The transfer of a drug from high concentrated areas to low concentrated areas is generally defined as:
1. infusion
2. levigation
3. diffusion
4. dissolution
3 The transfer of a drug from a high concentrated area to a low concentrated area is defined as diffusion.
The addition of a levigating agent into a solid to blend to make a paste is defined as levigation i.e. the addition of glycerine to the sulfa powder.