Stock material or miscellaneous articles – Composite – Of metal
Patent
1995-05-03
1996-09-17
Richter, Johann
Stock material or miscellaneous articles
Composite
Of metal
546 24, 558166, 558169, 558170, B32B 1504, C07F 909
Patent
active
055567100
DESCRIPTION:
BRIEF SUMMARY
This application was filed under 35 U.S.C. 371 and was upon PCT International Application No. PCT/GB93/00853, filed Apr. 23, 1993.
This invention relates to new compounds useful as metal coatings to render metal surfaces biocompatible, a process for their preparation, and their use in rendering a metal surface biocompatible.
The clinical use of blood contacting devices and prostheses is of major importance today in cardiovascular surgery and other fields of medicine. Heart valves and blood vessel prostheses, balloon pumps and catheters are being implanted in daily surgical practice to restore or diagnose cardiovascular function. Artificial organs are routinely employed in blood detoxification by absorptive haemoperfusion and in oxygenation (membrane oxygenators and heart-lung devices). Considerable effort and capital is invested in Europe and the U.S.A. in the development and experimental evolution of an implantable artificial heart system. The devices are commonly constructed from metals and, when in use, a blood-metal contact is present. This contact will cause a reaction in the recirculating blood, which, depending on the choice of metal, the design parameters, the flow or the addition of the anticoagulants, may lead to protein deposition, adhesion and destruction of red blood cells (haemolysis), platelet (thrombocyte) adhesion and aggregation and blood coagulation leading to formation of a haemostatic plug (thrombus). The occurrence of thromboembolism in cardiovascular surgery continues to be a problem, notwithstanding routine treatment with anticoagulants. For these reasons the search for biocompatible non-thrombogenic materials has been an important research objective over the last two decades.
In addition, certain diagnostic procedures designed for the rapid analysis of analytes in body fluids are compromised by non-specific binding of fluid components. This problem is particularly acute in biosensors which use parameters such as the mass or the refractive index of the analyte to determine analyte concentration. For instance, small changes in refractive index associated with the binding of body fluid components to a metal film can be measured using surface plasmon resonance (SPR).
We have now devised new compounds which aim to mimic some of the interfacial characteristics of the outer cell surface of for example red blood cells, and in particular the lipid component of the biological membrane which is the simplest common factor of such surfaces. The compounds are derivatives or analogues of phosphorylcholine that can be linked to the metal surface which is to be rendered biocompatible via a thiol or disulphide functional group in the compounds. This deposits a phosphorylcholine type of residue on a surface. Such residues are commonly found in lipid membranes.
Accordingly the present invention provides compounds of formula (I) ##STR1## in which the groups R are the same or different and each is hydrogen or a straight or branched C.sub.1 -C.sub.4 alkyl group, preferably methyl; n is from 2 to 4, preferably 2, and X is a straight or branched C.sub.1-30 alkylene group, preferably a group of formula --(CH.sub.2).sub.a --, or X is a group of formula --(CH.sub.2 CH.sub.2 O).sub.b --, or --(CH.sub.2).sub.c --Ar--(CH.sub.2).sub.d -- where a is from 1 to 30, b is from 1 to 20, c and d are the same or different and each is from 0 to 5, and Ar is a para- or meta-disubstituted aryl group such as a phenyl, biphenyl or naphthyl group (preferably a para-disubstituted biphenyl group) which is optionally further substituted by one or more C.sub.1 -C.sub.4 alkyl groups; and either alkylcycloalkyl, aryl, alkylaryl, heterocyclic, alkylheterocyclic group or a group of formula (II): ##STR2## where Y, X, R and n are as hereinbefore defined; or Y is a trivalent alkylene group, alkylaryl, cycloalkyl or alkylcycloalkyl groups and bonded to the group Y so --Y--S--Z.sup.1 form a 5 to 8 membered, preferably 5 or 6 membered, ring containing a disulphide linkage;
Without wishing to be limited by the theory of the invention, it is
REFERENCES:
patent: 4492659 (1985-01-01), Bosies et al.
patent: 5380904 (1995-01-01), Chapman et al.
Charles Stephen A.
Russell Jeremy C.
Yianni Yiannakis P.
Ambrose Michael G.
Biocompatibles Limited
Richter Johann
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