cis-4-(Ethylamino)-5,6-dihydro-6-methyl-4H-thieno[2,3-b]thiopyran-2-sulfonamide 7,7-dioxide monohydrochloride;Dorzolamide Related Compound B (15 mg) ((4R,6S)-4-(Ethylamino)-6-methyl-5,6-dihydro-4H-thieno[2,3-b]thiopyran-2-sulfonamide 7,7-dioxide hydrochloride);Dorzolamide EP Impurity B;rac-cis Dorzolamide;Dorzolamide EP Imp B;(4R,6S)-4-(ethylamino)-6-methyl-7,7-dioxo-5,6-dihydro-4H-thieno[2,3-b]thiopyran-2-sulfonamide:hydrochloride;(4RS,6SR)-4-(Ethylamino)-6-methyl-5,6-dihydro-4H-thieno[2, 3-b]thiopyran-2-sulfonamide 7,7-dioxide HCl;Dorzolamide Hydrochloride impurity B