Study to explore host-guest inclusion complexes of cyclodextrins with biologically active molecules in aqueous environment

• α and β-CD form inclusion complex with L-Asn and L-Asp in aqueous media.
• Surface tension and conductivity studies confirm their 1:1 stoichiometry.
• Density and viscosity studies inform about the host-guest interactions.
• Encapsulations in the cavity of α and β-CD are higher in case of L-Asn than L-Asp.
• β-CD is better host for both the amino acids than α-CD.

Molecular inclusion of two natural amino acids, viz., L-asparagine and L-aspartic acid as guest into the host cavity of α and β-cylodextrins in aqueous solution have been studied which have various applications in the field of present bio-medical science for controlled delivery of necessary amount of the guest at the targeted site for a period of time efficiently and precisely. Surface tension and conductivity studies establish the formation of inclusion complexes with 1:1 stoichiometry. The inclusion complexes have been characterized by various thermodynamic factors basing upon density and viscosity studies. Contributions of various groups of the guest amino acid molecules toward the limiting apparent molar volume and viscosity B-coefficient have been calculated, as well as the solvation and hydration numbers are determined to support the inclusion phenomenon. Formations of the inclusion complexes have been explained with the help of hydrophobic effect, H-bonding, electrostatic forces and structural effects.

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