Roselet S. L, et al. Materials Today: Proceedings, 2020, 21, 514-518.
(2-Hydroxypropyl)-α-Cyclodextrin (HPα-CD) was strategically applied to form inclusion complexes with Metformin Hydrochloride (MFH), a hydrophilic biguanide antidiabetic agent, to improve its oral bioavailability—a critical pharmacokinetic limitation of MFH.
The experimental design involved both liquid and solid-phase inclusion complex preparation. In the liquid complexation protocol, MFH was dissolved in methanol and titrated against aqueous HPα-CD solutions of varying molar concentrations. Solid-state complexes were synthesized by prolonged stirring (48 h) of methanolic MFH with aqueous HPα-CD, followed by solvent evaporation and drying of the resultant precipitate. This methodological approach effectively simulated in vivo interaction conditions.
Comprehensive physicochemical characterizations affirmed the formation and stability of the HPα-CD/MFH inclusion complexes. UV–Vis and fluorometric analyses revealed significant spectral shifts, indicative of host–guest interactions. Benesi-Hildebrand plots confirmed a 1:1 complex stoichiometry, corroborated by AL-type phase solubility diagrams and elevated stability constants. Furthermore, ¹H NMR spectroscopy provided molecular-level evidence of MFH's encapsulation within the cyclodextrin cavity, confirming a complete inclusion event.
