The paper evaluated the compressibility of dry binders prepared in the ratios of 3:1, 1:1, and 1:3 from Pharmatosa DCL 15 and DCL 21 and Avicel PH 200, and the sensitivity of the mixtures to an addition of the lubricant magnesium stearate from the standpoint of the effect on the strength of tablets. Mixtures of lactoses with Avicel PH -200 in a ratio of 3:1 proved to be most advantageous. The strengths of tablets made of these mixtures oscillated in the optimal range and they showed the least sensitivity to the added lubricant. An increase in stearate concentration did not result in a marked decrease in the strength of compacts. Pharmatosa DCL 21 in a mixture with Avicel PH 200 yielded stronger compacts at lower compression force than Pharmatosa DCL 15.

        Key words: mixed dry binders – Pharmatosa DCL 15 – Pharmatosa DCL 21 – Avicel PH 200 – magnesium stearate – tensile strength of tablets