Polyacrilic acid derivatives are used as constituents of hydrogels in the preparations for dermatological and cosmetical application. The gels are produced relatively simply and their features are good stability, clarity, compatibility with a number of dermatological and cosmetically "active" substances. Different types of polyacrilic acid derivatives differ in-between themselves by their molecular mass, plotting, molecular structure and thereof render variety of properties to gels.

The objective of the paper was to formulate and characterise hydrogels with various polyacrilic acid derivatives (Carbopolâ -BF Goodrich-USA, Tego Carbomersâ -Goldschmidt, Germany) as carriers for Aloe Vera gel. In the gel production were used: Carbopolâ 934P, Carbopolâ 940, Carbopolâ Ultrez 10 Polymer i Tego Carbomerâ 140, in the concentration of 1%. All hydrogels were produced with purified water (Ph Jug IV), by adding 5% glycerol (humectans), 1% triethanolamine-neutralizing agent for polyacrilic acid and 3% Aloe Vera gel (Terra, USA).

The organoleptic properties of the gel, pH values (pH meter, H 8417 Hanna Instrument, USA) and its rheological behaviour (rotating viscometer Rotovisko RV 12, Haake, Germany) have been absorbed for 6 months. The pH values of the produced gels was within the limits of 5.26-5.92. The subject gels had satisfactory clarity and indicated plastic low type with expressed tixotropy.

Measuring parameters weredetermined at 48 hours, 7 days, 1, 3 and 6 months after the sample make, stored at t=20 (± 2)°C, packed in aluminium tubes. During the observation period there were no changes in their organoleptic characteristics, pH values of all gels were within the limits ± 0.3 pH unit from the initial value. Rheological behaviour remained the same, as it was 48 hours after the gel make. The values of relative viscosity with all gels measured at the specified speed (15 rpm) were somewhat smaller after 6 months storage compared to the initial values. It could be concluded that all applied polyacrilic acid derivatives could be used for Aloe Vera extract gel carriers.