Stress relaxation studies of granules as a function of different lubricants.

Viscoelastic properties of granules may be studied using stress relaxation. The effect of viscoelastic properties of different lubricants, namely magnesium stearate (Mgst), talc and precirol, on granule compaction properties was examined using texture analyzer TA-XT2i at low pressure. Normalized compact curves of stress relaxation have been discussed in relation to some parameters (flowability, porosity, viscoelasticity as well as particle size).

Comparative tablet and rheological properties of new microcrystalline cellulose: direct compression and wet granulation methods.

The overall objective of this study was to compare the rheological properties and tablet characteristics of two new varieties of celluloses (Vivacel 101 and 102), recently produced and commercialized, with the classical varieties of celluloses (Avicel and Elcema). The results showed no significant differences in the rheological properties of Vivacel and Avicel, while significant differences were found between the two celluloses and Elcema. Furthermore, there were no statistically significant differences in the disintegration times and Td values of Vivacel and Avicel.

Controlled-release behavior of diphenhydramine hydrochloride loaded neutral microgranules and coated using ethylcellulose water dispersion.

The development of a loading method of a water-soluble drug using aqueous binding solution to produce microgranules that were then coated with an aqueous ethylcellulose dispersion to sustain drug release is described. The results, in terms of drug used, showed that besides the fluidized bed parameters, the amount of drug dissolved in the binder solution plays an important role in obtaining a satisfying result during the spraying process. Thus, it seems necessary to determine the critical concentration above which the material started to adhere to the interior of the fluidization column, and the possibility of drug layering onto carrier material is aggravated.