Anticoagulant supramolecular-structured polymers: Synthesis and anticoagulant activity of taurine-conjugated carboxyethylester-polyrotaxanes

Polyrotaxanes with both sulfonyl and carboxyl groups were synthesized and characterized for mimicking the anticoagulant activity of heparin. A polyrotaxane consisting of α-cyclodextrins (α-CDs) and poly(ethylene glycol) (PEG) was synthesized, and carboxyethylester (CEE) groups and taurine were successively conjugated with the polyrotaxane to obtain taurine-conjugated carboxyethylester-polyrotaxanes (TAU-CEE-PRxs). The number of α-CDs and the anionic groups could be varied by synthetic conditions. The structural factors of TAU-CEE-PRxs affecting anticoagulant activity were suggested as following: (i) relatively lower threading percentage of α-CDs, (ii) the ratio of anionic groups similar to heparin, and (iii) lower molecular weight of PEG. The TAU-CEE-PRx that sufficiently meet the mentioned requirements showed enhanced antithrombin III (AT III) activity, indicating that the TAU-CEE-PRx interacts with AT III and/or thrombin. From these results, it is suggested that the sliding and rotation of free α-CDs with anionic groups are related with enhancing anticoagulant activity.