Pharmaceutical pyrazolybenzothiazole compositions of formula (1) are provided. The compositions may be pharmaceutically acceptable salts. R1, R2 and R3 at each occurrence are independently selected from amino, aminosulfinyl, aminosulfonyl, aryl, azido, halogen, heteroalkyl, heteroaryl, hydrazinyl, hydrocarbyl, hydrogen, hydroxyl, nitro, nitroso, phosphate, phosphinate, phosphonate, phosphonium, phosphorothioate, phosphoryl, sulfamoyl, sulfate, sulfinic acid, sulfonamido, sulfonate, sulfonic acid, sulfonyl, sulfoxido, thiol, thioureido, and ureido, and R4 is selected from hydrogen, heteroalkyl, heteroaryl, and hydrocarbyl.