Two Component Sealing Systems Including Synthetic Matrices and Biosynthetic Adhesives

Abstract

The present invention is directed to a hemostatic patch comprising a porous substrate and at least a pair of co-reactive polymer reagents comprising at least one nucleophilic polyalkylene oxide based component and at least one electrophilic polyalkylene oxide-based on the porous substrate in a molar ratio of about 0.2 to about 0.9:1 of primary nucleophilic groups in excess to available electrophilic groups. The present invention is also directed to processes for the manufacture and use of such hemostatic patches.

Claims

1. A hemostatic patch comprising a porous substrate having available acidic carboxylic groups and at least a pair of co-reactive polymer reagents comprising at least one nucleophilic polyalkylene oxide-based component and at least one electrophilic polyalkylene oxide-based component, both said components disposed on the porous substrate in a molar ratio of about 0.2 to about 0.9 : 1 of primary electrophilic groups to nucleophilic groups.

2. A hemostatic patch according to claim 1, wherein at least one of said co-reactive polymer reagents is a three-arm arm polyethylene glycol-based nucleophile.

3. A hemostatic patch according to claim 1, wherein at least one of said co-reactive polymer reagents is a three-arm arm polyethylene glycol-based electrophile.

4. A hemostatic patch according to claim 1, wherein at least one of said co-reactive polymer reagents is a four-arm arm polyethylene glycol-based nucleophile.

5. A hemostatic patch according to claim 1, wherein at least one of said co-reactive polymer reagents is a four-arm arm polyethylene glycol-based electrophile.

6. A method for manufacturing a hemostatic patch according to claim 1 wherein at least a pair of the co-reactive polymer reagents are applied to the substrate from a non-aqueous solvent spray via an ultrasonic air spray.

7. A method according to claim 6 wherein the non-aqueous solvent comprises an organic solvent.

8. A method according to claim 6 wherein the non-aqueous solvent comprises acetone.

9. A method according to claim 6 wherein at least a pair of the co-reactive polymer reagents are applied sequentially with intervening drying.

10. A method according to claim 9 wherein at least a pair of the co-reactive polymer are applied in sequential and discreet layers of the first co-reactive polymer and the second co-reactive polymer.

11. A method according to claim 10 wherein the layer of at least one polyethylene glycol-based electrophile is applied as a first layer in sequence .

12. A hemostatic patch according to claim 1 wherein the porous substrate comprises oxidized cellulose or oxidized regenerated cellulose.

13. A hemostatic patch according to claim 1 wherein the porous substrate is a bilayer construct that comprises at least a first layer of an oxidized cellulose-containing material or oxidized regenerated cellulose-containing material with at least a second layer of a polyglactin-containing polymer.

14. A hemostatic patch according to claim 1 wherein said at least one electrophilic polyalkylene oxide based component has an average molecular weight Mw of about 10 kD.

15. A hemostatic patch according to claim 1 wherein said at least one nucleophilic polyalkylene oxide based component has an average Mw of about 4 kD to 5 kD.

16. The hemostatic patch according to claim 1, wherein said porous substrate is a synthetic, biodegradable and flexible matrix.

17. The hemostatic patch according to claim 16, wherein said porous substrate comprises at least one layer of a non-woven mesh made of polyglactin 910 and a second attached layer of a non-woven mesh consisting essentially of oxidized cellulose or oxidized regenerated cellulosic material that provides localized acidic groups upon tissue application.

18. The hemostatic patch according to claim 1, wherein the electrophile component comprises a polyethylene glycol succinimidyl glutarate ester (PEG-SG).

19. The hemostatic patch according to claim 1, wherein the nucleophilic component is selected from the group consisting of any polymeric source of primary amine (NH.sub.2) groups.

20. A hemostatic patch according to claim 1, wherein the at least two co-reactive polymer reagents are deposited on the substrate with a density of between about 6.4 mg polymer/cm.sup.2 of substrate and 25.5 mg/cm.sup.2.

21. A hemostatic patch according to claim 20, wherein the at least two co-reactive polymer reagents are applied onto a bi-layer substrate without amine groups at a fixed molar ratio of 1.2:1.0 as between succinimidyl groups (PEG-SG) and amine groups (PEG-Amine).

Description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0026] Polyethylene glycol succinimidyl glutarate (PEG-SG) has a well-established safety profile in medical devices and has been used in sealant products such as Duraseal and Coseal. The succinimidyl glutarate reacts with amine groups on proteins, e.g., collagen, under mildly alkaline conditions forming an amide bond. The cleavable ester linker designed into the PEG enables the polymer to be degradable in vivo. This form of PEG also provides the ability to cross-link across multiple collagen fibers due to its long spacer region allowing intermolecular cross-linking.

[0027] In one embodiment, the two reactive component sealant preferably includes a synthetic matrix that is adapted to be placed onto the tissue of a soft organ. In one embodiment, the synthetic matrix may be a mesh matrix or a non-woven matrix that is placed on the tissue surface together with the reactive components. In one embodiment, the non-woven matrix is flexible and/or conformable and is adapted for being placed onto a tissue surface, with the biosynthetic adhesive being applied to the synthetic matrix.

[0028] In one embodiment, the synthetic matrix preferably includes fibers and interstices that are disposed between the fibers.

[0029] In one embodiment, the biosynthetic or synthetic adhesive is applied to a biodegradable synthetic matrix (e.g., VICRYL® non-woven PG910) in a manner that prevents substantial reaction of the co-reactive components. The biosynthetic adhesive components may be a solution of the PEG-NH2 and polyethylene glycol succinimidyl glutarate (PEG-SG) that is pre-mixed immediately prior to use in which one component has a protective leaving group that prevents reaction at the pH for delivery. Alternatively, the biosynthetic adhesive components can be provided on the matrix by sequential applications and drying of individual solutions of the co-reactive components. Still further, the biosynthetic adhesive components can be provided individually or as a blend onto the matrix in powder form.

[0030] Comparative Examples 1 and 2: Since PEG-NHS is an electrophile that would likely react with amine nucleophiles present in blood proteins and tissue, it was anticipated that coating PEG-NHS individually onto a textile substrate would promote adhesion of the substrate to a bleeding wound. However, it was found that applying only the electrophile, the PEG-NHS without the nucleophile PEG-NH2 was not effective at adhering a patch to a bleeding surface.

[0031] As an example, 16.0 mg/cm.sup.2 of a 4-arm (10 kDa) PEG-NHS was deposited onto a non-woven carboxylmethylcellulose (CMC) substrate, which was evaluated on a porcine spleen biopsy punch bleeding model. In this model the exemplary CMC patch was not effective in providing hemostatic efficacy.

[0032] Likewise, applying only the nucleophile, the PEG-NH2 without the electrophile PEG-NHS was not effective at adhering a patch to a bleeding surface. As an example, applying 6.5 mg/cm.sup.2 of 4-arm (4 kDa) PEG-NH2 onto a non-woven carboxymethylcellulose (CMC) substrate was not effective in providing hemostatic efficacy.

[0033] Apply 25.5 mg/cm.sup.2 in total of PEGs (PEG-NHS, 4 arms at 10 kDa [4ARM-SG-10K] and PEG-NH2 4 arms at 5 kDa [4ARM-NH2-5000]) onto an 4 inch by 2 inch substrate composed of layer of woven oxidized regenerated cellulose and a non-woven absorbable polymer (PG910) (Bi-Layer Substrate). While the total PEGs loading density remained the same, the molar ratio of PEG-NHS to PEG-NH2 varied: 0.6, 1.2 and 1.8.

TABLE-US-00001 PEG-NHS PEG-NH2 Total PEG PEG-NHS/ density Density loading PEG-NH2 Run # mg/cm.sup.2 mg/cm.sup.2 mg/cm.sup.2 Molar ratio 3 13.9 11.6 25.5 0.6 1 18 7.5 25.5 1.2 2 20 5.5 25.5 1.8

[0034] The results of Applicants' studies indicate that the hemostatic efficacy decreases as the molar ratio of PEG-NHS to PEG-NH2 increases between 0.6 and 1.8. In addition, the results indicate that the PEGs molar ratio is a significant variable in the hemosta performance of these prototypes in this model.

[0035] In addition, it was found that a molar ratio of PEG-NHS to PEG-NH.sub.2 ratio was 0.25 (30.6 mg/cm.sup.2 PEG-NH2, 19.2 mg/cm.sup.2 PEG-NHS) demonstrated hemostatic efficacy in a heparinized porcine bleeding model (Spleen, liver biopsy punch, and partial nephrectomy). (PEG Amine PEG-AM-4K; PEG-NHS—4-arm N-hydroxysuccinimide glutarate ester terminated PEG, Mw˜10,000 g/mol, 4ARM-SG-10K)

[0036] Observations from 3 studies taken together enabled the inventors to discover that the molar ratio of the PEG does not follow a linear trend, When PEG-NHS to PEG-NH2 molar ratio approaches zero, the hemostatic efficacy of the prototype does not continue to increase compared to 0.25 and drops to zero hemostatic efficacy. When the PEG-NHS to PEG-NH2 molar ratio approaches infinity, the hemostatic efficacy drops to zero as well as the two PEGs are required to create a cohesive gel complex. The data supports an optimal PEG-NHS to PEG-NH2 molar ratio range of 0.25 to 1.8.

[0037] To demonstrate that samples within the suggested range of the PEG ratio are functional in a relevant bleeding acute animal model, the following study was performed. Test articles demonstrated hemostatic efficacy in a heparinized porcine bleeding model (Spleen biopsy punch, and spleen resection). PEG-NH2 (4-armed, and molecular weight of 4K) and PEG NHS (4-armed, n-hydroxysuccinimide glutarate ester terminated PEG, molecular weight of 10k, 4ARM-SG-10K). The substrate used was the Bi-Layer Substrate, and the acetone solution of each of components was sprayed ultrasonically onto the Bi-Layer Substrate: first the PEG-NH2 solution, and then the PEG-NHS solution. The coating levels and hemostasis models are listed below:

TABLE-US-00002 PEG-NHS PEG-NH2 Total PEG PEG-NHS/ density Density loading PEG-NH2 Hemostatic model mg/cm.sup.2 mg/cm.sup.2 mg/cm.sup.2 Molar ratio Test article 1 Spleen biopsy 16 10 26 0.64 punch (Mild to moderate bleeding) Test article 2 Spleen resection 16 14 30 0.46 (Severe bleeding)

[0038] PEG deposition density (mass of total PEGs deposited per substrate surface area) was evaluated, with a fixed molar ratio of 1.2:1.0 between succinimidyl groups PEG-SG and amine groups on PEG-Amine, for its effect on tissue peel force. Peel adhesion forces were evaluated for Bi-Layer prototypes with deposition densities ranging from 0 mg/cm.sup.2 (uncoated) to 51.0 mg/cm.sup.2 (200% of the standard S1 deposition density). Interestingly, peel force increased initially with increasing PEG deposition density, but plateaued at densities from 6.4 mg/cm.sup.2 up to 25.5 mg/cm.sup.2 (from 25% of standard S1 deposition density up to 100%). Beyond 25.5 mg/cm.sup.2 deposition density, peel force begins to decline.

[0039] This trend suggests that the interfacial, chemical adhesion and subsequent gel formation of PEG-coated PEM to tissue is low, threshold-dependent on deposition density of PEG at the above fixed ratio, while above the threshold of 6.4 mg/cm.sup.2, PEG layers have sufficient functionality to both adhere to tissue and form a strong, cross-linked gel with one another. However, above a PEGs density of 25.5 mg/cm.sup.2 the ability to form a strong interconnected gel between the tissue surface and both PEGs may be hindered by the excessive spatial separation of the individual PEG layers.

TABLE-US-00003 PEG Average Deposition Tissue Standard Density Peel Force Deviation (mg/cm2) (N/m) (N/m) 0.0 4.47 0.48 1.3 81.00 17.22 3.8 146.89 16.43 6.4 186.23 27.08 12.8 193.27 31.62 25.5 180.70 32.33 51.0 91.30 6.27

[0040] Example: Manufacturing Via Sequential Solution Spray (Ultrasonic)

[0041] In this process, a coating layer of an individual PEG is applied using an ultrasonic sprayer until target density of that PEG is reached. Dry air is used as a carrier gas for the atomized polymer solutions, though an inert gas can also be used such as nitrogen or argon. In one embodiment, the first coat of PEG-NH2 layers onto the matrix until reaching a target density, then drying the matrix under vacuum and subsequently coating layers of PEG-SG until reaching that respective target density. The fully-coated matrix is then dried under vacuum, and packaged.

[0042] The sealing system disclosed herein is independent of a patient's clotting system. Thus, surgeons can attain hemostasis and sealing independent of the patient's coagulation status, which could be impaired in patients being resected since most clotting proteins are produced in the liver. The sealing system may also be used for patients on antiplatelet and anticoagulant therapy, e.g., aspirin, heparin or warfarin.

[0043] In one embodiment, the electrophile may include PEG-SG. In one embodiment, the nucleophile may be selected from any polymeric source of NH.sub.2 group, such as polyethylene glycol amines (PEG-NH2), and combinations of albumin and PEG-NH2.

[0044] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, which is only limited by the scope of the claims that follow. For example, the present invention contemplates that any of the features shown in any of the embodiments described herein, or incorporated by reference herein, may be incorporated with any of the features shown in any of the other embodiments described herein, or incorporated by reference herein, and still fall within the scope of the present invention.