Hemoactive compositions and methods for their manufacture...

Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Peptide containing doai

Reexamination Certificate

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C514S054000, C514S055000, C514S057000, C514S060000, C514S777000, C514S944000, C530S354000, C530S356000, C530S357000, C530S362000, C530S380000, C530S402000, C424S078020, C424S078060, C424S400000, C424S412000, C424S478000, C424S480000, C435S810000

Reexamination Certificate

active

06706690

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to biocompatible polymeric compositions and methods for their production and use. More particularly, the present invention relates to compositions for promoting hemostasis and delivery of bioactive substances.
The ability to inhibit bleeding in a patient (hemostasis) and deliver bioactive substances to the patient (drug delivery) are both of great medical importance. Over the years numerous devices, compositions, and biological agents have been developed for both purposes. As no one device, composition, or approach can fulfill all medical needs, there continues to be a need to provide alternative and improved modalities for achieving both hemostasis and drug delivery.
In particular, it would be desirable to provide new and alternative compositions which are suitable for performing either or both hemostasis and drug delivery to patients. Preferably, such compositions should be a convenient matrix for topical delivery to surgical and/or traumatic wounds to a patient's tissue structures or skin. In particular, such compositions should be dry, be capable of storage for prolonged periods, be in a sheet or other easily manipulable form to facilitate placement, require minimum preparation by a user prior to use, be relatively easy to fabricate, be compatible with the delivery of a wide variety of biological and other active agents, and the like. In the case of hemostatic materials, it would be particularly advantageous to be able to remove excess material without causing further bleeding or other adverse events. At least some of these objectives will be meet by the embodiments of the invention described hereinafter.
2. Description of the Background Art
Biodegradable injectable drug delivery polymers are described in U.S. Pat. No. 5,384,333 and by Jeong et al. (1997) “Nature,” 388:860-862. Biodegradable hydrogels for controlled released drug delivery are described in U.S. Pat. No. 4,925,677. Resorbable collagen-based drug delivery systems are described in U.S. Pat. Nos. 4,347,234 and 4,291,013. Aminopolysaccharide-based biocompatible films for drug delivery are described in U.S. Pat. Nos. 5,300,494 and 4,946,870. Water soluble carriers for the delivery of taxol are described in U.S. Pat. No. 5,648,506.
Polymers have been used as carriers of therapeutic agents to effect a localized and sustained release (Langer, et al., Rev. Macro. Chem. Phys., C23(1), 61, 1983; Controlled Drug Delivery, Vol. I and II, Bruck, S. D., (ed.), CRC Press, Boca Raton, Fla., 1983; Leong et al., Adv. Drug Delivery Review, 1:199, 1987). These therapeutic agent delivery systems simulate infusion and offer the potential of enhanced therapeutic efficacy and reduced systemic toxicity.
Other classes of synthetic polymers which have been proposed for controlled release drug delivery include polyesters (Pitt, et al., in Controlled Release of Bioactive Materials, R. Baker, Ed., Academic Press, New York, 1980); polyamides (Sidman, et al., Journal of Membrane Science, 7:227, 1979); polyurethanes (Maser, et al., Journal of Polymer Science, Polymer Symposium, 66:259, 1979); polyorthoesters (Heller, et al., Polymer Engineering Scient, 21:727, 1981); and polyanhydrides (Leong, et al., Biomaterials, 7:364, 1986). U.S. Pat. No. 5,595,735 describes a thrombin paste composition using polyethylene glycols as carriers.
Collagen-containing compositions which have been mechanically disrupted to alter their physical properties are described in U.S. Pat. Nos. 5,428,024; 5,352,715; and 5,204,382. These patents generally relate to fibrillar and insoluble collagens. An injectable collagen composition is described in U.S. Pat. No. 4,803,075. An injectable bone/cartilage composition is described in U.S. Pat. No. 5,516,532. A collagen-based delivery matrix comprising dry particles in the size range from 5 &mgr;m to 850 &mgr;m which may be suspended in water and which has a particular surface charge density is described in WO 96/39159. A collagen preparation having a particle size from 1 &mgr;m to 50 &mgr;m useful as an aerosol spray to form a wound dressing is described in U.S. Pat. No. 5,196,185. Other patents describing collagen compositions include U.S. Pat. Nos. 5,672,336 and 5,356,614.
A polymeric, non-erodible hydrogel that may be cross-linked and injected via a syringe is described in WO 96/06883.
The following pending applications, assigned to the assignee of the present application, contain related subject matter: U.S. Ser. No. 09/032,370, filed on Feb. 27, 1998; U.S. Ser. No. 08/903,674, filed on Jul. 31, 1997; U.S. Ser. No. 60/050,437, filed on Jun. 18, 1997; U.S. Ser. No. 08/704,852, filed on Aug. 27, 1996; U.S. Ser. No. 08/673,710, filed Jun. 19, 1996; U.S. Ser. No. 60/011,898, filed Feb. 20, 1996; U.S. Ser. No. 60/006,321, filed on Nov. 7, 1996; U.S. Ser. No. 60/006,322, filed on Nov. 7, 1996; U.S. Ser. No. 60/006,324, filed on Nov. 7, 1996; and U.S. Ser. No. 08/481,712, filed on Jun. 7, 1995. The full disclosures of each of these applications is incorporated herein by reference. WO 98/08550, which claims priority from U.S. Ser. No. 08/903,674, described cross-linked biological polymers which are useful as a component of the materials of the present invention.
SUMMARY OF THE INVENTION
According to the present invention, hemoactive materials comprise a dried, cross-linked biologically compatible polymer which forms a hydrogel when exposed to blood and a non-cross-linked biologically compatible polymer which solubilizes when exposed to blood. A cross-linked polymer is dispersed in a dried matrix of the non-cross-linked polymer, and the materials are delivered to surgical sites, wounds, and other target regions in tissue which are subject to bleeding or otherwise have blood present. By “hemoactive,” it is meant that the compositions will interact in some way with blood when exposed to blood. At a minimum, the non-cross-linked biocompatible polymer will solubilize in the presence of blood and release the cross-linked biologically compatible polymer so that it can hydrate and form a gel as it absorbs water from the blood. Thus, the non-cross-linked biologically compatible polymer forms a binder which maintains the cross-linked polymer in a desirable form prior to use. Usually, the compositions will be in the form of a sheet, typically having a thickness in the range from 1 mm to 25 mm, preferably from 2 mm to 15 mm. Alternatively, the materials can be formed into powders, pellets, large blocks, plugs, cylinders, tubes, split tubes, or other forms which may be conveniently delivered or placed to target tissue sites. Additionally, the “hemoactive” materials may include other bioactive agents capable of providing desirable bioactivities. Of particular interest, the hemoactive materials may include hemostatic agents, such as blood clotting agents, e.g., thrombin, which will promote hemostatic activity of the material. A wide variety of other bioactive agents may be delivered, including other proteins, carbohydrates, nucleic acids, inorganic and organic biologically active molecules such as enzymes, enzyme inhibitors, antibiotics, anti-neoplastic agents, bacteriostatic agents, bactericidal agents, antiviral agents, anesthetics, anti-inflammatory agents, hormones, anti-angiogenic agents, antibodies, neurotransmitters, and the like. Additional components may be provided in the compositions, such as buffering agents, antioxidants, preservatives, viscosity modifiers, solubility modifiers, and the like, in order to enhance or modify the properties or shelf-life of the material. Preferably, the materials will be sterilized and maintained in a sterile package. Conventional sterilization methods include &ggr;-irradiation, exposure to ethylene oxide, electronic beam irradiation, aseptic processing, and the like.
The compositions of the present invention will preferably comprise cross-linked biologically compatible polymers which are relatively persistent, usually having a degradation time of at least 1 day, preferably having a degradation time in

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