DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 01, 2024, is being examined under the first inventor to file provisions of the AIA .
Status of the Application
Receipt is acknowledged of Applicants’ claimed invention filed on 03/01/2024 in the matter of Application N° 18/688,418. Said documents are entered on the record. The Examiner further acknowledges the following:
The present application, filed on or after March 01, 2024, is being examined under the first inventor to file provisions of the AIA .
Thus, claims 1-8 represent all claims currently under consideration.
Information Disclosure Statement
Two Information Disclosure Statements, filed on 03/01/2024, and 04/23/2025 is acknowledged and have been considered.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-8 are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. (WO2015052008A1), in view of Bacchetta et al. (WO2013048787A1), and Weiquiang et al. (CN106110383A).
Regarding claims 1, and 6, Zhang et al. disclose wherein hemostatic dressings comprising a fabric formed from biocompatible aldehyde modified polysaccharide fibers and a porous polymeric matrix of a biocompatible water-soluble or swellable polymer that is at least partially dispersed within the fabric. Zhang et al. teaches such dressings for stopping bleeding and methods of making the same. This teaches hemostatic composition, polysaccharide-based matrix, polymeric scaffold/dressing format, and hemostasis function (See abstract and paragraph 0001).
Although Zhang et al. does not explicitly disclose kaolin, chitosan, calcium chloride, or oxidized dextran cryogels, Zhang et al. establishes the foundational concept of a polysaccharide-based hemostatic matrix dressing.
However, Bacchetta et al. disclose wherein hemostatic formulations containing kaolin, and chitosan optionally combined with additional hemostatic agents and incorporated into a polymeric carrier layer applied to textile substrates for wound treatment. This teaches inclusion of kaolin as a pro-coagulant mineral, inclusion of chitosan as a bioactive hemostatic polymer, use of these components within polymeric matrices and dressings (See abstract and claim 1). Thus, Bacchetta et al. supplies the missing limitation of incorporating kaolin and chitosan into a hemostatic dressing composition of the type taught by Zhang et al.
Weiqiang et al. disclose a chitosan alginate dressing prepared by dissolving chitosan, combining with alginate, freeze-drying, and cross-linking using calcium chloride, followed by additional freeze-drying to produce a porous dressing with hemostatic, antibacterial, and wound-healing properties (See Abstract). This teaches chitosan-based wound dressings, use of calcium chloride for crosslinking polysaccharide matrices, freeze-drying/sub-zero processing (cryogenic formation equivalent to cryogel formation), hemostatic functionality, and porous structure beneficial for blood absorption and clot formation. Thus, Weiqiang et al. provides calcium chloride component, sub-zero processing/cryogel-type structure, and polysaccharide matrix crosslinked by calcium ions.
It would have been obvious to one of ordinary skill in the art at the time of the invention to modify the hemostatic dressing of Zhang et al. by incorporating the kaolin and chitosan hemostatic agents taught by Bacchetta et al. and further include calcium chloride crosslinking and freeze-drying processing taught by Weiqiang et al. because each reference addresses the same field (hemostatic wound dressings). Each teaches that its respective additives improve coagulation, absorption, or structural performance. Substituting or combining known hemostatic agents is a routine optimization recognized in the art for enhancing clotting performance. Calcium crosslinking of polysaccharide is a well-known technique for strengthening polymeric wound matrices. Freeze-drying to form porous matrices is a standard method to increase absorbency and surface area, which are known to improve hemostasis.
The claimed approximate quantities (1 g chitosan, 2.5 g kaolin, 0.5 g CaCl2, 3 g oxidized dextran) would have been obvious matter of routine optimization, because the references teach that relative concentrations of hemostatic components may be varied to achieve desired absorption, clotting speed, and mechanical properties. Optimization of ingredient ratios for performance is considered a result-effective variable routinely determined by experimentation.
Therefore, claim 1, is unpatentable over Zhang et al. in view of Bacchetta et al. and Weiqiang et al. because the prior art collectively teaches or suggests all claimed elements, and it would have been obvious to combine them with a reasonable expectation of success to obtain the claimed hemostatic cryogel composition.
Regarding claim 2, Zhang et al. teach aldehyde-modified polysaccharide fibers used in hemostatic dressings. Aldehyde modification of polysaccharides is a known oxidative surface modification technique that introduces reactive aldehyde groups onto polysaccharide chains. Such oxidation inherently modifies the surface chemistry of the polysaccharide fibers. Therefore, Zhang et al. teaches or at least suggests the limitation of dextran oxidized through surface modification, because oxidized polysaccharides having aldehyde functionalities are structurally and functionally analogous to oxidized dextran prepared via surface oxidation. Substituting one oxidized polysaccharide for another would have been obvious to one of ordinary skill in the art because polysaccharides such as dextran, cellulose, alginate, and chitosan are recognized as interchangeable biocompatible polymer matrices used for wound dressings and hemostatic scaffolds.
It would have been obvious to employ oxidized dextran as the oxidized polysaccharide component of the composition of claim 1 since oxidized dextran was a known biocompatible aldehyde functional polysaccharide used for biomedical matrices and crosslinkable networks, and substitution of one known oxidized polysaccharide for another represents a predictable variation yielding expected results.
Regarding claim 3, Zhang et al. disclose wherein oxidizing adjacent 2,3-hydroxyl groups in a carbohydrate with periodic acid or an alkali metal periodate generates a dialdehyde or related dialdehyde derivatives. The resulting aldehyde functionalities readily undergo reaction with primary amine groups, such as those found on amino acid residues at the N-terminus of proteins (See paragraph 0055). A quantity of 20.8 g of sodium periodate was dissolved in the solution, and the mandrel was rotated in the mixture at a moderate speed for approximately 21 hours at room temperature. The oxidation step must be carried out in the absence of light (See paragraph 0075).
Regarding claim 4, Zhang et al. disclose oxidizing polysaccharide containing materials using sodium periodate under controlled conditions. Specifically, Zhang et al. teaches dissolving sodium periodate in solution and contacting the substrate while rotating at moderate speed for an extended period, wherein oxidation is conducted in the dark, and the oxidized material is subsequently washed with ethylene glycol-containing water to quench residual oxidant and remove reaction byproducts. Zhang et al. does not expressly disclose specific reagent concentrations (0.5 g in 2.5 mL water), temperature of 4 degree Celsius, dropwise addition, dialysis step, freeze-drying step, exact stirring speed of 300 rpm, reaction time of 1 hour.
The claimed parameters (temperature, reagent amount, stirring speed, addition rate, and reaction time) represent result-effective variables routinely optimized in oxidation reactions. Adjusting such variables to achieve a desired oxidation level is considered ordinary skill experimentation. It is well established that reaction temperature affects oxidation rate, reagent concentration controls degree of oxidation, stirring speed affect’s reaction uniformity, reaction time determines conversion level. Optimization of these parameters is a standard practice in chemical process development and does not constitute a patentable distinction. It was well known in the art that periodate oxidation of polysaccharides is commonly performed in aqueous solution under cooled conditions to control reaction rate with quenching agents such as ethylene glycol, followed by purification steps such as dialysis or washing, and optionally freeze-drying to isolate the oxidized polymers. Such purification and isolation techniques are conventional post-reaction processing steps for water-soluble polymers.
Substituting Zhang’s reaction conditions with known alternative conditions (e.g. cooling dropwise addition, dialysis purification) constitutes the predictable use of prior-art elements according to their established functions.
A person of ordinary skill would have been motivated to modify Zhang’s oxidation process by applying known oxidation-control and purification techniques to control oxidation level, improve uniformity of modification, prevent over-oxidation, remove residual oxidant salts, obtain purified oxidized polysaccharide suitable for biomedical use.
Therefore, claim 4 is unpatentable over Zhang et al. because Zhang et al. teaches the claimed oxidation chemistry and reaction features, and the remaining claimed process parameters represent routine optimization and conventional post-reaction processing steps that would have been obvious to one of ordinary skill in the art.
Regarding claim 7, Zhang et al. as applied in the rejection of claim 1, teach a hemostatic dressing comprising a fabric substrate supporting a polymeric hemostatic matrix. Bacchetta et al. teach inclusion of hemostatic agents such as kaolin and chitosan in wound dressings applied to textile substrates. Zhang et al. teaches that the hemostatic composition is supported on a fabric substrate. Textile substrates used in wound dressings were well known in the art to include cotton, cotton blends, cellulose-based fabrics, gauze materials, and nonwoven textile equivalents. Cotton is one of the most conventional and widely used bandage base materials due to its absorbency, softness, biocompatibility, availability, and low cost.
The claim does not recite any structural or functional property that distinguishes the claimed cotton base layer from conventional textile substrates used in the prior art dressings. Accordingly, the limitation is considered to encompass known equivalent dressing material.
It would have been obvious to one of ordinary skill in the art at the time of the invention to select cotton or a material with similar properties as the base layer of the bandage of Zhang et al. because selection of substrate material is a design choice based on desired absorbency, flexibility, and comfort; cotton is a standard substrate used in wound dressings and bandages; substituting one known textile substrate for another known equivalent textile substrate represents a predictable substitution of known materials. No unexpected result would have been produced by using cotton in place of another textile substrate taught by Zhang et al. since cotton performs the same known function of providing a flexible, absorbent support for the hemostatic composition.
Regarding claims 5 and 8, Zhang et al. teach methods for preparing hemostatic dressings comprising polysaccharide-based matrices supported on fabric substrates. Zhang et al. further teaches oxidation of polysaccharide materials using sodium periodate under controlled conditions, followed by washing, quenching, of residual oxidant with ethylene glycol, and drying to obtain oxidized material suitable for biomedical dressings. Zhang et al. teaches preparation of polysaccharide matrices, incorporation into textile substrates, oxidation chemistry used to modify polysaccharide, and post-reaction washing and isolation steps.
Weiqiang et al. teach preparation of chitosan based wound dressings formed by dissolving chitosan in acid solution, mixing with additional components, freeze-drying to form porous matrices, crosslinking with calcium chloride, performing cooling and drying steps. Weiqiang et al. further teaches that such processing produces dressings with hemostatic activity, antibacterial properties, moisture absorption, and structural stability. Bacchetta et al. teach hemostatic formulations containing kaolin and chitosan incorporated into polymeric matrices applied to textile substrates for hemorrhage control. The reference does not explicitly disclose the exact quantities recited, exact mixing times or speeds, specific temperature durations, exact cryostat temperature of -12 degrees Celsius, precise order of combining steps. The claimed parameters (temperature, reagent, amount, stirring speed, addition rate, and reaction time) represent result-effective variables routinely optimized in oxidation reactions. Adjusting such variables to achieve a desired oxidation level is considered ordinary skill experimentation. It is well established that reaction temperature affects oxidation rate, reagent concentration controls degree of oxidation, stirring speed affect’s reaction uniformity, reaction time determines conversion level. Optimization of these parameters is a standard practice in chemical process development and does not constitute a patentable distinction. Each claimed step represents a known technique used in preparing polymeric biomedical materials: dissolving polymers in solvent, combining polymer solutions, cooling mixtures, molding, freeze-drying, and purification.
A person of ordinary skill would have been motivated to combine the teaching of Zhang et al. Weiqiang et al. and Bacchetta because all references are directed to hemostatic wound dressings, polysaccharide-based matrices, improved structural and clotting performance.
One of ordinary skill in the art would reasonably expect that combining known hemostatic agents and known fabrication methods would yield a functional dressing with predictable properties.
Conclusion
No claim is allowed.
Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/KIMBERLY BARBER/Examiner, Art Unit 1615
/Robert A Wax/Supervisory Patent Examiner, Art Unit 1615