(A) A titration mixture of ibuprofen, cinoxacin, L-proline (Pro), and adenosine 5’-triphosphate disodium salt (ATP) with increasing concentrations (i) 0 μM, (ii) 0.4 μM, (iii) 1.0 μM, and (iv) 3.0 μM of HSA. (B) Only ibuprofen binds HSA and the decrease in peak intensity describes the binding curve from eq 1. The resulting equilibrium dissociation constant (KD) for ibuprofen was 0.46 ± 0.8 μM with a NMR line width ratio constant (c) of 31.8.