Descriptive terms
Parts of solvent needed for 1 part solute
Very soluble
<1
Freely soluble
1-10
Soluble
10-30
Sparingly soluble
30-100
Slightly soluble
100-1000
Very slightly soluble
1000-10,000
Practically insoluble or insoluble
>10,000
Table 2:
Classifying solubilities of drugs as per US Pharmacopeia (USP, 2011).