Compositions – Physical separation agents
Patent
1997-04-28
1998-07-07
Green, Anthony
Compositions
Physical separation agents
435 2, G01N 3348
Patent
active
057763577
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to serum or plasma separating compositions for use in centrifuging blood utilizing a difference in specific gravity between blood components.
BACKGROUND ART
Blood testing containers for collecting blood therein are already known which have contained in the bottom thereof a serum or plasma separating thixotropic composition such as a mixture of silicone and silica (Unexamined Japanese Patent Publication No. 83654/1976). When blood is collected in the container, allowed to stand for a suitable period of time and thereafter centrifuged, the serum or plasma separating composition, which is in the form of a gel, is fluidized by the centrifugal force. In specific gravity, the gel of the serum or plasma separating composition is intermediate between the serum or plasma and the clot or cellular (corpuscle) component of the blood, so that the composition gradually rises from the bottom of the container through the collected blood and becomes positioned between a layer of serum or plasma and a layer of blood clot or cells, separating the serum or plasma from the clot or cellular component. The serum or plasma thus separated from the clot or cellular component can be readily withdrawn from the container and subjected to various tests, or can be preserved without being transferred to another container.
The compounds already known for use as the main component of such serum or plasma separating thixotropic compositions include, in addition to the above-mentioned silicone, .alpha.-olefin-maleic acid diester copolymer (Unexamined Japanese Patent Publications No. 166956/1981 and No. 168159/1990), polyester polymer (Unexamined Japanese Patent Publication No. 233368/1986), acrylic polymer (Unexamined Japanese Patent Publication No. 42283/1978), chlorinated polybutene (Unexamined Japanese Patent Publication No. 9718/1982), cyclopentadiene resin (Unexamined Japanese Patent Publication No. 295163/1989) and modified cyclopentadiene resin prepared by introducing a hydroxyl, ester, ether, epoxy or like group into cyclopentadiene resin (Unexamined Japanese Patent Publication No. 95257/1990). The materials to be admixed with such a main component as required include, for example, inorganic fillers such as silica, which serves as specific gravity adjusting agents and also as gelling agents for giving thixotropy, substances having polar groups at opposite ends of the molecule, such as propylene glycol and ethylenediamine (such fillers and substances being disclosed in Unexamined Japanese Patent Publication No. 295163/1989), and organic gelling agents such as condensation products of sorbitol and an aromatic aldehyde (Unexamined Japanese Patent Publication No. 168159/1990).
However, silicone is poor in compatibility with the inorganic filler, undergoes a curing reaction when sterilized by radiation (e.g., gamma ray and electron ray) irradiation and is therefore almost out of use presently. .alpha.-Olefin-maleic acid diester copolymer, polyester polymer, acrylic polymer, modified cyclopentadiene resin and the like which have a polar group are relatively less likely to affect the determination of substances in the blood under clinical examination, but frequently exert an influence on the measurement of concentration of drugs in the blood (for example, the measurement of concentration of antiepileptics, such as phenobarbital, carbamazepine and phenytoin, in the blood).
On the other hand, the use of chlorinated polybutene entails the problem that when it is to be disposed of by incineration after use, the composition releases chlorine gas to cause damage to the incinerator and exert an adverse influence on the environment.
As a serum or plasma separating composition free of these drawbacks, Unexamined Japanese Patent Publication No. 203965/1992 proposes a composition comprising an oligomer of cyclopentadiene and a condensation product of sorbitol and an aromatic aldehyde as an organic gelling agent. The serum or plasma separating composition solved the above-mentioned problems of the prior
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Anraku Hideo
Okamoto Ryusuke
Green Anthony
Sekisui Kagaku Kogyo Kabushiki Kaisha
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