Found a note by a meth addict talking about having "some dry" and a "2 ml dose" and I don't know what drug they're talking about?

My friend let a friend stay with them because they're going through a rough time but their friend starting using meth. They found a letter where the meth user wrote a letter to some person telling them they were leaving them " some dry" and a "2ml dose." Any idea what kind of drug they're talking about?