Rheological properties exert influence on the manufacturing processes, stability and usability of a dosage form as well as the biological availability of an active ingredient. The present paper examines the effect of Carbopol® 980 concentration on rheological properties of hydrogels with and without trimecainium chloride for a period of 2, 7, and 14 days after their preparation. On the basis of an evaluation of the changes in structural viscosity in dependence on the period of measurement, it has been concluded that for formulation of trimecainium chloride to a dermal dosage form, Carbopol® 980 concentrations of 0.5 and 1.2 % are suitable.

        Key words: Carbopol® 980 – trimecainium chloride – hydrogels – rheological properties