The active component of PROVENTIL® HFA (albuterol sulfate) Inhalation Aerosol is albuterol sulfate, USP racemic ?1 [(tert-Butylamino)methyl]-4-hydroxy-m-xylene-?,?'-diol sulfate (2:1)(salt), a relatively selective beta2-adrenergic bronchodilator having the following chemical structure: