Table 4.

The energy difference (ΔE_int) of binary systems for the three functional methods.

$\mathrm{\Delta }{E}_{\text{int}}=E_{\mathit{AB}}-E_A-E_B+E_{\mathit{BSSE}}$a
Binary systems
	B3LYP-D3(BJ)	M06-2x	WB97xd
Acetaminophen-PEGb	− 16.59	− 16.84	− 16.90
Ibuprofen-PEG	− 9.44	− 9.28	− 9.63

^aThe E_AB indicate the energy of binary systems, The E_A demonstrative of the energy of Drugs and The E_B demonstrative of the PEG energy in the mentioned systems.

^bAce = Acetaminophen, Ibo = Iboprophen, PEG = Poly ethylene glycol.