Comparison of different in vitro and ex vivo methods to evaluate mucoadhesion of glycol-palmitoyl chitosan micelles

Glycol palmitoyl chitosan (GPC) is a hydrophobic derivative of chitosan described in literature as capable of self assembling in polymeric micelles. The palmitoyl derivatization involves the amino groups of the polysaccharide. These are the same groups generally considered responsible for the good mucoadhesive properties of chitosan, due to the ionic interaction with the sialic acidic moieties of the mucin. In the present work, the mucoadhesion properties of GPC micelles were evaluated by comparing the information obtained using different methods described in literature. This is a comparison which is not commonly found in literature. The results obtained by rheological synergism determination, turbidimetric analysis, zeta potential measurements, quantification of unadsorbed mucin and finally an ex vivo washability test were compared. Poloxamer micelles were also evaluated for comparison. The results obtained with all of the methods used were in good accordance to each other and indicated that even after self assembling in micelles, GPC maintains positive mucoadhesion properties.