PVA is biodegradable but the human body can only eliminate up to a certain Mw, what is?
Common medical uses of PVA are in soft contact lenses" but not alone because PHEMA is the main polymer used", eye drops, embolization particles, tissue adhesion barriers, and as artificial cartilage and meniscus. It is also interesting to know that the sheets of beds & pillow covers in hospitals in some countries are collected in PVA bags which are thrown into the washing machines! As a rule of thumb, a polymer is utilized at reasonable average molecular weight (say ~ 20,000 to below 100,000).
According Jindich Kopecek & Karel Ulbrich work published in Prog. Polym. Sci., Vol. 9, pp. 1-58, 1983, say that: "Owing to its low molecular weight (10000-15000)after application in vivo, the polymer is eliminated from the organism by glomerular filtration." However when I read some works with PVA for medical applications mostly use high molecular weights. For that reason I felt a little bit confused.
When this science was born in the 1920s, the word "high" used to accompany the word "polymer(s)",so in old books or old research papers "high polymers" was repeatedly used. Afterwards, there has been widespread agreement to remove the word "high" and to recognize a true polymer as one which has average molecular weight of >10,000. Polymers with lower molecular weights were called "oligomers".
Generally speaking, PVA & other polymers are used at the molecular weight range I mentioned above. It may be used when having 10,000-15,000 molecular weight especially in foods or the adhesive on stamps or letters envelopes' adhesives or even medicines to utilize its enhanced solubility in water which allows its removal by glomerual filtration more easily.
Dear Julina please kindly request to read my recent paper in this topic which i used PVA for electrospun and soft tissue engineering application.
http://www.sciencedirect.com/science/article/pii/S2187076415000810
The polymer solution was prepared by dissolving different ratios 90:10, 80:20, 70:30, 60:40 of PVA/IGT in 100 ml of deionized water. We selected an 80:20 ratio of PVA/IGT, as it obtained a maximum solubility in comparison with other solvents used for electrospinning. The NC in different concentrations, 0.0%, 1%, and 3% (w/w), was used. The effect of NC on the nanobiopolymers was investigated by FTIR analysis. The homogenized NC was then slowly added to the PVA/IGT solution with stirring process at room temperature. The solution was allowed to stir for 30 min in a sealed container and the obtained mixture was further sonicated for 5 min.
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