INVESTIGADORES
GONZALEZ Jimena Soledad
capítulos de libros
Título:
POLY (VINYL ALCOHOL) HYDROGELS: INFLUENCE OF PROCESSING VARIABLES ON GENERAL BEHAVIOR AND DRUG RELEASE DEVICE PERFORMANCE
Autor/es:
JIMENA SOLEDAD GONZALEZ; VERA ALEJANDRA ALVAREZ
Libro:
In: Advances in Materials Science Research
Editorial:
Nova Science Publishers, Inc
Referencias:
Año: 2011; p. 265 - 285
Resumen:
Poly (vinyl alcohol) (PVA) hydrogels have a
number of interesting properties whose make it an excellent candidate for several
applications. One of the well known uses of these materials is like drug
delivery device for their high hydrofilicity and water uptake capability.
Hydrogels of PVA were obtained by two
different routes: chemical method (by using a crosslinking agent, such as
glutaraldehyde (GA)) and by physical method (carried out by freezing/thawing
(F/T), resulting in cryogels). The main advantages of F/T are its easiness that
does require neither high temperatures nor toxic agents as waste that can be
harmful to the human body. It is possible, for biomedical applications, that
un-reacted residue from the crosslinking agent may eluted slowly over time
resulting in the release of toxic agents; being this toxicity undesirable for
pharmaceutical applications because the activity of the drug or agent being
released could be destroyed.
The properties of PVA hydrogels depend
mainly on their density or degree of crosslinking and crystallinity.
Nevertheless, it is still unclear what role of processing variables play on the
significant properties of the material. These properties can be driven by the
numbers of F/T cycles, the cycle extent, the freezing temperature, the rate of
thawing, the polymer concentration and its molecular weight (Mw).
The aim of this chapter was to analyze the
effect of some processing variables on the characteristic and properties of PVA
hydrogels and to look at the delivery system behavior in aspirin and ibuprofen
drugs. For this purpose, cryogels with different: numbers of F/T cycles (1 to
4), cycles extent (1, 12 and 24 h), Mw (18000; 40500, 93500 and 155000 g/mol)
and polymer concentration (5 to 15 wt.%) were synthesized and analyzed by means
of thermogravimetric analysis (TGA), differential scanning calorimetric (DSC),
swelling studies, X-ray diffraction (XRD), rheological tests and mechanical
properties. In addition, cryogels were compared with chemically based hydrogels
by means of selected characterization techniques.
The results obtained in the present study
suggest that it is possible to obtain cryogels with controlled properties and
to be optimist about the future use of these kinds of hydrogels, avoiding the
use of toxic crosslinking agent, for applications such as drug delivery.