Patent Application: US-201113068184-A

Abstract:
the present invention relates to the preparation of a hemostatic dressing in the form of a powder that is particularly applicable for stemming severe bleeding and for incorporation of the powder into dressings that can stabilize the site of tissue injury , and simultaneously act as an antimicrobial agent .

Description:
the pectin utilized in the preparation of the silver pectate has a degree of esterification ( de ) of less than 30 percent and a degree of amidation ( da ) of less than 50 percent . the entire composition was mixed to ensure homogeneity and placed in a ceramic dish . the ceramic dish containing the entire composition was placed in an oven set at 85 - 90 ° c . and dried for 18 hours , resulting in a dried brittle solid . the entire dried contents were ground in a mill to a fine powder and the powder placed onto a 100 mesh screen . any of the powder that passed through the 100 mesh screen was then collected and tested . one ml ( 1 ml ) of normal citrated sheep blood was placed into each of 3 test tubes . add 0 . 5 grams of the 100 mesh powder prepared in example i into the first tube ; clotting of the blood results in 8 . 5 seconds . placing 1 gm of the 100 mesh powder prepared in example i into the second test tube resulted in clotting of the citrated blood in 6 . 0 seconds . placing 1 . 5 gm of the 100 mesh powder prepared in example i into the third test tube resulted in clotting of the citrated blood in 4 . 0 seconds . seven grams ( 7 gm ) gm of the 100 mesh powder prepared as in example i was added to 50 milliliters ( ml ) of deionized or distilled water . the above ingredients were thoroughly mixed to ensure a foamed homogeneity and layered onto a fibrous cloth or alternatively layered into a thin ceramic dish . the dish was incubated at 40 ° c . for twelve hours at which time it was removed and the following tests were performed : a drop of citrated sheep blood was dropped onto the surface of the dried composition and the time measured for its complete absorption into the dressing . with the composition as shown in this example iii , the entire drop of blood was completely absorbed in six seconds . preparing the same composition as in example iii , except adding 4 . 0 grams of hydrophilic polymer , all other ingredients remaining the same , a drop of citrated sheep blood was absorbed in 4 . 5 seconds . the above descriptions and examples illustrate particular constructions including the preferred embodiments of the solutions . however , the invention is not limited to the precise constructions describer herein , but , rather , all modifications and improvements thereof encompassed within the scope of the invention . many of the examples described herein utilize the surface active agents such as those characterized as tween 80 or sodium lauryl so 4 . these surface - active agents are utilized primarily to effect a homogenous dispersion between the non - aqueous soluble components with the aqueous soluble components in order to ensure homogeneity . these surface active agents are also utilized in order to improve the wetting of a medical dressing or bandage in the event that a wound may be exudating , and the enhanced wicking in such a bandage or medical dressing serves to quickly absorb any blood or serum from a wound site into the dressing . other surface active agents , such as a member of the group of tweens : ( tween 20 , polyoxyethylene sorbitan monolaurate ; tween 40 , polyoxyethylene sorbitan monopalmitate ; or tween 85 , polyoxyethylene sorbitan trioleate may be incorporated into the pectin composition without deviating from the novelty of the invention described herein . the use of glycerin or propylene glycol provide a soft texture of the gel composition and are well known in the profession ; their attributes of which have been recorded in the past such as in u . s . pat . no . 6 , 696 , 077 b2 . the concentrations of glycerin or propylene glycol are provided here in order to effect the texture and softness of the gel dressing as prepared as described herein , but it is clear that other concentrations of the glycerin or propylene glycol may be provided without in any way deviating from the hemostatic activity for which the dressing has been principally compounded . it is well known in the profession that various glycols will act as plasticizers and may be used to improve the flexibility of gels or fibers . the plasticizer that we have principally used in the examples described herein has been glycerin because of its low cost , low toxicity , and ready availability . it is clear , however , that other plasticizers may be utilized such as ethylene glycol without deviating from the novelty of the invention described herein . in the examples cited herein , calcium gluconate has been utilized to provide the calcium ions which precipitate the aqueous insoluble calcium pectate which insolubilization may also serve to entrap and / or restrain the release and migration of the silver ions from the silver pectate matrix as described herein . it is clear , as has been mentioned , that other salts may be utilized to precipitate the pectins such as those of aluminum , zinc , copper or chromium . such insoluble pectates may be readily utilized to precipitate the various mixtures described in the examples provided herein without deviating from the essential merits of this invention . however , if the pectate compositions are to be utilized in or on biological tissues , the particular salt utilized to precipitate the pectin should be dictated by any restraints of toxicity or other untoward reactions that might result from their use for the preparation of hemostatic dressings . in the examples cited , the pectin had a degree of esterification of less than 30 percent in order to achieve a relatively high degree of reactivity with calcium and other ions . it is clear however , that pectins other than those having a degree of esterification of less than 30 percent may be utilized without deviating from the essential tenets of the invention . in the examples cited the silver pectate composition of example i was dried in an oven set at 85 - 90 ° c . temperatures other than 85 - 90 ° c . may be utilized to dry the subject composition without deviating from the essential tenets of the invention . in the example cited , the silver pectate dried contents were ground in a mill to a fine powder which was then passed through a 100 mesh screen . the particle size of the powder may be placed through a mesh screen achieving larger or smaller particle sizes without deviating from the essential tenets of the invention . it is sufficient to indicate that the smaller the mesh size utilized would therefore provide a powder having a much higher surface area that is expected to improve the speed of the hemostatic activity . de cristofaro r , de candia e ( 2004 ). “ thrombin domains : structure , function and interaction with platelet receptors ”. j . thromb . trombolysis 15 ( 3 ): 151 - 63 . felt , o . buri , p ., & amp ; 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