A method of purifying at least one of THC and CBD from a cannabis-containing composition includes heating the cannabis-containing composition to a temperature sufficient to volatilize at least one of THC and CBD into a vapor and condensing the vapor on a substrate. A drug delivery cartridge includes a substrate coated with at least one of THC and CBD and configured to allow for passage of air through the cartridge to volatilize at least one of THC and CBD for inhalation by a user to induce a medicinal or therapeutic effect to the user.