RU2477998C2 - Universal contact medium - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical gels, and may be used as a contact medium for physical diagnostic techniques: ultrasound examination, including Doppler sonography and ultrasonography; electrocardiography, electroencephalography; therapy: electric stimulation and defibrillation, cosmetology. A universal contact medium contains a water-soluble polymer with additionally attached hydrocarbon group length of which makes 8 to 30 carbon atoms (C8-C30), an electrically conducting ingredient, a preserving agent, a neutralising agent, and water. The water-soluble polymer is e.g. presented by acrylate/steareth-20 metacrylate crosspolymer, or PEG-120 methyl glucose dioleate. The contact medium under the invention is universal: it is high-transparent for laser light; good electrical conductivity makes it possible to use it in electrocardiography.

EFFECT: use of the contact medium under the invention provides the high quality of ultrasonic images with the contact medium being non-toxic and hypoallergenic.

8 cl, 1 tbl

Description

The invention relates to medical gels and can be used as a contact medium for physical diagnostic methods: ultrasound (ultrasound), including dopplerography and echography, electrocardiography (ECG), electroencephalography (EEG); treatments: electrical stimulation and defibrillation, cosmetology.

Currently, special contact media are known that are intended only for ultrasound or only for ECG, for example, gel for ultrasound "Mediagel" or gel for ECG "Uniagel" (Russia).

It is well known to use vaseline oil or “starch gel” (5% aqueous starch solution) as the contact medium in ultrasound diagnostics. However, liquid paraffin, being an effective absorber of ultrasound, impairs the resolution of the ultrasound method, which reduces the quality of diagnosis. In addition, liquid paraffin is not hygienic to use - it leaves greasy stains on patients' bodies and clothes that are difficult to wash off.

“Starch gel” has low operational characteristics: low viscosity and a tendency to delamination under the influence of microorganisms, which significantly reduces its shelf life (no more than 24 hours at a storage temperature of 20-25 ° C), in addition, “starch gel” causes corrosion of sensors .

The well-known foreign acoustic contact pastes Sonogel (Germany), Aquasonik (USA), the basis of which is a carboxylic polymer. These pastes have good acoustic characteristics, high viscosity. However, Sonogel paste dries quickly, has a high stickiness, which makes it difficult to remove it from the patient’s skin and the surface of the sensor, and Aquasonik paste provokes corrosion of the sensor and, in addition, during prolonged studies causes unpleasant sensations in patients.

Known contact medium for ultrasound, in which polyethylene glycol is used as a thickener in amounts of up to 10 weight%, and chlorhexidine is used as a preservative in amounts of up to 0.5 weight% (RF patent 2061471, IPC A61K 9/06, publ. 10.06.1996 ) The contact medium with the indicated, rather high content of polyethylene glycol, contributes to skin irritation and drying, and chlorhexidine, which is part of the medium in the indicated amounts, causes complete sanitation of the mucous membranes.

Contact media are known based on acrylic copolymers (see RF patents No. 2051679, IPC A61K 31/75, A61K 31/78, publ. 10.01.1996; No. 2083160, IPC A61B 8/00, C08L 33/08, publ. 07/10/1997).

The ultrasound contact medium according to patent No. 2083160, selected as a prototype of the claimed object, contains a water-soluble polymer, for example, a rare crosslinked copolymer of acrylic acid obtained with a crosslinking agent from a mixture of diallyl, triallyl and tetraallyl pentaerythritol esters, preservative-2-bromo-2-nitro-2-nitro -1,3-diol and / or p-hydroxybenzoic acid esters, aliphatic alcohol and a neutralizing agent.

The known contact medium has a sufficiently high viscosity and, as a result, does not spread over the body, has a low drying rate, which ensures long-term contact of the sensor with the patient’s skin. However, the high viscosity of the known contact medium prevents the sensor from sliding over the patient’s body, which reduces the resolution of the sensor and, accordingly, the clarity of the clinical picture of the organ under examination. In addition, the known contact medium has a narrow use, only for ultrasound.

The objective of the invention is to create a universal contact medium, weakly absorbing ultrasound, having an electrical conductivity not lower than the electrical conductivity of human body tissues and good viscosity, high transparency, providing long-term contact of the sensor with the patient’s skin and good sliding over it, without causing irritation to the patient’s skin and corrosion of the sensor.

Technical results from the use of the inventive contact medium are its versatility, high clarity of the resulting clinical pictures, the absence of the irritating effect of the medium on the skin and the corrosive effect on the sensor.

The technical results of the invention are achieved due to the fact that in a universal contact medium containing a water-soluble polymer, a preservative, a neutralizing agent, water, a polymer with an additionally attached hydrocarbon group, the length of which is from 8 to 30 carbon atoms, is used as a water-soluble polymer ( C8-C30), which is a rheological modifier. In addition, the contact medium additionally contains an electrically conductive component, while the ratio of components in wt.%:

Water soluble polymer - 0.3-5

The conductive component is 0.2-2.0

Preservative - 0.05-0.5

Neutralizing agent - 0.05-0.5

Purified water - up to 100

The following can be used as a water-soluble polymer: a copolymer of styrene and acrylic acid containing a C8 hydrocarbon group; a styrene-acrylamide copolymer containing a C8 hydrocarbon group; acrylate / vinyl neodecanoate cross-polymer, representing an acrylic copolymer with a hydrocarbon group of length C10; acrylate / stearet-20 methacrylate cross-polymer, which is an acrylic copolymer with a hydrocarbon group of length C18; acrylate / behenet-25 methacrylate cross-polymer, which is an acrylic copolymer with a hydrocarbon group of length C22; acrylate / C10-30 alkyl acrylate cross-polymer, which is an acrylic copolymer with hydrocarbon groups with a length of from C10 to C30; PEG-120 (polyethylene glycol with an average degree of polymerization of 120) methyl glucose di and trioleate containing a C18 hydrocarbon group; PEG-150 distearate containing a C18 hydrocarbon group.

Ethylene diamine tetraacetic acid (EDTA) or its mixture with sodium benzoate, esters of para-hydroxybenzoic acids (parabens), isothiazolinone derivatives, etc. are used as preservatives.

Chloride, sulfate, sodium phosphate or potassium are used as the electrically conductive component. It is advisable to use up to 2% by weight of the electrically conductive component, since in this case the electrical conductivity of the contact medium becomes higher than the electrical conductivity of body tissues, which is usually up to 2 S / m, and does not limit the transmission of electric current. Also, the preservatives EDTA or sodium benzoate, as well as salts formed during the production of the contact medium, can serve as electrically conductive components. For example, the sodium salt of polyacrylic acid, which is formed by neutralizing acrylic copolymers with sodium hydroxide.

Sodium or potassium hydroxides or various amines, for example ammonia or triethanolamine, are used as a neutralizing agent (up to pH = 7.0).

The presence of a hydrocarbon group in a water-soluble polymer, the length of which is from 8 to 30 carbon atoms (C8-C30), gives the polymer more pronounced properties of the rheological modifier. The presence of hydrophobic groups C8-C30 makes the solution highly pseudoplastic, providing a high degree of discontinuous thinning associated with the rapid destruction of the action of the van der Waals forces. This contributes to the fact that in the range of shear rates used in medical diagnostics, the gel viscosity instantly and reversibly decreases at the passage of the sensor, further facilitating its sliding. After passing the sensor, the viscosity is restored, the gel remains on the skin and does not flow. Due to the hydrophilic and lipophilic functionality of the polymer, it has surfactant properties and therefore improves the wetting of the skin surface and sensors. The contact medium does not require the additional addition of oils (or other lipids) to facilitate the sliding of the sensor, which could make the gel cloudy, inhomogeneous and worsen its conductive ultrasound or laser radiation properties. The presence in the water-soluble polymer of a hydrocarbon group, the length of which is from 8 to 30 carbon atoms (C8-C30), also leads to a stronger interaction of the polymer molecules with each other and, as a result, greater stability of the gel structure in the presence of salts.

The combined use of EDTA and any other preservative in the gel formulation ensures both water softening by binding traces of divalent and trivalent metal ions, thereby increasing the transparency of the contact medium (which is extremely important for its use in laser cosmetology), and also extends the shelf life of the gel, due to their synergistic preservative effect.

All components of the universal contact medium are approved for use, in the concentrations used are non-toxic and do not cause allergic reactions, do not cause corrosion of the sensors of medical equipment.

Get the contact medium as follows.

In a chemical reactor equipped with a stirrer, a rheological modifier is added to water at room temperature, left without stirring for 15 minutes to enter the water, then EDTA, sodium chloride, sodium benzoate are added, stirred with a stirrer for 15 minutes (until the components are dissolved) , then the gel is neutralized with a 5% sodium hydroxide solution to pH = 7.0, stirred for another 10-30 minutes to obtain a more uniform solution. The contact medium is a homogeneous, highly transparent gel, due to the low content of dissolved components, the acoustic properties of the medium are similar to those of water, the speed of propagation of ultrasound is 1500 m / s. The resulting gel has a pleasant texture, good conductivity and good visibility of the image sent by ultrasonic pulses, and is also easily removed from the skin with a regular tissue due to the proposed composition.

Examples of specific compositions of the contact medium are shown in table 1.

Table 1.  Technical characteristics of various contact media; in addition to the polymer indicated in the table, the medium contains 0.5% sodium chloride, 0.1% EDTA, 0.4% sodium benzoate, sodium hydroxide to pH = 7.0, water - up to 100%. No. Polymer used Type of
polymer The polymer content,% Transparency (transmission of light with a wavelength of 420 nm),% Specifications one. Acrylate / Stearet-20 Methacrylate Crosspolymer ionic 1,6 ≥95% Crystal clear gel, easily distributed on the skin, has a pleasant light texture, does not flow. 2. Acrylate / C10-30 alkyl acrylate crosspolymer ionic 1,0 ≥92% Transparent gel, easily distributed over the skin, slightly thicker than according to claim 1, does not flow. 3. Acrylate / Behenet-25 methacrylate crosspolymer ionic 0.5 ≥98% Crystal clear gel, easily distributed over the skin, noticeably less thick than according to claim 1, slightly flowing. four. Acrylate / Vinyl Neodecanoate Crosspolymer ionic 0.3 ≥98% Crystal clear gel, easily distributed over the skin, noticeably less thick than according to claim 1, slightly flowing. 5. PEG-120 methyl glucose dioleate non-ionic 4.0 ≥92% Transparent gel, easily distributed over the skin, has a “sticky” texture, as a result of which the sensor glides worse and does not leak. 6. PEG-120 methyl glucose trioleate non-ionic 4.0 ≥89% The opalescent gel is easily distributed over the skin, has a slightly “sticky” texture, as a result of which the sensor glides worse and does not leak. 7. PEG-150 distearate non-ionic 5,0 ≥92% Transparent gel, easily distributed on the skin, has a pleasant texture, does not flow.

The inventive contact medium is universal: it is highly transparent to laser radiation, and good electrical conductivity contributes to its use in electrocardiography. Tests in medical institutions have shown that the use of the contact medium of the claimed composition provides high quality images with ultrasound, while the contact medium is hypoallergenic.

Claims (8)

1. A universal contact medium containing a water-soluble polymer, a preservative, a neutralizing agent, water, characterized in that as a water-soluble polymer using a polymer with an additionally attached hydrocarbon group, the length of which is from 8 to 30 carbon atoms (C ₈ -C ₃₀ ), an electrically conductive component, wherein the ratio of components, wt.%:
Water soluble polymer 0.3-5 Conductive component 0.2-2.0 Preservative 0.05-0.5 Neutralizing agent 0.05-0.5 Water up to 100 2. The universal contact medium according to claim 1, characterized in that acrylate / stearet-20 methacrylate cross-polymer is used as a water-soluble polymer. 3. The universal contact medium according to claim 1, characterized in that acrylate / C _10-30 alkyl acrylate cross-polymer is used as a water-soluble polymer. 4. The universal contact medium according to claim 1, characterized in that acrylate / behenet-25 methacrylate cross-polymer is used as a water-soluble polymer. 5. The universal contact medium according to claim 1, characterized in that acrylate / vinyl neodecanoate cross-polymer is used as a water-soluble polymer. 6. The universal contact medium according to claim 1, characterized in that PEG-120 methyl glucose dioleate is used as a water-soluble polymer. 7. The universal contact medium according to claim 1, characterized in that PEG-120 methyl glucose trioleate is used as a water-soluble polymer. 8. The universal contact medium according to claim 1, characterized in that PEG-150 distearate is used as a water-soluble polymer.