DEVELOPMENT OF POLY(AMIDO AMINE) BASED CONTRAST AGENTS FOR MAGNETIC RESONANCE IMAGING

• Main Author: Ayurini, Meri
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34414
• Institution: Institut Teknologi Bandung

A series of water soluble homopolymers and copolymers based on poly(amido amine) has been successfully synthesized by means of aza-type Michael polyaddition. Their characterizations were carried out by 1H-NMR spectroscopy and Gel Permeation Chromatography (GPC). One of the resulting copolymers, poly(MBA-DAB-ABOL) I containing 100% N,N?-Methylenebis(acrylamide) (MBA), 27 % 1,4-butadiamine (DAB), and 73 % 4-amino-1-butanol (ABOL), then was further developed as a potential novel contrast agent based on gadolinium for magnetic resonance imaging (MRI). Grafting of diethylenetriaminepentaacetic acid (DTPA) onto the poly(MBA-DAB-ABOL) I was carried out by isothiocyanate (NCS) coupling reaction in DMSO and triethylamine (3:1) at 45 °C for 2 days, yielding 96 % coupling efficiency according to the 1H-NMR spectrum. A colorimetric assay employing 4-(2-pyridylazo)-resorcinol (PAR) was used to quantify the chelated and free gadolinium in the system. This was carried out in 100 mM MES buffer at pH 5.5. The binding constant (Log K) of the Gd3+-PAR (1:1) complex at pH 5.5 is 4.43 ± 0.09 M-1. Furthermore, ligand competition experiments employing PAR, Gd3+, and several ligands (i.e. DTPA, DOTA, and EDDA) were carried out in order to observe the behavior of Gd3+ with the ligands. According to the results, it was found that both DTPA and DOTA bind Gd3+ strongly. On the other hand, EDDA only binds Gd3+ weakly. Furthermore, the ligand competition experiment was carried out to observe the complexation behavior between Gd3+ and the synthesized DTPA grafted poly(MBA- DAB-ABOL)I. Strong complexation between them was observed. In general, this research has demonstrated that the synthesized poly(amido amine) grafting DTPA is potential for being macromolecular contrast agent based gadolinium for MRI. Moreover, colorimetric assay employing PAR is a fast and inexpensive method in order to observe the complexation behavior between targeted molecules and Gd3+.