화학공학소재연구정보센터
Journal of Applied Polymer Science, Vol.73, No.11, 2143-2150, 1999
Aliphatic polyamides prepared by ester-amine polycondensation as potential drug carrier polymers
Aliphatic polyamides of interest as macromolecular drug carriers are synthesized by base-catalyzed polycondensation of aliphatic diesters with diamines. The reactions are conducted in the presence of anhydrous sodium carbonate at temperatures ranging from ambient to 65 degrees C, initially in the undilute state. The addition of aprotic solvent at a later stage serves to maintain sufficiently low viscosity for proper homogenization. The comonomers, diethyl 3,6,9-hioxaundecanedioate and 4,7,10-trioxa-1,13 -tridecanediamine, copolymerize to form polymer 1, a straight-chain polyamide devoid of specific functionality. Use of diethyl tartrate in lieu of the aforementioned diester leads to polyamide 2 possessing hydroxyl side groups. Other experiments in which diamines incorporating additional (secondary) amino groups are employed afford polyamides 3-8 containing such secondary amine functions as main-chain constituents. The water-soluble target polymers are crudely fractionated by aqueous dialysis (12000-14000 molecular mass cut-off) and collected by freeze-drying in yields of 20 to 40%. The low-yield range has been accepted in this investigation as the price to be paid for the realization of linear polyamide structures in accordance with compositional expectations, a requirement vital for the proper functioning of the polymers as drug carriers. The practicability of drug binding (conjugating) is exemplified by the coupling of ferrocene as a drug model to polyamide 5 via amide Linkage. The water-soluble conjugate 5-Fc features an iron content corresponding to one ferrocene group in the repeat unit.