shape of a crystal and this is called the crystal habit which is
the consequence of the rate at which different faces grow.
Changes in internal packing usually (but not always) give an
easily distinguishable change in the crystal habit. With any
crystalline material, the largest face is always the slowest
growing and some crystal faces may have more exposed polar
groups and others may be relatively non-polar that are depend
on the packing geometry of the molecules into the lattice. In
other words, the growth on different faces will depend on the
relative affinities of the solute for the solvent and the growing
faces of the crystal. It is technically possible to engineer
changes in crystal habit by deliberately manipulating the rate
of growth of different faces of the crystal [5]. Crystallization,
particularly crystallization from solutions, is the vitally
important operation in the production of pharmaceutical solid
particles because most of drug particles (