Modern Chemistry & Applications

Abstract

Evaluation of the Physicochemical Properties of a Novel Antimalarial Drug Lead, Cyclen Bisquinoline

Mohammad Faisal Hossain, Amoyaw PNA, Hardeep S Saluja and Faruk Khan MO

The purpose of this study was to evaluate physicochemical properties of an antimalarial drug lead, 4,10-bis(7- chloroquinoline)-1,4,7,10-tetraazacyclododecane (Cyclenbisquinoline; CNBQ) and its hydrochloride salt. The free base (FB) of CNBQ is a white polymorphic crystalline powder and the salt is off-white powder. The application of standard experimental protocol including differential scanning calorimetric (DSC) analyses revealed that the FB has at least four different crystalline polymorphs melting at 166°C, 178°C, 195°C and 234°C, respectively, and the salt showed a broad endotherm, suggesting it to be amorphous in nature. Equilibrium solubility and stability of both FB and salt were carried out in different mediums, and samples were analyzed using reverse phase-high performance liquid chromatography (RP-HPLC). The compound is highly hydrophobic; however, salt formation improved its water solubility by approximately 370-fold. Both FB and salt forms were stable in a wide range of conditions (acid, base, water, light and heat), except oxidation. All these properties, in addition to previously determined and published log P and pKa values would be useful in implementing the modern quality by design (QbD) approaches for further development of the drug lead.