[Effect of polymer concentration on rheological properties of Carbopol 980 hydrogels containing trimecainium chloride]. / Vplyv koncentrácie polyméru na reologické vlastnosti hydrogélov Carbopolu 980 s obsahom trimekaíniumchloridu.

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.

[Effect of pharmaceutical aids on physico-chemical indicators in solutions of substance XXII B]. / Vplyv pomocných látok na fyzikálno-chemické ukazovatele roztokov látky XXII B.

Within a study of optimization of auxiliary substances in the formulation of a hydrogel containing a potential local anaesthetic agent, substance XXII B, the paper evaluated the effect of a preservative (Ajatin) and humectants (glycerol, propylene glycol, sorbitol) on selected physicochemical indices, which included the partition coefficient, surface tension, and viscosity of the solutions of potential drug XXII B. On the basis of the statistical evaluation of the results, the optimal combination of auxiliary substances in this case seems to be Ajatin + glycerol.

[Rheologic properties of Vivastar P 5000 hydrogel]. / Stúdium reologických vlastností hydrogélov VIVASTARU P 5000.

Within the framework of pre-formulation studies, the paper evaluates the rheological properties of hydrogels whose gel-forming substance is a polymer supplied by the firm J. Rettenmaier & SöhneGMBH + CO. It is VIVASTAR P 5000, a modified derivate of carboxymethyl starch. The evaluation of rheological properties included hydrogels with 1.5, 2.0 and 2.5 w % of VIVASTAR P 5000. The highest viscosity was shown by the hydrogel with 2.0% concentration of the polymer. The system without and with the model drug with a local anaesthetic effect was thixotropic. From the viewpoint of topical administration, VIVASTAR P 5000 in 2.0% is optimal for hydrogel formulation.