Effect of β-cyclodextrin on Rheological Properties of some Viscosity Modifiers

Cyclodextrins are a group of novel excipients, extensively used in the present pharmaceutical industry. Sometimes they show significant interactions with other conventional additives used in the formulation of dosage forms. The effect of β-cyclodextrin on the rheological properties of aqueous solutions of some selected viscosity modifiers was studied in the present work. β-cyclodextrin showed two different types of effects on the rheology of the selected polymers. In case of natural polymers like xanthan gum and guar gum, enhanced apparent viscosity was found and in case of semi-synthetic polymers like sodium carboxymethyl cellulose and methyl cellulose, reduction in apparent viscosity was found. β-cyclodextrin was included at 0.5, 1 and 2% w/v concentrations into the polymeric solutions. These findings are useful in the adjustment of concentrations of viscosity modifiers during the formulation of physically stable disperse systems.