A description is given of some 2 or 3 dialkylaminoalkyl derivatives of 8-acetylamino-2H-pyridazino[4,5-b][1,4]benzothiazin-1(10H)-one (IV a...d) and 8-acetylamino-3H-pyridazino[4,5-b][1,4]benzothiazin-4(10H)-one (VIII a...d). The derivatives were subjected to pharmacological examination.