Correlation between crystal habit and the composition of solvated and nonsolvated cholesterol crystals.

The correlation between the crystal habit and the composition of cholesterol crystals formed in four organic solvents (methanol, acetonitrile, ethanol, and acetone) was studied. Anhydrous and monohydrate cholesterol were precipitated in anhydrous and aqueous organic solvent mixtures, respectively. The main conclusions derived from the study were that 1) the appearance of plates does not automatically guarantee the presence of hydrated cholesterol, and 2) the presence of 5% or more of water in the crystallization solvent may not results in the formation of monohydrate cholesterol.