The present invention relates to the compound of the formula (I) or pharmaceutically acceptable salts thereof, wherein R1 is arylalkyl or aryloxyalkyl (as further defined herein), as well as compositions containing the same, and processes for the preparation of the same. Therapeutic methods of use thereof are disclosed. The compound and pharmaceutically acceptable salts may be useful as sodium channel blockers and, particularly, in promoting hydration of mucosal surfaces and the treatment of diseases including chronic obstructive pulmonary disease (COPD), asthma, bronchiectasis, acute and chronic bronchitis, cystic fibrosis, emphysema, and pneumonia.
