Odor Absorbing Hydrocolloid Dressings for Direct ...

ORIGINAL RESEARCH

Odor Absorbing Hydrocolloid Dressings for Direct Wound Contact Roger D.A. Lipman, PhD and Davy van Bavel, BSc

WOUNDS 2007;19(5):138–146 From Avery Dennison Medical, Turnhout, Belgium Address correspondence to: Davy van Bavel, BSc Avery Dennison Medical Tieblokkenlaan 1 2300 Turnhout Belgium Phone: 32 14 404 928 Fax: 32 14 404 878 E-mail: [email protected] Disclosure: Dr. Lipman discloses that he has received monetary compensation to conduct the study, write the manuscript, and lecture for the company producing the products discussed from Avery Dennison Medical. This study was fully funded by Avery Dennison Medical.

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Abstract: Charcoal based odor-absorbing dressings for management of odoriferous chronic wounds have been marketed for many years. However, the presence of wound serum deactivates the charcoal and inhibits the adsorption of odor molecules. Charcoal dressings also generally need adjunct fixation to hold them in place. A new series of hydrocolloid adhesives based on cyclodextrins has been developed to provide an alternative technology for the adsorption of chronic wound odors. Dressings incorporating this technology are suitable for direct wound contact. In presence of serum, superior odor absorption with these new materials in comparison with charcoal dressings has been demonstrated in vitro. These new dressings have significant fluid absorption potential, are self-adhesive, and require no additional fixation. Some of the factors affecting performance of these new materials in vitro are presented. Comparisons of fluid handling and odor prevention abilities of 3 hydrocolloid dressings, Exuderm OdorShield® (Medline, Mundelein, Ill) a hydrocolloid dressing containing cyclodextrins, coded MED 9150H, TegaSorb® (3M Health Care, St. Paul, Minn), and DuoDerm Extra Thin® (ConvaTec, Deeside, UK) are made. Preliminary results of the in-vivo performance of the MED9150H product on chronic wounds are also given.

atients in institutional settings, such as hospitals and nursing homes, often have or acquire chronic wounds such as those resulting from venous insufficiency and pressure ulcers—these wounds can possess a very offensive odor.1 The most direct way of avoiding or eliminating wound odor is to prevent or eradicate the infection responsible for it.Topical antibiotics, such as metronidazole gel (0.8 w/v) have proved to be quite effective, but can generate resistant organisms. Further, the action of metronidazole can be sluggish; often several days are needed for any infection to be resolved, and meanwhile the odor is still being generated.Thus, in practice, other methods such as charcoal-based dressings are often used with or without concomitant antibiotic therapy. Odor absorbing dressings have been marketed in one form or other for many years. During the past decades a number of charcoal based dressings have been introduced into the market. Some of the more current products are Actisorb® Silver (Johnson & Johnson Medical Ltd, Gargrave, UK), CarboFlex® (ConvaTec, Princeton, NJ), Carbonet® (Smith and Nephew

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WOUNDS A Compendium of Clinical Research and Practice

Lipman and van Bavel

Medical Ltd, Hull, UK), and LyoFoam® C (SSL International PLC, Canute Court, Toft Road, Knutsford, Cheshire, UK). One study2 investigated the effectiveness of the various charcoal cloths of odor absorbing dressings in adsorbing n-butyric and valeric acids each at an initial concentration of 0.04% (v/v). These aliphatic acids are two of the most common malodorous organic acids found in wounds.The charcoal based material was placed into a vial containing a dilute mixture of the acids and the Figure 1. Schematic diagram of test method. residual concentration of acids measured using combination of gas chromatography and mass spectroscopy (GC/MS). The absorbing dressings. A study performed by The Surgical charcoal material from Actisorb Plus and CarboFlex were Materials Test Laboratory, (Princess of Wales Hospital, found most effective, while those from Carbonet and Bridgend, UK) developed a technique using diethylamine LyoFoam C were found inferior to the other two.A further (DEA) detector to monitor strikethrough of liquid satuconclusion from an extension of this study3 was that the rated with DEA.4 Another study evaluated absorption of presence of wound serum greatly inhibited adsorption of fatty acid mixture on commercial dressings using gas fatty acids. Wound malodor obviously emanates in part chromatography (GC). Presence of wound serum was from bacterial decomposition of the proteins present in shown to inhibit fatty acid absorption.2 Another report serum, and the inhibition of charcoal odor absorbency by evaluated the passage of smelly wound exudate through dressing using GC.3 the odor precursor is a drawback to its use. The present study describes a new test method using Clearly, the propensity of charcoal to lose effectiveness in the presence of wound exudates is a serious lim- electronic nose (e-nose) technology that gives rapid, itation. Charcoal is also of course black and noncon- reproducible determination of odor absorption. Standard formable. Neither attribute is optimal for construction of solutions of odor are prepared and corresponding e-nose wound dressings, which ideally should be self-adhesive, responses are determined to give a calibration curve. conformable and able to contact the wound surface. A Residual odor in the vapor phase above the samples is new series of adhesives has been developed that provide measured; the odor concentration in the vapor phase is an alternative technology for the adsorption of chronic proportional to the odor concentration in solution. wound and other odors. The new odor absorbent adhe- Odoriferous substances, such as n-butyric acid, valeric sives can be made into dressings designed to be in direct acid, cadaverine, and putrescine were employed used as test odors.A diagram of the experimental set up is shown contact with the wound. Skin barriers can also be made from these adhesives in Figure 1. The measuring equipment used was an Airsense for the protection of the skin around body openings, especially around stomas, the surgically created openings Analytics Portable Electronic Nose Model PEN2, supplied known as colostomies, ileostomies, and urostomies. by WMA Airsense Analysentechnik GmbH, Schwerin, These novel skin barriers are able to absorb the odor Germany. The e-nose is software driven (WinMuster V. molecules that are associated with feces and urine and, 1.5.2, January 2003) and has an array of 10 different metal thus, are potentially able to assist in the control of the oxide semiconducting sensors positioned in a small chamber. Pumps serve to draw the test odor over the senodor often associated with stomas. sors from the headspace and over the absorbent dressing Methods in the test cell.The detection limit of the hot sensors can Methods have been developed for assessment of odor be as low as 1 ppm, dependent on the material.The selecVol. 19, No. 5 May 2007

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tivity of the sensors is determined with the material, the sensor geometry, and the temperature. Sensors with good selectivity for sulphur compounds, hydrocarbons, alcohols, and amines were used in the study. The e-nose is capable of detecting complex mixtures of gases and vapors.The e-nose also possesses the capability to sense and record deviations from standard smells to which it has been calibrated. In the present study, only single compounds were used in testing. The equipment was calibrated daily with the compounds in use to provide a standard curve against which an unknown odor level could be interpolated. Corrections were always made for the “internal smell” of the dressing, ie, the response of the e-nose to any background odor detectable in the absence of test odor. With the Airsense equipment, the calculations are software-driven and involve the use of statistical methods such as Euclidian, PCA factor analysis, DFA discriminant function analysis, or artificial neural network mapping (Kohonen mapping). The odor absorption data presented are comparative. They are obtained usually after 24 hours absorption time, and since the method involves a dynamic sweeping of the headspace over the sensors with pumped air, represent the instantaneous condition in the headspace above the sample. In some instances psychosensory testing, using a trained panel to smell and rank order odor intensity was used to assess the headspace odor in the test vials 24 hours post testing. In this way, it was confirmed that the new adhesives provide a permanent removal of odor. Some commercial standard adhesive products may appear to absorb some odor in the authors’ e-nose testing, but this absorption is superficial, and psychosensory evaluation confirms that the odor leaches out over time.This psychosensory testing is discussed later in the manuscript.

New Adhesive Developments Hydrocolloid adhesives are a unique kind of medically useful pressure sensitive adhesive.They have 2 phases, a rubbery phase that provides pressure sensitive tack, sometimes called “dry tack”, and within which is dispersed a discontinuous phase of absorbent material. Depending upon the nature of the absorbents, and especially whether the absorbent is soluble in aqueous media or merely swellable, the adhesive composition can develop “wet tack” as it becomes imbibed with fluid. Such wet tack can also influence the adhesive power of the hydrocolloid. Hydrocolloid adhesives have a duality of attrib140


utes in that they are inherently adhesive and inherently absorbent.They have been used for many years as wound dressings because they can be applied directly to open wounds and can be secured on the surrounding intact skin, and as skin barriers because they protect the peristomal skin of ostomy patients. Hydrocolloid adhesives provide what has become known as “moist wound healing” by maintaining the skin and wound in a hydrated condition. An optimally hydrated wound heals faster,5–7 while hydrated intact skin is less subject to irritation and injury from repeated application and removal of adhesives. Macerated skin (as opposed to optimally hydrated skin, as is observed with hydrocolloids in general), which can result from the use of conventional pressure sensitive adhesive constructions, is more vulnerable to mechanical shear forces during wear and removal. The authors have found that hydrocolloid adhesives are extremely useful vehicles for further modification by incorporation of cyclodextrins. It is well known that cyclodextrins are used in consumer products for absorption of adventitious odors around the home, such as those resulting from smoking and from pets.The patent literature on the subject on cyclodextrins also details a number of cyclodextrin-containing products for the absorption of odors associated with the use of personal hygiene products, such as feminine sanitary hygiene products. No adhesive-based, cyclodextrin-containing odor absorbing products have heretofore been reported,8 and the present study presents the results of the research undertaken in this particular field. Cyclodextrin materials are cyclic oligosaccharides containing a minimum of 6 D-(+)-glucopyranose units attached by α- (1 > 4) glucosidic bonds.Three cyclodextrins called α, β‚ and γ are naturally occurring and have, respectively, 6, 7, and 8 glucose units. Cyclodextrins are known that contain up to 12 glucose units. Cyclodextrin materials can also be manufactured from starch by enzymatic degradation. In addition, many synthetic modifications of the natural material are known, for example methyl-β-cyclodextrin and hydroxypropyl-β-cyclodextrin.The conformations of the cyclic structures of these molecules are such that the molecules are arranged in rigid conical molecular shapes that have hollow interiors of well defined sizes. These internal cavities are hydrophobic in nature because the interior of the toroidal shape is predominantly composed of hydrogen atoms. The interior shapes of the cyclodextrins are able to form inclusion complexes, sometimes referred to as “host-guest” complexes, or clathrate compounds, with


organic molecules which fit, completely or Table 1. Cyclodextrins need water to allow efficient odor absorption. partially, into the cavities defined by the µL of deionized water added toroidal shapes.9,10 0 5 10 100 2000 Cyclodextrins, and especially mixtures of % absorption by: % % % % % cyclodextrins with cavities of different sizes, 0 70 77 79 86 α-cyclodextrin, 0.6 g can therefore be used to control odors, and it β-cyclodextrin, 0.6 g 0 0 0 52 45 may be thought obvious to incorporate γ-cyclodextrin, 0.6 g 0 0 0 0 0 0 0 0 0 0 cyclodextrins into pressure sensitive adhe- Sodium carboxymethylcellulose, 0.6 g 0 0 0 80 28 Cyclodextrin hydrocolloid sives to give useful odor absorbing compositions. However, if this is done, it will be found adhesive, 2.0 g 0 0 0 0 0 Negative control: no absorbent that such compositions absorb odorous mole- in test tube cules very slowly at best. This is because the complexation of odorous molecules by The experiment confirms that cyclodextrins need water for molecule absorption: the odor absorption increases with increasing amounts of cyclodextrin is hindered not only by a slow water. It becomes clear that it is not the NaCMC present in the hydrorate determining diffusion process through colloid that absorbs the odor. On the other hand the table explains that the adhesive but also because absorption of a small molecule like butyric acid is absorbed best by α-cyclodextrin, odor by the cyclodextrin is facilitated by the the cyclodextrin with the smallest cavity. presence of water. Test conditions: For this test, a variable volume of deionized water (rangThe authors have addressed this problem ing from 0 to 2000 µL) was added to the test tube containing the by formulating a dressing material containing absorbent with 5 µl of 100% butyric acid. After incubating the tubes at both cyclodextrins and conventional hydro- 31˚C for 24 h, the samples were measured with the e-nose. The concencolloids, such as sodium carboxymethyl cellu- tration was determined with interpolation on the 0, 1250, and 2500 ppm lose. The authors believe that the absorption generated calibration curve. All samples were measured in triplicate. of wound fluid (or other body fluid, dependBy combining cyclodextrins with aqueous absorbing ing on how the product is to be used) by the conventional hydrocolloid provides the moisture in the adhesive agents within the adhesive matrix, a synergistic combinato activate the odor absorbing properties of the tion that absorbs odor molecules at rates and amounts cyclodextrin in situ, thus, the hydrocolloid and the comparable to the performance of charcoal based cyclodextrin act synergistically to provide both fluid and absorbents has been created. The hydrocolloid composition created also possesses other advantages over charodor absorbency. coal based materials. The water necessary for the Results and Discussion cyclodextrin to function will normally be present in the The effect of water concentration on the odor absorp- wound fluid, or in contaminating urine or feces, or even tion by the pure cyclodextrins as well as by hydrocolloid be released by the skin through normal transpiration. It is adhesives containing these cyclodextrins was studied. through absorption of this water by the adhesive that it is This was done by placing the odor absorbent material in made available to activate the cyclodextrin for odor a vial, adding 5 µL of the test odor and a variable amount absorption. The choice of cyclodextrin employed in a of water with micropipettes. The vial was then held at given formulation may be decided on the basis of the 31˚C overnight and the residual odor concentration properties desired in the finished product, and the spedetermined after 24 hours. Table 1 shows the effect of cific role that the cyclodextrin is expected to fulfill. water in facilitating n-butyric acid complexation by the Unmodified β-cyclodextrin is not very water-soluble and cyclodextrin, sodium carboxymethylcellulose (a polysac- is generally not preferred if high odor absorbency is charide usually present in most hydrocolloid composi- needed.Alpha-cyclodextrins, γ-cyclodextrins, and certain tions), and by the adhesive containing the cyclodextrin. modified β-cyclodextrins are more water soluble and Also shown in the same table is the effect of cyclodextrin more appropriate for clinical use. Mixtures of cyclodexcavity size on n-butyric acid absorption.The smaller cav- trins are often preferred, because these will absorb a ity of the α-cyclodextrin is a more effective absorber wider range of malodorous molecules than will a single than the β-cyclodextrin, while the γ-cyclodextrin cavity is cyclodextrin.The cyclodextrins to be used for a specific odor will, of course, be determined by the size, shape, too large to effectively immobilize the butyric acid. Vol. 19, No. 5 May 2007

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and polarity of the active molecules to be absorbed. Table 2 shows a general comparison of the performance of % absorbed, 24 h Actisorb Carboflex Carbonet D1-76A* D1-120C* prototype cyclodextrin adhe93 87 100 100 95 Valeric acid, 2500 ppm sives (D1-76A and D1-120C) 88 84 100 90 87 Butyric acid, 2500 ppm with commercially available 100 73 100 100 100 Cadaverine, 5000 ppm charcoal based dressings. The 100 73 100 100 77 Putrescine, 5000 ppm superior fluid absorption of the The aim is to compare 3 commercial charcoal dressings with cyclodextrin containing cyclodextrin-containing adhehydrocolloid adhesives (D1-76A and D1-120C). The odor absorption of the cyclodextrin sive is evident. containing hydrocolloids is clearly proven. However, in general the efficiency to remove The new hydrocolloid adheodors in the saline medium is higher for charcoal dressings. Note that the saline solution is not a surrogate for real wound fluid. sive is much thinner and, thus, more conformable for the Test conditions: A 5 cm x 5 cm sample of each charcoal dressing was cut and placed in patient than commercially availthe test tube. Two grams of D1-76A and D1-120C was weighed; this equals a 5 cm x able charcoal dressings while the 5 cm hydrocolloid dressing of 0.6-mm thickness. To each tube, 2 mL of saline solution fluid absorption can be up to 3 with test odor was added. The concentrations of the test odors are shown in the table. After incubating the tubes at 31˚C for 24 h, the samples were measured with the etimes higher. nose. The concentration was determined via interpolation on the generated calibration However, as has been reportcurve for each odor. All samples were measured in triplicate. ed previously,4 the odor absorbing ability of charcoal-based Table 2b. Fluid absorption at 25˚C after 24 h. dressings is inhibited by wound % absorbed, 24 h Actisorb Carboflex Carbonet D1-76A* D1-120C* serum.The ability of charcoal to absorb butyric acids drops 1263 4208 1323 942 3500 Saline, g/m2 3.80 1.10 3.20 0.77 1.10 Dressing thickness, mm when the charcoal is first treated with new-born calf serum,4 *Sterilized with gamma radiation at > 25 Kgy. Hydrocolloids outperformed charcoal dressings with respect to fluid absorption. due to nonspecific adsorption of protein and peptides that Table 3. Percentage butyric acid absorbed from a 2500 ppm solu- block the active adsorption sites on the chartion as a function of medium: physiological saline versus newborn coal surface. Because of this, charcoal dresscalf serum. ings are best designed with a number of layD1-76A* Actisorb Carboflex Carbonet ers to keep the wound exudate from contacting the odor-absorbing layer. This study 100% saline 88 93 88 100 compared the ability of several commercial 50%/50% serum/saline 98 86 80 100 charcoal based dressings—Actisorb® 100% serum 100 77 83 93 (Johnson & Johnson Medical Limited, *cyclodextrin containing adhesive, sterilized with gamma radiation at Gargrave UK), CarboFlex® (ConvaTec, > 25 Kgy. Deeside UK), Carbonet® (Smith and The odor absorption capacity for the charcoal dressings drops as serum is Nephew, Hull, UK)—to absorb odor from a added. Cyclodextrin containing hydrocolloids (D1-76A) perform better calf serum medium.This study also measured than charcoal dressings in the presence of newborn calf serum, a reprethe odor absorbing ability of a cyclodextrinsentative surrogate for wound exudate. based adhesive using the same calf serum Test conditions: A 5 cm x 5 cm sample of each charcoal dressing was cut medium. and placed in the test tube. Two grams of D1-76A was weighed; this A graduated series of media, with increasequals a 5 cm x 5 cm hydrocolloid dressing of 0.6-mm thickness. To each ing levels of serum, were used in these tube, 4 mL of saline solution, 50%/50% serum/saline or 100% serum experiments. The media used consisted of with 2500 ppm test odor was added. After incubating the tubes at 31˚C for 24 h, the samples were measured with the e-nose. The concentration 100% saline, 50%/50% saline/serum, and was determined via interpolation on a calibration curve prepared for the 100% serum. As the amount of serum was test odor. All samples were measured in triplicate. increased, the odor absorption performance

Table 2a. Comparison of commercially available charcoal dressings with prototypes of cyclodextrin containing hydrocolloids with respect to odor uptake and saline absorption.

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Table 4. Stability of cyclodextrin containing hydrocolloid MED9150H. % absorbed Valeric acid Butyric acid Actisorb (as obtained commercially) Carbonet (as obtained commercially) Carboflex (as obtained commercially) MED9150H 25KGy RT unaged lot 0249 MED9150H 25KGy 50˚C 13 weeks lot 0249 MED9150H 25KGy 50˚C 13 weeks lot 0250 MED9150H 50KGy RT lot 0249 MED9150H 50KGy RT lot 0250

91 89 88 96 98 95 95 93

78 93 85 87 93 94 84 91

Comparison of aged MED9150H with un-aged charcoal dressings. The percent of test odors absorbed from 4 mL serum containing 2500 ppm nbutyric acid or valeric acid is shown in the table. Severe circumstances (like storage at 50˚C for 13 weeks and sterilization at 50 kGy) do not affect the odor absorption capacity of the cyclodextrin containing hydrocolloid. Test conditions: A 5 cm x 5 cm sample of each type of charcoal dressing was cut and placed in the test tube. For MED9150H a 5 cm x 5 cm dressing was cut, this equals 2 g of hydrocolloid. To each test tube, 4 mL of 100% serum with 2500 ppm test odor was added. After incubating the tubes at 31˚C for 24 h, the samples were measured with the e-nose. The concentration was determined via interpolation on a calibration curve prepared for each odor. MED9150H was sterilized at 25 or 50kGy. All samples were measured in triplicate.

serum, a good surrogate of real wound fluid; the novel cyclodextrin based hydrocolloid adhesive (D1-76A) outperformed the 3 commercial charcoal products. These data are shown in Table 3. The authors believe that serum protein may enable the odor absorption capacity of the cyclodextrins by binding to the more hydrophilic external surface of the cyclodextrin cavity, and thereby, may modify its ability to absorb polar odor molecules. It is well known that covalent attachment of similar polar moieties to cyclodextrin structures modifies dramatically the ability of cyclodextrins to deliver certain drug actives. This is discussed in detail in the review by Loftsson et al.9

Development of Final Product for the Clinic

Conclusions from the above data were used to formulate MED9150H, a commercial cyclodextrin-containing hydrocolloid formulation. MED9150H is an island dressing, which is composed of a 0.3 Table 5. Comparison of MED9150H with competitive hydrocolloids with respect mm standard hydrocolloid top layer and is covered by a to fluid and odor absorption. polyurethane carrier. The % absorbed MED9150H island consists of a Thickness Fluid absorption, Valeric Acid Butyric acid 0.3 mm cyclodextrin-containg/m2/24 h (mm) ing hydrocolloid. Evaluations were based on the odor absorb0.60 MED9150H ing performance of this new 95 2525 93 0.53 3M Tegasorb Thin 76 2202 83 construction and charcoal conConvaTec Duoderm Extra Thin 0.61 74 1684 63 taining dressings in calf serum. Cyclodextrin containing hydrocolloid MED 9150H outperforms commercial hydrocolThe MED9150H odor absorbenloids with comparable thickness with respect to odor absorption and saline uptake. A cy was measured after sterilizapsychosensory test confirmed that MED9150H keeps the odor in a irreversible way, tion to 25 and 50 KGy, and after while the odor is released continuously by the commercial products. aging at 13 weeks at 50˚C. These severe conditions did Test conditions: A 5 cm x 5 cm sample of each dressing was cut and placed in the test tube. To each tube, 4 mL of 100% serum with 2500 ppm test odor was added. The not affect the odor absorbency concentrations of the test odors are given in the table. After incubating the tubes at of MED9150H, which performs 31˚C for 24 h, the samples were measured with the e-nose. The concentration was generally better than the 3 determined via interpolation on a calibration curve prepared for both odors. All samcommercial dressings. The perples were measured in triplicate. Med 9150H has been gamma irradiated at 25 kGy. data on the formance MED9150H formulation appear of the cyclodextrin-based material was enhanced, while in Table 4.To obtain the data of Table 4 the e-nose was the performance of all 3 commercial charcoal based calibrated with 0 ppm, 1250 ppm, and 2500 ppm nproducts was negatively affected. In 100% newborn calf butyric and valeric acids. Two grams of hydrocolloid Vol. 19, No. 5 May 2007

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Patient 1. An 81-year-old woman with a foot wound.

A: the left heel on April 20, 2005 B: inner aspect of the knee on April 20, 2005 C: inner aspect of the knee on May 4, 2005

Patient 2. A 74-year-old woman with diabetes, bilateral amputation, and sacral wounds.

D: The sacral pressure ulcer on April 20, 2005 E: The same ulcer on May 4, 2005 F: A pressure ulcer on the right ischium G: The same ulcer on May 4, 2005 looking much improved

Figure 2. Cyclodextrin-containing hydrocolloid dressings used in a pilot study on 2 patients.

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were used and a 25-cm2 sample size was taken for the commercial charcoal dressings. The MED9150H was compared in odor absorbency and fluid absorbency to Tegasorb (3M Health Care, St. Paul, Minn) and DuoDerm Extra Thin (ConvaTec, Deeside, UK). The data in Table 5 show MED9150H to have significantly greater fluid absorption in vitro and dramatically superior odor absorbency. The data of Table 5 bring out an important limitation of the test method the authors have used to date.The test method is a dynamic technique.Air sweeps the contents of the headspace over the sensors, and thus, determines only the instantaneous concentration of odor in the headspace. The method as used says nothing about the way in which the odor is bound to the adhesive, nothing about the propensity of the odor absorbed on or in the adhesive to leach out over time. This factor has been investigated for the 3 adhesives shown in Table 5 using an adjunct psychosensory determination. Using a trained panel of observers to assess headspace odor in the vials 24 hours after the test data in Table 5 were obtained, no perception of odor in the vials containing MED9150H was found, while the odor is readily perceivable in the headspace above the Tegasorb and DuoDerm samples. Psychosensory evaluation confirms that the test odors are bound to the MED9150H adhesive in an irreversible manner. A separate study is being organized to evaluate in more depth this time effect.

Clinical Use Profile

absorbing adhesive compositions. The results suggest that these cyclodextrin materials provide a new method of controlling some of the problem odors associated with wound care and ostomy care.The new formulation MED9150H possesses the key features of fluid handling along with odor absorbency, while the traditional odor absorbing charcoal containing products seem to be noticeably short on fluid handling properties. The data also suggest that in the presence of wound serum, these new materials may outperform conventional charcoal based products in odor control. Comparison against conventional hydrocolloid dressings showed similar or better fluid handling capability, and notably better ability to absorb odors.The mechanism through which the odor is absorbed by the cyclodextrin molecule is the familiar host-guest physicochemical interaction process seen with cyclic molecules, such as cyclodextrin. The presence of serum may be accentuating these odor-absorbing interactions in the formulations tested. Early in-vivo performance with hydrocolloid dressings based on these materials appears to confirm the laboratory performance. Further studies that are randomized and controlled are in progress on this novel MED9150H formulation. Wound care dressings using this technology are being introduced into the market by Medline Industries Inc (Mundelein, Ill) under the brand name Exuderm Odorshield®.

Acknowledgement The authors are grateful to Avery Dennison Medical for their support and for permission to publish this manuscript.

The cyclodextrin-containing hydrocolloid dressings were used in a pilot trial on 2 patients with pressure ulcers.The results are shown in Figure 2. Patient 1 is an 81-year-old woman with a foot wound. Patient 2 is a 74year-old woman with diabetes, bilateral amputation, and sacral wounds. The clinical nurse made the following anecdotal comments,“The second lady has very bad skin and has cream applied but it is evident how much better the skin is underneath where the dressing has been. There is absolutely no odor at all with either patient despite the softening of the necrotic tissue. Normally it would be expected that odors characteristic of both dressing and wounds would be discernible” (personal communication, June 2005).

2.

Conclusion

4.

This report describes initial results on new odor

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