Physicochemical Analysis and Molecular Modeling of the Fosinopril β-Cyclodextrin Inclusion Complex

Table 3

Hydrogen bonds and the most important van der Waals interactions between FOS and β-CD, for each complex type, as resulting from PM3 calculations.

Min	Form	Interactions FOS-βCD in complex
1	COONa	(i) 2 weak H-bonds secondary OH⋯O=C amide; (ii) vdW contacts: C6H5(CH2)4 with the H-3′ and H-5′β-CD, as for enalapril in [24]
2	COONa	(i) 1 moderate and 1 weak H-bond secondary OH⋯O=C amide and ester, respectively; (ii) vdW contacts: (CH2)4, CH3(Et) with H-3′β-CD
3	COONa	(i) 3 moderate H-bonds secondary OH⋯OOC carboxyl; (ii) vdW contacts: cyclohexyl CH2, prolyl CH and (N)CH2, (P)CH2(C=O) with H-3′ and H-5′β-CD, and CH2(Et), CH i-Pr with (C)H2-6′β-CD
1	COO^−	(i) 2 weak H-bonds secondary OH⋯O=C amide; (ii) vdW contacts: C6H5(CH2)4, CH3(Et) with the H-3′ and H-5′β-CD
2	COO^−	(i) 1 moderate and 1 weak H-bond secondary OH⋯O=C amide and ester, respectively; (ii) vdW contacts: C6H5(CH2)4 interactions with H-3′ and H-5′, and (C)H2-6′β-CD, and between CH3(Et) and H-3′, H-5′β-CD
3	COO^−	(i) 4 moderate H-bonds secondary OH⋯OOC carboxyl; (ii) vdW contacts: (C6H5)CH2, prolyl CH and (N)CH2, (P)CH2(C=O) with H-3′ and H-5′β-CD, and CH2(Et), CH i-Pr, C6H5CH2 with (C)H2-6′β-CD