A Comparison of Viscosity and Water Retainability between a Thickener and Oral Moisturizers

Abstract

　To assess the moisturizing effect of a thickener, the water retainability of a thickener and oral moisturizers was compared in vitro. Using a commercial thickener TsururinkoQ^®, xanthan gum and dextrin and commercial moisturizers, WetCare^® and Oralrefre Gel^®, the viscosities were measured with a SV-10 or ViSmart viscometer and the water retainability was assessed with a filter-paper method. In the concentration range of 1.5～3.0% (w/v), the viscosities of TsururinkoQ^®, xanthan gum and dextrin were 60.8～210, 526～1,307, 0.76～0.82 mPa・s, respectively. Those of WetCare^® and Oralrefre Gel^® were 1.19 and 1.37 mPa・s, respectively. From the changing curve pattern of residual water content, distilled water, WetCare^®, 0.3% (w/v) dextrin, 3.0% (w/v)dextrin and 1.5% (w/v)hyaluronic acid showed pattern Ⅰ. 0.3% (w/v) TsururinkoQ^®, 0.3% (w/v) xanthan gum and Oralrefre Gel^® pattern Ⅱ. 3.0% (w/v) TsururinkoQ^® pattern Ⅲ, and 3.0% (w/v) xanthan gum pattern Ⅳ. In the order of pattern Ⅰ, Ⅱ, Ⅲ and Ⅳ, the water retainability increased. Further, the rate of residual weight of 3.0% (w/v) TsururinkoQ^® was 1.3%. From these results, it was suggested that in the concentration range of 1.5～3.0% (w/v), the viscosity of TsururinkoQ^® might be 51.1～176 times that of WetCare^® and 44.4～153 times that of Oralrefre Gel^®, respectively and also TsururinkoQ^® might possibly have both greater water retainability than oral moisturizers and little dry residues.