Complexation of enalapril maleate with beta-cyclodextrin: NMR spectroscopic study in solution
A detailed NMR (¹H , COSY, ROESY) spectroscopic study of complexation of enalapril maleate with beta-cyclodextrin was carried out. The ¹H NMR spectrum of enalapril maleate confirmed the existence of cis-trans equilibrium in solution, possibly due to hindered rotation along the amide bond. The cis-trans ratio remained almost the same in the presence of beta-cyclodextrin but in one case it was found significantly different which suggests a catalytic role of beta-cyclodextrin in the isomerization. ¹H NMR titration studies confirmed the formation of an enalapril-beta-cyclodextrin inclusion complex as evidenced by chemical shift variations in the proton resonances of both the host and the guest. The stoichiometry of the complex was determined to be 2:1 (guest: host). The mode of penetration of the guest into the beta-cyclodextrin cavity as well as the structure of the complex were established using ROESY spectroscopy.
| Main Authors: | , , , |
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| Format: | Digital revista |
| Language: | Portuguese |
| Published: |
Sociedade Brasileira de Química
2006
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422006000400011 |
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