DETAILED ACTION
Status of the Application
Receipt is acknowledged of Applicants’ Amendments and Remarks, filed 10 November 2025, in the matter of Application N° 18/552,458. Said documents have been entered on the record. The Examiner further acknowledges the following:
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
No claims have been canceled. Claim 17 has been added and is supported by the originally-filed disclosure.
Claims 1, 5, and 6 have been amended. Claim 1 adds the adjective “antimicrobial” to the coating that already comprises chlorhexidine phosphate. Claims 5 and 6 have been respectively amended to remove the “-based” language from the claims and replace it with “comprising polyacrylate” and “comprising silicone”. The amendments are supported.
No new matter has been added.
Thus, claims 1-17 now represent all claims currently under consideration.
Information Disclosure Statement
No new Information Disclosure Statements (IDS) have been filed for consideration.
Withdrawn Rejections
Rejection under 35 USC 112
Applicants’ amendments to claims 5 and 6 are persuasive in overcoming the previously raised indefiniteness rejection. Said rejection is withdrawn.
Maintained Rejections
The following rejections are maintained from the previous Office Correspondence dated 8 September 2025 since the art that was previously cited continues to read on the amended and previously recited limitations.
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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
This application currently names joint inventors. In considering patentability of the claims the Examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicants are advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the Examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-16 are rejected under 35 U.S.C. 103 as being unpatentable over Söderström et al. (EP 2 995 324 A1) in view of Andrews et al. (US Pre-Grant Publication Nº 2017/0095431 A1), McGuire (US Pre-Grant Publication Nº 2013/0239977 A1), Wiegand et al. (Skin Pharmacology and Physiology; 2015), and Barbour et al. (Int. J. of Nanomed.; 2013).
The instantly claimed invention is directed to a wound care product comprising a backing layer and an adhesive layer. The adhesive layer inherently comprises both skin-facing and non-skin-facing surfaces, and further comprises an antimicrobial coating which is characterized as being hydrophilic (i.e., soluble in an aqueous medium) and which comprises chlorhexidine phosphate.
Söderström discloses a medical dressing comprising a substrate comprising a first chemical compound, said substrate having a first surface, wherein said medical dressing further comprises an adhesive layer having a skin-facing surface that will adhere said dressing to dermal surface. At least a portion of the skin-facing surface will comprise a coating which comprises a second chemical compound (see e.g., Abstract; claim 1).
Claim 10 discloses definitions for the first and second chemical compounds in that they may be independently selected from such compounds as chlorhexidine and any salts thereof. See also ¶[0031]-¶[0033], ¶[0073]-¶[0076], and ¶[0080].
What this conveys to the person of ordinary skill in the art is that the second chemical compound coated to the adhesive layer may comprise chlorhexidine or any of its salt forms, as instantly claimed.
Where Söderström is seemingly deficient is with respect to the definition of the “salts” of chlorhexidine; chlorhexidine phosphate is not expressly disclosed. However, the Examiner does consider the instantly claimed salt to be readily encompassed by the disclosure, as evidenced by such showings in the art as Andrews.
Briefly, Andrews is directed to a method for incorporating an active agent into an adhesive article for delivery of said agent to a substrate, wherein said agent comprises an antimicrobial agent (see e.g., claims 1 and 2). Though claim 3 further specifies chlorhexidine gluconate as a preferred active agent, ¶[0032] further discloses that other pharmaceutically acceptable chlorhexidine salts that may be used as antimicrobial agents include such salts as chlorhexidine di-acid phosphate (i.e., chlorhexidine phosphate).
Based on the combined teachings of the references, the Examiner submits that a person of ordinary skill in the art would have had a reasonable expectation of success at producing the instantly claimed composition. The artisan practicing the invention of Söderström and incorporating “any salts” of chlorhexidine into the coating applied to the adhesive layer, would have understood this disclosure to be inclusive of chlorhexidine di-acid phosphate, as is made further evident by Andrews.
Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, and absent a clear showing of evidence to the contrary.
Claim 2 recites that the wound care product releases at least 60% of the antimicrobial coating and is “configured” to be dissolved within three hours of exposure to an aqueous medium. Looking to Applicants’ instant specification, the limitation appears to be a property and/or functional limitation that is tethered to and definitive of the instantly encompassed wound care product discussed therein (see Spec., pg. 10, lines 1-19). As such, consistent with MPEP §2111.01(IV), §2112.01(I) and (II), and §2173.05(g), the Examiner submits that where Applicants’ defining product is disclosed in the prior art, the recited limitation of claim 2, will also be considered met.
The foregoing disclosure provided by Söderström and Andrews is considered to meet the instantly claimed compositional and structural limitations, and therefore, considered to meet the recited limitation of claim 2.
Paragraph [0070] of Söderström additionally discloses that the second chemical compound (e.g., chlorhexidine salt) is present on the composition carried by a chemical compound that mas more or less solubility in an aqueous solution (e.g., wound fluid)
The limitations of claim 3 recite that a release liner is detachably attached to the skin-facing surface of the adhesive layer. Söderström discloses in Example 1, for instance, that a polyethylene coated paper was added to cover the silicone adhesive layer of the prepared product. See ¶[0094].
The foregoing is also considered to teach the limitations recited by instant claim 6.
The limitations of instant claims 4 and 5 are also met by the teachings of Söderström (see e.g., claim 1).
Regarding the compositional requirements of claim 5, Söderström discloses in ¶[0071], for instance, that the adhesive used in the practiced invention may also be an acrylic adhesive. See also ¶[0091].
Regarding the limitations of claim 5, the wound care product being styled as a surgical incision drape is considered to be directed to a recitation of intended use, notably as the compositional and structural limitations of the claimed product are met by the teachings of Söderström and Andrews.
However, the Examiner additionally notes that the state-of-the-art recognizes that such uses are known. Such showings in the art as McGuire affirm the Examiner’s position as evidenced by the definition of an adhesive “incise drape” in ¶[0003] of the reference. Therein, such a structure is defined as “one where a surgical incision is made directly through the drape and into a patient. By definition, a skin surface covered by a sterile incise drape is bacteria-free (i.e., sterilized) at the beginning of a surgical procedure. Ideally, the skin surface remains bacteria-free during the procedure, resisting the transfer of bacteria from, for example, gloves, instruments, and sponges that may come in contact with not only the surgical wound but also the surrounding skin. Nevertheless, a drape's barrier and antimicrobial properties are typically effective only so long as the drape is securely attached to the skin. Many types of surgical drapes and medical dressings are known. Some include an adhesive layer for adhering the surgical drape to a patient's skin or other surface.”
Thus, what the person of ordinary skill in the art would readily understand from such a disclosure is that the adhesive medical dressing of Söderström is one that is applied in the same fashion as that disclosed by McGuire. McGuire simply elaborates on the additional intended use of being able to make a sterilized incision through the adhered layer.
The structural limitations recited by claim 7 are considered to be met by Figures 2b and 2c and the descriptions thereto. Therein, it is shown that in Figure 2c and disclosed in ¶[0070] that the coating of the second chemical compound (e.g., chlorhexidine salt) is discontinuously applied to the skin-contacting surface of the adhesive layer.
Instant claim 8 recites that the chlorhexidine phosphate active is present in the coating in a concentration ranging from 5-1,000 µg/cm2. Söderström discloses in claims 10 and 12 that the second chemical compound may be chlorhexidine or any of its salts, as discussed above, and further that the concentration of the second chemical compound (i.e., the agent applied to the adhesive layer) may range from 1-2,500 µg/cm2. Paragraph [0078] discloses narrower ranges for this component as well, such as 1-150 µg/cm2.
MPEP §2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.”
The limitations of claim 9 recite that the product is a dressing that further comprises an absorbent pad arranged between the backing layer and the adhesive layer. Söderström discloses that its practiced medical dressing product comprises a substrate which further comprises an absorbent material (see e.g., claims 1, 13, and 14). Lyofoam™ Max is disclosed in ¶[0091] as an example of such an absorbent backing layer substrate that is formed of a hydrophilic polyurethane foam that includes a polyurethane backing film present on one side of the foam layer.
The limitations recited by claim 10 add that the absorbent pad of the claimed product will contain at least a second antimicrobial compound. The foregoing disclosure of Söderström teaches that the backing layer of the practiced product will structurally have a backing layer attached to a hydrophilic foam material, placing said foam between the adhesive layer and the backing. The reference additionally teaches in claim 1 that the substrate will contain a first chemical compound, which as further defined in claim 10, is selected from antimicrobial agents as discussed above.
Thus, to clarify, the reference’s disclosure of a first chemical compound reads on the instantly claimed second antimicrobial compound, and the disclosed second chemical compound reads on the instantly claimed first antimicrobial compound (i.e., chlorhexidine salt).
The limitations of claim 11 recite that the adhesive layer comprises at least a third antimicrobial compound. The Examiner broadly and reasonably interprets this as claiming that the overall product contains at least a third antimicrobial compound and that it is located in the adhesive layer in addition to chlorhexidine phosphate. Compositionally and structurally, this makes it the at least second antimicrobial compound located in the adhesive layer.
Claim 15 of Söderström discloses that the adhesive layer comprises a third chemical compound distributed within said adhesive layer, thereby expressly meeting the claimed limitations. See also ¶[0038].
The limitations of instant independent claim 12 are directed to a method of manufacturing a wound care product comprising:
providing a backing layer and an adhesive layer, the latter of which has a skin-facing surface, the wound care product optionally comprises an absorbent layer located between the backing and adhesive layers;
providing an aqueous solution of chlorhexidine phosphate by dissolving chlorhexidine in phosphoric acid and water;
applying the aqueous solution onto at least a portion of said skin-facing surface of the adhesive layer; and
drying said aqueous solution on the surface of the adhesive layer.
Claim 16 of Söderström discloses producing a medical dressing comprising the steps of providing a substrate, providing an adhesive layer, and providing a coating comprising a second chemical compound (i.e., chlorhexidine salt) on said adhesive layer. The Examples and ¶[0070] further disclose that the second chemical compound (e.g., silver sulfate) is provided as an aqueous solution that is sprayed onto the adhesive layer and allowed to dry to said layer in the form of a film whose hydrophilic nature will allow the compound to be delivered to an aqueous environment (e.g., wound fluid).
The reference is considered to meet the recited limitations of claims 12, 13, 15, and 16 with the exception that Söderström does not expressly disclose that its practiced chlorhexidine salts are inclusive of chlorhexidine phosphate.
Andrews, as discussed above, is considered to remedy this perceived deficiency, as it is directed to a method for incorporating an active agent into an adhesive article for delivery of said agent to a substrate, wherein said agent comprises an antimicrobial agent (see e.g., claims 1 and 2). Though claim 3 further specifies chlorhexidine gluconate as a preferred active agent, ¶[0032] further discloses that other pharmaceutically acceptable chlorhexidine salts that may be used as antimicrobial agents include such salts as chlorhexidine di-acid phosphate (i.e., chlorhexidine phosphate).
Based on the combined teachings of the references, the Examiner again submits that a person of ordinary skill in the art would have had a reasonable expectation of success at producing the instantly claimed composition. The artisan practicing the invention of Söderström and incorporating “any salts” of chlorhexidine into the coating applied to the adhesive layer, would have understood this disclosure to be inclusive of chlorhexidine di-acid phosphate, as is made further evident by Andrews.
The limitations recited by claim 13 state that the aqueous solution of chlorhexidine phosphate will have a pH ranging from 4-6.
The Examiner acknowledges that neither Söderström nor Andrews expressly disclose a pH value or range for their applied aqueous solutions.
Wiegand, however, is considered to provide an evidentiary showing in the art disclosing that the bactericidal activity of chlorhexidine is pH-dependent and that it is shown to provide activity in a pH range of 5.0-9.0 (see e.g., Abstract). Figures 3a and 3b, for instance, depict that the tested chlorhexidine solution was the most effective against certain bacterial strains when it had a pH of 5.
Thus, based on the combined guidance, the Examiner submits that a person of ordinary skill in the art would have had a reasonable expectation that the chlorhexidine solution (e.g., chlorhexidine di-acid phosphate) applied in preparation of the practiced medical dressings would have a pH value within the range of 4-6 as claimed. Per Wiegand, ensuring that the chlorhexidine solution was used in a pH range correlates to the solution possessing an optimal level of bactericidal activity.
Lastly, claim 14 further limits step b) of claim 12 reciting that preparation of the aqueous chlorhexidine solution is done by combining chlorhexidine and phosphate in a ratio of 1:1 to 1:3.
The Examiner again acknowledges that the combined teachings of Söderström and Andrews teach and suggest employing a chlorhexidine phosphate solution. However, neither reference teaches how the preparation of the component.
Barbour is considered to remedy this deficiency teaching that stable colloidal formulations of chlorhexidine phosphate (i.e., chlorhexidine hexametaphosphate) are synthesized by combining equimolar aqueous solutions of chlorhexidine digluconate (i.e., chlorhexidine) and sodium hexametaphosphate (i.e., phosphate).
Based on the combined teachings of the references, the Examiner submits that a person of ordinary skill in the art would have had a reasonable expectation of success at producing the instantly claimed chlorhexidine component and applying it to the surface of the adhesive, skin-facing surface of the wound dressing disclosed by Söderström. As is reiterated by Andrews and Wiegand as well, chlorhexidine salts (e.g., phosphate salts), like their free form, possess known, efficacious bactericidal activity against both gram-negative and gram-positive bacteria. Thus, were the skilled artisan to modify the method of Söderström by coating the adhesive layer with the composition prepared by Barbour, it would have presented the said artisan with a reasonable expectation of conveying antibacterial activity to the dressing.
Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, and absent a clear showing of evidence to the contrary.
Response to Arguments
Applicants’ arguments with regard to the rejection of claims 1-17 under 35 USC 103(a) as being unpatentable over the combined teachings of Söderström et al., Andrews et al., McGuire, Wiegand et al., and Barbour et al. have been fully considered, but they are not persuasive.
Applicants traverse the rejection on the grounds that the instant application demonstrates unexpected results that are commensurate in scope with the invention as instantly claimed.
At the outset, the Examiner notes that Applicants address only the Söderström and Andrews references covering the Examiner’s obviousness rejection demonstrating that the skilled artisan would understand that chlorhexidine phosphate is encompassed by Söderström.
Applicants allege that chlorhexidine phosphate, “compared to other chlorhexidine salts, was found to have a lower minimum concentration required to eliminate microorganisms, less transfer of antimicrobial to the release liner, and higher rate of dissolution.”
Regarding the tested MBC in Table 1, chlorhexidine phosphate (CHP) is tested against silver sulfate and a singular chlorhexidine salt, the gluconate salt (CHG).
The Examiner acknowledges that the data do demonstrate that a lower MBC is required for CHP than CHG. However, the Examiner submits that the data would not have been unexpected to the skilled artisan in possession of the teachings of Söderström and Andrews.
Söderström, like the instant application, discloses conducting antimicrobial efficacy testing using Pseudomonas aeruginosa and Staphylococcus aureus, two of the tested microorganisms of the instant invention. See ¶[0105]. Though chlorhexidine or any of its salts are not the subject antimicrobial of the Examples, it would have well within the purview of the skilled artisan to reproduce the testing method determining the antimicrobial effect of a given agent with any of the disclosed agents. As such, the skilled artisan in possession of Söderström and Andrews would have understood that CHP was a salt of chlorhexidine and that in their comparison of CHP and CHG, would have ascertained the improved efficacy of CHG over CHP with respect to the two microorganisms.
Applicants next discuss the transfer to the release liner data which purports to have studied “various types of chlorhexidine salts” to determine how much of the antimicrobial agent remains on the release liner following its removal and how much is retained by the dressing to be applied. Example 2 is cited.
Again, only a single salt was tested in comparison to CHP, as opposed to various salts. The Example establishes that about 30% more CHP was retained on the dressing than CHG (66% vs. 36%).
The Examiner, in response, notes that like the MBC testing, Söderström also conducts retention testing of its final products that have been removed from the release layer. See Example 4 at ¶[0098]-[0100]. Here, a release liner such as the liner tested by instant Example 2 is used (i.e., formed of a combination of polyurethane and silicone adhesive) and a total amount of antimicrobial agent present in the final product was able to be determined. The Examiner submits that while Example 4 of Söderström uses silver sulfate, that it would have again, been well within the purview of the ordinarily skilled artisan to reproduce the test with other antimicrobial agents such as chlorhexidine or any of its salts (e.g., phosphate).
The Examiner acknowledges that Andrews preferably discloses CHG; however, the reference is relied upon to further define that which is already disclosed by Söderström, that “any of its salts” is inclusive of the phosphate salt of chlorhexidine.
Lastly, Applicants provide dissolution data singularly comparing CHP against chlorhexidine acetate (CHAc) which shows that CHP was 100% released from the dressing compared to only 28% CHAc after 3h and only 39% within 24 hours.
The Examiner acknowledges that this singular example demonstrates a particular advantage. However, contrary to the assertion, the data are not commensurate in scope with the claimed composition or method of preparing it.
Applicants’ arguments, for the above reasons, are found unpersuasive. Said rejection is therefore maintained.
All claims under consideration remain rejected; no claims are allowed.
Conclusion
THIS ACTION IS MADE FINAL. Applicants are 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 extension fee 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.
Correspondence
Any inquiry concerning this communication or earlier communications from the Examiner should be directed to Jeffrey T. Palenik whose telephone number is (571) 270-1966. The Examiner can normally be reached on 9:30 am - 7:00 pm; M-F (EST).
If attempts to reach the Examiner by telephone are unsuccessful, the Examiner’s supervisor, Robert A. Wax can be reached on (571) 272-0623. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Jeffrey T. Palenik/
Primary Examiner, Art Unit 1615