Hard drugs Hard drugs are nonmetabolizable compounds characterized either by high lipid solubility and accumulation in adipose tissues and organelles or high water solubility They are poor substrates for the metabolizing enzymes, the potentially metabolically sensitive parts of these drugs are either sterically hindered or the hydrogen atoms are substituted with halogens to block oxidationHard Drugs • Hard drugs are nonmetabolizable compounds, characterized either by high lipid solubility and accumulation in adipose tissues and organelles or high watersolubility. • They are poor substrates for the metabolizing enzymes; the potentially metabolically sensitive parts of these drugs are either sterically hindered or the hydrogen atoms are substituted with halogensto block oxidation