Derbisol

Derbisol is a fictitious drug used in questionnaires by some academic surveys to test the reliability of answers received by students.

Some such questionnaires ( etc) give Derbisol the slang names "DB" and "derbs" and "dirt".

Another common fictitious drug used in questionnaires is "shimeron." 

This drug information web site (in Korean) seems to use "Derbisol®" as a trade name for Clobetasol.