A TSM sensor investigation of low crystallinity cellulose films

A thickness shear mode (TSM) quartz sensor has been used to characterize th e substantivity, viscoelasticity, and mucoadhesive properties of low crysta llinity cellulose (LCC) films. LCC is a novel pharmaceutical excipient that has been attributed with mucoadhesive properties. Thin films of LCC were d eposited onto TSM sensors by a spin coating technique. The films were treat ed by passing water or 1.0% w/v mucin solution (pH 3.7 or 7.0) over the sur face. Changes in the mass and viscosity of the film were observed by monito ring changes in the impedance spectra of the coated TSM sensors. Scanning e lectron micrographs (SEMs) of each film were used to assist the interpretat ion of the TSM sensor data. This study showed that LCC forms highly tenacio us and viscoelastic films able to withstand prolonged (approximately 1 h) e xposure to both water and mucin solution. Furthermore, these results indica te that the films may have mucoadhesive properties as LCC was found to bind significant (P < 0.05) amounts of mucin in comparison with control measure ments. Mucin binding to the LCC sensor was greater at pH 3.7 (P < 0.05) tha n at pH 7.0, suggesting that the LCC formulation is mucoadhesive under thes e conditions. (C) 2001 Elsevier Science B.V. All rights reserved.