The main problems which occur during the preparation of solid dosage forms (especially
tablets and capsules) are the insufficient flow of the particles, poor compactibility
and inadequate stability of the materials. The aim of preformulation, therefore, is
to eliminate such problems, if possible. The effects of granulation and coating were
examined. Dimenhydrinate was chosen as a model drug with low-flow properties and decomposition
at the melting point. The shape of the particles and the flow properties (angle of
repose, mass by volume, flow time, the Hausner factor and Carr's index) were determined.
Differential scanning calorimetry was used to check the features of the sample on
exposure to heat and to measure the melting point. The effect of the coating film
on the melting point was observed during melting.