Contact medium

Abstract

The present invention relates to a contact medium for use in medical and non-medical sonography, electrocardiography, electroencephalography, or defibrillation comprising 0.05-2.5% by weight of a gel-forming agent, 0.05-3.5% by weight of a cleaning agent, and 0.1-4.0% by weight of an emulsifier and optionally additives, with the remaining components being water.

Description

Technical Field

[0001] The present invention relates to a coupling medium preferably used in medical sonography. However, the coupling medium according to the present invention can also be used in non-medical methods for the inspection of technical structures by ultrasound, as well as in other medical procedures that do not rely on ultrasound but require a coupling medium.

Background Art

[0002] Sonography, also known as echography or ultrasound examination, is an imaging procedure for the non-destructive inspection of organic or technical structures based on the fact that combined sound waves in different media propagate at different speeds and are partially reflected at interfaces with different wave impedances. Wave impedance refers to the resistance to the propagation of waves. The greater the difference in wave impedance at the interface, the greater the reflected portion of the combined wave. The flight time and intensity of the reflected wave are detected and converted into structural information.

[0003] For example, compared with X-ray examination in computed tomography (CT), an important advantage of sonography in medical imaging diagnosis is the harmlessness of the sound waves used. The equipment-related expenditure and associated costs, as well as the required space, are also generally significantly less for sonography than for computed tomography or magnetic resonance imaging. Therefore, sonography diagnosis is also used in small-scale medical practices that can provide sufficiently meaningful information.

[0004] In medical sonography, not only for the examination of organic structures such as tissues, organs, blood vessels, bones, etc., but also for the visualization of blood flow velocity by methods such as Doppler, ultrasound in the frequency range of about 1 to 40 MHz is used. The ultrasound is generated within the probe and is typically introduced into the body as short, directional sound wave impulses through the surface. The reflected wave is received by a detector. The detector is usually arranged within the probe, converted into an electrical signal, and processed. Information regarding the examined structure is determined from the flight time and the intensity of the reflected wave.

[0005] In addition to tests where the probe is inserted into the vascular system, for example, through body openings (vaginal, rectal) or catheters, acoustic impulses are introduced externally into the body in most applications of sonography. Here, the probe head is usually manually placed on the patient's skin by the physician performing the examination, moved across it, and tilted to various angular positions.

[0006] The difference in acoustic impedance between air and water or organic structures containing skin is very large (air: approximately 410 kg / m 2 s; skin, fat, water, muscle: > 106 kg / m 2 s), so the ultrasonic probe needs to be coupled to the skin via an aqueous contact medium so that sound is not already reflected by air pockets between the probe head and the skin surface, which exist due to skin irregularities and hair loss.

[0007] The same applies to other test methods where air pockets can interfere with the measurement, such as ultrasonic material testing of non-organic technical structures, or tests for measuring very low currents, such as CG or EEG tests, where the measurement is greatly distorted or made impossible because the electrical resistance becomes very high when air is mixed in.

[0008] In medical sonography, a viscous aqueous gel produced according to various formulations is mainly used as a contact medium for attaching the probe head to the skin surface. Such gels can be costly to manufacture due to their components and have other drawbacks. For example, due to their viscosity, generally more gel than necessary is applied. Therefore, the consumption of the gel is high and the cost increases. Viscous gels often stain the clothes of patients who are not fully undressed, consume a large amount of paper for wiping the gel, incur additional costs, and need to be discarded. In many cases, patients feel that the contact medium is unpleasantly cold. Therefore, it is desirable to be able to preheat the contact medium on the patient's skin before application. However, with conventional viscous gels, this can change the physical properties and lead to uncontrolled drainage and film breakage. The application of viscous gels is usually done from a soft-walled disposable plastic container from which the gel can be extruded. After use, these disposable containers are usually discarded, and a significant amount of the gel remaining in the container is often discarded unused. When applying the gel from the opening of the container, there is always a risk of touching the patient's skin as a result of bacterial infection between patients.

[0009] During a sonography examination, the probe head must be moved on the skin, so in addition to good film formation that completely covers the skin area to be examined, good sliding ability is also required. Since viscous gels fully meet these requirements, they are still mainly used despite the above-mentioned drawbacks. However, in principle, only a thin contact medium film is required for the attachment between the probe head and the skin.

[0010] DE 44 34 626 C2 describes a highly fluid ultrasonic contact medium that contains, in addition to water, a detergent content of 0.5 to 10% by volume and an ethanol content of 1 to 25% by volume. Here, satisfactory products are obtained only with a detergent content of 1% by volume and an ethanol content of 3 - 5% by volume. The said products form a permanent liquid film with good slip properties and sound wave transmission corresponding to that of commercially available viscous contact medium gels. However, the contact medium was not acceptable to users and manufacturers of ultrasonic devices because of its high ethanol content required for sufficient film formation. With long-term use, there is a risk that the ethanol component may attack the material of the probe head. Furthermore, the evaporation of ethanol during application causes an unpleasant cold sensation to the patient and an undesirable alcohol odor.

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, the problem addressed by the present invention was to provide a new contact medium that overcomes, or at least mitigates, the drawbacks of known contact media, particularly in medical sonography.

Means for Solving the Problems

[0012] This problem is solved by the following: 0.05 - 2.5% by weight of a gelling agent, 0.1 - 4.0% by weight of a detergent, 0.1 - 4.0% by weight of an emulsifier, Optionally additives, preferably selected from preservatives, acidifying agents, skin care additives, and mixtures thereof, and Water as the remaining component, wherein the gelling agent is selected from the group consisting of hydroxyethyl cellulose, carboxymethyl cellulose, xanthan gum, guar gum, collagen, gelatin, pectin, chitin, starch, sodium alginate, potassium alginate, and calcium alginate, and mixtures thereof, The cleaning agent is a nonionic surfactant or a mixture of nonionic surfactants, The emulsifier is selected from the group consisting of glycerol monofatty acid esters and glycerol difatty acid esters and mixtures thereof, wherein the remaining fatty acids are preferably C7-C20-saturated fatty acids, C16-C20-mono-unsaturated fatty acids, and / or C18-C20-di-unsaturated fatty acids, preferably stearic acid, oleic acid, caprylic acid, capric acid, and / or linolenic acid. It is solved by a contact medium having a pH value in the range of 5 to 7.

Mode for Carrying Out the Invention

[0013] The contact medium according to the present invention has higher fluidity than conventional contact gels and thus has a lower viscosity, i.e., higher fluidity. The viscosity, i.e., fluidity, of the contact medium according to the present invention can be adjusted by selecting the components used, in particular the amount of the gelling agent. The determination of the fluidity of the contact medium according to the present invention is carried out herein in accordance with ISO 2431 (DIN EN ISO 2431:2020-02) at room temperature (25°C) and, where applicable, body temperature (37°C) using an ISO outflow beaker No 4 equipped with a nozzle of 4 mm diameter by measuring the outflow time of a 100 ml measured amount of the contact medium composition. According to a preferred embodiment, the contact medium according to the present invention has an outflow time thus determined in the range of 5 to 200 seconds at 25°C, preferably in the range of 10 to 150 seconds, particularly preferably in the range of 10 to 100 seconds, and very particularly preferably in the range of 10 to 50 seconds.

[0014] If the viscosity of the contact medium according to the present invention is too low, insufficient film formation is achieved and there is a risk of film breakage. If the viscosity of the contact medium according to the present invention is too high, the described disadvantages of the viscous contact medium gel occur.

[0015] When used in medical sonography, the contact medium according to the present invention forms a thin contact medium film that covers the skin area to be treated well and seamlessly, without significant film breakage, despite its high fluidity, i.e., low viscosity on the skin. At the same time, it ensures good gliding ability of the probe head on the skin. The sound wave transmission of the contact medium according to the present invention is comparable to that of commercially available viscous contact medium gels and may even be superior depending on the composition.

[0016] Furthermore, the contact medium according to the present invention can be easily removed from the skin and requires a relatively small amount, resulting in less paper consumption compared to commercially available contact gels.

[0017] A further specific advantage of the contact medium according to the present invention is that it can be applied with an applicator suitable for highly fluid media, such as a commercially available spray bottle. Since the spray bottle can be refilled and reused after the contact medium is used up, it can save package waste. The application of the contact medium using a spray bottle also reduces the risk of carrying bacteria from one patient to the next by avoiding contact with the patient's skin. For example, the contact medium can be refilled from a large container. Therefore, there is no unusable contact medium left in the disposable applicator as in the case of viscous contact medium gels sold and used with disposable applicators that have to be discarded.

[0018] Furthermore, the contact medium according to the present invention can be manufactured more cost - effectively than commercially available contact medium gels by using inexpensive components.

[0019] The contact medium according to the present invention can contain a gelling agent in an amount between 0.05 and 2.5% by weight. When the proportion of the gelling agent exceeds 0.5 - 2.5% by weight, the contact medium can already have a viscosity close to that of commercially available contact gels depending on the gelling agent used. In this case, while having the above - mentioned advantages, the contact medium can be thinly applied.

[0020] However, according to a particularly preferred embodiment, the contacting medium according to the invention contains the gelling agent in an amount of 0.05 to 0.5% by weight. Such a contacting medium according to the invention is particularly highly fluid, has all the advantages described herein, and in particular can be applied very effectively, for example by means of a spray bottle. Furthermore, since less gelling agent is required, the cost-effectiveness of production is increased.

[0021] In addition to the gelling agent, the detergent and the emulsifier, the contacting medium according to the invention can optionally contain further additives such as preservatives, buffers or acidifying agents, skin care additives, etc. Such additives can be used advantageously, but can be used in such small amounts that they do not impair, or at least do not significantly impair, the advantageous properties of the contacting medium, such as flow and film-forming properties, slip ability, and sound wave transmission.

[0022] According to one embodiment, the contacting medium according to the invention contains a preservative, preferably in an amount of 0.05 to 1.0% by weight, where the preservative is particularly preferably selected from the group consisting of sodium benzoate, potassium benzoate, sodium sorbate, potassium sorbate, and mixtures thereof. If there is too little preservative, there is no preservative effect or it is too little. If the ratio is too high, no substantial additional preservation effect is obtained and / or it may adversely affect the physical and / or chemical properties of the contacting medium. According to one advantageous embodiment of the invention, the contacting medium contains a mixture of about 0.3 to 0.5% by weight of sodium benzoate and about 0.1 to 0.3% by weight of potassium sorbate. The addition of the preservative improves the durability and shelf life of the contacting medium according to the invention without significantly impairing further advantageous properties.

[0023] The contact medium according to the invention has a pH level in the range of 5 to 7. Thus, this medium is already well tolerated by the skin. Furthermore, it has been shown that a pH level in the range of 5 to 7 stabilizes the advantageous physical and chemical properties of the contact medium achieved by the combination of the gelling agent, detergent, and emulsifier according to the invention. According to a further advantageous embodiment of the invention, the contact medium has a pH level in the range of 5 to 6.5, preferably in the range of 5 to 6, particularly preferably in the range of 5 to 5.6. In many cases, a pH level in the range of 5 to 6, and even a lower pH level of 5.6 or less, is advantageous. This is because, inter alia, a better preservation effect is obtained in the presence of preservatives than at a high pH level.

[0024] Depending on the choice and amount of the gelling agent, detergent, emulsifier, and additives used, it may be necessary to lower or buffer the pH level. Thus, according to one embodiment, the contact medium according to the invention contains an inorganic or organic buffer system or acidifying agent for adjusting and / or buffering the pH level. A suitable acidifying agent according to the invention is citric acid. Suitable buffer systems according to the invention are sodium citrate-citric acid buffer or phosphate-citric acid buffer, for example disodium phosphate-citric acid buffer. The amount of the required buffer or acidifying agent is small and is routinely determined by those skilled in the art. In experiments, for example, it has been proven that an amount of 2% by weight of citric acid is suitable for lowering the pH level of the composition according to the invention to 5.6.

[0025] Furthermore, the contact medium according to the invention can advantageously contain skin care additives. Suitable skin care additives are known to those skilled in the art from the field of cosmetics and medical and non-medical skin care products. Advantageous skin care additives according to the invention are, for example, aloe vera alone or a mixture with other skin care additives. The amount of the skin care additive added should be routinely selected so as to achieve the desired skin care effect without significantly impairing the advantageous properties of the contact medium according to the invention.

[0026] When combined, the substantial components of the contacting medium according to the invention that achieve the physical and chemical properties of the contacting medium advantageous for the uses described herein are a gelling agent, a detergent, and an emulsifier.

[0027] Particularly suitable and preferred gelling agents according to the invention are hydroxyethylcellulose, preferably 2-hydroxyethylcellulose (CAS# 9004-62-0) having an average degree of substitution (DS) of 0.85 to 1.35 and / or a molar degree of substitution (MS) of 1.5 to 3.0. The gelling agent can be used alone or in admixture with more of the aforementioned gelling agents. Hydroxyethylcellulose particularly suitable as the gelling agent according to the invention is commercially available under the names Natrosol® (Ashland Inc.), Cellosize® (Dow Chemical), and Tylose® (Shin-Etsu). In the examples described below, the product Natrosol® 250 HX was used.

[0028] According to a preferred embodiment of the contacting medium according to the invention, 80% by weight or more, preferably 90% by weight or more, of the gelling agent is hydroxyethylcellulose. According to an even more preferred embodiment of the contacting medium according to the invention, the entire gelling agent is hydroxyethylcellulose.

[0029] According to one advantageous embodiment, the contacting medium according to the invention contains 0.1 to 0.3% by weight of the gelling agent. Surprisingly, in combination with the detergents and emulsifiers according to the invention, it has been shown that such a small amount of the gelling agent can be sufficient to obtain a contacting medium having the properties and advantages described herein, in particular excellent film-forming properties, sliding ability, and sound wave transmission.

[0030] The cleaning agent is a nonionic surfactant or a mixture of nonionic surfactants. Those skilled in the art with knowledge of the present invention can select an appropriate nonionic surfactant. Preferably, the cleaning agent is selected from the group consisting of polyethoxylated castor oil, poloxamer, and mixtures thereof. According to a preferred embodiment of the contact medium according to the present invention, 80% by weight or more, preferably 90% by weight or more of the detergent is polyethoxylated castor oil. According to an even more preferred embodiment of the contact medium according to the present invention, the entire cleaning agent is polyethoxylated castor oil commercially available under the name Cremophor® or Kolliphor®. In the following examples, the product Kolliphor® RH40 (alias Cremophor® RH40; macrogol glycerol hydroxystearate, PEG-40 castor oil; CAS number: 61788-85-0; Merck KGaA, Darmstadt, Germany) was used.

[0031] According to one advantageous embodiment, the contact medium according to the present invention contains 0.075 to 0.5% by weight of the cleaning agent. Surprisingly, it has been shown that such a small amount of the cleaning agent may be sufficient to obtain the contact medium in the composition according to the present invention having the properties and advantages described herein, in particular excellent film-forming properties, sliding ability and sound wave transmission.

[0032] The emulsifier is selected from the group consisting of glycerol monofatty acid esters and glycerol difatty acid esters and mixtures thereof, wherein the remaining fatty acids preferably originate from C7-C20-saturated fatty acids, C16-C20-mono-unsaturated fatty acids, and / or C18-C20-di-unsaturated fatty acids, preferably stearic acid, oleic acid, caprylic acid, capric acid and / or linolenic acid.

[0033] According to a preferred embodiment of the contacting medium according to the present invention, 80% by weight or more, preferably 90% by weight or more of the emulsifier is glycerol monofatty acid ester. According to a more preferred embodiment of the contacting medium according to the present invention, the entire emulsifier is glycerol monofatty acid ester. Suitable commercially available emulsifiers according to the present invention can be obtained under the name Imwitor®. In the examples described below, the product Imwitor® 742, glycerol monocaprylocaprate (macrogol-6-glycerol caprylocaprate) available from IOI Oleo GmbH (Hamburg, Germany) was used.

[0034] According to one advantageous embodiment, the contacting medium according to the present invention contains 0.2 to 0.8% by weight of an emulsifier. Surprisingly, it has been shown that such a small amount of emulsifier may be sufficient to obtain the contacting medium in the composition according to the present invention having the properties and advantages described herein, in particular excellent film-forming properties, sliding ability and sound wave transmission.

[0035] According to a further advantageous embodiment, the contacting medium according to the present invention contains 0.1 to 0.3% by weight of a gelling agent, 0.075 to 0.5% by weight of a detergent, and 0.2 to 0.8% by weight of an emulsifier.

[0036] The contacting medium according to the invention exhibits its advantageous properties completely based on water, with a low material usage, thus enabling inexpensive production and its high fluidity, i.e., low viscosity compared to commercially available contacting medium gels. The addition of monohydric alkanols, especially ethanol, as an additional component is not necessary. Thus, the contacting medium according to the invention requires ethanol in a proportion of 3 to 5% by volume to obtain satisfactory products with respect to film formation and sound wave transmission, but also has advantages compared to known highly fluid contacting media that are unacceptable to users and manufacturers of ultrasonic devices due to the ethanol content. A small amount of ethanol is not destructive in the contacting medium according to the invention, but does not bring further advantages; rather, it brings known disadvantages. Therefore, it is expedient that the contacting medium according to the invention contains at most 1% by weight, preferably at most 0.5% by weight, of monohydric alkanol, and particularly preferably does not contain monohydric alkanol.

[0037] The advantageous properties of the contacting medium according to the invention are achieved only when the components of the gelling agent, detergent, and emulsifier are combined at the concentrations according to the invention. The respective chemical and physical properties of these components were generally known. What was unexpected and thus surprising was the combination according to the invention and their cooperation at the low concentrations according to the invention to form a contacting medium having excellent properties, especially in sonography. The effect of the components in the contacting medium according to the invention exceeds the mere additive effect of the properties of the individual components. This effect is demonstrated by the results of the following examples. In fact, since the properties of the individual components were known, disadvantages were expected for the combination of the components. Therefore, the advantageous properties of the contacting medium according to the invention are considered to be based on a synergistic effect of the components, an effect that was not itself expected. This effect was confirmed by experiments in which individual components were omitted or used at concentrations outside the scope of the invention.

[0038] For example, in a conventional contact medium gel, the formation of a continuous contact medium film and the good gliding ability of the ultrasonic probe head on the skin are substantially due to a high concentration of the gelling agent. In order to achieve a consistency of higher fluidity or lower viscosity than the conventional contact medium gel, if the concentration of the gelling agent is significantly lowered, it was initially expected that the film formation and sliding properties would deteriorate. In fact, with the low-concentration gelling agent according to the present invention, even without two additional components of a detergent and an emulsifier, the formation of spherical gel droplets and even the formation of bubbles are observed, which is contrary to the compatibility as a contact medium for sonography. The addition of the detergent according to the present invention reduced the formation of spherical gel droplets that may be due to a change in surface tension, but the film formation characteristics were still insufficient. Furthermore, since a significant amount of bubbles (bubble formation) were formed, this combination of the gelling agent and the detergent does not seem to be usable as a contact medium for sonography because the contact medium is for eliminating the destructive influence of air pockets when coupling sound waves to the skin. When only the emulsifier was added to the gelling agent, the film formation characteristics were slightly improved, but the formation of droplets and bubbles was still observed. Only in the combination according to the present invention of the gelling agent, the detergent, and the emulsifier were particularly good film formation and sliding characteristics, a significant reduction or disappearance of destructive bubbles, and good sound wave transmission found, despite the low concentration.

[0039] Due to the small amount of material used and thus the ability to be manufactured inexpensively, the combination according to the present invention has sound wave transmission characteristics equal to or better than those of commercially available contact gels, and at the same time, has high fluidity such as sprayability, no significant film breakage or good gliding ability, and covers the treated skin area completely, resulting in a contact medium having advantages in handling and use. The advantageous properties of the contact medium according to the present invention are retained even when the contact medium is heated to at least a temperature at which the patient feels comfortable, for example, 37 °C (body temperature). Furthermore, when using a contact medium sprayed from a distance, the risk of bacterial infection is very low.

Examples

[0040] In the test series, different compositions of gelling agents, detergents, and / or emulsifiers were produced individually, in different combinations, and at different concentrations, and their properties such as film formation, wetting, durability of the contact medium film, bubble formation, sprayability from a pump spray bottle, glide properties (including the ability to glide on the skin with the probe head), and suitability as a contact medium for sonography (sound wave transmission) were investigated. These properties of the compositions were tested using both a patient "in vitro" model and an "in vivo" model.

[0041] In vitro model In the in vitro model, the patient's skin was simulated by a commercially available office film wrapper with a slightly rough surface, and the contact surface of the probe head was simulated by a film wrapper with a particularly smooth surface. The formation, uniformity, and durability of the contact medium film were tested on an office foil wrapper with a slightly rough surface. The uniformity of the contact medium film was evaluated visually, and the durability was evaluated through observation over time. The glide properties of the contact medium were also tested and compared by rubbing the composition with a disposable PE glove. The formation or absence of bubbles was evaluated visually.

[0042] Sprayability was evaluated by observing the spray cone emerging from the nozzle when spraying the composition from a commercially available spray bottle. Good sprayability was assumed at a spray cone angle of approximately 30°, and very good sprayability was assumed at a spray cone angle of 50°.

[0043] In vivo model In the patient "in vivo" model, the properties of the composition were tested as a contact medium in the same way as conventional sonography. The sound wave transmission properties of the contact medium were visually evaluated by comparing the obtained sonography images with those obtained using a commercially available contact medium gel (Sonogel, Sonogel Vertriebs GmbH) used in medical sonography. In the same patient, prominent organ structures of the same organ were imaged with contact media of different compositions.

[0044] The formation of a bubble-free, uniform liquid film and the sliding ability of the probe head were also evaluated in an in vivo model of the patient, and the support of the liquid film when exceeding the limits of the wetted area was also evaluated.

[0045] Preparation of the composition In the experiments described below, the following components were used to prepare the composition: a) Gel former: hydroxyethyl cellulose (Natrosol® 250HX) b) Detergent: polyethoxylated castor oil (Kolliphor® RH40, CAS# 61788-85-0) c) Emulsifier: glycerol monocaprylocaprate (Imwitor® 742).

[0046] The gel former Natrosol is present as a powder, and the detergent Kolliphor and the emulsifier Imwitor are present as waxy masses. Imwitor is homogenized in a heating chamber at 60 °C for about 12 hours before the start of production. Kolliphor and water (distilled water) are also preheated to 60 °C. While stirring, the preheated Imwitor at 60 °C is first added to water while stirring, and then Kolliphor is added while stirring. Subsequently, a small amount of Natrosol powder is gradually introduced while stirring strongly to avoid aggregation. The composition is stirred until homogeneous and then cooled and left to stand until the bubbles formed during production collapse. Next, the composition can be filled and, if appropriate, sterilized in an autoclave.

[0047] Additives such as preservatives can be introduced after the addition of Kolliphor and / or after the stirring of Natrosol and dissolved by stirring. The pH level can be adjusted by measuring the ongoing pH level and adding an acid or buffer, such as citric acid, after the addition of Kolliphor and / or after the stirring of Natrosol. Approximately 1.5 - 2.0 wt% citric acid was used in the conventional composition to achieve a pH level of about 5.5 - 5.6.

[0048] Example 1 In the test series, the individual components according to the invention (gel former, detergent, and emulsifier), combinations of two components, and combinations of all three components were first investigated and evaluated in different compositions with respect to different properties (A - I). The investigated and evaluated properties (A - I) and evaluation criteria are summarized in Table 1 below. The results are shown in Tables 2 and 3 below.

[0049]

Table 1

[0050]

Table 2

[0051]

Table 3-1

Table 3-2

[0052] Example 2 From the compositions in Table 3 of Example 1, promising mixtures were selected, further diluted, and tested "in vivo" on the skin of patients. The acoustic transmission properties were equally good for all mixtures.

[0053] The selected compositions were investigated and evaluated for various properties (J - N). A commercially available contact medium gel (Sonogel, Sonogel Vertriebs GmbH) was used as a comparative composition. The investigated and evaluated properties (J - N) and evaluation criteria are summarized in Table 4 below, and the results are shown in Table 5 below.

[0054]

Table 4

[0055] Example 3 Based on Composition #28 (0.5% Imwitor, 0.125% Kolliphor, 0.2% Natrosol) from Example 2, Table 5, water was added to prepare various dilutions (#28 / water: 2 / 1 = 66%; 1 / 1 = 50%; 1 / 2 = 33%). The spraying behavior was evaluated in comparison with the undiluted composition (1 / 0 = 100%). The pH level of the composition was 5.9. After the previous Test A, no foam formation was observed in any of the compositions.

[0056] In a further step, the dilutions and the undiluted composition were mixed with a preservative (0.4 wt% sodium benzoate + 0.15 wt% potassium sorbate), different concentrations of citric acid were added, and the pH level was measured again. The addition of the preservative did not change the starting pH level of the composition. The results are shown in Table 6 below.

[0057] Example 4 The composition #28 (0.5% Imwitor, 0.125% Kolliphor, 0.2% Natrosol) from Example 3 and its dilutions were evaluated for spraying characteristics, film formation, and gliding ability according to Tests J, K, M, and N of Example 2. Furthermore, 0.8 mL of the composition was spread over a skin surface area of 20 cm 2 and the loss of substance was evaluated by drying, measuring the surface loss after 1 hour at ambient temperature. The results are shown in Table 7 below.

[0058] Example 5 The specific gravity was determined from Compositions #10, 14, 17, 23, 28, and the fluidity was measured at 25 °C and 37 °C according to DIN EN ISO 2431:2020-02. The results are shown in Table 8 below.

[0059]

Table 5

[0060]

Table 6

[0061]

Table 7

[0062]

Table 8

[0063] Discussion on the results Pure water is highly fluid, has excellent sprayability, and does not generate bubbles. However, compared to the catalyst medium composition according to the present invention, which is also very well sprayable and shows no or only slight formation of bubbles, water separated from the skin without forming a liquid film. Therefore, water alone cannot be used as a contact medium.

[0064] Only the combination of the gelling agent, detergent, and emulsifier according to the present invention provided excellent properties, particularly good sliding properties, good film formation, low or no foam formation, and very good acoustic transmission properties.

[0065] Particularly quantitatively, surprisingly good results were obtained with the combination of the gelling agent, detergent, and emulsifier. As expected, higher concentrations showed good properties of the mixture and were directed towards the described criteria. It was surprising that these properties were also observed at low concentrations.

[0066] A further advantage of the present invention was the sprayability of the contact medium according to the invention compared to conventional contact medium gels. Furthermore, the contact medium can also be heated up to body temperature without losing its function. For this purpose, a heating device is suitable, for example, for keeping a baby milk bottle warm during use. Other devices such as heating pads are also conceivable. In the medical field, regardless of the type of transducer and ultrasonic technology, the medium can be used with both diagnostic and therapeutic ultrasounds. In addition to the application to medical ultrasound, the contact medium according to the present invention can also be advantageously used for electrocardiogram examination (ECG), defibrillation, and outside the medical field (for example, technical ultrasound).

Claims

1. The following: 0.05 to 2.5% by weight of a gelling agent, 0.1 to 4.0% by weight of a detergent, 0.1 to 4.0% by weight of an emulsifier, Optionally, additives selected from preservatives, acidifying agents, skin care additives, and mixtures thereof, and water as the remaining element, comprising, wherein the gelling agent is selected from the group consisting of hydroxyethyl cellulose, carboxymethyl cellulose, xanthan gum, guar gum, collagen, gelatin, pectin, chitin, starch, sodium alginate, potassium alginate, and calcium alginate, and mixtures thereof, the detergent is a nonionic surfactant or a mixture of nonionic surfactants, the emulsifier is selected from the group consisting of glycerol monofatty acid esters and glycerol difatty acid esters and mixtures thereof, A contacting medium having a pH value in the range of 5 to 7.

2. The contacting medium according to claim 1, characterized in that the fatty acid moiety of the fatty acid ester is derived from C7-C20-saturated fatty acids, C16-C20-mono-unsaturated fatty acids, and / or C18-C20-di-unsaturated fatty acids.

3. The contacting medium according to claim 1, characterized in that the fatty acid moiety of the fatty acid ester is derived from stearic acid, oleic acid, caprylic acid, capric acid, and / or linolenic acid.

4. The contacting medium according to any one of claims 1 to 3, characterized in that it contains the gelling agent in an amount of 0.05 to 0.5% by weight.

5. The contacting medium according to claim 1 or 2, characterized in that more than 80% by weight of the gelling agent is hydroxyethyl cellulose.

6. The contacting medium according to any one of claims 1 to 5, characterized in that all of the hydroxyethyl cellulose is 2-hydroxyethyl cellulose. **Claim 7**: The contact medium according to any one of claims 5 or 6, wherein the hydroxyethyl cellulose is cellulose 2-hydroxyethyl ether (CAS# 9004-62-0) having an average degree of substitution (DS) of 0.85 to 1.35 and / or a molar degree of substitution of 1.5 to 3.

0. **Claim 8**: The contact medium according to any one of claims 1 to 7, wherein more than 80% by weight of the cleaning agent is polyethoxylated castor oil. **Claim 9**: The contact medium according to claim 8, wherein all of the cleaning agent is polyethoxylated castor oil. **Claim 10** The contact medium according to any one of claims 1 to 9, wherein the cleaning agent is selected from the group consisting of polyethoxylated castor oil, poloxamer, and mixtures thereof. **Claim 11**: The contact medium according to any one of claims 1 to 10, wherein more than 80% by weight of the emulsifier is glycerol monofatty acid ester. **Claim 12**: The contact medium according to claim 11, wherein all of the emulsifier is glycerol monofatty acid ester. **Claim 13** Having a pH value in the range of 5 to 6.5 and optionally containing an inorganic or organic buffer system or acidifying agent for adjusting the pH level, the contact medium according to any one of claims 1 to 12. **Claim 14**: The contact medium according to claim 13, wherein the inorganic or organic buffer system or acidifying agent for adjusting the pH level is selected from citric acid, sodium citrate-citric acid buffer, and phosphate-citric acid buffer. **Claim 15**: Containing a preservative in an amount of 0.05 to 1.0% by weight, wherein the preservative is selected from the group consisting of sodium benzoate, potassium benzoate, sodium sorbate, potassium sorbate, and mixtures thereof, the contact medium according to any one of claims 1 to 14. **Claim 16** Furthermore, the contact medium according to any one of claims 1 to 15, characterized by containing a skin care additive.

17. The contact medium according to any one of claims 1 to 16, characterized by having an outflow time in the range of 5 to 200 seconds, determined using an outflow beaker equipped with a 4 mm nozzle at 25°C in accordance with DIN EN ISO 2431:2020 - 20.

18. The contact medium according to any one of claims 1 to 17, characterized by containing a monohydric alkanol of 0.5 wt% or less.

19. The contact medium according to any one of claims 1 to 18, characterized by containing a gelling agent of 0.1 - 0.3 wt% and / or a detergent of 0.075 - 0.5 wt% and / or an emulsifier of 0.2 - 0.8 wt%.

20. A kit comprising the contact medium according to any one of claims 1 to 19, and at least one applicator, and optionally at least one refill container filled with the contact medium.

21. The kit according to claim 20, comprising at least one heating device configured to heat the contact medium in the applicator and / or the refill container, wherein the heating device includes an electric heating device.

22. Use of the contact medium according to any one of claims 1 to 19 as a contact medium in medical and non - medical sonography, electrocardiogram examination, electroencephalogram examination, and / or defibrillation by electric impulse.

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