Functionalized (–HCO, –OH, –NH2) Iridium-doped graphene (Ir@Gp) nanomaterials for enhanced delivery of Piroxicam: Insights from quantum chemical calculations

Hitler Louis, Innocent Benjamin, Anthony C. Iloanya, Chioma B. Ubah, Anthony E. Essien, Gideon A. Okon, Adedapo S. Adeyinka

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Delivery of piroxicam into the body has been associated with various health complications, such as gastrointestinal problems, cardiovascular problems, renal problems, injection site reactions, systemic side effects, drug interactions, and localized tissue damage. In this study, the geometry of Ir@Gp functionalized with OH, HCO, and NH2 was investigated using density functional theory (DFT) at the ωB97XD/def2svp level of theory to determine the system with the best delivery potential for piroxicam. The results of the study showed that all studied systems had an increase in bond length, except for Pxm_NH2_Ir@Gp, which had a decrease in bond length. This suggests that Pxm_NH2_Ir@Gp is reactive to the drug's adsorption and is consistent with the chemical quantum descriptors calculated from frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis. Substantially, the quantum theory of atom in molecules (QTAIM) established that partially covalent interactions were more evident in the Pxm_HCO_Ir@GP and Pxm_OH_Ir@GP systems, while noncovalent interactions were supported by the weakest bonds of the interaction at H65-H98 and H92-H64, respectively. The findings of the non-covalent interactions (NCI) further affirmed that the effectiveness of the drug's delivery to target sites depended on the presence of weak interactions between the studied systems. The calculated Eads calculated in the gas phase showed that weak chemical binding of the drug towards the adsorbent was obtained in Pxm_Ir@GP, Pxm_OH_Ir@GP, and Pxm_HCO_Ir@GP. Whereas, in the water phase, the adsorption energy values for all complexes (pxm_Ir@GP) were mostly negative, indicating that the water molecules energetically favor the adsorption of the drug onto the surfaces studied than the gas-phase. Among the water-phase complexes, pxm_Ir@GP revealed the highest negative adsorption energy of −5.116 eV, indicating that it has the highest affinity for water. This result, which corresponds with other analyses in this study, shows that Pxm_NH2_Ir@GP can be used as an efficient material for the effective carriage of pirixocam to the target cells in both gas and water phase. Overall, it can be said that the systems' adsorption efficiency is as follows: pxm_Ir@GP > pxm_NH2_Ir@GP > pxm_OH_Ir@G. Summarily, this results which undoubtedly corresponds with other analysis in this study shows that pxm_NH2_Ir@GP (in both gas and water phase), can be used as an efficient and sensitive biosensor material for the effective carriage of pxm drug to bio cells.

Original languageEnglish
Article number122068
JournalJournal of Molecular Liquids
Publication statusPublished - 1 Aug 2023


  • DFT
  • Drug delivery
  • Functionalization
  • Graphene
  • Perixocam

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry


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