Abstracts Book - IMRC 2018

• SB2-P019
THERMO AND -pH SENSITIVE POLYURETHANE CATHETERS OF N-
VINYLIMIDAZOLE AND N-ISOPROPYLACRYLAMIDE SYNTHETIZED
BY RADIATION-GRAFTING.
Jessica Cecilia Audifred Aguilar 1 , Victor Hugo Pino Ramos 1 , Emilio Bucio 1
1 Instituto de Ciencias Nucleares UNAM, Macromolecules Radiation Chemistry, Mexico.
The surface modification of medical devices has emerged as an effective alternative
to obtaining materials with a better biocompatibility with living tissue by
enhancement in their hydrophilicity. Polymers widely used in medicine for example:
silicones, polyurethane (PU), polyethylene (PE), among others are characterized by
their own hydrophobic properties that make them susceptible to bacterial
adhesion. In recent years a new class of polymers has emerged, which are known
as smart polymers or stimulus sensitive, which undergo phase transitions when
they are exposed to variations in pH or temperature of their surrounding
environment. Ionizing radiation represents an important and innovative tool in the
synthesis of biomaterials since it plays the role of initiator in the grafting-radiation
without need chemical agents.
In this work, were synthesized thermos and -pH sensitive materials by means of
grafting of N-vinylimidazole and N-isopropylacrylamide in two steps by using graftradiation
method on polyurethane catheters. Monomer concentration and dose
effects were studied on the grafting yield. The grafted catheters were characterized
by infrared spectroscopy (FTIR-ATR), thermogravimetric analysis (TGA), nuclear
magnetic resonance in solid state ( 13 C CP/MAS NMR). Hydrophilicity of binary graft
copolymers was studied through swelling degree and wettability. The critical pH and
critical temperature (LCST) were determined gravimetrically by changes in the
welling degree varying the pH and temperature, respectively. Drug loading and
release studies were carried out in aqueous medium and the amount of loaded
drug was quantified by UV-vis. The binary graft copolymers obtained in this work
could have potential biomedical applications as drug delivery systems and also
antimicrobial properties.
Acknowledgment: This work was supported by DGAPA-UNAM under Grant
IN201617. The authors thank B. Leal and M Cruz ICN-UNAM for their technical
assistance.
Keywords: Grafting-radiation, Drug release, Catheters
Presenting authors email: jess.audifred@gmail.com