Amphoteric Linear Poly(amido-amine)s as Endosomolytic Polymers:  Correlation between Physicochemical and Biological Properties

• Published in: Macromolecules 2000-10, Vol.33 (21), p.7793-7800
• Main Authors: Ferruti, Paolo, Manzoni, Sara, Richardson, Simon C. W, Duncan, Ruth, Pattrick, Nicola G, Mendichi, Raniero, Casolaro, Mario
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polycondensation; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma000378h

Five poly(amido-amine)s (PAAs) carrying two ter-amino groups and one carboxyl group per repeating unit were prepared by hydrogen-transfer polyaddition of 2-methylpiperazine (ISA 23), 1,2-bis(N-methylamino)ethane (DMEDA-BAC), 1,2-bis(N-ethylamino)ethane (DEEDA-BAC, 1,3-bis(N-methylamino)propane (DMEPDA-BAC), or 1,6-bis(N-methylamino)hexane (DMEXA-BAC), in each case to 2,2-bis(acrylamido)acetic acid (BAC). The resultant PAAs had an M n in the range 7 985−24 980 g/mole and an M w in the range 11 420−42 710 g/mole. Considerable differences were observed in the basicity of the amino groups present (log K°1 = 7.5−9.5; log K°2 = 3.2−8.4), whereas the log K°3 value (2−3) of the carboxyl groups was consistent with that of a fairly strong acid. DEEDA-BAC, DMEDA-BAC, and ISA 23 were nontoxic (IC50 > 5 mg/mL). Those PAAs with the highest log K°2 values were more cytotoxic (IC50 = 3.55 mg/mL for DMEPDA-BAC, and IC50 = 0.23 m/mL for DMEXA-BAC). All the PAAs displayed pH-dependent haemolysis (most lytic at pH 5.5), consistent with their proposed use as endosomolytic polymers.