FIELD: polymer production. SUBSTANCE: invention relates to polyesters containing one or more free carboxylic groups at COOH/OH ratio more than 1 and having (i) one motif selected from group including: L-lactic acid, D-lactic acid, DL-lactic acid, ε-caprolactone, p-dioxanone, ε-caproic acid, alkylene oxalate, cycloalkylene oxalate, alkylene succinate, β-hydroxybutyrate, substituted or unsubstituted trimethylene carbonate, 1,5-dioxepan-2-one, 1,4-dioxepan-2-one, glycolide, glycolic acid, L-lactide, D-lactide, DL-lactide, mesolactide, and all their optically active isomers, racemates or copolymers and (ii) one motif selected from malic acid, citric acid, and 1,6-hexanediol and all their optically active isomers, racemates or copolymers. Average polymerization degree of indicated polyester lies between 10 and 300 and average molecular weight between 1200 and about 40000. In polyester conjugate, polyester is bound to active polypeptide containing at least one ionogenic amine group, wherein at least 50 wt.% of polypeptide is bound ionically. EFFECT: extended choice of biologically active compounds. 12 cl, 3 dwg, 6 tbl
