Biocompatibility study for PVP wound dressing obtained in different conditions
Introduction
Hydrogels to be used as wound burn dressings were invented by Rosiak et al. (1989) and they have many interesting properties: immediate pain control; easy replacement; transparency to allow healing follow up; absorb and prevent loss of body fluids; barrier against bacteria; good adhesion; good handling; oxygen permeability; control of drug dosage and so on.
PVP wound dressing were prepared by radiation crosslinking and simultaneous sterilization of poly(vinyl-1-pyrrolidone) [PVP], polyethyleneglycol(PEG) and agar. The technology had to be adapted to the needs of the physicians, climate and raw materials. Key points of these technology have been studied: hydration/dehydration and mechanical properties were studied as a function of PVP molecular weight, PEG, agar concentration and irradiation dose, as well the polymeric structure of membrane (Lugão et al., 1998). Even though the starting materials were very pure, analytical or medical grade, the final product has to be biologically evaluated.
The aim of this work was to study in vitro biocompatibility of PVP membranes prepared in different conditions, determining the hemolysis and cytotoxicity of the membranes.
Section snippets
Materials
PVP with molecular weight of 1.2×106 (K-90) and 2.8×106 (K-120), from GAF Co.; PEG with molecular weight of 400, from Oxiteno and technical grade agar supplied by Oxoid. The hydrogel mixture solutions prepared according to the formulations listed in Table 1 were poured into molds, properly packed and submitted to irradiation in a Dynamitron electron accelerator with 1.5 MeV energy, dose rate of 11.3 kGy/s.
Hydrogel properties measurement
The measurements of mechanical properties were carried out using an Instron machine at a
Results and discussion
The membrane swelling and mechanical properties were shown in Table 1. Sorption of water, tensile strength and elongation decreased with increasing dose of radiation, but the values were in an acceptable range. The effect of increasing PVP concentration from 8.0 to 16.0% was shown with the tensile strength raised values, which could be attributed to the crosslinking formation caused by the closer proximity of PVP molecules in higher concentration.
In the cytotoxicity assay the relative
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Study of wound dressing structure and hydrating/dehydrating properties
Radiat. Phys. Chem
(1998) - ISO document 10 993-5 1992 Biological evaluation of medical devices, Part 4, Selection of tests for interactions with...