Interactional behaviour of analgesic drugs in aqueous solution of caffeine at different temperatures using multi-technique approach

Abstract

Drug combination therapies have been a promising strategy to overcome drug resistance. However, unexpected drug–drug interaction may cause adverse reactions, which puts patients in danger. Keeping this in mind, the interactions between pain killers, paracetamol (PCM), and ibuprofen sodium with caffeine (CAF) have been studied. Apparent molar volumes ( V2,ϕ) and apparent molar isentropic compression ( Ks,2,ϕ) for analgesic drugs in aqueous (1, 2, 5, and 10 mmol·kg−1) CAF solutions have been determined from measured densities, ρ, and speeds of sound, u, respectively, at T = 288.15–318.15 K and at pressure p = 101.3 kPa. The results have also been interpreted in terms of various interactions occurring in the mixed solution. Calorimetrically determined negative values of ΔtrΔdil H0 indicate the exothermicity and thus the occurrence of energetically more favorable process. The hyperchromic shift (UV absorption) in the spectra of PCM in aqueous solution of CAF suggests the dominance of solute–cosolute interactions through the hydrophobic–hydrophobic/hydrophilic groups (1H NMR) of PCM + CAF system.