[Studies on the mixing and the stability of diphenhydramine-containing powders (author's transl)]

The anti-allergic agent diphenhydramine (Dimedrol) is of poor mixability. Mixing is facilitated by the addition of 2.5--5% Aerosil 380 or of only 0.5--1% Aerosil 200 and R 972. The volume of weight of the powder mixtures is increased by adding 0.5% of any of these adjuvants, and the angle of inclination is considerably reduced by the addition of 0.5--1%. Flowable mixtures are obtained only with Aerosil 380 and R 972. Stability was best in mixtures containing 2.5--5% Aerosil 380. Such mixtures are most suited with regard to mixability and stability.