A method of purifying herbal extract(s) from an herbaceous plant composition includes heating the herbal extracts-containing composition to volatilize at least one of herbal extract(s) into a vapor and condensing the vapor on a substrate or wet extracting the herbal extract(s) by treatment of the herbaceous plant composition or a derivative thereof with a solvent for the herbal extract(s), separating the solution of herbal extract(s), forming a concentrate and casting the concentrate on the substrate to form a coating of the herbal extract(s) on the substrate. A corresponding delivery cartridge and delivery system can include a controllable heating element and the substrate coated with at least one of herbal extract(s). These are configured to allow passage of air over the substrate to volatilize or entrain the herbal extract(s) as a vapor, gas or aerosol for administration to a user.