Vitamin biocompatibility

Cellulose acetate (CA), the acetate ester of cellulose, is one of the most commonly used biocompatible materials for the preparation of semi-permeable membranes to be used for dialysis, ultrafiltration, and reverse osmosis. CA membranes have very low absorption characteristics and thermal stability with high flow rates. Cellulose-based materials are also widely used in the bio-pharmaceutical industry as the matrix for adsorbent beads and membranes. Moreover, CA nanofibers can be used as carrier for delivery of vitamins or pharmaceutical products [15]. 

Alternative AOs for providing melt-processing stability include natural or s)m-thetic vitamin E (as oi-tocopherol, its active form). As a safe, biocompatible alternative for food and health product packaging and human-contart applications, vitamin E is a fast-acting, hindered-phenolic AO that stabilizes via a complicated reaction mechanism analogous to its reactions in a living body, ft is more expensive than other phenohc AOs, though it can be used in lower concentrations (0.025% or lower) [1-1, 3-5]. 

Figure 11.1 shows a collection of FTIR spectra through the thickness of a shelf-aged, EtO-sterilized cup where bulk oxidation was evident. Gamma irradiation of the UHMWPE was ruled out by examination of the transvinylene region of the ETIR spectra. The absorption at 1718 cm i is attributed to ketones. In this case, the oxidation was associated with poor consolidation of the UHMWPE, rather than the result of the sterilization process itself. These results suggest that prosthetic UHMWPE needs stabilization, as the totality of commercial polyolefines. Biocompatible stabilizers, such as vitamin E (an a-tocopherol), are easily available on the market and already employed in a number of different applications (Costa et al. 1998b, Costa et al. 2000). 

Bio-rejuvenation or bio-revitalization (mesolift) is a technique that utilizes the injection of absorbable and biocompatible substances into the superficial dermis in order to increase skin firmness, brightness, and moisturization. Most utilized agents include nonreticular hyaluronic acid 0.2-3% alone or associated with vitamins, amino acids, minerals, coenzymes, nucleic acids, antioxidants and beta-glucan, polynucleotidic macromolecules, organic silicium, autologous cultured fibroblasts, growth factors, and homeopathic products. 

Negative results of protein adsorption, such as membrane fouling, thromboembolitic effects of implants, deffects of contact lens and others have been considered and some ways to reduce undesirable processes are given. To remove these difficulties it is useful to use low energetic surfaces of optimal surface energy with well water saturated surfaces, to avoid essential contributions of electrostatic interactions between the surfaces of protein and adsorbent, as well as conditions inducing denaturation of proteins in a solution. Materials with pre-adsorbed HSA, or a mixture of HSA and vitamin C are useful especially for biocompatibility improving. 

The blend created for tissue engineering scaffolds can also be used as a material for drug delivery. Reddy et al7 reported the development of a bone filler and drug delivery vehicle using a bionanocomposite, which was filled with bone morphogenetic protein, which stimulates bone formation. Besides that, a hydro>yapatite/chitosan nanocomposite was used in the controlled release of vitamins from the matrix. The blending of PHAs could also be used in a similar way since they share the same features, such as the biocompatibility and not causing adverse effects, which produce desirable clinical outcomes. Chan et developed P(3HB)/EtC blends with a... 

Most recently, in 2009, Ticona introduced two new vitamin E-blended resins to the orthopedic community to improve the oxidation resistance of UHMWPE after irradiation. GUR 1020-E and 1050-E are blended with 1,000 ppm of the biocompatible antioxidant, vitamin E, but otherwise conform to the properties and processabihty of GUR 1020 and 1050. Further details about vitamin-E blended UHMWPE are summarized in Chapter 16. 

According to the results obtained using norms EN 30993-5, DIN UA 12, and in vivo animal tests reported in the literature, vitamin E and its products of oxydegradation are biocompatible and not cytotoxic [64—66]. 

Another proposed biocompatible cross-linker was vitamin B2 (Sridhar et al., 2014]. Upon UV treatment, the vitamin generates singlet oxygen radicals that assist the cross-linking process of GL microfibers, acting simultaneously as cross-linker and bioactive molecule to be released. 

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