Biocompatible and biodegradable poly (phosphoester-urethanes)

A biocompatible and biodegradable poly-(phosphoester-urethane) of the formula:

• ##STR6## wherein R is hydrogen, alkyl having C.sub.1 -C.sub.12, or a residue of a therapeutic agent capable of being released in a physiological environment;
• R.sub.1 is selected from the group consisting of C.sub.2 -C.sub.20 alkylene, C.sub.6 -C.sub.20 arylene,
• C.sub.7 -C.sub.20 aralkylene, C.sub.6 -C.sub.20 cycloalkylene, and a divalent residue of an amino acid, an amino acid derivative or an amino acid mimetic;
• R.sub.2 is selected from the group consisting of C.sub.2 -C.sub.6 polyalkylene having a molecular weight of from about 500 to about 2000, C.sub.2 -C.sub.6 polyalkenylene having a molecular weight of from about 500 to about 2000, C.sub.7 -C.sub.20 aralkylene, (R.sub.3 O).sub.l wherein R.sub.3 is C.sub.2 -C.sub.6 alkylene or acyl having from 2 to 6 carbons, and l is an integer of from 5 to 30, and ##STR7## wherein R.sub.4 is hydrogen or alkyl having C.sub.1 -C.sub.12 ;
• n is an integer of from 2 to 6;
• and
• m is an integer of from about 10 to about 10.sup.5.