0 exhibits moderate interaction energies with the anticancer drug FU, leading to improved solubility and stability.