Evaluation of the binding interactions of p-acetylaminophenol, aspirin, ibuprofen and aminopyrine with norfloxacin from the view of antipyretic and anti-inflammatory

In this work, the binding interactions of norfloxacin (NRF) with p -acetylaminophenol (AAP), aspirin, ibuprofen , and aminopyrine were investigated by molecular modeling and fluorescence quenching methods. The results indicated the existence of the electrons transferring during the π–π stacking interaction with face to face stacking of them. NRF acts as electron acceptor during the NRF-AAP and NRF-aminopyrine complexes and acts as electron donor during the NRF-aspirin, NRF-ibuprofen complexes. Fluorescence quenching of NRF induced by AAP, aspirin, ibuprofen, and aminopyrine are the formation of complexes. The binding ability of NRF with AAP, aspirin, ibuprofen, and aminopyrine indicated that the order are from top to bottom aminopyrine, AAP, aspirin, and ibuprofen and the number of the binding site n is about 1.