Random block copolymers having the formula: ##STR1## wherein R.sub.1 is --CH.dbd.CH-- or (--CH.sub.2 --).sub.j, in which j is zero or an integer from one to eight; R.sub.2 is selected from hydrogen, straight and branched alkyl and alkylaryl groups containing up to 18 carbon atoms and derivatives or biologically and pharmaceutically active compounds covalently bonded to said copolymer; each R.sub.3 is independently an alkylene group containing up to 4 carbon atoms; y is an integer between about 5 and about 3000; and f is the percent molar fraction of alkylene oxide in the copolymer and ranges between about 1 and about 99 mole percent. Implantable medical devices and drug delivery implants containing the random block copolymers are also disclosed, along with methods for drug delivery and for preventing the formation of adhesions between injured tissues employing the random block copolymers. Polyarylate random block copolymers are also described.