The present invention relates to a poly (ester amide) (PEA) having a chemical formula described by structural formula (IV), wherein m+p varies from 0.9-0.1 and q varies from 0.1 to 0.9 m+p+q=1 whereby m or p could be 0 n is about 5 to about 300； (pref. 50-200) R1 is independently selected from the group consisting of (C2-C20) alkylene, (C2-C20) alkenylene, —(R9—CO—O—R10—O—CO—R9)—, —CHR11—O—CO—R12—COOCR11— and combinations thereof； R3 and R4 in a single backbone unit m or p, respectively, are independently selected from the group consisting of hydrogen, (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C6-C10)aryl, (C1-C6)alkyl, —(CH2)SH, —(CH2)2S(CH3), —CH2OH, —CH(OH)CH3, —(CH2)4NH3+, —(CH2)3NHC(═NH2+)NH2, —CH2COOH, —(CH2)COOH, —CH2—CO—NH2, —CH2CH2—CO—NH2, —CH2CH2COOH, CH3—CH2—CH(CH3)—, (CH3)2—CH—CH2—, H2N—(CH2)4—, Ph-CH2—, CH═C—CH2—, HO-p-Ph-CH2—, (CH3)2—CH—, Ph-NH—, NH—(CH2)3—C—, NH—CH═N—CH═C—CH2—. R5 is selected from the group consisting of (C2-C20)alkylene, (C2-C20)alkenylene, alkyloxy or oligoethyleneglycol R6 is selected from bicyclic-fragments of 1,4:3,6-dianhydrohexitols of structural formula (III)； R7 is selected from the group consisting of (C6-C10)aryl (C1-C6)alkyl R8 is (CH2)4-； R9 or R10 are independently selected from C2-C12 alkylene or C2-C12 alkenylene. R11 or R12 are independently selected from H, methyl, C2-C12 alkylene or C2-C12 alkenylene whereby a is at least 0.05 and b is at least 0.05 and a+b=1.
