Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1988-03-03
1988-12-20
Kight, John
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528287, 528288, 528299, 528398, 528399, 528400, 528425, 528950, 523105, 523112, 523113, 523200, 523205, 623 1, 623 11, 623 13, 424 78, C08G 6366, A61L 2700, A61L 3100
Patent
active
047925990
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to polyester materials having biocompatible properties, in particular polyesters involving repeating units derived from glycerophosphorylcholine.
Blood contacting devices are of major importance in the practice of modern medicine but suffer from the problem that, when a foreign surface is brought into contact with blood, absorption of certain blood components results in the formation of blood clots. Previous solutions to this problem included coating any surfaces of the devices which will come into contact with blood with haemocompatible materials, for instance materials mimicking the inert surfaces of, red or white blood cells. Experiments with phosphatidylcholine polymers indicate that these substances do not alter (reduce) the blood clotting time.
There are certain disadvantages involved in coating these devices and further investigation has enabled identification of materials which have biocompatible surfaces without the need for a coating treatment.
Accordingly, the present invention provides a biocompatible polyester comprising repeating units derived from glycerophosphorylcholine (GPC) or glycerophosphorylethanolamine (GPE) and at least one di- or poly-functional acid or reactive derivative thereof.
Polyesters according to the present invention are derived from the compounds of formula (I) ##STR1## wherein R is hydrogen (GPE) or methyl (GPC).
GPC is a bifunctional alcohol which may be isolated from egg or soyabean lecithins in the form of its cadmium chloride complex. This dihydric alcohol may be treated with a bifunctional acid or active derivative thereof such as an acid chloride to make a linear polyester. For branched chain polyesters a polyfunctional, e.g., a trifunctional, acid or reactive derivative such as an acid chloride may be used.
The linear polyesters of GPC or GPE according to the present invention comprise repeating units of formula (II) ##STR2## wherein --A-- is straight or branched C.sub.1-15 alkylene or straight or branched C.sub.2-15 alkenylene and .circle.P is a phosphate head group of formula (III) ##STR3## wherein R is methyl or hydrogen.
Branched chain polyesters will have corresponding repeating units but having branch points in the residues of the polyfunctional acids.
The physical properties of the polyester may be adjusted by incorporation of various other monomers, examples of which are as follows: The softness of the polyesters is controlled by including other dihydric alcohols in the reaction mixtures. Incorporation of some long chain diols along with GPC or GPE produces polymers with more elasticity. Ethylene glycol may be added to produce polymers having lower melting points than those containing GPC or GPE as sole diol.
Branched chain polyesters are more insoluble than the linear materials and also have greater solidity. High amounts of GPC or GPE in these esters increases their melting points. Some high GPC or GPE branched chain polymers decompose on heating.
Preferred polyesters according to the present invention include repeating units derived from one of more of the following-
(1) Acid Chlorides
(2) Acids
(3) Alcohols
In a particular preferred aspect the polyesters according to the invention comprise units derived from GPC and GPE. More preferably such repeating units are present in a molar ratio of 99:1 to 50:50, most preferably 80:20, GPC derived units to GPE derived units.
The present invention also includes a physical admixture of GPC polyester and GPE polyester as descrbed above, preferably in proportions affording molar ratios of GPC- and GPE- derived repeating units as mentioned above.
Polyesters according to the invention are advantageous in being haemocompatible at any exposed surface. This allows articles formed of the polyesters to be shaped, and worked after crude shaping, without, subsequent coating treatment. Moreover, scratching or other damage to the surfaces of such articles simply exposes fresh haeomocompatible material. Polyesters according to the present invention may be used to prepare artificial tendons, blood
REFERENCES:
patent: 4689386 (1987-08-01), Chapman et al.
Acquah S. A.
Biocompatibles Ltd.
Kight John
LandOfFree
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