Therapeutic agents

Quinolone sulphonates of formula I in which R1 is lower alkyl; R2 is lower alkyl; and R3, R4 and R5, which may be the same or different, are hydrogen, lower alkyl, lower alkoxy, lower alkylthio, lower alkylsulphinyl, lower alkylsulphonyl, halo, halogenated lower alkyl, halogenated lower alkoxy, cyano, phenyl or phenyl substituted by 1 or 2 groups independently selected from lower alkyl, lower alkoxy and halo, have antihypertensive activity. Processes for preparing compounds of formula I and pharmaceutical compositions containing them are described. Compounds of formula I are also indicated for use in the treatment of heart failure and ischaemic heart disease.