Method of Manufacturing Fibrous Hemostatic Bandages

Abstract

A method of manufacturing a sturdy and pliable fibrous hemostatic dressing by making fibers that maximally expose surface area per unit weight of active ingredients as a means for aiding in the clot forming process and as a means of minimizing waste of active ingredients. The method uses a rotating object to spin off a liquid biocompatible fiber precursor, which is added at its center. Fibers formed then deposit on a collector located at a distance from the rotating object creating a fiber layer on the collector. An electrical potential difference is maintained between the rotating disk and the collector. Then, a liquid procoagulation species is introduced at the center of the rotating disk such that it spins off the rotating disk and coats the fibers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present invention claims the benefit of the filing date of prior U.S. provisional application 60 / 743,866 filed 28 Mar. 2006, the text of which is included by reference herein.GOVERNMENT LICENSE RIGHTS[0002]The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of contract No. 2004-02653 awarded by the United States Department of Agriculture, and U.S. Army contract No. WA1XWH-05-1-0527 with LNKChemsolutions as a Subcontractor.TECHNICAL FIELD[0003]This invention relates to a method of manufacturing hemostatic compositions useful in reduction and cessation of blood loss from battlefield injuries, surgical procedures and traumatic wounds.BACKGROUND ART[0004]This invention complements another invention titled, “Methods for Making a Multicomponent Hemostatic Dressing,” disclosed in patent application PCT...

AI Technical Summary

Benefits of technology

[0026]There is a need for a method of manufacturing fibers used for a hemostatic dressing that permits rapid customization of the fibers using one apparatus.

[0035]The present invention provides a capability to manufacture separate bandages in a continuous manufacturing operation employing modular bandage manufacturing devices. Modularity assures that the invention can be deployed in a manufacturing setting in multiple, independently operating lines to create redundancy in bandage manufacturing and thus improve the efficiency and continued operation of the process even when one or more of the devices experiences operational problems.

Problems solved by technology

The production rate of this process is slow and often measured in quantities that are less than one gram per hour per nozzle, and the fiber strength is usually low, creating a fragile fiber.

This prior art, however, does not teach a micrometer or sub-micrometer scale coating of the fibers.

Despite this prior art, electrospinning of aqueous protein solutions is generally problematic because the chemical solution compromises the chemical stability or shelf-life of the proteins.

However, practical problems in using this approach in situations involving arterial bleeding are that it is time consuming and requires a level of skill not often present in environments such as the battlefield.

For direct application by electrospinning of aqueous protein solutions to wounds, two additional problems became evident: this electrospinning approach uses a lot more protein than by just coating biocompatible polymer fibers, such as those made from polylactic acid; and, electrospinning of proteins in fluorinated hydrocarbons is cell-toxic if even a trace fluorinated hydrocarbon remains in the fibers.

Second, proteins such as thrombin and fibrinogen that would otherwise initiate blood coagulation cascade reactions on molecular contact, thereby significantly reducing the shelf-life of the hemostatic bandage, are kept in separate coatings but, more importantly, at distances ranging from one micron to one millimeter to ensure very rapid interaction between these two coagulation cascade proteins on contact with blood from a wound.

The Rothwell patent teaches a method of adding a solution of propyl gallate to a bandage, but does not teach using propyl gallate dispersed into the bulk of fibers.

This prior art does not teach the manufacture of a bandage nor does it describe the elements needed to create a functional hemostatic bandage composed of coated fibers or multicomponent fibers assembled into a dressing.

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