Non-Covalent Bonding Interaction between Primaquine as Guest and 2-(Hydroxypropyl)-β-Cyclodextrin as Host

An inclusion complex of Primaquine (PQ) with 2-(Hydroxypropyl)-β-Cyclodextrin (2-HP-β-CD) in liquid state have been investigated by using absorption and fluorescence spectral techniques. From the spectral data, a binding constant (K) and the stoichiometric ratio between the host-guest system is calculated by using the Benesi–Hildebrand equation. Gibb’s free energy changes of the complexation process are spontaneously at room temperature. The host-guest complex of PQ with 2-HP-β-CD is prepared by various methods like physical mixture, kneading, and co-precipitation methods. The solid inclusion complexes are characterized by using FT-IR, SEM, Powder XRD, and DSC analysis. The orientation and structure of the inclusion complex are proposed based on the results of PM3 optimization. Mutual interactions between the guest (PQ) and host (2-HP-β-CD) are identified by NBO analysis. The anticancer activity also performed for pure PQ and its inclusion complex with 2-HP-β-CD. It clearly showed that the solid complex did not enhances in their anticancer activity than PQ alone.