Poly amino dicarboxylic acid-co-anhydro amino dicarboxylic acid derivative

A polyaminodicarboxylic acid-co-anhydroaminodicarboxylic acid derivative of the Formula I ##STR4## in which n is 1 or 2,

• x is 1 to 500,
• y is 1 to 500, where
• x+y is 2 to 1000 and
• R is NH--R.sup.2, in which
• R.sup.2 is (CH.sub.2).sub.m --OR.sup.1, and
• m is 2 to 6 and
• R.sup.1 is H, aryl, aralkyl, arylalkenyl, alkyl or C.sub.3 -C.sub.8 -cycloalkyl, where aryl is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl, C.sub.2 -C.sub.4 -alkenyl, C.sub.1 -C.sub.4 -alkylcarbonyloxy, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxy or hydroxyl, where
• the alkyl radicals for R.sup.1 have 1-22 carbon atoms and the alkenyl radicals have 2-22 carbon atoms, which are uninterrupted or interrupted by a carbonyloxy or oxycarbonyl group, or
• R.sup.1 is the monovalent residue of a biologically inactive steroid alcohol or an amino acid,
• where the repeating units in square brackets are distributed randomly or in blocks or both randomly and in blocks in the polymers and where both the repeating units indicated by x and y are identical or different and where the amino acids are .alpha.- or .beta.-linked or both .alpha.- and .beta.-linked.