阅读说明：本技术 包含铁螯合剂的凝血酶原时间试剂 (Prothrombin time reagent comprising an iron chelator ) 是由 萨比内·皮尔格林 托马斯·维塞尔 诺贝特·赞德 于 2018-11-27 设计创作，主要内容包括：本发明属于凝血诊断领域,涉及基于重组或天然组织因子蛋白和磷脂的凝血酶原时间试剂,其能够通过添加选自由铁载体和3,5-二苯基-1,2,4-三唑构成的组中的铁螯合剂来稳定。(The present invention is in the field of coagulation diagnostics and relates to a prothrombin time reagent based on recombinant or natural tissue factor proteins and phospholipids, which can be stabilized by adding an iron chelator selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole.)

1. A prothrombin time agent comprising tissue factor protein and phospholipid, characterized in that the agent further comprises at least one iron chelator, wherein the at least one iron chelator is selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole.

2. The prothrombin time reagent of claim 1, wherein the siderophore is selected from the group consisting of desferoxamine, a fluorescent siderophore, and a ferrichrome.

3. The prothrombin time reagent according to claim 1, wherein the 3, 5-diphenyl-1, 2, 4-triazole is selected from the group consisting of deferasirox, [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetic acid ethyl ester, and 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole.

4. The prothrombin time reagent according to any one of the preceding claims, comprising at least one of the iron chelators at a concentration of 0.007 to 2.5 mmol/L, particularly preferably 0.01 to 0.5 mmol/L.

5. The prothrombin time agent according to any of the preceding claims, further comprising Ca²⁺Ions.

6. The prothrombin time reagent according to claim 5, comprising 5 to 500 mmol/L calcium chloride.

7. The prothrombin time agent according to any of the preceding claims, wherein the tissue factor protein is selected from the group consisting of human or animal recombinant tissue factor protein and natural human or animal tissue factor protein from tissue extracts.

8. A composition for preparing a composition comprising tissue factor protein and phospholipid and optionally Ca²⁺A method of providing an ionic liquid prothrombin time reagent, characterized by providing a liquid comprising tissue factor protein, phospholipid and at least one iron chelator selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole; and the liquid is filled into the reagent bottle without lyophilizing the liquid.

9. A composition for stabilizing a composition comprising tissue factor protein and phospholipid and optionally Ca²⁺A method of ionic prothrombin time reagents, characterized in that at least one iron chelator selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole is added to the reagent.

10. The method according to claim 9, wherein an amount of at least one of the iron chelating agents is added such that the reagent comprises at least one of the iron chelating agents in a concentration of 0.007 to 2.5 mmol/L, particularly preferred 0.01 to 0.5 mmol/L.

11. The method of claim 8 or 9, wherein the siderophore is selected from the group consisting of desferoxamine, a fluorescent siderophore and a ferrichrome.

12. The process according to claim 8 or 9, wherein the 3, 5-diphenyl-1, 2, 4-triazole is selected from the group consisting of deferasirox, [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetic acid ethyl ester and 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole.

13. Use of the prothrombin time reagent according to any one of claims 1 to 7 in a method for determining a coagulation parameter in a plasma sample.

14. A method for determining a coagulation parameter in a plasma sample, characterized by mixing the plasma sample with a prothrombin time reagent according to any one of claims 1-7 to a reaction mixture and determining the coagulation parameter in the reaction mixture.

15. The method according to claim 14, for determining coagulation parameters in the group consisting of prothrombin time, derived fibrinogen and thrombin generation potential.

16. The method of claim 14 for determining prothrombin time, wherein the change in absorbance of the reaction mixture is measured photometrically and the time from the point in time at which the prothrombin time reagent is mixed with the plasma sample until a threshold value is reached is determined.

17. Use of an iron chelator selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole for the preparation of a prothrombin time reagent comprising tissue factor protein and a phospholipid.

18. The use according to claim 17, wherein the siderophore is selected from the group consisting of desferoxamine, a fluorescent siderophore and a ferrichrome.

19. Use according to claim 17, wherein the 3, 5-diphenyl-1, 2, 4-triazole is selected from the group consisting of deferasirox, ethyl [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetate and 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole.

Technical Field

The present invention is in the field of coagulation diagnostics and relates to a prothrombin time reagent based on recombinant or native tissue factor protein and phospholipids, which can be stabilized by adding an iron chelator selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole.

Background

Tissue factor protein (tissue factor or thromboplastin for short, and tissue factor in English) is a transmembrane protein which is important for blood coagulation. It is expressed by cells that are not normally in contact with flowing blood, for example by cells in the endothelium (smooth muscle) and cells surrounding blood vessels (e.g. fibroblasts). However, in the case of vascular damage, cells expressing tissue factor proteins come into contact with factor VII, a procoagulant factor that circulates in the blood. In the presence of calcium, tissue factor protein and factor VII form a complex and the activity of factor VII increases by about one thousand fold (F VII > FVIIa). In the presence of phospholipids and calcium, the complex consisting of tissue factor protein and factor VIIa catalyzes the conversion of non-activated coagulation factor X to activated factor Xa, thereby accelerating the coagulation process. Together with factor VII, tissue factor forms the so-called extrinsic coagulation pathway by which blood clots as quickly as possible to prevent vascular damage.

In the diagnosis of coagulation, different in vitro test methods have been developed, by means of which it can be determined whether the blood or plasma of a patient can be coagulated without problems or whether a coagulation disorder is present. In the case of blood coagulation disorders, it is often desirable to obtain a more precise knowledge of the cause of the presence of the disorder in order to be able to select the best treatment. In order to study the different partial functions of blood coagulation, and in particular to study the extrinsic system of blood coagulation, tissue factor proteins are used as activators. The most widely known application of tissue factor proteins as a coagulation activator is the so-called rapid test for determining Prothrombin Time (PT) (synonym: thrombin time). In rapid tests and variants thereof, a plasma sample is typically mixed with a mixture of tissue factor protein, phospholipid and calcium ions and the duration from the point in time of mixing until fibrin formation can be detected is measured in seconds. Alternatively, in coagulation tests using chromogenic substrates, one test method measures the duration from the point in time of mixing until a particular change in absorbance is achieved. Tissue factor proteins are also used in other test methods which are not used for determining the clotting time, but rather for determining individual components of the coagulation system, such as the thrombin generation potential (ETP) (EP-A2-420332). In principle, tissue factor proteins are useful in all tests involving components of extrinsic coagulation.

The prothrombin time reagents (tissue factor reagents, PT reagents) have central significance for the corresponding tests. Typically, the prothrombin time agent includes tissue factor and a thromboplastin. Tissue factor proteins are either obtained as tissue extracts from different organs (e.g. brain, placenta, lung) of different species (e.g. rabbit, human, bovine) or are produced recombinantly. Various methods for obtaining tissue factor protein and preparing prothrombin time reagents are known in the art, and many prothrombin time reagents are commercially available.

Currently, most commercially available prothrombin time reagents are sold in lyophilized form and must therefore be dissolved in the reconstitution medium, e.g., in distilled water or buffer solution, prior to use. The reason for this is the poor stability of the liquid reagent. The disadvantage of reagents provided in lyophilized form is not only that the manufacturer and the user have to perform additional time and cost intensive process steps (lyophilization and reconstitution), but also that these additional steps involve a risk of errors that may result in impaired reagent quality. Therefore, liquid, ready-to-use reagent formulations are desired. However, a problem with providing prothrombin time reagents in liquid form is their poor stability. The stability of the prothrombin time agent can be understood, for example, as maintaining the prothrombin time to a defined plasma (e.g., normal plasma) during storage. Ideally, the prothrombin time reagent should maintain its specifications during its storage or use, or, at best, retain the attributes and characteristics that it had at the time of its production.

Different strategies for stabilizing liquid prothrombin time reagents are described in the prior art. In EP-A2-942284 a liquid prothrombin time reagent based on recombinant tissue factor is described, which is stabilized by the combined addition of ascorbic acid and serum albumin. In US 3,522,148 a liquid prothrombin time agent is described comprising a (native) tissue factor protein extracted from tissue, which is stabilized by the addition of a specific sodium or calcium salt. Another liquid prothrombin time agent based on natural tissue factor protein is described in EP-a1-585987, which is stabilized by the addition of different stabilizers (e.g. albumin or polyethylene glycol) and different antibacterial active substances (e.g. sodium azide or antibiotics). In EP-A2-524803 a method for preparing prothrombin time reagents is described in which a metal ion chelator, in particular EDTA or EGTA, is used for tissue factor extraction and can be included in the prepared reagent. The amount of calcium ions bound to the metal ion chelating agent can be replaced by adding additional calcium salts.

In US2017/0234895a1 a two-piece kit for preparing a ready-to-use liquid prothrombin time reagent is described, which kit comprises in a first container a first solution with tissue factor protein and phospholipids and in a second container a calcium chloride solution. For stabilization purposes, a calcium chelator is included in the first solution. The two solutions are first mixed with each other by the user immediately before use. In this case, the user must always mix the two liquids with one another in order to obtain the ready-to-use prothrombin time reagent, although lyophilization can be dispensed with on the part of the manufacturer and reconstitution of the lyophilized reagent can be dispensed with on the part of the user.

Disclosure of Invention

It is therefore an object of the present invention to provide a ready-to-use prothrombin time agent which is stable in the liquid state for a long time, which can comprise at least one tissue factor protein and a phospholipid, and can optionally also comprise calcium ions.

It has been found that the addition of iron chelators, in particular iron chelators from the group comprising siderophores (for which in particular desferoxamine, fluorescent siderophores (pyroflavin) or ferrichromes (ferrichrome) are added), or iron chelators from the group of 3, 5-diphenyl-1, 2, 4-triazoles (for which in particular dellamol is added), improves the stability of aqueous solutions comprising tissue factor and phospholipids and optionally calcium ions. The prothrombin time reagent according to the invention, which is stable and stored in liquid form, still provides a Prothrombin Time (PT) measurement which deviates less than 20% from the PT measurement at the beginning of the time frame after 10 weeks of storage at +37 ℃. Forced storage at +37 ℃ for 10 weeks for rapid assessment: whether storage stability for 12 months or longer can be expected in the case of +2 ℃ to +8 ℃. If a stable prothrombin time reagent provides a Prothrombin Time (PT) measurement that deviates less than 20% from the PT measurement at the beginning of the time frame after storage for 10 weeks at +37 ℃, the reagent can be expected to be stable for 12 months or longer at storage temperatures of +2 ℃ to +8 ℃.

The subject of the present invention is therefore a prothrombin time reagent comprising tissue factor protein and phospholipids, further comprising at least one iron chelator, wherein the at least one iron chelator is selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole.

Siderophores are a class of iron-binding chelators, which are formed by microorganisms (e.g., bacteria and fungi) and by plants, and which are resistant to iron (III) ions (Fe)³⁺Ions) have a high affinity. Preferred siderophores are siderophores from the group of the hexadentate hydroxamates, such as deferoxamine, fluorosiderophores and ferratin (ferricin).

Preferably, the iron chelator from the group of siderophores is selected from the group consisting of desferoxamine, fluorescent siderophores and ferrichromes.

In one embodiment, the prothrombin time reagent according to the invention comprises an iron chelator: deferoxamine, which comes from the group of hexadentate hydroxamates (synonym: deferoxamine; trade name: Desferal), and which is formed, for example, by Streptomyces pilosus (Desferal).

In another embodiment, the prothrombin time agent according to the invention comprises an iron chelator: fluorescent siderophores, non-ribosomal polypeptides, which are formed, for example, by Pseudomonas fluorescens (Pseudomonas fluorescens) and are classified into the group of hexadentate mixed hydroxamate-type siderophores and catecholate-type siderophores. Other suitable iron chelators from the group of hexadentate mixed hydroxamate and catechol/salt type siderophores are, for example, hetereobactins (hetereobacterin) and yersinicins (yersinibacterin).

In another embodiment, the prothrombin time agent according to the invention comprises an iron chelator: ferrichrome, a cyclic hexapeptide consisting of three glycines and hydroxylated and acetylated ornithine groups (synonym: deferoxamine), which is formed, for example, from smut (Ustilago sphaerogena) and is likewise classified in the group of hexadentate hydroxamates.

3, 5-diphenyl-1, 2, 4-triazoles are a class of iron-binding chelators which have also been developed for therapeutic purposes (EP-B1-0914118). Preferably, the 3, 5-diphenyl-1, 2, 4-triazoles are deferasirox, ethyl [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetate and 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole.

In a corresponding embodiment, the prothrombin time reagent according to the invention comprises an iron chelator from the group of 3, 5-diphenyl-1, 2, 4-triazoles, in particular for this purpose deferasirox (IUPAC name: 4- [ (3Z,5E) -3, 5-bis (6-oxocyclohex-2, 4-dien-1-yl) -1,2, 4-triazol-1-yl ] benzoic acid), [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetic acid ethyl ester or 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole.

The prothrombin time reagent according to the invention comprises one of the above suitable iron chelators in a concentration of preferably 0.007 to 2.5 mmol/L, particularly preferably 0.01 to 0.5 mmol/L.

The prothrombin time agent according to the invention can comprise one of the above suitable iron chelating agents, or a combination of two, three, four or more of the above suitable iron chelating agents.

For this purpose, the prothrombin time reagent can comprise calcium chloride in a concentration preferably of 5 to 500 mmol/L.

The tissue factor protein comprised in the prothrombin time agent is preferably selected from the group consisting of recombinant tissue factor proteins of humans or animals (e.g. rabbits, cows, etc.) and natural human or animal tissue factor proteins from tissue extracts (e.g. from brain, placenta, lungs, etc.).

The phospholipids can be derived from natural and/or synthetic sources.

Although the particular advantage of the invention is that the prothrombin time reagent according to the invention can be stored as a ready-to-use liquid reagent, it is of course also possible to provide the reagent in the form of a lyophilisate which can be reconstituted in water or buffer.

Another subject of the invention is a method for preparing a liquid prothrombin time reagent, wherein a liquid is provided, which liquid comprises tissue factor protein, a phospholipid and at least one iron chelator selected from the group consisting of a siderophore, preferably a desferrioxamine, a fluorosiderophore or a ferrichrome, and a 3, 5-diphenyl-1, 2, 4-triazole, preferably deferasirox, ethyl [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetate or 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole; and the liquid is filled into the reagent bottle without freeze-drying the liquid.

Another subject of the invention is a method for stabilizing a composition comprising a tissue factor protein and a phospholipid and optionally Ca²⁺A method of preparing an ionic prothrombin time reagent by adding to the reagent at least one iron chelator selected from the group consisting of a siderophore and a 3, 5-diphenyl-1, 2, 4-triazole, wherein the siderophore is preferably desferrioxamine, a fluorosiderophore or a ferrichrome and the 3, 5-diphenyl-1, 2, 4-triazole is preferably deferasirox, [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazole]Triazol-1-yl]Ethyl acetate or 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4]A triazole.

Preferably, in the stabilization method according to the invention, the iron chelator is added in an amount such that the reagent comprises the iron chelator in a final concentration of 0.007 to 2.5 mmol/L, particularly preferably 0.01 to 0.5 mmol/L.

A further subject of the invention is the use of the prothrombin time reagent according to the invention in an in vitro method for determining a coagulation parameter in a patient sample, in particular for determining a coagulation parameter in the group consisting of prothrombin time (PT, also known as the rapid test) and variants thereof, fibrinogen derived from prothrombin time and thrombin generation potential (ETP). The reagents according to the invention are suitable as activators of the coagulation cascade, for example in tests based on the detection of fibrin clots, and in tests based on chromogenic or fluorescent substances.

The invention also relates to a method for determining a coagulation parameter in a plasma sample, wherein the plasma sample is mixed with a prothrombin time reagent according to the invention to a reaction mixture and the coagulation parameter in the reaction mixture is determined. The coagulation parameter can be, for example, the prothrombin time or thrombin generation potential of a sample (e.g., a human whole blood or plasma sample).

For determining the prothrombin time, the change in absorbance of the reaction mixture is preferably measured photometrically and the duration from the point in time at which the prothrombin time reagent according to the invention is mixed with the plasma sample until the threshold value is reached is determined.

To determine the derived fibrinogen concentration from the prothrombin time ("derived fibrinogen"), the increase in absorbance of the reaction mixture is measured photometrically; this increase in absorbance correlates with fibrinogen concentration.

The invention also relates to the use of an iron chelator selected from the group consisting of siderophores and 3, 5-diphenyl-1, 2, 4-triazole in the preparation of a prothrombin time reagent comprising tissue factor protein and a phospholipid. Group of iron-derived carriers preferably used iron chelating agents are selected from the group consisting of desferrioxamine, fluorescent siderophores and ferrichromes. The iron chelating agents preferably used from the group of 3, 5-diphenyl-1, 2, 4-triazoles are selected from the group consisting of deferasirox, [3, 5-bis (2-hydroxyphenyl) - [1,2,4] triazol-1-yl ] acetic acid ethyl ester and 3, 5-bis (2-hydroxyphenyl) -1- (2,2, 2-trifluoroethyl) -1H- [1,2,4] triazole.

Drawings

Fig. 1 shows the prothrombin time variation in seconds (PT [ s ]) of normal quality control plasma Ci-Trol 1 with a PT reagent stabilized with deferoxamine (9 ═ 9 mg/L ═ 0.0137mM deferoxamine; 12 ═ 12 mg/L ═ 0.0183mM deferoxamine; 15 ═ 15 mg/L ═ 0.0228mM deferoxamine) over a period of several weeks (t), compared to the unstabilized, deferoxamine-free reagent (0 ═ 0 mg/L ═ 0mM deferoxamine), and to a reference reagent (R) stored freeze-dried and freshly dissolved at the corresponding time points.

Fig. 2 shows the prothrombin time variation in seconds (PT [ s ]) of an abnormal quality control plasma Ci-Trol 2 with a PT reagent stabilized with deferoxamine (9 ═ 9 mg/L ═ 0.0137mM deferoxamine; 12 ═ 12 mg/L ═ 0.0183mM deferoxamine; 15 ═ 15 mg/L ═ 0.0228mM deferoxamine) over a period of several weeks (t), compared to the unstabilized, deferoxamine-free reagent (0 ═ 0 mg/L ═ 0mM deferoxamine), and to a reference reagent (R) stored lyophilized and freshly dissolved at the corresponding time points.

Fig. 3 shows the prothrombin time variation in normal quality control plasma Ci-Trol 1 in Seconds (PTs) over several weeks (t) with a desferrioxamine stabilized PT reagent (15 mg/L-0.0228 mM desferrioxamine; 75 mg/L-0.114 mM desferrioxamine; 150-150 mg/L-0.228 mM desferrioxamine), compared to the unstabilized PT reagent without desferrioxamine (0-0 mg/L-0M desferrioxamine), these reagents were stored at a temperature of 37 ℃.

Fig. 4 shows the prothrombin time variation in seconds ((PT [ s ]) of abnormally quality controlled plasma Ci-Trol 2 with a PT reagent stabilized with deferoxamine (15-15 mg/L-0.0228 mM deferoxamine; 75-75 mg/L-0.114 mM deferoxamine; 150-150 mg/L-0.223 mM deferoxamine) over a period of several weeks (t), as compared to the unstable PT reagent without deferoxamine (0-0 mg/L-0 mM deferoxamine), these reagents were stored at a temperature of 37 ℃.

Detailed Description

The following examples are intended to illustrate the invention but are not to be construed as limiting it.