Blood bags

Aliphatic isocyanates have a small but growing market application in thermoplastic polyurethanes (TPU). Medical appflcafions include wound dressings, catheters, implant devices, and blood bags. A security glass system using light-stable TPU as an inner layer is under evaluation for shatterproof automotive windshield appflcafions. 

Poly(tetramethylene oxide) polyols (PTMEG) are high performance polyethers that are crystalline waxes at molecular weights above 650 and liquids at lower molecular weights. They are only available as diols, but they produce adhesives with good hydrolysis resistance and moisture resistance, which is why these adhesives are even used in medical devices, blood bags, catheters, and heart-assist devices [25]. Certain thermoplastic polyurethane adhesives and solvent-borne adhesives are also based on PTMEG s. 

By derogation from other rules, blood bags are in Class lib. 

Medical - artificial joints, blood bags , anaesthetics, disinfectants, anti-cancer dmgs, vaccines, dental fillings, contact lenses, contraceptives. 

The identity of each blood donor should be recorded, and all donor blood bags must be labelled carefully. Traceability of individual blood donors/donations is essential, in case the donor or product is subsequently found to harbour blood-borne pathogens. The risk of contamination of blood during collection/processing is minimized by using closed systems and strict aseptic technique. 

Medical devices may be assisted in their function by pharmacological, immunological or metabolic means, but as soon as these means are not any more ancillary with respect to the principal purpose of a product, the product becomes a medicinal product. The claims made for a product, in accordance with its method of action may, in this context, represent an important factor for its classification as MD or medicinal product. Examples of MDs incorporating a medicinal substance with ancillary action include catheters coated with heparin or an antibiotic, bone cements containing antibiotic and blood bags containing anticoagulant. ... 

Rule 18 puts blood bags into Class Ilb. 

The development of plasticizers has been plagued with toxicity problems. Thus the use of highly toxic polychlorinated biphenyls (PCBs) has been discontinued. Blood stored in plasticized PVC blood bags and tubing may extract phthalic add esters, such as DOP. These aromatic esters are also distilled slowly from PVC upholstery in closed automobiles in hot weather. These problems have been solved by using oligomeric polyesters as nonfugitive plasticizers instead of DOP. 

Di(2-ethylhexyl) phthalate was detected in whole blood at levels ranging from 16.8 to 46.1 ig/mL [mg/L] and in packed cells at levels ranging from 32.6 to 55.5 p,g/mL [mg/L] in PVC blood bags stored at 5 °C. These levels increased with storage. The average content was 6.7 4.6 ig/mL in cryoprecipitate and 7.4 2.8 Xg/mL in fresh frozen plasma. Both values were independent of the storage period (Sasakawa Mitomi, 1978). 

Jaeger, R.J. Rubin, R.J. (1972) Migration of a phthalate ester plasticizer from polyvinyl chloride blood bags into stored human blood and its localization in human tissues. New Engl. J. Med., 287, 1114-1118... 

The need to transfuse blood components such as plasma, platelets, factor VIII, in addition to red blood cells (RBC) has generated the development of plasmapheresis (plasma separation from whole blood) and more generally that of apheresis (fractionation of blood components). Plasma collection from donors by centrifugation of blood bags began only in 1944. This technique was extended to therapeutic plasma purification in 1950, but RBCs were fragilized by the centrifugation and the plasma was not completely platelet-free. 

Experiments have been conducted to simulate leaching of phthalates from blood bags by allowing human plasma to extract added phthalates from coated Celite (Albro and Corbett 1978). It was found that more than 80% of the DEHP was associated with lipoproteins, in the order LDL > VLDL > HDL > chilomicrons. The remaining DEHP was adsorbed weakly and nonspecifically to other proteins including albumin. MEHP was in equilibrium between free in solution and adsorbed to albumin, no MEHP was bound to lipoproteins. Rock et al. (1986) reported that in human plasma, the lipase that hydrolyzes DEHP copurified with the albumin, and once in the plasma, the MEHP bound to albumin. An earlier study by Jaeger and Rubin (1972) reported that in human blood stored in PVC bags, the bulk of DEHP was associated with lipoproteins, but a substantial amount was in a fraction likely to represent DEHP soluble in plasma water as well as bound to plasma proteins and cell membranes. 

Bannai M, Mazda T, Ishikawa Y, et al. 1987. The effect of di-(2-ethylhexyl)phthalate, a chemical leached from blood bags on platelet adenosine diphosphate aggregability. Chan Pharm Bull 35 43284331. 

In some technological and medical applications protein adsorption and/or cell adhesion is advantageous, but in others it is detrimental. In bioreactors it is stimulated to obtain favourable production conditions. In contrast, biofilm formation may cause contamination problems in water purification systems, in food processing equipment and on kitchen tools. Similarly, bacterial adhesion on synthetic materials used for e.g. artificial organs and prostheses, catheters, blood bags, etc., may cause severe infections. Furthermore, biofilms on heat exchangers, filters, separation membranes, and also on ship hulls oppose heat and mass transfer and increase frictional resistance. These consequences clearly result in decreased production rates and increased costs. 

PVC is often used in food packaging and blood bags. This study concerns mass transfers between plasticised PVC, having been subjected to a treatment, and liquid food or food simulants. The treatment reduces the diffusion of the plasticiser and the influence of some factors of this processing were investigated. A mathematical model, able to simulate these mass transfers and to quantify treatment parameters, is proposed to quantify the diffusion rate in terms of an average diffusion coefficient. 16 refs. 

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