From sterilised hydrogel containing 60 g/l of hydroxypropylmethylcellulose and graded amounts of added electrolyte, xerogel foils were lyophilised and shaped into samples of the size of ophthalmic lamellae. Under stationary conditions with modifications of the releasing solution of sodium chloride, the release of pilocarpinium chloride, atropinium sulfate, scopolaminium bromide and tetracainium chloride from a comparable amount of 3.6 mg of hydroxypropylmethylcellulose in the structure of xerogel was tested. A linear dependece of the rate of release on the amount of active ingredients was demonstrated. Finally, the rates of liberation of the individual active ingredients from hydrated xerogel were compared.

        Key words: lyophilisation – hydroxypropylmethylcellulose – xerogel – liberation