Difluoroprostaglandin derivatives and their use

A fluorine-containing prostaglandin derivative of the following formula (1) or a salt thereof:

• ##STR4## wherein A is an ethylene group, a vinylene group, an ethynylene group, --OCH.sub.2 -- or --SCH.sub.2 --,
• R.sup.1 is a substituted or unsubstituted aryloxyalkyl group,
• each of R.sup.2 and R.sup.3 which are independent of each other, is a hydrogen atom or an acyl group, or forms a single bond together with Z,
• X is --CH.sub.2 --, --O-- or --S--,
• Z is --OR.sup.4, --NHCOR.sup.5, --NHSO.sub.2 R.sup.6 or --SR.sup.7, or forms a single bond together with R.sup.2 or R.sup.3,
• each of R.sup.4, R.sup.5, R.sup.6 and R.sup.7 which are independent of one another, is a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group or an aralkyl group,
• and a dual line consisting of solid and broken lines is a single bond, a cis-double bond or a trans-double bond.