Derivater af isosorbid-mononitrat og deres anvendelse som vasodilaterende midler med formindsket tolerance

Disclosed are derivatives of isosorbid mononitrate and pharmaceutically acceptable salts thereof which have a vasodilator activity with a reduced tolerance effect, having the general formula (I) wherein A and B represent independently any of the groups NO2 and-CO-R, Z being an atom of oxygen or sulfur, and R being optionally substituted C1-C4 alkyl, aryl or aralkyl group or the group (a) wherein R is hydrogen or optionally substituted C1-C4 alkyl, aryl or aralkyl group,so that always either A or B is NO2 but never both at the same time, when Z is a sulfur atom R is optionally substituted C1-C4 alkyl, aryl or aralkyl group, and when Z is an oxygen atom R is the group (a).