DE102007037056A1 - Hemostyptic made of freeze-dried collagen, useful e.g. to increase absorption capacity of liquids, preferably blood and treat blood vessel leakage, comprises a water-soluble biocompatible organic acid, preferably hydroxyl carboxylic acid - Google Patents

Abstract

Hemostyptic made from freeze-dried collagen, to increase the absorption capacity of liquids, comprises a water-soluble biocompatible organic acid. An independent claim is included for the preparation of the hemostyptic comprising lyophilizing the aqueous collagen dispersion with a portion of the water-soluble biocompatible organic acid (0.01-3 wt.%), relative to the total weight of the collagen dispersion. ACTIVITY : Hemostatic. MECHANISM OF ACTION : None given.

Description

The The present invention relates to a porous hemostatic agent freeze-dried collagen, which increases its capacity for liquids.

to Hemostasis on soft parenchymatous tissues various techniques and tools used. For example Sutures and staples are used in pulsating bleeding Circulation of the arteries used. The problem is the use of sutures, however, in diffuse parenchymatous Bleeding, because of the many venous blood vessels can not be reversed enough. It can also in this treatment technique in exceptional cases even too an injury to the affected parenchyma.

The Sclerotherapy of injured parenchymatous tissue By electrocoagulation is indeed a powerful alternative to the above-mentioned treatment technique and can in particular in Diffuse bleeding can be used. The disadvantage here, however, that organ tissue can be destroyed irreversibly.

A gentler treatment for haemostasis illustrates the use of fibrin adhesives. Such tissue adhesives actively support the blood clotting process. Indeed the storage and in particular the preparation of Fibrin adhesives are particularly expensive, so the glue in an emergency not immediately available. In addition exists In the case of tissue adhesives, there is always a risk that they may be present heavy bleeding from the wound environment, before the wound is sealed sufficiently and the bleeding is stopped is.

In hemostatic care of internal wounds, especially in the laparotomy, nowadays a variety of wound dressings are used. These wound dressings are usually in a nonwoven or spongy form. For example, a corresponding collagen sponge for hemostasis from the EP 1 368 419 B1 known. The wound dressings are normally pressed onto the wound under light manual pressure until the bleeding stops. Frequently, however, the hemostatic properties of the wound dressings used are not sufficient, so that several layers of the wound dressing are required for laying on the wound. The individual layers can slip against each other, which can cause higher blood loss in patients. In addition, more foreign material is brought into the body in this way. Since the degradation of foreign material is associated with inflammatory reactions, the strength of which in principle also correlates with the amount of material, in addition strong inflammatory reactions may occur, which represent a further risk to the patient.

In order to improve the haemostatic properties of wound dressings, they are very often provided with blood coagulation-promoting compounds, for example fibrinogen and / or thrombin. Such a wound dressing on the basis of collagen, for example, goes from the EP 1 343 542 B1 out. However, the isolation and especially purification of naturally occurring coagulation-promoting compounds is usually very expensive. In particular, increased precautionary measures must be taken in order to be able to largely rule out an infection risk for the patient.

The The present invention thus has as its object a hemostyptic to provide, which compared to the prior art known haemostatic agents improved hemostatic properties and in particular for a simple and low-risk Use in the care and emergency surgery is suitable.

These Task is solved by a hemostyptic (haemostatic or hemostatic agent) of porous freeze-dried Collagen, wherein the hemostatic to increase the liquid intake capacity at least one water-soluble biocompatible organic acid contains.

Surprisingly could be found that collagen, which is at least one water-soluble biocompatible organic acid contains and is present in lyophilized form known collagenous hemostyptics significantly improved Has properties for haemostasis.

The has hemostatic agent according to the invention preferably a sponge-like structure. In particular, the hemostyptic essentially free of a collagen fiber structure.

In a preferred embodiment, the hemostyptic in water has a pH <4 The hemostatic agent in water preferably has a pH of between 3.0 and 3.5.

The Pore size of the hemostyptic is preferably below 500 microns, especially below 300 microns, preferably below 100 μm. The small pore size of the Hemostyptic allows the appearance of larger Capillary forces, creating a larger Absorbance for liquids, in particular Body fluids, preferably blood, results.

In In another embodiment, the hemostyptic has over flexible and especially stable properties. Preferably the acidity in the hemostyptic so high that these properties are not affected. The salary of acid in the hemostyptic is preferably between 1 and 25 wt .-%, in particular between 2 and 15 wt .-%, especially preferably between 3 and 10 wt .-%.

In a further embodiment, the water-soluble biocompatible organic acid is a non-volatile Acid. Preferably, the acid is an aliphatic one Acid. For example, the acid may be a carbon chain having 1 to 6 carbon atoms, preferably 3 to 6 carbon atoms, exhibit. The acid may be an oligofunctional, especially bi- or trifunctional, acid act. The In particular, acid may be a polyvalent, for example be divalent, acid. Preferably, it is in the Acid to a hydroxycarboxylic acid. For example The acid may also be a sugar acid.

at the water-soluble biocompatible organic Acidity of a hemostatic is preferential an acid from the group comprising citric acid, Tartaric acid, ascorbic acid, tartaric acid, gluconic acid, Mucic acid, glutaric acid and adipic acid. malic acid (Malic acid) is particularly preferred.

The water-soluble biocompatible organic acid of the hemostatic agent, in particular in the form of a salt available. The salt compound is preferably a calcium salt of the acid, for example calcium citrate. The use of a calcium salt is particularly advantageous since the hemostasis can be accelerated by calcium ions.

In Another preferred embodiment is the hemostyptic in flat form. For example, the hemostyptic in the form of a disk. It can also be in the form of a three-dimensional Body, in particular a cuboid, are present. in principle Other forms are conceivable.

In another possible embodiment the hemostyptic in particulate form, in particular as a powder or granules, before. The particulate hemostyptic can by a grinding process, especially with a laboratory mill, to be obtained. The particulate hemostyptic can be made into a paste prior to its surgical use and is particularly suitable in this form minimally invasive procedures. To make the paste can be the hemostyptic for example in water of the quality wfi (water for injection) be slammed.

The layer thickness of the hemostyptic is preferably 1 to 10 mm, in particular 3 to 8 mm, preferably 5 to 8 mm. Furthermore, the hemostyptic may have a basis weight of 5 to 25 mg / cm ² , in particular 5 to 20 mg / cm ² , preferably 10 to 20 mg / cm ² . The density of the hemostatic agent is preferably 1 to 50 g / dm ³ , in particular 10 to 40 g / dm ³ , preferably 10 to 20 g / dm ³ .

In Another embodiment has the hemostyptic a pore volume of more than 90% by volume, in particular of 96 up to 99% by volume. Due to the high pore volume is the outer and in particular inner surface of the hemostyptic greatly enlarged. This increases the capacity of the hemostyptic for Additional liquids. The hemostyptic can continue by compressing to a pore volume of 60 to Be set 90 vol .-%.

As already mentioned, it is preferred that the hemostyptic has stable properties. Preferably, the hemostyptic up to a maximum punching force of 8 to 15 N, in particular 10 to 13 N, stable. The determination of the punch pressing force takes place in dry condition. For this purpose, the hemostyptic in cut flat pieces. Subsequently the pieces are placed in a jig of a tensile testing machine clamped. Thereafter, the maximum force required is measured is to put a bullet at a certain speed through the To press hemostyptic pieces.

In a particularly preferred embodiment, the hemostatic agent has a liquid absorption capacity of 20 to 60 times, in particular 30 to 60 times, its own weight equivalent. The water absorption capacity is preferably at least 3000%. Preferably, the water absorption capacity of the hemostatic agent is between 3000 and 4500%. The very high capacity for liquids allows a fast and lasting hemostasis of the wounds to be treated. The hemostatic agent is preferably wettable with water within a period of <100 seconds, in particular <60 seconds, ie on its outer and inner surface.

In Another embodiment is the hemostyptic free of other protein components except collagen. The collagen may be, in particular, type I to IV collagen. Prefers the collagen is tendon collagen. The collage is furthermore preferably of xenogenic origin. That's how the collage works in particular porcine, bovine or equine origin. The In addition, collagen used in the context of the present invention can have a molecular weight of at least 120 kDa (kilo daltons).

The The present invention further relates to a process for the preparation a hemostatic, wherein an aqueous collagen dispersion with a proportion of a water-soluble biocompatible organic acid between 0.01 and 3 wt .-%, based on the total weight of the collagen dispersion is lyophilized.

In a preferred embodiment is for the production of the hemostatic a watery collagen dispersion with an acid content of 0.01 to 2.5 wt .-%, in particular 0.01 to 1 wt .-%, preferably 0.1 to 0.5 wt .-%, based on the Total weight of collagen dispersion, lyophilized.

In In a further embodiment, an aqueous Collagen dispersion with a collagen content of 1 to 5 wt .-%, based on the total weight of the collagen dispersion.

When Dispersant may be either pure water or a mixture from water and an alcohol, especially isopropanol become. The collagen dispersion is typically in the form of a collagen suspension provided.

to Lyophilization is the aqueous collagen dispersion conveniently in a shaping environment, for example, in a Lyophilisationsschale transferred and frozen at low temperatures. The freezing of collage dispersion especially in a temperature range between -20 and -60 ° C, for example at about -40 ° C, be made.

The The invention further comprises a hemostyptic which manufactured or produced according to the method described above is.

The Hemostyptic may be used in particular for hemostatic care of parenchymal organs, especially the liver, spleen, pancreas, the kidneys, the lungs, the adrenals, but also the thyroid and / or Lymph nodes are used. The hemostyptic is suitable also for a thoracic surgery, for example for sealing and sealing air leaks in the lungs. Furthermore, the hemostyptic for a surgical Intervention in the gastrointestinal system, in particular for sealing of intestinal anastomoses. Besides the hemostyptic for gynecological, urological and / or vascular Operations are used. For example, with Help of a hemostatic parenchymatous bleedings be supplied to the ovary and / or uterus. In particular, you can also be treated for blood leaks. The Hemostyptic may also be used to remove tonsils (Tonsillectomy) are used.

Further Details and features of the invention will become apparent from the following Description of preferred embodiments in the form of Figures, examples and subclaims. In these embodiments For example, individual features of the invention may be used alone or in combination be realized with other features. All figures are hereby incorporated by express reference made this description.

In the figures show the following:

1 : graphical representation of the basis weight of hemostyptics according to the invention,

2 : graphical representation of the water absorption capacity of hemostyptics according to the invention,

3 FIG. 2: a graphical representation of the stamping force of hemostyptics according to the invention, FIG.

4 : graphical representation of the wetting time of hemostyptics according to the invention,

5 FIG. 2: graphical representation of the water absorption of a hemostyptic according to the invention as a function of the citric acid content, FIG.

6 : SEM image of a hemostatic agent according to the invention.

figure description

1 Graphically shows the basis weights of various hemostatic agents according to the invention in comparison with a collagenous hemostyptic without acid. The graph illustrates that the amount of acid contained in the hemostatic agents according to the invention has no significant influence on the weight per unit area.

2 shows graphically the water absorption capacity Q of various hemostatic agents according to the invention in comparison to a collagenic hemostyptic without acid. The latter has a water absorption capacity of about 2085%. In contrast, the water absorption capacity of the hemostyptics according to the invention is significantly higher. Thus, the water absorption capacity of all hemostyptics according to the invention is more than 1.5 times the water absorption capacity of the acid-free hemostyptic.

To determine the water absorption capacity Q, the nonwovens were cut into 3 × 5 cm pieces and, after determining the dry weight (W _dry ), placed in 100 ml of distilled water until they were completely permeated with liquid. From the wet weight to be determined (W _wet ) the water absorption capacity Q could be calculated according to the following equation:

3 Graphically shows the stamping force of various hemostatic agents according to the invention compared to an acid-free collagen hemostatic. It is clear from the graph that the acid-containing hemostyptics have a significantly increased mechanical stability compared to the acid-free hemostyptic.

Around the influence of acids on the stability of the to determine hemostatic agents according to the invention was measured the so-called punch pressing force in a dry state. For this, the hemostyptics were in 3 × 5 cm large Cut pieces and into a jig one Tensile testing machine (Zwick) clamped. Subsequently was using a ball (diameter 13 mm), the maximum force measured, which was required to move the ball at a speed of about 100 mm per minute through the hemostyptics to press.

4 shows graphically the water absorption of a hemostatic agent according to the invention as a function of its citric acid content compared to a collagenous hemostyptic without acid (left bar). The graph shows that with an acid content in the hemostatic between 1.6 and 23.2 wt .-%, the water absorption capacity is well above 3000%. The highest uptake capacity for water was found in hemostyptics with an acid content of between 3.1 and 7.4% by weight. With these hemostyptics the water absorption capacity is approx. 4000%. This corresponds approximately to twice the absorption capacity of a comparable hemostyptic without acid (left bar of the graph).

5 Graphically shows the wetting times of various hemostyptics according to the invention and an acid-free collagen hemostatic agent. Most of the hemostyptics according to the invention have a wetting time of significantly less than 100 seconds.

6 represents the SEM image of a collagenous hemostyptic with citric acid. The image shows a sponge-like structure that is essentially free of collagen fibers. In the photograph, the size of individual pores is partially marked. The pore size of the hemostyptic is sometimes well below 100 microns. The small pore size contributes with particular advantage to the high suction power of the hemostyptics according to the invention.

Example 1:

Production of a hemostyptic with citric acid based on collagen

In 660 ml ultrapure water (MilliQ water, Millipor, Germany), 33 g of collagen are swollen. The swollen collagen is suspended for about 20 minutes in a solvent mixture of 1155 ml ultrapure water and 165 ml isopropanol. About 1.32 g of acid (0.1% by weight, based on the total weight of the collagen suspension) are then dissolved in about 1,320 ml of suspension. Subsequently, in each case 130 g of the suspension are poured onto lyophilization dishes having a base area of about 165 cm ² , frozen at -40 ° C. and lyophilized. As a product rectangular collage plates are obtained. The thickness of these plates varies with the filling quantity of the lyophilization dishes.

In terms of The acids used are those listed in Example 2 Referenced acids.

For the animal experiments became the basis weight of the hemostyptics reduced, instead of 130 g of suspension, only 65 g of suspension were weighed into the lyophilization dishes.

Example 2:

Determination of pH

The hemostyptics were cut into 3 x 5 cm pieces and placed in 20 ml of deionized water. After 1 minute, the pH was measured, the values of which are listed in the table below. composition pH of the water pure collages 4.5 Collagen + citric acid 3.4 Collagen + tartaric acid 3.2 Collagen + ascorbic acid 3.7 Collagen + malic acid 3.3 Collagen + gluconic acid 3.5 Collagen + mucic acid 3.4 Collagen + glutaric acid 3.5 Collagen + adipic acid 3.7 Collagen + lactic acid 3.2

The tabulated ph values show that the presence the acids in the hemostyptics the pH of the Water lowers on average by about one pH unit.

Example 3:

Hemostasis in a pig liver

A laparotomy was performed on an anesthetized pig and the animal's lobes were exposed. On the lateral liver lobe of the pig a diffuse bleeding was caused by a partial resection (length 5 cm). Correspondingly, bleeding was also produced on the intermedial and medial lobe of the liver. The bleeding wounds were each covered with a 5 × 4 cm hemostyptic containing malic acid and having a basis weight of about 10 mg / cm ² . The hemostyptics were modulated by the surgeon on the tissue surfaces. Thereafter, the time to stop the bleeding was stopped. The bleeding was breastfed within 180 seconds. In each case only one layer of the hemostyptic was applied to the bleeding.

at two more animals became a 2 × 2 cm large produces capsular hemorrhage at the spleen, which coincides with a 3 × 5 cm hemostyptic with the previously mentioned. In the context of this Trial also became the time after the application of the hemostyptic measured until hemostasis. The bleeding could be within Be breastfed for 90 seconds. Again, only one location of the hemostatic on the bleeding.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1368419 B1 [0005]
• - EP 1343542 B1 [0006]

Claims (24)

Hemostatic agent of porous freeze-dried collagen, characterized in that it contains at least one water-soluble biocompatible organic acid to increase the liquid absorption capacity. Hemostatic agent according to claim 1, characterized in that that it has a pH <4 in water has. Hemostatic agent according to claim 1 or 2, characterized characterized in that the pore size is less than 500 microns, in particular less than 300 microns, preferably less than 100 microns, is located. Hemostatic after one of the preceding Claims, characterized in that the content of acid in the hemostyptic between 1 and 25 wt .-%, in particular between 2 and 15% by weight, preferably between 3 and 10% by weight. Hemostatic after one of the preceding Claims, characterized in that the acid is a is non-volatile acid. Hemostatic after one of the preceding Claims, characterized in that the acid is a is aliphatic acid. Hemostatic after one of the preceding Claims, characterized in that the acid is a polyvalent, especially diacid, is. Hemostatic after one of the preceding Claims, characterized in that the acid is a Hydroxycarboxylic acid is. Hemostatic after one of the preceding Claims, characterized in that the acid in Form of a salt, in particular in the form of a calcium salt is present. Hemostatic after one of the preceding Claims, characterized in that it is in areal Form is present. Hemostatic after one of the preceding Claims, characterized in that its layer thickness 1 to 10 mm, in particular 3 to 8 mm, preferably 5 to 8 mm. Hemostatic agent according to one of the preceding claims, characterized in that it has a basis weight of 5 to 25 mg / cm ² , in particular 5 to 20 mg / cm ² , preferably 10 to 20 mg / cm ² . Hemostatic agent according to one of the preceding claims, characterized in that its density is 1 to 50 g / dm ³ , in particular 10 to 40 g / dm ³ , preferably 10 to 20 g / dm ³ . Hemostatic after one of the preceding Claims, characterized in that it has a pore volume> 90 vol .-%, in particular from 96 to 99% by volume. Hemostatic after one of the preceding Claims, characterized in that it by compression is set to a pore volume of 60 to 95 vol .-%. Hemostatic after one of the preceding Claims, characterized in that it is up to a maximum punching force of 8 to 15 N, in particular 10 to 13 N, is stable. Hemostatic after one of the preceding Claims, characterized in that it is a liquid absorption capacity that is 20 to 60 times, especially 30 to 60 times, its Own weight corresponds. Hemostatic after one of the preceding Claims, characterized in that it is within a Period of <100 s, in particular <60 s, is completely wettable with water. Hemostatic agent according to one of the preceding claims, characterized in that it releases of other protein components except collagen. Hemostatic after one of the preceding Claims, characterized in that the collagen a Collagen type I to IV is. Hemostatic after one of the preceding Claims, characterized in that the collagen xenogeneic is, in particular, porcine, bovine or equine origin. Process for the preparation of a hemostyptic according to any one of the preceding claims, wherein an aqueous Collagen dispersion with a proportion of a water-soluble biocompatible organic acid between 0.01 and 3% by weight, based on the total weight of the collagen dispersion, is lyophilized. Hemostatic after one of the preceding Claims 1 to 21, prepared by a method according to Claim 22. Hemostatic after one of the preceding Claims 1 to 21, produced by a method according to Claim 22.