EP1501558A1 - Resorbable pharmaceutical formulation for the continuous release of thrombin - Google Patents

Abstract

The invention relates to resorbable pharmaceutical formulations for the continuous local release of thrombin. The thrombin is embedded in resorbable polymer spheres which are incorporated in a collagen sponge. The inventive formulation provides a resorbable haemostatic for using in surgery, especially dental surgery, in dentoalveolar operations.

Description

 RESORBABLE PHARMACEUTICAL FORMULATION FOR CONTINUOUS THROMBINE RELEASE

The present invention relates to a resorbable pharmaceutical formulation for continuous local thrombin release comprising thrombin which is embedded in resorbable spheres of polymers, the spheres being incorporated in a sponge. The formulation according to the invention provides a resorbable hamostatic agent for use in surgery, in particular dental surgery / in dento alveolar interventions.

Due to various diseases, the number of patients requiring therapeutic anticoagulation (anticoagulation) is increasing. These include, for example, patients with artificial heart valve prostheses or patients who have had a stroke or venous thrombosis.

The therapeutically induced anticoagulation is almost without exception by the daily oral administration of vitamin K antagonists (coumarin derivatives such as e.g.

Phenprocoumon in the form of Marcumar®, or Falithrom® or Coumadin derivatives in

Form of Warfarin®). By inhibiting blood clotting, even small surgical interventions, such as tooth extraction, are associated with a high risk of bleeding. For this reason, the patients concerned are usually treated under cost-intensive inpatient conditions. The permanent oral anticoagulation is replaced by the intravenous administration of heparin, which also inhibits blood clotting. However, heparin has a significantly shorter half-life, which makes it easier to control the anticoagulant if bleeding complications occur, without having to forego the necessary protection against thrombosis. In addition to these therapeutically induced forms of blood coagulation inhibition, postoperative bleeding is also caused by the piasmin system. The piasmin system, the physiological antagonist of the blood coagulation system, ensures a dissolution of at a systemic level Blood clots. However, this function is not desirable if there is an increased risk of bleeding after surgery.

In addition to the above-mentioned indications, there are other patient groups that are due to a congenital disorder of the blood coagulation system, e.g. Protein C, protein S or antithrombin deficiency require therapeutic anticoagulation with vitamin K antagonists, but also a congenital factor deficiency such as Hemophilia A or B, or von Willebrand-Jürgens syndrome or an isolated lack of factors within the prothrombin complex can lead to considerable rebleeding even with small, local interventions. In order to avoid subsequent bleeding events after tooth extractions or dental - surgical interventions without endangering the necessary thrombosis protection, the following "state of the art" procedures have been established. However, it is also not possible to prevent subsequent bleeding with these two therapy regimens:

I.) Implementation of permanent oral antocoagulation by vitamin K antagonists to an intravenous permanent heparinization in the so-called therapeutic range (PTT 2-3 times the normal range). Due to the relatively short duration / half-life of heparin, subsequent bleeding, the cause of which is related to heparin anticoagulation (PTT over 80 sec), should be managed by reducing the amount of heparin administered. However, therapeutic heparinization to protect against thromboembolic complications is often no longer available (PTT <2-fold norm). In addition, due to the temporary hospitalization of the patients, this procedure is associated with considerable costs for the insurance carriers.

II) Continuation of oral oral medication by vitamin K antagonists and implementation of small dental surgery in the upper limit of oral anticoagulation (quick value of 25% -35%). However, the problem arises here that patients who require strict anticoagulation (Quick maximum 25% with an artificial heart valve in the mitral position) cannot be reached with this concept. Furthermore, the physiological, perioperative consumption of the residual coagulation factors in the circulation results in a further reduction of the endogenous factor supply, because with the continued administration of vitamin K antagonists these are only reproduced to an insufficient extent. This further reduces the PTT and there are postoperative bleeding complications. The bleeding frequency increases in some cases up to 10 times.

The optimal local wound care is the same for both concepts: after the extraction of the teeth or after a smaller dental intervention, the bone wound is tamponized with a collagen vial (e.g. Lyostypt) or a gelatin sponge (e.g. Topostatin). The mechanical compression of the bone wound brought about by this can achieve an initial hemostasis. If there is increased bleeding from the tooth compartment intraoperatively, a local hemostatic agent based on thrombin or fibrin glue preparation can also be applied to the bone wound.

To reduce the fibrinolytic influence of saliva, the mucosal wound is then closed with saliva-tight atraumatic sutures. For the same reason, a wound protection plate made of plastic is often used in patients and attached to the remaining teeth.

As a result of a separate prospective study by the inventors, the following causes for the occurrence of postoperative bleeding in dental surgical measures with continued marcoumarization could be identified (Gerhards et al., Gerhards F., Wagner W .: “On the bleeding risk after dental surgery under continued surgery Marcumarisierung ". Dtsch Zahnärztl Z. (1997) 52: 53-56):

1. Consumption of the remaining coagulation factors circulating in the bloodstream and

2. their additional inactivation by the intravenous administration of heparin (inactivation of the entire prothrombin complex).

The object of the present invention is therefore to provide a pharmaceutical formulation with which the active end product of the blood coagulation cascade, thrombin, can be made available over a limited period of time. The period until stable intraoral wound healing is considered to be the required period of time. This corresponds to 7 to 10 days. After this period, stable wound healing has occurred, which means that external mechanical influences on the wound can no longer have any effect. To achieve this, thrombin is embedded in resorbable spheres, preferably from commercially available polymers that are already used for other medical devices (e.g. surgical sutures) (see Figure 1).

The term “spheres” in the context of the invention is understood to mean particles, capsules or liposomes which contain the active ingredient embedded, enclosed, dispersed or dissolved, as described, for example, in Voigt, Pharmaceutical Technology, Deutscher Apothekerverlag Stuttgart, 2000, pages 467-471.

The term “spheres” in the sense of the present invention is understood in particular to mean microparticles or nanoparticles which contain an active ingredient embedded in a polymer matrix without the formation of a separate capsule skin

Spheres with a size of 0.1 to 1000 / ym are preferred, very particularly with a size of 10 to 150 μm.

The loading of the spheres can be 0.1 to 20%, depending on the corresponding thrombin preparation, and the loading of the collagen sponge can be 0.1 to 50%. The total dose should be 1 I.U. up to 2000 IU, preferably 250 IU up to 1000 IU Thrombin per implant.

The spheres can be produced with the aid of known processes, in particular emulsion techniques (w / o; o / w; w / o / w - emulsion evaporation or extraction method) or spray drying. The methods are described in the prior art. For example, EP 0 330 180 describes microspheres of the polylactic acid type containing physiologically active substances and processes for their production. Other manufacturing processes include Müller RH and Hildebrand GE, Pharmaceutical Technology: Modern Pharmaceutical Forms, Wissenschaftliche Verlagsgesellschaft Stuttgart, 1998, pp. 243-258 and S339-355, Eldrigé J. et al., J. Controlled Release 1990, 11, 205 -214; Jeffery J. et al. Pharm. Res. 1993, 10, 362-368 and Pavanetto et al., Int. J. of Pharmaceutics 1992, 84, 152-159. Resorbable polymers used according to the invention for producing the resorbable spheres include poly sugar and their derivatives, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polylactic acid (PLA), polylactides, polyhydroxybutyrate (PHB), poly-L-lysine, their homologues and cocondensates, lactic acid Glycolic acid copolymer (PLG), in particular Resomer RG 504 and 505 from Boehringer Ingelheim. Other usable polymers are disclosed, inter alia, in Müller RH and Hildebrand GE, Pharmaceutical Technology: Modern Pharmaceutical Forms, Wissenschaftliche Verlagsgesellschaft Stuttgart, 1998, pp. 243-258 and S339-355.

The spheres thus obtained are in turn incorporated into resorbable sponges, in particular collagen sponges. This is done, for example, by freeze-drying an aqueous collagen or an aqueous collagen suspension or gelatin solution in which the spheres are uniformly dispersed. The production of collagen sponges is e.g. in US 4,515,637, EP 562862 and by Chvapil, J. Biomed. Mater. Res. H, 721-741 (1977).

collagen

The collagen used according to the present invention should preferably be soluble in vivo by enzymatic degradation or other biological processes. Preferred is native collagen in its potentially soluble form or natural insoluble collagen which is inherently cross-linked and is insoluble in either an acidic or alkaline medium such as e.g. also described in US 4,515,637. The collagen used is preferably type 1 collagen.

The origin of the collagen for use in the present invention is not particularly limited. Generally, collagen is used which is derived from the skin, bone, cartilage, tendons, internal organs, etc. of a mammal such as e.g. comes from humans, horses, cattle, pigs, sheep, rabbits, mice. Collagen-like protein derived from birds, fish or the like can also be used. Genetically engineered collagen can also be used, and genetic engineering is currently in progress (e.g. ZymoGenetics, WA, U.S.A.)

thrombin

The thrombin used in the present invention can be obtained from a variety of sources, e.g. pooled human or animal plasma. Bovine thrombin is e.g. available from a variety of commercial sources. Recombinant thrombin can also be used in accordance with the invention (e.g. ZymoGenetics, WA, U.S.A.).

This can be obtained from a variety of recombinant sources such as transformed host cells (bacteria, yeast or mammalian cells). You can also thrombin-like compounds such as proteolytic snake venom, and thrombin precursors such as prothrombin can be used as sources for thrombin.

Therefore, the term “thrombin” as used here also includes thrombin precursors and thrombin-like compounds and refers to all proteins and amino acid polymers of natural or synthetic origin which are able to catalyze the formation of fibrin clots from fibrinogen and / or to activate the blood platelets other coagulation factors such as factor VIII can also be used

This formulation according to the invention has various advantages since, on the one hand, the use of collagen sponges for mechanical wound compression and the platelet aggregation induced by collagen, the existing therapy concept is only slightly changed and, on the other hand, the healing of the wound is supported over a period of 7-10 days by the released thrombin , The platelet aggregation caused by collagen, through the release of mediators, activates plasmatic blood coagulation.

In summary, it can be stated that the combination of the collagen according to the invention, with its anti-platelet-promoting properties, and a temporary local release of the coagulation factor Na (thrombin) sufficient for the period of wound healing, a local hemostasis over a longer period of time, which is independent of systemic influences is possible. The release is preferably 0 to 14 days, particularly preferably 7 to 10 days.

In addition, the preparation can be supplemented with therapy-supporting antifibrinolytics such as tranexamic acid, ε-amino caproic acid, 4- (aminomethyl) benzoic acid, aprotinin, EPO, acetaminonaphtone, thromboplastin, menadione sodium bisulfonate sulfonate sulfonate sulfonate sulfonate, and add become. This enables additional thrombolytic influences from the piasmin system and the fibrinolytic salivation effect to be balanced until wound healing is complete. The spheres according to the invention can also contain further active substances such as antibiotics, anti-infectives or local anesthetics. The release of active thrombin from resorbable polylactic acid-co-glycolide spheres was investigated and demonstrated in vitro using a chromogenic substrate.

Figure 2 shows a release profile of thrombin from poly (DL-lactide-co-glycolide) 50:50 (Boehringer Ingelheim RG 504) at 37 ° C in PBS buffer. The time-dependent cumulative thrombin release is shown, determined by means of the Bradford test measured in vitro over the release period of 28 days.

Figure 3 shows a release profile of thrombin from poly (DL-lactide-co-glycolide) 50:50 (Boehringer Ingelheim RG 504) at 37 ° C in PBS buffer. The time-dependent cumulative thrombin release is shown, which is measured by the elimination of p-nitroaniline from the chromogenic substrate, in vitro over the release period of 28 days. 1 NIH thrombin corresponds to 0.324 +/- 0.073 μg thrombin. The amount of p-nitroaniline released is proportional to the active thrombin, the thrombin used had an activity of 50 NIH / mg.

The present invention further provides the use of the pharmaceutical formulation according to the invention as a local hemostatic agent, in particular for local hemostasis in blood-clot-inhibited / blood-coagulation-incompetent patients. The cause of the anticoagulation can be iatrogenic, i.e. due to an inhibition of blood clotting due to the administration of vitamin K antagonists such as phenprocoumon or coumadin, platelet aggregation inhibitors such as acetylsalicylic acid, tirofiban, dipyramidol, ticiopidine or eptifibatide or is endogenously caused as in patients with a congenital defect in blood clotting in a mild form. These include e.g. Hemophilic A / B, von Willebrand-Juergens syndrome and an isolated factor deficiency within the prothrombin complex.

As is known from the literature and already discussed above, the frequency of postoperative bleeding in coagulation-incompetent patients is approximately 30% and the required duration of hospitalization is several days (on average 5 days). The clinical use of the pharmaceutical formulation according to the invention significantly reduces the frequency of subsequent bleeding and thereby shortens the duration of hospitalization. It also enables certain outpatient procedures Interventions. In addition to a significantly reduced risk for the patients, this also means considerable cost savings in the healthcare system.

Claims

claims 1. Absorbable pharmaceutical formulation for continuous local thrombin (coagulation factor Ila) release comprising thrombin which is embedded in resorbable spheres of polymers, the spheres being incorporated in collagen sponges and the resorbable spheres optionally additionally containing one or more antifibrinolytics. ² - Absorbable pharmaceutical formulation according to claim 1, wherein the polymer is selected from poly sugars and their derivatives, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polymethyl methacrylate (PPMA). Polyalkylcyanoacrylate (PACA), acrylic copolymers, polyethylene-vinyl acetate, polyhydroxypropyl cellulose, polyorthoesters, poly-ε-caprolactones, polyamino acids, polyurethanes, polyethylene glycol, polylactic acid (PLA), polylactides, polyhydroxybutyrate (PHB), poly-L and cocysates and their homologues, and their homologs Lactic acid-glycolic acid copolymer (PLG), Resomer RG 504 ® and Resomer RG 505®.- 3. Absorbable pharmaceutical formulation according to claim 1 or 2, wherein the diameter of the spheres is 0.1 to 1000 microns, preferably 10 to 150 microns. 4. Absorbable pharmaceutical formulation according to one of claims 1 to 3, wherein the KoUagen sponge (collagen type 1) is produced from collagen from a human, bovine, swine, equine source or from collagen produced by means of genetic engineering processes. 5. Absorbable pharmaceutical formulation according to one of claims 1 to 4, wherein thrombin is selected from bovine, swiner, equine or human origin or is the product of a genetic engineering production process. 6. Absorbable pharmaceutical formulation according to one of claims 1 to 5, wherein thrombin is present in an amount of 1 IU to 2000 IU, preferably 250 IU to 1000 IU per implant. 7. Absorbable pharmaceutical formulation according to one of claims 1 to 6, wherein the antifibrinolytics are selected from tranexanoic acid, ε-aminocaproic acid, 4- (aminomethyl) benzoic acid, aprotinin, EPO, acetaminonaphtone, thromboplastin, menadione sodium bisulfate, adrenochromomonoaminogonidinium carbosulfonate sulfonate. 8. Absorbable pharmaceutical formulation according to one of claims 1 to 7, wherein the release takes place over a period of 0 to 14 days, preferably 7 to 10 days. 9. resorbable pharmaceutical formulation according to any one of claims 1 to 8, further comprising an antibiotic, anti-infective or local anesthetic. 10. Use of a formulation according to one of the preceding claims as a Hamostyptic. 11. Use according to claim 10 in coagulation-incompetent patients. 12. Use according to claim 10 or 11, wherein the patients are under therapeutically induced anticoagulation or suffer from congenital defects in blood clotting of the mild form. 13. Use according to any one of claims 10 to 12 in patients with venous thrombosis, pulmonary embolism, stroke, heart attack, atrial fibrillation, or artificial heart valve prostheses, or in therapeutic anticoagulation due to congenital protein C, protein S or antithrombin deficiency. 14. Use according to any one of claims 10 to 12, in patients with hemophilia A / B, von Willebrand-Jürgens syndrome or isolated factor deficiency within the prothrombin complex. 15. Use according to any one of claims 9 to 14 in surgical or dental surgery.