Spectrophotometric studies of a novel Gedunin-2-Hydroxypropyl- β-cyclodextrin binary system

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Supramolecular Chemistry

Background:

• Gedunin, a limonoid, exhibits antimalarial, anticancer, and anti-allergic properties.
• Poor solubility of gedunin limits its bioavailability and pharmacological efficacy.
• Inclusion complexation is a strategy to enhance drug solubility and absorption.

Purpose of the Study:

• To prepare an inclusion complex of gedunin with 2-hydroxypropyl-p-cyclodextrin (HBD).
• To enhance the solubility of gedunin in polar solvents for improved in vivo absorption and bioavailability.
• To investigate the potential enhancement of gedunin's pharmacological effects.

Main Methods:

• Gedunin isolation from Entandrophragma angolense heartwood using chromatography.
• Confirmation of gedunin structure via spectroscopic methods (NMR).
• UV-VIS spectrophotometry and Job's method to determine complex formation, stoichiometry, and binding constants.

Main Results:

• Evidence of interaction between gedunin and HBD observed in various solvents.
• Complex formation confirmed with a 1:1 stoichiometric ratio.
• Formation constants at 25°C and 37°C were 9.539 x 10³ M⁻¹ and 1.853 x 10⁴ M⁻¹, respectively, indicating stable complexation.
• Thermodynamic analysis suggested hydrophobic interactions driving complex formation.

Conclusions:

• A stable inclusion complex of gedunin and HBD was successfully formed at room and body temperatures.
• The complex formation involves encapsulating poorly soluble gedunin within the HBD hydrophobic core.
• This complexation strategy holds potential for enhancing the in vivo pharmacological activity of gedunin.