Evaluation of pharmaceutical availability of drugs from topical preparations is usually aimed to evaluate the capability of the dosage form to release the drog for its therapeutic action. Permeation cells have been used for this purpose, employing soud membranes including cellophane. Within a study of phenylcarbamic acid derivatives with local anaesthetic effect, the present paper evaluates the dosage form for topical administration containing potential drog XIX M, the chemical name N-[2-(2-heptyloxyphenylcarbamoyloxy)-ethyl]-morpholinium chloride and potential drog XXII B, the chemical name N-[2-(2-octyloxyphenylcarbamoyloxy)-ethyl]-dimethylammonium chloride. The selected auxiliary substance in the formulation of the dosage form was a cellulose derivative - methylcellulose in increasing concentrations from 0.5 to 1.5 %. On the basis of the obtained results it can be stated tkat the examined polymer methylcellulose with increasing concentration decelerated the release of both potential drugs approximately in the same way and tkat it can be used in practice to prolong the local anaesthetic effect.

        Key words: colloidal dispersion - potential local anaesthetics - methylcellulose -