A TSM sensor investigation of low crystallinity cellulose films

A thickness shear mode (TSM) quartz sensor has been used to characterize the substantivity, viscoelasticity, and mucoadhesive properties of low crystallinity cellulose (LCC) films. LCC is a novel pharmaceutical excipient that has been attributed with mucoadhesive properties. Thin films of LCC were deposited onto TSM sensors by a spin coating technique. The films were treated by passing water or 1.0% w/v mucin solution (pH 3.7 or 7.0) over the surface. Changes in the mass and viscosity of the film were observed by monitoring changes in the impedance spectra of the coated TSM sensors. Scanning electron micrographs (SEMs) of each film were used to assist the interpretation of the TSM sensor data. This study showed that LCC forms highly tenacious and viscoelastic films able to withstand prolonged (approximately 1 h) exposure to both water and mucin solution. Furthermore, these results indicate that the films may have mucoadhesive properties as LCC was found to bind significant (P<0.05) amounts of mucin in comparison with control measurements. Mucin binding to the LCC sensor was greater at pH 3.7 (P<0.05) than at pH 7.0, suggesting that the LCC formulation is mucoadhesive under these conditions.