It depends on the pH of the dilutant. if the dilution substance is base the acidic solution will become less acidic moving toward neutral pH, the more it is diluted the less acidic it will become. A base solution will remain base or about 7 pH
Normally medicines are not highly acidic or basic. They are mainly weakly acidic or basic substances or salt of weakly acidic or basic substances. Only a few drugs are acidic or basic. The properties of the medicines are depends on the route of administration and target area of the drug.