Interpretation of mucoadhesive properties of polymer gel preparations using a tensile strength method

We have developed a new tensile strength method for assessing mucoadhesive properties of polymer gels utilising freshly excised porcine nasal mucosa and a texture analyser. In conjunction with this, we propose a method for interpreting the mucoadhesive properties that is based on reasoning about the locus of the failure of a mucoadhesive joint. This involves measuring the cohesiveness of the gel and the mucus layer, respectively, and comparing these results with those obtained from a mucoadhesion measurement. Linear polymers (sodium carboxymethylcellulose, poly(acrylic acid) and sodium hyaluronate) and a cross‐linked polymer (poly(acrylic acid)) were used as model polymers in this study. It was shown that the withdrawal speed of the probe should be low, about 0.1 mm s−1, and that a contact time of 2 min was sufficient. In the mucoadhesion measurements there was no dependence of the results on the contact time in the interval 2–20 min. The tensile work appeared to be more applicable than the fracture strength for interpreting mucoadhesive properties. Furthermore, it was concluded that the interpretation procedure offers a good basis by which to assess whether the measured tensile work reflects a cohesive failure of the gel or a true interaction of the gel with the mucus layer.