Degradable haemostat composition

Abstract

The present invention relates to a fibrous haemostat composition that is able to safely gradually and fully degrade in a human or animal body within about 30 days and so can be utilised by physicians to stem a flow of blood and promote healing both after as well as during surgical procedures.

Claims

1. A method of manufacturing a haemostat composition, the method comprising: providing a chitosan salt or a chitosan derivative in a fibrous form: and combining it with a physiologically acceptable acid in an amount of acid that is from 25 to 70% by weight of the haemostat composition: wherein the haemostat composition is in a fibrous form and is able to fully degrade in a human or animal body within about 30 days.

2. A method according to claim 1, comprising coating the chitosan salt or chitosan derivative with a physiologically acceptable acid.

3. A method according to claim 1, further comprising the step of washing chitosan prior to forming the chitosan salt to reduce the presence of endotoxins prior to the coating step, the washing comprising contacting the chitosan with an alkali solution to form a mixture, and then leaving the mixture for a period of time before drying it.

4. A method according to claim 1, further forming the fibres into a woven or non-woven textile fabric.

5. A method according to claim 2, wherein the physiologically acceptable acid is only applied after the formation of the fibres into a woven or non-woven textile fabric.

Description

DETAILED DESCRIPTION

EXAMPLES

(1) Method

(2) The total absorbency of the haemostat composition of the invention is determined using simulated wound fluid, serum and lysozyme solution. This is undertaken by determining the maximum absorbency of the materials by slowly adding fluid to the materials until no more can be absorbed. The amount of fluid absorbed is calculated from the wet weight minus the dry weight.

(3) Using the total absorbency volume for the material to be tested, this volume of lysozyme solution, simulated wound fluid or serum is decanted into a clean sealable beaker.

(4) The haemostat composition is added into the solution (the solution volume being greater than the maximum absorbency of the haemostat composition), ensuring that the weight of product is not greater than the absorbency potential for the volume of fluid within the beaker.

(5) The haemostat composition and solution are sealed and incubated at 37? C. (i.e. body temperature) for up to 30 days.

(6) At each time point the solution is visually assessed to determine whether and to what degree the haemostat composition has degraded.

(7) It is to be noted that at maximum absorbency at day 1, the degradation time is quicker than if the same volume of solution is applied gradually over a 5 day period.

(8) The haemostat composition is considered to have completely degraded if the viscosity of the lysozyme solution, simulated wound fluid or serum falls below 10 cps as measured at 20? C. on a Brookfield viscometer, measured by setting the viscometer to spindle 64 and setting the spindle speed to 10 rpm, or if the fluid in the beaker becomes optically clear with no particles or insoluble matter visible to the human eye.

(9) The degradation data is provided in Table 1.

(10) TABLE-US-00001 TABLE 1 Testing/Examples Days to full degradation Sample SWF Lysozyme solution Chitosan/Viscose/Acid >30 days >30 days blend Celox gauze >30 days >30 days Chitosan nonwoven with >30 days >30 days 10% Acid Chitosan nonwoven with 1 day 4 days 35% Acid Chitosan nonwoven with 1 day 1 day 55% Acid

(11) In the examples in Table 1, a chitosan nonwoven fabric, 135 gsm, was coated with the designated quantity of a lactic acid solution, dried, and then sterilised under gamma irradiation.

(12) It can therefore be seen that the fibrous haemostat compositions according to the invention degrade effectively over a desired period of between 1 and 30 days in conditions designed to replicate those that would be encountered in the human or animal body, and would be able to safely remain in the human or animal body post-surgery to aid in reducing and preventing incidences of re-bleeding and promoting healing, before completely degrading and being excreted from the body naturally.

(13) It is of course to be understood that the present invention is not intended to be restricted to the foregoing examples which are described by way of example only.