Solubility Enhancement of Lawsone by Complexation with Beta Cyclodextrin

Abstract

Introduction: Lawsone is a phyto-constituent obtained from the leaves of the Lawsonia inermis. It has antibacterial, antifungal, antiviral, wound healing, antiparasitic, tuberculostatic, anti-fertility, analgesic, anti-inflammatory, enzyme inhibitory, nematicidal, anticoagulant, and protein glycation inhibitory activities. It has poor water solubility (hydrophobic), poor bioavailability, and poor dissolution characteristics. Aim: The purpose of this research is to improve the aqueous solubility of Lawsone by preparing the inclusion complexes of Lawsone with beta-cyclodextrin. Materials and Methods: Inclusion complexes of Lawsone were prepared by different methods such as physical mixture, kneading method and co-precipitation method. Characterization of the complexes were done by Fourier Transform Infrared (FTIR) spectroscopy and in vitro dissolution study. Differential scanning calorimetry (DSC), Nuclear Magnetic Resonance spectroscopy (NMR), and Powder X-Ray Diffraction (PXRD). were used to evaluate the co-precipitation technique inclusion complexes. Antimicrobial studies of complexes against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), and Pseudomonas aeruginosa (P. aeruginosa) were done by colony counting method. Results: Phase solubility study revealed the molar ratio of Lawsone to beta-cyclodextrin in the complex is 1:1. At the third hour, the drug release was 64%, 78%, 93%, and 97% for pure drug, physical mixture, inclusion complexes formed by kneading technique and co-precipitation technique respectively. DSC, NMR, and PXRD confirmed the formation of complexes of Lawsone. The order of antibacterial activity of inclusion complexes was E. coli > B. subtilis > P. aeruginosa > S. aureus.