[0001] The present disclosure relates to an antimicrobial formulation. Specifically, the present disclosure relates to an antimicrobial lotion formulation comprising glycolipids and silver nanoparticles, and having antimicrobial properties.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] According to the World Health Organization (WHO), viral diseases continue to emerge and represent a serious issue to public health. In the last twenty years, several viral epidemics such as the severe acute respiratory syndrome corona virus (SARS-CoV) from 2002 to 2003, and H1N1 influenza in 2009, have been recorded. Most recently, the Middle East respiratory syndrome corona virus (MERS-CoV) was first identified in Saudi Arabia in 2012. COVID-19, otherwise known as corona virus disease 2019, is a new illness caused by a previously unknown virus called SARS-CoV-2. The virus is part of a family of corona viruses which are responsible for lots of different illnesses from the common cold to the flu. But this new strain can be more severe in some populations. Discovered in December 2019, the virus has since spread around the world and on 11 March, the World Health Organization (WHO) declared it a pandemic.
[0004] Preventive measures are the current strategy to limit the spread of cases. Epidemics will increase as long as R0 is greater than 1 and control measures must focus on reducing the value to less than 1. Preventive strategies are focused on the isolation of patients and careful infection control, including appropriate measures to be adopted during the diagnosis and the provision of clinical care to an infected patient. For instance, droplet, contact, and airborne precautions should be adopted during specimen collection, and sputum induction should be avoided. The most important strategy for the populous to undertake is to frequently wash their hands and use portable hand sanitizer and avoid contact with their face and mouth after interacting with a possibly contaminated environment. In that case, a topical formulation of the lotion which is composed of advanced virucidal agents and will provide long-lasting protection is an urgent need.
[0005] Additionally, the emergence and spread of antibiotic resistance pathogen is an alarming concern in clinical practice. Many organisms such as MRSA, HIV-1, Hepatitis-B Virus, and Ampicillin resistant E. coli are difficult to treat. Moreover, the multi-resistant pathogens due to antigenic shifts and/or drifts are ineffectively managed with current medications. This resistance to medication by pathogens has become a serious problem in public health. The prior art available in this field disclose compositions generally composed of alcohol with one or two active ingredients and lack cleansing action. Alcohol itself causes skin irritation and rashes, making it a secondary choice. Additionally, the effectiveness of the product is compromised due to short term activity. However, there is a need for a better composition that is effective against a broad range of bacteria, including the multi-drug resistant types, thereby providing an effective anti-microbial solution. While being strong antiseptics the solutions must also be gentle on the skin, as they are frequently used products in the industry.
[0006] Use of noble metals at nano sizes to treat many conditions is gaining importance and though the use of silver nanoparticles as antimicrobials is known, the interaction of silver nanoparticles with viruses is a largely unexplored field as their mechanism of action against viruses are not fully understood.
[0007] Therefore, there is a strong need to develop antimicrobial formulation that can be used topically against a variety of pathogens to prevent the spread of the infection and illness, are effective as bactericides and virucides, are economical, safe for frequent use, and gentle on skin.

OBJECTS OF THE INVENTION
[0008] An object of the present disclosure is to provide an antimicrobial formulation that is highly effective in providing bactericidal, fungicidal, and virucidal action.
[0009] Another object of the present disclosure is to provide an antimicrobial topical formulation having excellent and long term protection against microbes, including viruses.
[0010] Another object of the present disclosure is to provide an antimicrobial formulation that is effective on enveloped and non-enveloped viruses.
[0011] Another object of the present disclosure is to provide an antimicrobial lotion formulation suitable for all skin types.
[0012] Another object of the present disclosure is to provide an antimicrobial lotion formulation that is economical and safe to use.

SUMMARY OF THE INVENTION
[0013] This summary is provided to introduce a selection of concepts in a simplified form that is further described below in the detailed description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0014] The present disclosure relates to an antimicrobial lotion formulation having antibacterial and antiviral properties.
[0015] In an aspect, the present disclosure provides an antimicrobial lotion formulation that is suitable for topical application.
[0016] In an embodiment, the present disclosure provides an antimicrobial lotion formulation that provides effective inhibition of spread of contact infection in patients and health care workers.
[0017] Another aspect of the present disclosure relates to an antimicrobial lotion formulation comprising a) a biosurfactant; b) silver nanoparticles and c) a preservative acid.
[0018] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a bio-surfactant wherein the bio-surfactant is a glycolipid selected from sophorolipid, rhamnolipid, trehalolipids and mannosylerythritol lipids.
[0019] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising silver nanoparticles having size in the range from 10 nm to 1000 nm.
[0020] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a preservative acid selected from sorbic acid, calendula oil, benzoic acid, citric acid, triclosan, triclocarban, phenoxyethanol, benzyl benzoate, benzyl alcohol, zinc pyrithione, benzalkonium chloride, or combinations thereof.
[0021] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a moisturizer selected from tea-tree oil, jojoba oil, cucumber extract, coco-glucoside, shea butter, cocoa butter, argan oil, aloe vera, olive oil, sunflower oil, avocado oil, butylene glycol, vegetable glycerine, or combinations thereof.
[0022] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a natural gel selected from Aloe vera, Aloe barbadensis, Aloe petricola, Aloe ciliaris, Aloe ferox, Aloe striata, Aloe aristata, Aloe arborescens, Aloe humilis, or combinations thereof.
[0023] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a natural emulsifier selected from polyacrylic acids and is preferably a carbomer.
[0024] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a thickener selected from methyl cellulose, guar gum, xanthan gum, carbopol, gum arabic, cornstarch, gelatin, or combinations thereof.
[0025] In yet another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a fragrance, wherein the fragrance is natural fragrance or a synthetic fragrance, and the fragrance is selected from lemon, jasmine, lavender, mint ice, peach, red berry, apple, vanilla, rose, rosemary, mogra, sandalwood, orange, or combinations thereof.
[0026] In another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a solvent, wherein the solvent is purified water or distilled water.
[0027] In still another embodiment, the present disclosure relates to an antimicrobial lotion formulation comprising a pH regulator selected from sodium hydroxide, citric acid, lactic acid, triethanolamine, glacial acetic acid, sodium carbonate, acetic acid, or combinations thereof.
[0028] In a preferred embodiment, the present disclosure provides an antimicrobial lotion formulation including, by weight of the formulation: bio-surfactant in an amount ranging from about 0.01% to about 2.0% and preferably from about 0.01% to about 1.0% weight; silver nanoparticles in an amount ranging from about 0.001% to about 0.006% and preferably in the amount ranging from about 0.001% to about 0.004% weight; preservative acid in an amount ranging from about 0.1% to about 1.0% and preferably in the amount ranging from about 0.1% to about 0.8% weight; thickener in an amount ranging from about 0.01% to about 7.0% and preferably in the amount ranging from about 0.01% to about 5.0% weight; emulsifier in an amount ranging from about 0.001% to about 3.0 % and preferably in the amount ranging from about 0.001% to about 2.0% weight; moisturizer in an amount ranging from about 0.01% to about 6.0%, preferably in the amount ranging from about 0.01% to about 4.0% weight; natural gel in an amount ranging from about 1% to about 50%, and preferably in the amount ranging from about 2% to about 40% weight; and fragrance in the amount ranging from about 0.01% to about 2.0% weight, of the overall formulation.
[0029] In an embodiment, the present disclosure relates to an antimicrobial lotion formulation provided in the form of a powder or liquid or gel, and preferably, is in liquid form.
[0030] Another aspect of the present disclosure relates to a process for preparing an antimicrobial lotion formulation comprising the steps of:
(i) dissolving xanthan gum with tea tree oil at room temperature and stirring at about 400 rpm;
(ii) mixing biosurfactant, preservative acid and silver nanoparticles by sonication for about 30 minutes in distilled water;
(iii) adding carbomer and natural gel to the mixture of step (ii) and mixing at a temperature range of about 50°C -60°C and stirring at about 1500 rpm;
(iv) adding the mixture of step (i) to the mixture of step (iii) at a temperature of 50°C -60°C and stirring at 1500 rpm;
(v) adding natural fragrance to the stirred mixture of step (iv); and
(vi) adjusting the pH of the mixture of step (v) to pH of about 6.9-7.1 using sodium hydroxide 10M and bringing the final solution to 100 gm/mL using distilled water.
[0031] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments

DETAILED DESCRIPTION OF THE INVENTION
[0032] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.
[0033] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0034] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0035] In some embodiments, numbers have been used for quantifying weight percentages, ratios, and so forth, to describe and claim certain embodiments of the invention and are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0036] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0037] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0038] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0039] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0040] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0041] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.
[0042] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0043] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0044] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0045] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements a, b, and c, and a second embodiment comprises elements b and d, then the inventive subject matter is also considered to include other remaining combinations of a, b, c, or d, even if not explicitly disclosed.
[0046] While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention.
[0047] The present disclosure provides an antimicrobial lotion formulation having antibacterial and antiviral properties and comprising (i) a biosurfactant, (ii) silver nanoparticles, and (iii) a preservative acid.
[0048] In an embodiment of the present disclosure, the bio-surfactant is a glycolipid selected from sophorolipid, rhamnolipid, trehalolipids, mannosylerythritol lipids, or combinations thereof. In a preferred embodiment, the bio-surfactant is sophorolipid.
[0049] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the bio-surfactant in an amount ranging from about 0.01% to about 2.0% and preferably from about 0.01% to about 1.0% by weight with respect to the overall formulation.
[0050] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises silver nanoparticles having size in the range from about 10 nm to about 1000 nm. In an embodiment, the silver nanoparticles may be prepared by any method known to a person of skill in the art.
[0051] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises silver nanoparticles in an amount ranging from about 0.001% to about 0.006% and preferably in the amount ranging from about 0.001% to about 0.004% by weight with respect to the overall formulation.
[0052] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises a preservative acid selected from sorbic acid, calendula oil, benzoic acid, citric acid, triclosan, triclocarban, phenoxyethanol, benzyl benzoate, benzyl alcohol, zinc pyrithione, benzalkonium chloride, or combinations thereof. Preferably, the preservative acid is citric acid.
[0053] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the preservative acid in an amount ranging from about 0.1% to about 1.0% by weight with respect to the overall formulation and preferably in the amount ranging from about 0.1% to about 0.8% by weight with respect to the overall formulation.
[0054] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises a thickener selected from methyl cellulose, guar gum, xanthan gum, gum arabic, cornstarch, gelatin, or combinations thereof. Preferably the thickener is xanthan gum.
[0055] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the thickener in an amount ranging from about 0.01% to about 7.0%, preferably in the amount ranging from about 0.01% to about 5.0% by weight with respect to the overall formulation.
[0056] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises a natural emulsifier, wherein the emulsifiers are polyacrylic acids. Preferably the natural emulsifier is a carbomer.
[0057] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the emulsifier in an amount ranging from about 0.001% to about 3.0 % and preferably in the amount ranging from about 0.001% to about 2.0% by weight with respect to the overall formulation.
[0058] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises moisturizer selected from tea-tree oil, jojoba oil, cucumber extract, coco-glucoside, shea butter, cocoa butter, argan oil, aloe vera, olive oil, sunflower oil, avocado oil, butylene glycol, vegetable glycerin, or combinations thereof. Preferably, the moisturizer is tea-tree oil.
[0059] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the moisturizer in an amount ranging from about 0.01% to about 6.0%, preferably in the amount ranging from about 0.01% to about 4.0% by weight with respect to the overall formulation.
[0060] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises a natural gel selected from Aloe vera, Aloe barbadensis, Aloe petricola, Aloe ciliaris, Aloe ferox, Aloe striata, Aloe aristata, Aloe arborescens, Aloe humilis, or combinations thereof. Preferably, the natural gel is obtained from Aloe vera.
[0061] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the natural gel in an amount ranging from about 1% to about 50%, and preferably in the amount ranging from about 2% to about 40% by weight with respect to the overall formulation.
[0062] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises a fragrance wherein the fragrance is natural fragrance or a synthetic fragrance; wherein the fragrance is selected from lemon, jasmine, lavender, mint ice, peach, red berry, apple, vanilla, rose, rosemary, mogra, sandalwood, orange, or combinations thereof. Preferably, the fragrance is a natural fragrance.
[0063] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the fragrance in the amount ranging from about 0.01% to about 2.0% by weight with respect to the overall formulation.
[0064] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises a pH regulator for adjusting the pH of the formulation to 7.0; wherein the pH regulator is selected from sodium hydroxide, citric acid, lactic acid, triethanolamine, glacial acetic acid, sodium carbonate, acetic acid or combinations thereof. Preferably, the pH regulator is sodium hydroxide.
[0065] In an embodiment of the present disclosure, the antimicrobial lotion formulation comprises the pH regulator in the amount sufficient to maintain the pH around 7.
[0066] In another embodiment, the antimicrobial lotion formulation of the present disclosure comprises a solvent selected from purified water or distilled water. The solvent is in a quantity sufficient to make up the weight percentage of the formulation to 100%.
[0067] In an embodiment, the present invention provides an antimicrobial lotion formulation comprising a) a biosurfactant, b) silver nanoparticles, c) a preservative acid, d) a thickener, e) a natural emulsifier, f) a moisturizer, g) a natural gel, and h) a fragrance.
[0068] In a preferred exemplary embodiment of the present invention, the antimicrobial lotion formulation comprises: sophorolipids in a percent weight range from 0.01% to 1.0%, silver nanoparticles in a percent weight range from 0.001% to 0.004%, citric acid in a percent weight range from 0.1% to 0.8%, xanthan gum in a percent weight range from 0.01% to 5.0%, carbomer in a percent weight range from 0.001% to 2.0%, tea tree oil in a percent weight range from 0.01% to 4%, aloe vera gel in a percent weight range from 2% to 40%, natural fragrance in a percent weight range from 0.01% to 2%, distilled water q.s.100 % and sodium hydroxide for adjusting pH to 7.0.
[0069] Without wishing to be bound by theory, the present inventors have found that silver nanoparticles in combination with surface-active biosurfactants, glycolipids preferably sophorolipids, and the acid, preferably citric acid, provide a synergistic composition resulting in effective antiviral activity and effectively prevents the spread of infection in patients, and contact infection in health care workers. The combination effectively inhibits the proliferation of corona virus by inhibiting the synthesis of viral negative-strand RNA and viral budding. Sophorolipids is a new biomolecule that is a biosurfactant, is biodegradable and non-toxic to human health because of their biocompatibility, and prevent antimicrobial infection as these biomolecules interfere with the lipid layer and trans-membrane proteins of the microbes to make them inactive.
[0070] The antimicrobial lotion formulation exhibits longer periods of disinfectant properties against microorganisms such as bacteria including antimicrobial-resistant bacteria, fungi, enveloped viruses including SARS-CoV-2, non-enveloped viruses, and prevent the spread of infections.
[0071] In an embodiment, the antimicrobial lotion formulation inhibits COVID-19 and SARS-CoV-2 infection by (i) disrupting the lipid layer of the SARS-CoV-2 virus, (ii) disrupting the three-dimensional structure of the spike protein (S) of the SARS-CoV-2 virus rendering the virus permanently inactive, (iii) disrupting the viral membrane, and thus inhibiting viral penetration into the host cell, and (iv) inactivating viruses by denaturing enzymes via reactions with sulfhydryl, amino, carboxyl, phosphate, and imidazole groups.
[0072] The advantageous synergistic technical effects of the antimicrobial lotion formulation is also attributed to the interplay of the triplet complex of silver nanoparticles, sophorolipids, and the preservative acid component which interfere with the trans-membrane protein and outer lipid layer of the microorganism rendering them functionally inactive and ultimately prevent the spread of infection and illness. This interplay of the three components provides long-lasting antimicrobial protection by slowly releasing the reactive oxygen species (ROS) on the skin surface. Therefore, if there are microbes in droplets or suspensions of microbes including virus on the skin, the microbes will interact with the triplet complex of the formulation applied on the skin and render the virus inactive. The formulation does not cause skin irritation or skin rashes unlike conventional alcohol based formulations.
[0073] In an embodiment, the present disclosure provides an antimicrobial lotion formulation that is antibacterial and is effective even on Methicillin Resistant Staphylococcus Aureus (MRSA).
[0074] In an embodiment, the present disclosure provides an antimicrobial lotion formulation that is antiviral and is effective against non-enveloped and enveloped viruses including SARS-CoV-2 virus. In some embodiments, the formulation was found to have over 99.9% efficacy in reduction of SARS-CoV2 virus.
[0075] In an embodiment, the present disclosure provides an antimicrobial lotion formulation that is an antifungal.
[0076] In an embodiment of the present disclosure, the antimicrobial lotion formulation may have a whitish or a light yellowing creamy appearance.
[0077] In an embodiment of the present disclosure, the antimicrobial lotion formulation may be provided in the form of a powder, liquid, gel, cream, or paste. Most preferably, the formulation realized in accordance with embodiments of the present disclosure is prepared in liquid form. In some embodiments, the formulation may be incorporated into other compositions or formulations.
[0078] In an embodiment, the present disclosure provides an antimicrobial lotion formulation that is suitable for topical application and provides effective inhibition of spread of contact infection in patients and health care workers.
[0079] In an embodiment of the present disclosure, the antimicrobial lotion formulation provides long lasting preventive care in the event of outbreaks of Corona virus infection (COVID-19), MRSA, influenza (flu) virus, Rhinovirus, Herpes Simplex 2 virus, Athlete’s foot fungus, blood borne pathogens such as HIV and HBV as well as Norovirus, E. coli, Enterobacter, Salmonella, and Staphylococcus. Long lasting protection of the formulation is seen as it does not require any rinsing off and can continue working as a disinfectant for up to 10-24 hours.
[0080] In another embodiment, a process for preparing an antimicrobial lotion formulation is provided.
[0081] In an embodiment of the present disclosure, the process for preparing an antimicrobial lotion formulation comprises the steps of:
(i) dissolving a thickener with a moisturizer at room temperature and stirring at about 400 to about 1000 rpm;
(ii) mixing a biosurfactant, a preservative acid and silver nanoparticles by sonication for about 30 to about 60 minutes in a solvent;
(iii) adding a natural emulsifier and natural gel to the mixture of step (ii) and mixing at a temperature range of about 50°C -60°C and stirring at about 1500 to about 2000 rpm;
(iv)adding the mixture of step (i) to the mixture of step (iii) at a temperature of about 50°C-60°C and stirring at about 1500 rpm to about 2000 rpm;
(v) adding a natural fragrance to the stirred mixture of step (iv); and
(vi)adjusting pH of the mixture of step (v) using a pH regulator and volume using the solvent.
[0082] In an embodiment of the present disclosure, the process for preparing an antimicrobial lotion formulation comprises the steps of:
(i) dissolving xanthan gum with tea tree oil at room temperature and stirring at 400 rpm;
(ii) mixing biosurfactant, preservative and silver nanoparticles by sonication for about 30 minutes in distilled water;
(iii) adding carbomer and natural gel to the mixture of step (ii) and mixing at a temperature range of about 50°C -60°C and stirring at about 1500 rpm;
(iv) adding the mixture of step (i) to the mixture of step (iii) at a temperature of about 50°C -60°C and stirring at about 1500 rpm;
(v) adding a natural fragrance to the stirred mixture of step (iv); and
(vi) adjusting the pH of the mixture of step (iv) to pH of about 6.9-7.1 using sodium hydroxide 10M and bringing the final solution to 100 gm/mL using distilled water.
[0083] In an embodiment, the present disclosure provides a method of inhibiting microbial growth on a surface by coating the surface with the antimicrobial lotion formulation. The surface may be human skin or inorganic surfaces.
[0084] These inorganic surfaces may include any surfaces coming frequently in contact with microbes. These surfaces may be found in health care facilities, schools, offices, buses, trains, cars, public transports, or restaurants.
[0085] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0086] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary.
[0087] MATERIALS: All the chemicals for the purposes of the examples were obtained from third party manufacturing. Silver nanoparticles were obtained from Amnium Technologies Pvt. Ltd.
Example 1: Preparation of antimicrobial lotion formulation
[0088] 0.5 mg xanthan gum was dissolved in 500 µL tea tree oil at room temperature and stirred at 400 rpm using a magnetic stirrer until properly mixed. In a separate vessel, 1 gm sophorolipid, 1 gm citric acid, and 1 gm silver nanoparticles were taken together, 50 mL of distilled water was added and the mixture was agitated by sonicating at 100 power with an interval of 15 seconds for 30 minutes. To this agitated mixture, 1 gm carbomer (Carbopol 940) and 10 gm/mL aloe vera gel were added and mixed using a magnetic stirrer at 1500 rpm at 60°C for 30 minutes. The mixture of xanthan gum and tea tree oil were then added to the above stirred mixture with the stirring continuing at 1500 rpm at 60°C. Finally, 1 mL of a natural fragrance (Natural Boutique) was added to the mixture and the pH adjusted to 7.0 using 10M of sodium hydroxide. The final solution was made up to 100 gm/mL using distilled water. Table 1 provides the list of components employed in the antimicrobial lotion formulation preparation.

Table 1: Components for an antimicrobial lotion formulation
S.No. Ingredients Composition (%)
1. Sophorolipids 0.01% to 1.0%
2. Silver Nanoparticles 0.001% to 0.004%
3. Citric Acid 0.1% to 0.8%
4. Xanthan Gum 0.01% to 5.0%
5. Carbopol 940 0.001% to 2.0%
6. Tea Tree Oil 0.01% to 4%
7. Aloe vera Gel 2% to 40%
8. Natural Fragrance 0.01% to 2%
9. Distilled water q.s.100 %
10. Sodium Hydroxide
pH-7.0
adjusted using 10 M Stock solution)

Example 2: Tests for the antimicrobial lotion formulation
[0089] 2.1 Antiviral activity: Antiviral activity of the formulation prepared in Example 1 was tested by a time kill assay of American Society for Testing and Materials - ASTM-E 1052-20. The results have been provided in Table 2 below.
Table 2: Results for Antiviral activity
S. No. Organism Initial viral count (pfu/mL) Log value Contact time Final viral count (pfu/mL) Log value Log reduction (LR) % reduction
1 E. coli
Bacteriophage MS2 virus (ATCC 15597-B1) 5.0x107 7.70 1 min 43000 4.63 3.067 99.142
12 hrs 7200 3.86 3.843 99.9856
where % reduction = 100 x (1-10-LR)
[0090] The formulation was tested against MS2 bacteriophage, a commonly used surrogate for SARS-CoV. MS2 Bacteriophage is used as a standard to study molecular biology processes of the enveloped & non-enveloped viruses. It includes viral RNA replication, translation method, and the psychology of infected cells. MS2 RNA coding for viral polypeptides includes protein A, coat protein, and RNA replicase complex. The structure of the MS2 virus consists of Protein A and coat protein makeup. The protein composition and molecular biology process of the MS2 virus are similar to the Coronavirus and these attributes make the MS2 virus as a Model for in-vitro virucidal efficacy. The antiviral efficacy of the formulation was conducted at different intervals of time and the formulation was found to be 99.99% effective in virus protection.
[0091] 2.2 Antimicrobial activity: Antimicrobial activity of the formulation prepared in Example 1 was tested by a time kill assay of American Society for Testing and Materials - ASTM-E 2315-16. The results have been provided in Table 3 below.
Table 3: Results for Antimicrobial activity
% reduction 99.92 99.88 99.86 99.91 99.89 99.99 99.90 99.86
Log reduction (LR) 3.08 2.92 2.85 3.02 2.95 4.20 2.99 2.87
Log value 4.60 4.85 4.61 4.18 4.79 3.56 4.58 4.65
Final Microbial count (cfu/mL) 40000 70000 41000 15000 61000 3600 38000 45000
Contact time (min) 1 1 1 1 1 1 1 1
Log value 7.68 7.77 7.46 7.20 7.74 7.76 7.57 7.52
Initial Microbial count (cfu/mL) 4.8x107 5.9 x107 2.9 x107 1.6 x107 5.5 x107 5.7 x107 3.7 x107 3.3 x107
Organism Candida albicans (MTCC 227) S. aureus (ATCC 6538) Staph. Epidermis
(ATCC12228) Escherichia coli (ATCC 8739) Listeria monocytogenes (ATCC 19111) Salmonella abony (NCTC 6017) P. aeruginosa (ATCC9027) Aspergillus brasilensis (ATCC16404)
S. No. 1 2 3 4 5 6 7 8

where % reduction = 100 x (1-10-LR)
[0092] The antimicrobial efficacy of the formulation was found to be 99.99% effective in protection against various microorganisms.
[0093] 2.3 Cell cytotoxicity and skin safety: The assay was done in a 96-well plate format in 3 wells for each sample. 1x10e4 VeroE6 cells were plated per well and incubated at 37-degree C overnight for the monolayer formation. Next day, cells were incubated with the formulation of Example 1(test substance) at the indicated concentration. The cells without the test substance were the control for water-soluble compounds. 24 and 48 hours later, cells were stained with Hoechst 33342 and Sytox orange dye. Images were taken at 10X, 16 images per well, which covers 90% of well area using ImageXpress Microconfocal (Molecular Devices). Hoechst 33342 nucleic acid stain is a popular cell-permanent nuclear counter stain that emits blue florescence when bound to dsDNA. It stains all live and dead cells. Sytox orange dye stains nucleic acids in cells with compromised membranes. This stain is an indicator of cell death. First, the software counts total number of cells in the Hoechst image. In the Sytox image, it will count, among Hoechst positive cells, how many cells are positive for Sytox. Results obtained from the tests are provided in Table 4 below.
Table 4: Results for Cell viability
Compound Name Concentration Cells Viability (%)
24 hr 48 hr
Remdesivir 10 µM 99.23 94.37
Formulation as per present disclosure 1µL added from 49.3 mg/mL solution in 200 µL 113.95 95.20
Formulation as per present disclosure 1µL added from the 10 times diluted solution in 200 µL 114.45 96.57

[0094] The cell cytotoxicity of the formulation was conducted at different intervals of time and was found to be 100% safe for skin.
[0095] From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein merely for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention and should not be construed so as to limit the scope of the invention or the appended claims in any way.

ADVANTAGES OF THE INVENTION
[0096] The present disclosure provides an antimicrobial lotion formulation having excellent antibacterial, antiviral, and antifungal activities.
[0097] The present disclosure provides an antimicrobial lotion formulation effective even on drug resistant bacteria such as Methicillin Resistant Staphylococcus Aureus (MRSA).
[0098] The present disclosure provides an antimicrobial lotion formulation effective on viruses such as non-enveloped and enveloped viruses including SARS-CoV-2.
[0099] The present disclosure provides an antimicrobial lotion formulation that is safe for topical application and suitable for all skin types.
[00100] The present disclosure provides an antimicrobial lotion formulation that provides long-lasting protection for medical care workers as it does not require any rinsing off.

WE CLAIM

An antimicrobial lotion formulation, wherein the formulation comprises: (i) a biosurfactant, (ii) silver nanoparticles, and (iii) a preservative acid.
2. The formulation as claimed in claim 1, wherein the bio-surfactant is a glycolipid selected from sophorolipid, rhamnolipid, trehalolipids, mannosylerythritol lipids, or combinations thereof.
3. The formulation as claimed in claim 1, wherein the bio-surfactant is present in an amount ranging from 0.01% to 2.0% by weight with respect to the overall formulation.
4. The formulation as claimed in claim 1, wherein the silver nanoparticles have size in the range from 10 nm to 1000 nm.
5. The formulation as claimed in claim 1, wherein the silver nanoparticles are present in an amount ranging from 0.001% to 0.006% by weight with respect to the overall formulation.
6. The formulation as claimed in claim 1, wherein the preservative acid is selected from sorbic acid, calendula oil, benzoic acid, citric acid, triclosan, triclocarban, phenoxyethanol, benzyl benzoate, benzyl alcohol, zinc pyrithione, benzalkonium chloride, or combinations thereof.
7. The formulation as claimed in claim 1, wherein the preservative acid is present in an amount ranging from 0.1% to 1.0% by weight with respect to the overall formulation.
8. The formulation as claimed in claim 1, wherein the formulation comprises a thickener selected from methyl cellulose, guar gum, xanthan gum, gum arabic, cornstarch, gelatine, or combinations thereof.
9. The formulation as claimed in claim 8, wherein the thickener in present in an amount ranging from 0.01% to 7.0% by weight with respect to the overall formulation.
10. The formulation as claimed in claim 1, wherein the formulation comprises a natural emulsifier which is a polyacrylic acid.
11. The formulation as claimed in claim 10, wherein the emulsifier is present in an amount ranging from 0.001% to 3.0% by weight with respect to the overall formulation.
12. The formulation as claimed in claim 1, wherein the formulation comprises a moisturizer selected from tea-tree oil, jojoba oil, cucumber extract, coco-glucoside, shea butter, cocoa butter, argan oil, aloe vera, olive oil, sunflower oil, avocado oil, butylene glycol, vegetable glycerine, or combinations thereof.
13. The formulation as claimed in claim 12, wherein the moisturizer is present in an amount ranging from 0.01% to 6.0% by weight with respect to the overall formulation.
14. The formulation as claimed in claim 1, wherein the formulation comprises a natural gel selected from Aloe vera, Aloe barbadensis, Aloe petricola, Aloe ciliaris, Aloe ferox, Aloe striata, Aloe aristata, Aloe arborescens, Aloe humilis, or combinations thereof.
15. The formulation as claimed in claim 14, wherein the natural gel is present in an amount ranging from 1% to 50% by weight with respect to the overall formulation.
16. The formulation as claimed in claim 1, wherein the formulation comprises a fragrance, wherein the fragrance is a natural fragrance or a synthetic fragrance.
17. The formulation as claimed in claim 16, wherein the fragrance is present in the amount ranging from 0.01% to 2.0% by weight with respect to the overall formulation.
18. The formulation as claimed in claim 1, wherein the formulation comprises a pH regulator selected from sodium hydroxide, citric acid, lactic acid, triethanolamine, glacial acetic acid, sodium carbonate, acetic acid, or combinations thereof.
19. The formulation as claimed in claim 1, wherein the formulation comprises a solvent selected from purified water or distilled water.
20. A process for preparing an antimicrobial lotion formulation comprising the steps of:
(i) dissolving a thickener with a moisturizer at room temperature and stirring at 400 rpm to 1000 rpm;
(ii) mixing a biosurfactant, a preservative acid and silver nanoparticles by sonication for 30 minutes to 60 minutes in a solvent;
(iii) adding a natural emulsifier and natural gel to the mixture of step (ii) and mixing at a temperature range of 50°C -60°C and stirring at 1500 rpm to 2000 rpm;
(iv) adding the mixture of step (i) to the mixture of step (iii) at a temperature of 50°C -60°C and stirring at 1500 rpm to 2000 rpm;
(v) adding a natural fragrance to the stirred mixture of step (iv); and
(vi) adjusting pH of the mixture of step (v) using a pH regulator and volume using the solvent.