Molecular encapsulation of andrographolide in 2-hydroxypropyl--cyclodextrin cavity: synthesis, characterization, pharmacokinetic and antiviral activity analysis against SARS-CoV-2.

In present investigation, AND-2-HyP--CYD (Andrographolide-2-Hydroxypropyl--cyclodextrin) complex was synthesized and characterized for antiviral and pharmacokinetic profile. The linear host-guest relation suggested synthesis of a 1:1 complex of AND with 2-HyP--CYD by inclusion mode. The Kc, stability constant of the two phase system of AND with 2-HyP--CYD computed to be 38.60 x 10M. H NMR spectrum of AND indicated the presence of triplet at 6.63-ppm which was up-fielded in AND-2-HyP--CYD complex at 6.60-ppm (doublet) confirmed the insertion of AND in cavity of 2-HyP--CYD through lactone ring. AND-2-HyP-β-CYD complex exhibited the IC of 0.1-g.mL (E gene) and 0.29-g.mL (N gene) against SARS-CoV-2 infected Vero6 cells. Moreover, a 1.5-fold increment in extent of absorption of AND was noticed post complexation. The bioavailability was estimated to be 15.87 ± 3.84% and 23.84 ± 5.46%, respectively for AND and AND-2-HyP--CYD complex. AND-2-HyP--CYD complex may be a prospective candidate for further studies to evolve as a clinically viable formulation against SARS-CoV-2.