Rifaximin is a rifamycin derivative, having extremely poor aqueous
solubility. The objective of present study was to improve dissolution and solubility
of drug using β-cyclodextrin inclusion complexes and also to evaluate the effect of
presence of sodium deoxycholate on solubilization efficiency of β-cyclodextrin. The
stochiometry of inclusion complexes of binary (drug-cyclodextrin) and ternary
system (drug-cyclodextrin-sodium deoxycholate) were determined by phase solubility studies at
25°C. The stability constants (K1:2) calculated from phase solubility analysis were 126M-1 and
267M-1 for binary and ternary systems respectively. The inclusion complexes were prepared by
solvent evaporation method with the inclusion efficiency of 43% and 56.9% for binary and ternary
systems followed by their characterization using fourier transform infrared spectroscopy, X-ray
diffractometry, differential scanning calorimetry and in-vitro antibacterial activity. The solubility of
drug was improved by 4.3 and 11.9 folds in binary and ternary inclusion complexes, respectively.
Therefore, it can be concluded that the ternary inclusion complexation having better solubilization
efficiency as compared to binary complexation.
Keywords: β-cyclodextrin, FTIR, phase solubility, Rifaximin, ternary inclusion complexes, X-RD,
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