Patent Application
20060147341
1. Field of Invention
This invention relates generally to an article and method for detecting the presence of a skin irritant, and more particularly, to an article and method for detecting a polyhydroxyaromatic skin irritant.
2. Discussion of Related Art
Exposure to naturally occurring skin irritants is a common hazard associated with outdoor activities. Contact with plants of the botanical family Anacardiaceae, and more particularly with the genus Toxicondendron, often causes a dermatological reaction, such as contact dermatitis. The plants, including poison ivy, poison oak, poison sumac, the lacquer tree, mango and cashew, belong to a group of plants with urushiols which typically irritate the skin.
About 80-90% of adults will get a rash if exposed to 50 micrograms of purified urushiol, which is a minute amount when considering that one grain of table salt weighs about 60 micrograms. Urushiol is a relatively stable compound which may remain potent for months or years in the absence of oxidation or polymerization. Contact with 100 year old herbarium specimens has caused contact dermatitis. Urushiols are also easily transferred to an individual from the contaminated fur of animals and from the surface of contaminated objects, such as clothes, tools and equipment.
Treating a contaminated surface, such as by washing, is an accepted practice. U.S. Pat. No. 5,409,908 to Sanchez et al. discloses a method of removing urushiols from a surface by binding the urushiols to cyclodextrins.
Early treatment, that is before the onset of symptoms, is desirable, However, such treatment is predicated upon knowing that actual contact with the toxic plants has occurred. Unfortunately, it may not be readily apparent to an individual that he or she has come into contact with these toxic plants. For example, poison ivy resembles other harmless plants so that an individual may not realize there has been contact. Moreover, contact with urushiols does not result in an immediate skin irritation. It is not uncommon for the first symptom, typically itching, to manifest itself between about 6 hours and about 24 hours after contact. Additional symptoms, such as redness and swelling may not occur for up to 48 hours after contact, followed eventually by the formation of microblisters.
U.S. Pat. No. 4,472,507, issued to Pluim, Jr., discloses a method for detecting exposure to poison ivy and the like. An indicator comprises a carrier treated with a reactant, such as ferric nitrate, which reacts with the toxin to produce a color change indicative of such contact.
The invention is directed to an abrasive article comprising abrasive material deposited on an adhesive configured in an identifying pattern on a substantially planar substrate. The identifying pattern corresponds to a characteristic of the coated abrasive article.
One embodiment is directed to an article for detecting the presence of a polyhydroxyaromatic skin irritant on a surface. The article comprises cyclodextrin configured to bind at least a portion of a polyhydroxyaromatic skin irritant present on the surface to at least a portion of the cyclodextrin, and an indicator in communication with the cyclodextrin and configured to react with the polyhydroxyaromatic skin irritant to provide indicia of the presence of the polyhydroxyaromatic skin irritant.
Another embodiment is directed to a kit for detecting the presence of a polyhydroxyaromatic skin irritant on a surface. The kit comprises a substrate comprising cyclodextrin configured to bind at least a portion of a polyhydroxyaromatic skin irritant present on the surface to at least a portion of the cyclodextrin, and a reservoir comprising an indicator in communication with the cyclodextrin and configured to react with the polyhydroxyaromatic skin irritant to provide indicia of its presence.
Another embodiment is directed to a method of determining the presence of urushiol on a surface comprising the acts of contacting a substrate comprising cyclodextrin with a surface, binding at least a portion of the a urushiol present on the surface to at least a portion of the cyclodextrin, and exposing an indicator to at least a portion of the urushiol bound to the cyclodextrin. The indicator is configured to react with the urushiol.
The accompanying drawings, are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:
This invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.
The present invention relates to a composition and method for detecting the presence of polyhydroxyaromatic skin irritants commonly found in plants known to cause skin irritations, such as contact dermatitis. These plants, typically from the genus Toxicondendron of the Anacardiaceae family, contain urushiols which often irritate exposed skin. For example, contact with the sap or oils of poison ivy, poison oak, poison sumac, the lacquer tree, mango, and cashew, is known to cause contact dermatitis. In one embodiment, the present invention provides a point of contact test that may be used by an untrained user in the field. Field use may also provide the user with immediate results, allowing the user to take preventative measures to avoid developing contact dermatitis, such as washing or changing clothes, in the event of a positive response indicating actual exposure to polyhydroxyaromatic skin irritants.
Urushiol is a generic term applied to the toxic substance in the sap or oil of a plant, and is commonly a mixture polyhydroxyaromatic compounds called catechols. Catechols are 1,2 dihydroxy-phenyls with typically a 15 or 17 carbon atom aliphatic side chain with various degrees of unsaturation. For example, poison oak urushiol contains primarily 17 carbon side-chains catechols or heptadecylcatechols. Poison ivy and poison oak urushiols contain primarily 15 carbon side-chains catechols, or pentadecylcatechols. The aliphatic hydrocarbon side group allows bonding to, and penetration of, the skin. The hydrocarbon side chain is hydrophobic, and the dihydroxy phenyl moiety is hydrophilic.
The present invention comprises cyclodextrin and an indicator capable of producing indicia, or a perceivable change, when contacted with the polyhydroxyaromatic skin irritants. Any cyclodextrin may be used in the present invention. Cyclodextrins are nonreducing cyclic oligosaccharides that are synthesized from starch by enzymes called cyclomaltrodextrin glucanosyltransferase. Cyclodextrins are most commonly composed of six to twelve D-glucose residues, although larger rings have been synthesized. α-Cyclodextrin consist of six glucose residues, β-cyclodextrin consists of seven glucose residues, and γ-cyclodextrin consists of eight glucose residues. Water solubility is generally higher for rings having an even number of glucose residues. In a preferred embodiment, the cyclodextrin is β-cyclodextrin.
Because the hydroxyl groups in cyclodextrin project outward, the outer surface is hydrophilic, while the cavity is relatively more hydrophobic. Cyclodextrins have a rigid conical shape. The three dimensional shape of cyclodextrin is represented below.
Cyclodextrin may be applied to a substrate to immobilize the urushiols to a specific location on the substrate. The Cyclodextrin may be deposited on a surface of the substrate, and/or deposited throughout the substrate, such as by immersing the substrate in a solution containing Cyclodextrin.
The substrate may be any material having a surface suitable for carrying cyclodextrin. Examples of substrates include, but are not limited to, a polymer sheet, fibrous sheet, fabric, paper, sponge, gauze, swab, gel, foam, a natural or synthetic woven or nonwoven, and the like. In a preferred embodiment, the substrate provides an outer surface for supporting the Cyclodextrin, while also providing an interior portion to absorb fluids, such as carrier solvents. Absorption of carrier solvent(s) in an inner portion of the substrate may wick the carrier solvent(s) away from the outer surface of the substrate while maintaining the reaction between the Cyclodextrin and the indicator at or near the surface of the substrate. By maintaining the reaction at or near the surface of the substrate, the reaction product may be easily detected. In a preferred embodiment, the substrate is gauze, more preferably a swab having a high density absorbent tip, such as Rayon.
The substrate may be configured to be removably attachable to a subject. As used herein, the term “subject” is used to define any person or animal that may have contacted, or has the potential to contact, urushiol containing plants. The substrate containing cyclodextrin may be positioned upon the individual or animal, thereby coming into direct contact with area vegetation, allowing the cyclodextrin on the substrate to bind with urushiols from toxic plants. The substrate may be directly and/or indirectly attached to the subject. The substrate may be configured to be removably attachable to an article worn by the individual or animal, such as sock, shoe, pants, shorts, shirt, collar, and bandana. The substrate may also be configured to be removably attachable directly to the subject's skin or fur.
The substrate need not be worn, but may be configured to be used by an individual after potential exposure to urushiol containing plants, or for direct identification of urushiol containing plants. For example, the substrate may be configured to be used as a wipe, which may be used to collect urushiols that have transferred to the individual or animal and may be used to sample a number of different surfaces with one substrate. A single wipe type substrate may be contacted with the skin of the legs, arms, and hands as well as with clothing worn by the individual. Similarly, the wipe type substrate may be contacted with the collar, bandana, and legs of an animal. The use of a wipe type substrate allows an individual to examine a larger area of potential contact with urushiols than a stationary substrate that is worn in one location. The ability to examine a number of different surfaces to produce a single point reaction may result in a more representative indication of exposure to urushiols. The substrate may be, but need not be, reusable in the event that a previous use indicated that urushiols are not present and therefore no indicia was formed. A positive indication of the presence of urushiol affords the subject the opportunity to take preventative measures, such as washing and or changing clothing.
The substrate may, but need not, be moistened by a liquid, gel, or foam. The liquid may be any liquid or solution that aids in the removal of urushiols from the surface of the subject and in the transfer of the urushiols to the surface of the substrate for reaction with the cyclodextrin present on the surface of the substrate. The liquid may be solvent or water based. In one embodiment, a 15% isopropanol in water solution containing cyclodextrin is applied to the substrate.
The indicator may be any compound capable of reacting with polyhydroxyaromatic compounds to produce indicia of the presence of a polyhydroxyaromatic compound. The indicia formed may be detected by any of the five senses. For example, a visible change, such as color or fluorescence, and/or a tactical change such as texture, may occur upon reaction between the indicator and the polyhydroxyaromatic compounds. Alternatively, or in addition to visible/tactile changes, the reaction may cause the formation of a particular aroma.
In one embodiment of the invention, the indicia is represented by the formation of color. Examples of indicators which form a visible color change when reacted with the polyhydroxyaromatic compounds include, but are not limited to, metal salts, such as ferric salts, salts of chromium, silver, and copper, diazammonium salts, and combinations thereof. In one embodiment, the indicator may be selected from the group consisting of: ferric citrate, ferric chloride, and ferric nitrate and combinations thereof, preferably ferric citrate, ferric chloride, and combinations thereof. In a preferred embodiment, a color change is formed by the reaction between Fe+3 and the polyhydroxyaromatic compounds.
The indicator may be in a liquid carrier that may be applied to the substrate, the surface of a subject, and/or directly a surface of a plant. The liquid may, but need not, assist in solubilzing urushiol, and may be water or solvent based. In one embodiment, the liquid carrier is selected to wet both the surface of the substrate and the cyclodextrin. The liquid carrier may also comprise a hydrophobic component to assist in contacting the indicator with the cyclodextrin. In one embodiment, the liquid carrier is a solution of water and isopropyl alcohol. In a preferred embodiment, the liquid carrier is a 15% isopropanol in water solution.
In one embodiment of the invention, a portion of the indicator from a reservoir is contacted with the substrate. The indicator may be applied to the substrate after the substrate is contacted with a surface that may be contaminated with urushiol, or prior to contact with the surface that may be contaminated with urushiol. Alternatively, the indicator may be applied directly to a surface believed to have urushiols thereon. The indicator may be applied to the various surfaces by conventional methods, such as by droplet, immersion, brush, roller, spray, and the like.
The indicator and the substrate comprising the cyclodextrin may be supplied in one article. Alternatively, the indicator and the substrate may be individual components to a kit. One embodiment utilizes an absorbent tipped swab having a hollow tube adjacent the tip, such as swabs manufactured by Swabplus, Inc., of Rancho Cucamonga, Calif. In one embodiment, the absorbent tip may comprise a foam, or a natural or synthetic woven or nonwoven material. The absorbent tip may be coated with cyclodextrin, and the hollow tube may house a liquid indicator. A user may contact the tip with several surfaces believed to have been exposed to urushiols, and then break the tube allowing the liquid indicator to flow into the absorbent tip. The formation of indicia indicates the presence of urushiol on the absorbent tip, and therefore, on one or more surfaces contacted with the absorbent tip.
Another embodiment, similar to swabs provided by Medical Packaging, Inc. (Camarillo, Calif.) is shown in
The use of the cyclodextrin may enhance the perceivable response of the reaction between the urushiol and the indicator by orientating the molecule by self-assembly, so that the reactive hydrophilic dihydroxy phenyl moiety may be at or near the surface and the hydrophobic hydrocarbon chain may be buried in the core of the cyclodextrin. When absorbent substrates are used, the presence of cyclodextrins on the surface of the substrate may prevent the urushiols from wicking away from the surface, thereby localizing the presence of urushiols.
In another embodiment, a hydrophilic polymer bearing pendant cyclodextrin rings may be used in the present invention. When a sufficient number of cyclodextrin rings are in the complexed form, that is reacted with urushiol, self-assembly will occur as illustrated in
In another embodiment, the cyclodextrin may be complexed with an unexposed chromophore. A hydrophobic molecule, such as a chromophore or a fluorescent molecule, may be linked or tethered to the cyclodextrin ring. As shown in
The invention may be further understood with reference to the following examples, which are intended to serve as illustration only, and not as a limitation of the present invention as defined in the claims herein.
In the following examples, 4-methyl catechol and 4-t-butyl catechol, shown below, were used as analogues of the natural urushiols.
Each catechol was dissolved in 15% isopropanol in water at a concentration of 1.0 g/mL to form a syrup to simulate the toxin. The toxins were reacted with various indicators both in the presence and in the absence of β-cyclodextrin. The reaction between the indicator and the toxin produced a color change. The intensity of the resultant color was recorded by a digital camera and scanned. The scanned images were analyzed with a quantitative densitometry program (SigmaScan® from Systat Software, Inc. of Richmond, Calif.) to determine the relative intensity of the toxin development.
Eighteen disks, having a diameter of about 0.5 cm, were prepared from Whatman #41 quantitative ashless filter paper. Nine disks were coated with 200 μL of a solution of β-cyclodextrin and dried. The solution of β-cyclodextrin was prepared by dissolving 500 mg of β-cyclodextrin in 1 mL of a 15% isopropanol in water solution and allowed to dry. The remaining nine disks were not coated with β-cyclodextrin. The coated and uncoated disks were divided into three sets, each set including three coated and three uncoated disks.
Toxin was prepared by mixing 4-methyl catechol with a 15% isopropanol in water solution at a concentration of 1.0 g/mL. Toxin was applied to each disk within each set. The first set of disks received 1 μL of toxin, the second set received 10 μL of toxin, and the third set received 100 μL of toxin.
Each disk was sprayed with ferric chloride at 30% w/v in 15% isopropanol in water causing a dark blue/black spot to form on the surface of the substrate. The intensity of the spot was measured and recorded. Each of the three trials was averaged and the highest response was set at 100%. The results are shown in
As shown in
In addition to increasing the intensity of the response, the disks coated with β-cyclodextrin are significantly more sensitive to smaller concentrations of toxin than the uncoated disks. As seen in
Without being bound to any particular theory, it is believed that the ability of the cyclodextrins to self assemble on the surface coupled with the orientation of the toxin in the cyclodextrin enhances the response to the ferric chloride, as illustrated in
Eighteen disks, having a diameter of about 0.5 cm, were prepared from Whatman #41 quantitative ashless filter paper. The disks were divided into six sets of three, wherein five sets of disks were coated with various concentrations of β-cyclodextrin, while the remaining set remained uncoated. A first set of disks was coated with an original β-cyclodextrin solution containing 500 mg β-cyclodextrin per 1 mL of a 15% isopropanol in water solution. The original β-cyclodextrin solution was diluted in decades so that the second set of disks was coated with a β-cyclodextrin solution of 50 mg/mL, the third set with 5 mg/mL, the fourth set with 0.5 mg/mL, and the fifth set with 0.5 mg/mL. Each set was heated to dry.
Each disk was then exposed to 10 μL of the toxin. The toxin was prepared by mixing 4-methyl catechol in a 15% isopropanol in water solution at a concentration of 1.0 g/mL. Each disk was sprayed with a ferric chloride at 30% w/v in 15% isopropanol in water causing a dark blue/black spot to form on the surface of the substrate. The intensity of the spot was measured and recorded. Each of the three trials was averaged and the highest response was set at 100%. The results are shown in
As shown in
Eighteen coated disks, having a diameter of about 0.5 cm, were prepared from Whatman #41 quantitative ashless filter paper. The disks were coated with a β-cyclodextrin solution containing 500 mg β-cyclodextrin per 1 mL of a 15% isopropanol in water solution, and dried. Eighteen uncoated disks of 0.05 cm were also prepared from Whatman # 41 quantitative ashless filter paper. Each coated and uncoated disk was then exposed to 10 μL of the toxin. The toxin was a solution of 4-methyl catechol in a 15% isopropanol in water solution at a concentration of 1.0 g/mL.
The eighteen coated disks and 18 uncoated disks were then divided into six sets of three coated and three uncoated disks. Each set was then sprayed with varying concentrations of ferric chloride in a 15% isopropanol in water solution. The first set was sprayed with a starting solution of ferric chloride at 30% w/v in 15% isopropanol in water. The starting solution was then diluted by decades so that the second set was sprayed with 20% w/v, the third set with 10% w/v, the fourth set with 1% w/v, the fifth set with 0.05% w/v and the six set with 0.1% w/v. The intensity of the resultant dark blue/black spot was measured and recorded. Each of the three trials was averaged and the highest response was set at 100%. The results are shown in
As shown in
The coated samples are also less sensitive to changes in ferric chloride concentration than the uncoated samples. As shown in
Eighteen coated disks and eighteen uncoated disks were prepared according to the procedure of Example IIIA. The disks were then divided into six sets of three coated and three uncoated disks. Each set was then sprayed with varying concentrations of ferric citrate in a 15% isopropanol in water solution. The first set was sprayed with a starting solution of ferric citrate at 30% w/v in 15% isopropanol in water. The starting solution was then diluted by decades so that the second set was sprayed with 20% w/v, the third set with 10% w/v, the fourth set with 1% w/v, the fifth set with 0.05% w/v and the six set with 0.1% w/v. The intensity of the resultant dark blue/black spot was measured and recorded. Each of the three trials was averaged and the highest response was set at 100%. The results are shown in
As shown in
The coated samples are also less sensitive to changes in ferric citrate concentration than the uncoated samples. As shown in
A comparison of
A number of different substrates were coated with a β-cyclodextrin solution, contacted with the toxin (4-methyl catechol) and an indicator (ferric ion). The use of a tightly woven, high density swab aided in contacting the toxin with the β-cyclodextrin. As the toxic solution was applied to the swab, the liquid was absorbed into the swab below the surface, leaving the toxin at the surface with the β-cyclodextrin.
The average percent response for samples prepared from Whatman #41 filter paper, Felt Disks (Boston Felt, East Rochester, N.H.), foams, natural and synthetic high density swabs (Qosina, East Rochester, N.H.) were similar as shown in
A number of disks of 0.05 cm were prepared from Whatman # 41 filter paper, and coated with 200 μL of the original β-cyclodextrin solution of 500 mg β-cyclodextrin per 1 mL of 15% isopropanol in water. The disks were divided into four sets. A first set received 100 mg of the 4-methyl catechol toxin solution, while a second set received 1 mg of the 4-methyl catechol toxin solution. A third set received 100 mg of 4-t-butyl catechol toxin solution, while the other set received 1 mg of the 4-t-butyl catechol toxin solution. A ferric chloride solution was applied to the disk. The average percent response was substantially the same whether the disk received 100 mg of toxin or 1 mg of either toxin.
Nine disks of 0.05 cm were prepared from Whatman # 41 filter paper, and coated with 200 μL of the original β-cyclodextrin solution of 500 mg β-cyclodextrin per 1 mL of 15% isopropanol in water. Each disk was contacted with 100 μL of various concentrations of the toxin. The original concentration of toxin (1 g of 4-methyl catechol per mL of 15% isopropanol in water) was diluted by half decades in the same solvent resulting in concentrations ranging from 100 μg/μL to 0.01 μg/μL. A 30% w/v in 15% aqueous isopropanol solution of ferric chloride was sprayed onto each disk. Each disk was photographed and scanned. The scanned images were analyzed using SigmaScan® as described above. The intensity of the dark blue/black spot was measured and recorded. The above test was replicated twice, and the results of the three runs were averaged and the highest response set at 100%.
As seen in
Nine disks of 0.05 cm were prepared from Whatman # 41 filter paper, and coated with 200 μL of the original β-cyclodextrin solution of 500 mg β-cyclodextrin per 1 mL of 15% isopropanol in water. Each disk was contacted with 100 μL of various concentrations of the toxin. The original concentration of toxin (1 g of 4-t-butyl catechol per mL of 15% isopropanol in water) was diluted by half decades in the same solvent resulting in concentrations ranging from 100 μg/μL to 0.01 μg/μL. A 30% w/v in 15% aqueous isopropanol solution of ferric chloride was sprayed on each disk. Each disk was photographed and scanned. The scanned images were analyzed using SigmaScan® as described above. The intensity of the dark blue/black spot was measured and recorded. The above test was replicated twice, and the results of the three runs were averaged and the highest response set at 100%.
As seen in
A comparison of the results in
Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.
