COMPOSITIONS FOR REMOVING NECROTIC OR INFECTED TISSUE FROM BODY SURFACE LESIONS

Abstract

A composition usable for removing biofilm and necrotic or infected tissue from a skin lesion, comprising ethanesulfonic acid or 1-propanesulfonic acid and a proton acceptor. The proton acceptor is selected from the group consisting of dimethyl sulfoxide, silicon dioxide, tetraethoxysilane, and mixtures thereof. This composition can be prepared in gel form.

Description

COMPOSITIONS FOR REMOVING NECROTIC OR INFECTED TISSUE FROM BODY SURFACE LESIONS FIELD OF INVENTION The invention relates to compositions that can be used to remove necrotic or infected tissue from body surface lesions, particularly skin lesions such as chronic wounds or ulcers. BACKGROUND OF THE INVENTION Chronic wounds are known to contain microorganisms, particularly bacteria, which replicate and trigger a persistent inflammatory response. Specifically, the so-called inflammatory cascade produces vasodilation and significantly increases blood flow to the wound area. In a chronic wound, the continuous presence of virulent microorganisms leads to a massive and persistent inflammatory response, which ultimately contributes to damage to the host organism. This is due to the persistent production of inflammatory mediators and the constant migration of neutrophils and granulocytes. These latter cells release cytolytic enzymes and free radicals into the wound, which are primarily responsible for tissue damage. Furthermore, macrophages are inhibited, resulting in the chronic wound's inability to self-regenerate.Localized thrombosis can also occur, and vasoconstrictive metabolites are released, which can induce tissue hypoxia, leading to increased bacterial proliferation and tissue destruction. Due to the high invasiveness of some infecting bacterial species, the microbial component can contribute to worsening lesions and increasing the biofilm layer. The term biofilm defines the thin layer of glycoprotein material produced by the active replication of bacteria that adheres to the wound bed. The biofilm that forms in an infected wound contributes to delayed healing. In fact, the presence of a biofilm creates conditions for individual microorganisms to interact, exchanging nutrients and metabolites to form well-organized bacterial communities. Biofilms thus act as protected foci of infection and bacterial resistance within the wound and are able to shield bacteria from the action of antimicrobial agents such as antibiotics and antiseptics. Typically, biofilms consist of multiple layers of microorganisms, and communication between microbial cells is crucial for biofilm development and maintenance. The term “chronic skin ulcer” defines skin lesions that do not progress to healing after at least six weeks of appropriate treatment. Regardless of the etiology (in fact, there are chronic diabetic, venous, arteriopathic, vascular, and post-traumatic ulcers), chronic skin ulcers share common pathogenic mechanisms that contribute to their chronicity. Among these mechanisms, the best known are: the excessive presence of inflammatory proteins (cytokines and proteases) in the exudate; persistent colonization of the lesion base by pathogenic microorganisms; and the development of a biofilm that renders the lesion base inaccessible to drugs and medications.These characteristics of chronic skin ulcers delay or stop the autolytic process of elimination of non-vital material, the proliferation of neovessels, indispensable for the formation of granulation tissue and the proliferation of dermal and epidermal cells. Chronic skin ulcers, such as chronic lower limb ulcers, are a global problem. In fact, it is estimated that 1.5% of the world's population is affected by this condition. Given that age is a significant risk factor, the prevalence of these chronic skin ulcers is low in childhood and very high in old age. Socioeconomic status is also a risk factor, which explains why the disease is more widespread in developing countries than in more economically advanced ones. Chronic comorbidities in the elderly population are also a risk factor for the development of chronic skin ulcers, and since the average age of the population is constantly increasing, the incidence of chronic skin ulcers is expected to rise progressively in the coming years. The therapeutic treatment of chronic skin ulcers requires a significant financial commitment from healthcare systems. In the US, approximately 2 million workdays are lost each year due to chronic ulcers. Furthermore, developed countries spend between 3% and 5.5% of their total healthcare budget on the treatment of chronic skin ulcers. Chronic skin ulcers represent a serious health challenge for patients, as these conditions are associated with increased morbidity and mortality and are often accompanied by chronic pain requiring strong analgesics. In addition, patients become dependent on nursing care, leading to a significant decline in their quality of life. It is now a common understanding among experts that activating the healing process of a chronic skin ulcer requires a balance between the inflammatory and regenerative processes, in order to bring the ulcer to a state comparable to that of an acute ulcer. This effect is typically achieved through a well-known procedure: debridement of the ulcer base. This procedure allows for the surgical removal of non-vital tissue, stratified secretions at the base of the lesion, and possibly also the biofilm that has formed there. One drawback of debridement is that, in order to be effective, it has to expose vital tissue throughout the base of the ulcer, which creates a significant risk of bleeding for the patient. Another drawback of debridement is that it is a surgical procedure and therefore requires a properly equipped operating room and the intervention of specialized personnel (physicians and anesthesiologists). Consequently, hospitalization is necessary. However, the required hospitalization and the complexity of performing the debridement increase the associated costs, making it accessible only to a minority of patients. Non-surgical debridement methods are known, such as the application of lytic enzyme ointments, negative pressure wound therapy, and some advanced medications. While substantially non-invasive, these methods are generally considered ineffective or require long application periods to be effective. Therefore, there is a great need to make the treatment of chronic skin ulcers more effective and less uncomfortable, and in particular, to overcome the significant limitations imposed by existing debridement methods (both surgical and non-surgical). From the foregoing, it is clear that the optimal treatment of skin pathologies (chronic skin ulcers) requires a drastic reduction in bacterial contamination, which in turn requires the effective removal of biofilm and necrotic or infected tissue. However, the most commonly used surgical method for removing necrotic or infected tissue, debridement, presents numerous drawbacks (risk of bleeding for the patient, need for hospitalization, complexity, and high costs). Therefore, there is a strong need to develop new compositions that can effectively remove biofilm and necrotic or infected tissues present in chronic skin ulcers. Objects of the invention An object of the invention is to improve known procedures for removing biofilm, as well as necrotic or infected tissue present in skin lesions, particularly in chronic skin ulcers. Another objective is to provide compositions that can be used to remove biofilm and necrotic or infected tissue present in chronic skin ulcers. Another objective is to provide compositions that can be easily applied to chronic skin ulcers and that allow for the rapid removal of biofilm and necrotic or infected tissue. BRIEF DESCRIPTION OF THE INVENTION According to the invention, a composition as defined in claim 1 is provided, which can be used to remove biofilm and necrotic or infected tissue from skin lesions. The composition according to the invention comprises sultanicus having as its active ingredient the formula R-SO3H, wherein R is an organic alkyl group selected from the ethyl and propyl groups. More precisely, the active ingredient of the composition according to the invention is selected from the group consisting of ethanesulfonic acid (CAS number: 594-45-6) and 1-propanesulfonic acid (CAS number: 5284-66-2). The composition according to the invention contains at least one of the aforementioned active ingredients in combination with suitable co-formulants (chemically inert substances) that can adjust, and in particular attenuate, the acidity of the composition. The composition according to the invention allows the aforementioned objectives to be achieved. In fact, the inventors have discovered and experimentally verified that a chemical composition containing a strongly hydrophilic substance is capable of exerting a strong dehydrating action on the surface of a chronic skin ulcer. This dehydrating action produces a variety of effects, namely the denaturation of inflammatory proteins, the drying and detachment of necrotic biological tissue, and, most importantly, the elimination of microorganisms, particularly bacteria and fungi. The composition according to the invention comprises ethanesulfonic acid or propanesulfonic acid as the active ingredient, in combination with suitable co-formulants (chemically inert substances) capable of regulating, and in particular attenuating, the acidity of the composition. The composition according to the invention is capable of removing biofilm and necrotic tissue from infected areas of the skin within a few tens of seconds of application. The composition can be applied directly to the area to be treated (chronic skin ulcer) using any suitable means that allows for its distribution. After a contact time of a few tens of seconds, the composition can be easily removed from the skin or mucous membranes using a simple gauze pad or by washing the treated skin surface with physiological saline solution or sterile water. Therefore, it is possible to achieve the same effects as surgical debridement by applying the composition according to the invention to a skin lesion, but without the known drawbacks associated with the latter procedure. This new and effective therapeutic option can be used to the patient's significant benefit in cases of mild, moderate, and severe severity. BRIEF DESCRIPTION OF THE DRAWINGS The invention can be better understood and implemented with reference to the accompanying drawings which illustrate one embodiment thereof by way of non-limiting example, in which: Figure 1 is a photograph of a Petri dish showing a halo of microbial growth inhibition around the deposition zone of a sample composition (containing ethanesulfonic acid) according to the invention. Figure 2 is a photograph of a Petri dish showing a halo of inhibition of microbial growth around the deposition zone of a sample of a composition (containing 1-propanesulfonic acid) according to the invention. Figures 3A to 3D are photographs showing a wound that was treated and healed after a single application of the composition (containing ethanesulfonic acid) according to the invention. Figures 4A to 4D are photographs showing a wound that was treated and healed after a single application of the composition (containing 1-propanesulfonic acid) according to the invention; DETAILED DESCRIPTION OF THE INVENTION The composition according to the invention comprises ethanesulfonic acid or 1-propanesulfonic acid as active ingredients and is formulated in the form of a gel, which can be easily applied to chronic skin ulcers. A surprisingly unexpected property of the composition according to the invention is that it is able to act in a few tens of seconds on the biofilm and on necrotic or infected tissues, causing rapid desiccation of the same and allowing its removal (by washing or sterile gauze) only a few seconds after application and thus avoiding complicated, painful and costly surgical procedures (debridement). The action of the composition is due to the release of hydrogen ions (H+) or protons which, having a high enthalpy of hydration (-1130 KJ / mol), cause the dehydration of the microbial species that form the biofilm or proliferate in the infected tissues. This mechanism of action is achieved independently of the microbial species present and makes the composition according to the invention active against any microbial species, whether bacterial, fungal or viral. The inventors have conducted research to identify the most suitable proton source, that is, a source that allows for the efficient release of protons upon contact with the skin, resulting in the denaturation of microbial proteins present therein. However, this source also causes damage to the healthy tissue surrounding the lesions. This necessitates the preparation of appropriate formulations that optimize proton release, for example, by varying the viscosity of the formulations according to the type of lesion for which the composition is intended. Potentially usable proton sources consist essentially of strong acids (HA), which must be used in concentrated form, i.e., in the presence of the least possible amount of water. This is necessary because the dissociation of the strong acid into protons H+ and anions A has to occur in contact with the microbial species, extracting water molecules from the latter, molecules that will form the hydration sphere of the protons H+ with the release of thermal energy (-1130 KJ / mol). The dosage of H+ protons released by acidic species in concentrated form is problematic, as it cannot be diluted with water. However, water is the best solvent for solubilizing ethanesulfonic acid or 1-propanesulfonic acid. As is known, the acid dissociation constant (Ka) for the reaction HA —> H++ A is defined by the following relationship: Ka = [H+][ A] / [HA] where the concentrations in moles / liter of the different species are indicated in brackets. The negative decimal logarithm of the acid dissociation constant is defined as pKa (pKa = -log Ka). Table 1 below shows the pKa values ​​(at a temperature of 25 °C) of the main strong acids, which dissociate completely, or almost completely, in aqueous medium. From Table 1, it can be inferred that trifluoromethanesulfonic acid is the strongest acid (i.e., the acid with the highest pKa value), while trifluoroacetic acid is the weakest acid: ινΐΛ / a / zuzz / uuy ii □ Table 1 Acid Chemical Formula pKa Trifluoromethanesulfonic CF3SO3H -13 Hydroiodic Hl -10 Perchloric HClO4 -10 Hydrobromic HBr -9 Hydrochloric HCl -8 Sulfuric H2SO4 -3 Nitric HNO3 -1.4 Ethanesulfonic acid 1-Propanesulfonic acid Trifluoroacetic CH3CH2SO3H -1.3 CH3CH2CH2SO3H -0.86 CF3COOH -0.25 iviA / a / ¿u¿¿ / uuui ίο Considering the volatility of hydroiodic, hydrobromic, hydrochloric, and trifluoroacetic acids, as well as the oxidizing action of perchloric and nitric acids, which can cause unwanted effects on the skin, the inventors focused their attention on sulfonic acid derivatives with ethyl and propyl substituents, which have much lower dissociation constants compared to sulfuric acid. The inventors further envisioned the use of ethanesulfonic acid or 1-propanesulfonic acid in combination with suitable proton acceptors (or proton acceptors), which allow the acidity of the composition to be adjusted according to the invention, and more precisely, reduced. The proton concentration must be reduced because if protons are released in excessive amounts, they can cause dehydration of epithelial cells with consequent edema, erythema, desquamation, and tissue necrosis with ulcer formation. By reducing the concentration of protons released by ethanesulfonic acid or 1-propanesulfonic acid, these acids can be used effectively in the treatment of lesions (chronic skin ulcers) where biofilm is present, producing a desired dehydrating effect against contaminating microbial species without damaging the surrounding healthy tissue. In one embodiment of the composition according to the invention, the proton acceptor comprises anhydrous dimethyl sulfoxide (DMSO), which is added to a concentrated solution of ethanesulfonic acid. The DMSO reduces the acidity of the composition according to the invention by protonating the oxygen atom of the composition. In another embodiment of the composition according to the invention, the proton acceptor comprises silicon dioxide particles with diameters in the range of 200–400 nm. This allows for a reduction in the acidity of the composition according to the invention by protonating the oxygen present on the surface of the silica particles, while simultaneously controlling the viscosity of the resulting gel. In another embodiment of the composition according to the invention, the rheology of the gel containing sultanitics can be controlled by the addition of tetraethyl orthosilicate, capable of binding the silicon dioxide particles. The different compositional forms according to the invention mentioned above allow for the establishment of an equilibrium between ethanesulfonic acid or 1-propanesulfonic acid (denoted by HA) and proton acceptors (generally denoted by B). This equilibrium is revealed by the reaction HA + B → A⁻ + HB and results in a reduction of the sulfonic acid concentration without the introduction of water. Table 2 First formulation (formulation containing ethanesulfonic acid) Component Percentage by weight Ethanesulfonic acid 70-90% Dimethyl sulfoxide 5-20% SiO2 1-8% TEOS 0.05-2% ινΐΛ / a / zuzz / uuy ii □ Table 3 Second formulation (formulation containing 1-propanesulfonic acid) Component Percentage by weight 1-propanesulfonic acid 70-90% Dimethyl sulfoxide 5-20% SiO2 1-8% TEOS 0.05-2% The procedures for preparing the formulations referenced in Tables 2 and 3 above are not described in detail below because the chemical components of the formulations can be added to the sultanices—that is, ethanesulfonic acid and 1-propanesulfonic acid—in any order without altering the properties of the final solution. In fact, the different chemical components dissolve without any reactions that could interfere with the protonation of the proton acceptors. By way of non-limiting example of the invention, the following examples are described: an in vitro antimicrobial activity assay of the composition according to the invention (Example 1); a procedure for the treatment of skin lesions using the composition according to the invention (Example 2); a treatment of a wound using the first formulation (containing ethanesulfonic acid) of the composition according to the invention (Example 3); a treatment of a wound using the second formulation (containing 1-propanesulfonic acid) of the composition according to the invention (Example 4). Example 1 - In vitro antimicrobial activity test The antimicrobial activity of a formulation containing 87% ethanesulfonic acid (first formulation) or a formulation containing 87% 1-propanesulfonic acid (second formulation), both formulations containing 9.8% DMSO, 0.05% Parared, 2.2% SiO2 and 0.95% TEOS, was tested against the following strains of microorganisms (acquired from Diagnostic International Distribution SpA): Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATOO 6538, Escherichia coli ATOO 10536, Enterococcus hirae ATCC 10541, and Candida albicans ATCC 10231 were used. Mixtures of the different microorganism strains were prepared, with concentrations expressed in colony-forming units (CFU) ranging from 1.5 x 10¹² to 5.5 x 10¹² for each species. 100 µL samples of the mixture were inoculated onto Petri dishes containing TSA (Tryptone Soy Agar) solid culture medium. Inoculation was performed according to a known and standardized analytical method, i.e., by depositing the liquid sample onto the agar surface using a micropipette and spreading it over the surface with sterile glass beads. Subsequently, 50 μI aliquots of the two formulations of the composition according to the invention were deposited in a central zone of the agar of each Petri dish.The boxes were then incubated at 37 °C for 24 h. Figures 1 and 2 show two Petri dishes, in each of which a 50 μI aliquot of the first and second formulation of the composition according to the invention was deposited respectively. After incubation, the plates were examined to assess microbial proliferation (colony formation) and the width of the inhibition zone (i.e., the width of the portion of medium in which microbial proliferation was inhibited) surrounding the agar zone onto which samples of the two formulations had been deposited. As shown in Figures 1 and 2, clear zones of microbial growth inhibition were observed in all Petri dishes, surrounding the deposit zones of the preparations according to the invention. The analytical result obtained indicates that the two formulations of the composition according to the invention are capable of inhibiting the growth of 10¹¹ CFU of Gram-positive bacteria, Gram-negative bacteria, and the fungal species Candida albicans. Example 2 - Treatment of patients affected by chronic skin ulcers The composition according to the invention (first formulation and second formulation) were tested on more than 10 volunteer patients each, applying a treatment protocol comprising the following stages: - Remove with a sterile gauze any easily removable necrotic materials present at the base of the ulcer; - Dry the base of the ulcer completely; - Only in the case of particularly sensitive patients for whom a painful response is expected, pretreat the base of the ulcer for about 5 minutes with a sachet of ointment containing 5% lidocaine; - Remove the dressing, wash the ulcer to remove the lidocaine ointment and dry; - apply the composition according to the invention onto the ulcer base and onto the surrounding skin up to approximately 1 cm beyond the edge of the ulcer, using the finger of one hand covered by a sterile single-use glove; - Allow the composition to act according to the invention for about 20-30 seconds; - Wash thoroughly with sterile physiological solution; - Dry with sterile gauze; - Rub the base of the ulcer with sterile gauze to remove the dried material; - Leave at the bottom of the ulcer any dried material that did not come off due to friction with the gauze; - Cover the ulcer with a sterile paraffin gauze or with another suitable medication (according to the operator's choice); - Bandaging the area according to a known procedure; - Follow-up checks at 7-day intervals, or at shorter intervals if deemed necessary. During each check, the aforementioned protocol stipulates proceeding as follows: - Remove the bandages and medication; - Gradually remove the dried material remaining at the bottom of the ulcer using normal tweezers and scissors, starting from the edges of the lesion; - Cover the ulcer with a sterile paraffin gauze or with another suitable medication (according to the operator's choice); - Bandaging the area according to a known procedure. When the base of the ulcer is covered by granulation tissue, upon completion of granulation and according to the operator's choice, it is possible to graft skin and / or a skin substitute onto the lesion to complete the healing process. The treatment protocol described above proved effective in desiccating the base of the ulcers in all treated patients. No systemic, local, or perilesional skin complications or side effects occurred. In all treated patients, the residual desiccated material gradually disappeared by the end of the procedure without the need for further intervention, leaving granulation tissue at the base of the lesion. Example 3 - Wound treatment by means of a single application of the composition according to the invention containing ethanesulfonic acid (first formulation) With reference to Figures 3A-3D, the treatment of a mixed arteriosovenous ulcer of a lower limb is shown. The treated patient did not respond to several previous treatments, and the ulcer persisted for almost a year. Figure 3A shows the ulcer before treatment. Figure 3B shows the ulcer immediately after application of the IVIA / a / ¿U¿¿ / UU3110 composition containing ethanesulfonic acid. The product's desiccant effect is clearly evident, as the wound bed instantly transformed into a dry layer. The surrounding skin appeared degreased, but without any inflammatory response. No redness, wheals, or blisters were observed. Furthermore, a marked demarcation between the wound bed and normal skin became apparent. Figures 3C and 3D show the ulcer 1 and 2 weeks after initial treatment, respectively. The desiccated material on the wound bed gradually disappeared, and granulation tissue covered the entire wound bed. The disappearance of the desiccated material is attributed to friction with gauze during follow-up medication. However, an autolytic effect due to the reactivation of the patient's macrophages, no longer inhibited by inflammatory proteins, cannot be ruled out. Example 4 - Treatment of a wound by means of a single application of the composition according to the invention containing 1-propanesulfonic acid (second formulation) Figures 4A to 4D show the treatment of a post-traumatic wound on a patient's leg, with the wound bed close to the bone. Figure 4A shows the skin ulcer before treatment: a yellow area in the upper right of the wound bed represents the presence of a biofilm. Figure 4B shows the skin ulcer immediately after application of the 1-propanesulfonic acid-containing composition and rinsing with saline solution. The drying effect is clearly visible without affecting the surrounding normal skin. The ulcer was then simply covered with a thick gauze dressing. As shown in Figure 4C, complete granulation of the wound bed was gradually achieved over the next two weeks. The paraffin-impregnated gauze was changed weekly. Figure 4D shows that complete healing by spontaneous re-epithelialization was achieved after 5 weeks. Examples 3 and 4 clearly show that the application of the composition according to the invention (containing ethanesulfonic acid or 1-propanesulfonic acid with proton acceptors) resulted in complete tissue restoration at the site of injury in all cases, promoting healing. The treatment protocol described above (see Example 2) can be applied to all patients and avoids complicated, costly, and potentially risky surgical procedures. Furthermore, treatment with the composition according to the invention can reduce the need for antibiotic therapies, which are substantially expensive and associated with the growing phenomenon of antibiotic resistance. As a person skilled in the art will understand, it is possible to make variations and / or additions to what has been described above. For example, although the compositions iviA / a / ¿u¿¿ / uu3i io described above were prepared on a laboratory scale, a person skilled in the art can provide preparation procedures that are suitable for industrial-scale production.

Claims

1. A composition characterized in that it comprises ethanesulfonic acid or 1-propanesulfonic acid, for use in the removal of biofilms and necrotic or infected tissue from a skin lesion.

2. The composition for use according to claim 1, characterized in that said ethanesulfonic acid is 97% ethanesulfonic acid and said 1-propanesulfonic acid is 98% 1-propanesulfonic acid.

3. The composition for use according to claim 1 or 2, characterized in that it further comprises a proton acceptor.

4. The composition for use according to claim 3, characterized in that said proton acceptor is selected from the group consisting of: dimethyl sulfoxide, silicon dioxide, tetraethoxysilane and mixtures thereof.

5. The composition for use according to any of claims 1 to 4, characterized in that it is prepared in gel form.

6. The composition for use according to claim 4 or 5, characterized in that it has the following formulation: Ethanesulfonic acid Dimethyl sulfoxide Silicon dioxide Tetraethoxysilane 70-90% by weight 5-20% by weight 1-8% by weight 0.05-2% by weight 7. The composition for use according to claim 4 or 5, characterized in that it has the following formulation: 1-Propanesulfonic acid Dimethyl sulfoxide Silicon dioxide Tetraethoxysilane 70-90% by weight 5-20% by weight 1-8% by weight 0.05-2% by weight 8. The composition for use according to any of claims 1 to 7, characterized in that said use comprises removing said composition from said skin lesion after a contact time of a few tens of seconds.

9. The composition for use according to any of claims 1 to 8, characterized in that said skin lesion is a chronic skin ulcer.