Polyoxazoline copolymer comprising calcium binding groups

A polyoxazoline (POx) copolymer comprising at least 20 oxazoline units, including at least 4 non-terminal oxazoline units that contain a calcium binding group selected from bisphosphonate, citrate, ethylenediaminetetraacetic acid (EDTA) and combinations thereof,

• wherein the copolymer comprises:
• (a) repeating units A of formula —[N(Ra)CH2CH2]—;
• (b) repeating units B of formula —[N(Rb)CH2CH2]—;
• (c) optionally repeating units C of formula —[N(Rc)CH2CH2]—;
• (d) optionally repeating units D of formula —[N(Rd)CH2CH2]—;
• and
• (e) optionally repeating units E of formula —[N(Re)CH2CH2]—;
• wherein:
• Ra is CO—(CHR1)t—H;
• Rb is CO—(CHR1)t—CONH—R2—X—CO—(CHR3)u—CONR4—CO-ccr;
• R1 represents H or optionally substituted C1-5 alkyl;
• R2 represents an optionally substituted C1-5 alkylene;
• R3 represents H or optionally substituted C1-5 alkyl;
• R4 represents H or CH3;
• X represents O, NR11, S or +NR11(R12);
• R11 and R12 represent H, methyl or ethyl;
• t represents 1, 2 or 3;
• u represents 1, 2 or 3;
• and
• ccr represents a calcium binding group.