EP4724138A1

EP4724138A1 - Method using radiofrequency and a cosmetic composition

Info

Publication number: EP4724138A1
Application number: EP24722022.1A
Authority: EP
Inventors: Patrycja NZOUNZA; Chloé VIALLARD; Maria Rosaria ANTONELLI
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2023-06-08
Filing date: 2024-04-25
Publication date: 2026-04-15
Also published as: FR3149509A1; CN121311277A; WO2024251432A1

Abstract

The invention relates to a method for non-therapeutic, cosmetic treatment of skin, comprising: a. applying a cosmetic composition to a target area of the skin comprising a non-polymeric cosmetic active agent having a molecular weight ranging from 100 Da to 700 Da, exposing the target area of the skin to a series of pulses of an electric current, with the pulses having a frequency ranging between 100 kHz and 100 MHz and the electric current being supplied by a bipolar radiofrequency cosmetic device having at least one electrode and at least one counterelectrode.

Description

Method using radiofrequency and a cosmetic composition

The present invention relates to a non-therapeutic cosmetic method for improving the appearance of the skin using a radiofrequency-based technology and a cosmetic composition.
More generally, a cosmetic product is a product as defined in EC Regulation No. 1223/2009 of the European Parliament and of the Council dated 30 November 2009 relating to cosmetic products.

Technological background

Non-ablative devices for domestic use are designed to deliver thermal energy to the skin for biological effects such as: stimulating the natural production of collagen, lifting and firming the skin in order to reduce wrinkles. In order to be compatible with domestic use, the thermal energy delivered to the skin must be limited within a certain range, in order to ensure good tolerance and to avoid burns.
Radiofrequency (RF) is an electromagnetic wave and not a photonic emission process. It is an alternating electric current: the change in polarity +/- on the surface of the skin causes a molecular vibration that produces an amount of heat that depends on the intensity of the current and the time according to Ohm’s law: E = I × R × t.
The radiofrequency current is a sinusoidal current. According to the general definition, the frequency of the current ranges between 3 kHz and 300 Ghz; in cosmetics, most of the listed instruments have a current frequency that is between 100 kHz and 10 MHz.
The complexity of radiofrequency techniques is linked to the various ways of delivering energy. It can be external, and, depending on the emission mode, a distinction is made between monopolar radiofrequency and bipolar radiofrequency, which is much more common. The current circulates between two electrodes, responsible for heating the tissue, which is the basis of the effective thermal effect. The depth of the thermal effect is equal to half the distance between said electrodes. Thus, multiplying the electrodes follows this logic for increasing the surface area and the depth of treatment, but the designations tri, quad or octopolar are essentially marketing terms.
Energy delivery is limited, as is the pulse duration, to avoid any thermal damage to the epidermis, with a risk of burns and even scarring. This observation helps to explain the operating mode for these “external bipolar” techniques, with a rotary movement being repeated on the surface of the skin for a variable length of time, depending on the device. However, of utmost importance is that limiting the delivered energy only results in a modification of the extracellular medium, comprising collagen and elastin.
Consequently, mono and bipolar radiofrequencies are described as subcutaneous (superficial) radiofrequencies, i.e., suitable for external and superficial treatment of the skin. The effectiveness of these treatments is limited by a risk of burning the skin above 42 °C.
In order to overcome this problem of an epidermal risk, another method has been proposed: namely, fractionated radiofrequency, which is still delivered externally, with probes that increase the pulse duration and reduce the energy level, while having a controlled coagulation action on superficial and dermal tissues. The active electrode is split into a multitude of micro-electrodes, in order to distribute the thermal energy more evenly than in the strict bipolar case, which multiplies the density of heat concentrated in a single point, as perceived in bipolar electrodes at the point of contact with the skin, into several small areas.
Finally, intra-tissue radiofrequency, or HiFR (High-intensity Focused Radiofrequency), has been developed more recently. There is no focussing in the “optical” sense of the term, yet there is a deep local action. The aim involves delivering all the energy deep into the tissue, using micro-needles, for example. This could be a fractionated, intra-tissue, multi-layer, high-intensity radiofrequency with micro-needles. This technique allows more power to be delivered because the micro-needles allow the skin barrier to be overcome. The thermal effect at the tip of the needle can reach 65°.
As a result, high-intensity radiofrequencies are referred to as subcutaneous radiofrequencies or deep radiofrequencies. They can be implemented for firming the tissues or for improving the quality of scars and stretch marks.
Radiofrequency technologies are known to be used for skin care or rejuvenation applications as described in documents CN113317870, CN107998509, CN110141355, WO2021243403, WO2016162234, WO201687289, CN111616794.
Document WO201540049 discloses a non-invasive treatment device for heating an inner region of the skin using a radiofrequency electric current, with an outer surface region of the skin adjacent to the inner region being provided with a treatment substance selected so as to be able to be conveyed through the skin under the influence of an electric field and also being selected so as to increase the electrical transmission of the inner region, the device comprising:
- a first treatment electrode configured and arranged to allow electric current to pass through an outer surface of the skin and through the inner region;
- a radiofrequency generator configured and arranged so that, during use, the electric current generated by the radiofrequency generator is applied through a first treatment electrode to the outer surface of the skin and through the inner region;
- a first field electrode configured and arranged to provide, during use, an electric field in the skin in order to convey the treatment substance towards the inner region;
- an electric field generator configured and arranged so that, during use, a DC electric field generated by the electric field generator is applied across the first field electrode to the treatment substance, by virtue of which at least some of the treatment substance is conveyed from the outer surface region to the inner region; and
- a control unit.
Document CN108452436 discloses a high-frequency radiofrequency micro-vibration device. The high-frequency radiofrequency micro-vibration device comprises a main control circuit board, a motor, an eccentric gear and a stainless steel output head. A current passes through the stainless steel output head and reaches the face, then passes through the face, the front chest, the arms, the palm and reaches the stainless steel buttons. It returns to the high-frequency radiofrequency micro-vibration device in order to form a closed loop, promoting better absorption of the cosmetics.
Document CN112007279 discloses a portable anti-wrinkle device with (a) a shell, which comprises a holding part and a head part; (b) at least one radiofrequency contact disposed on the head; and (c) a capsule holder adapted to hold a cosmetic composition capsule.
Document FR3014321 discloses a module for treating a product intended to be applied to the body of a user, notably a cosmetic and/or pharmaceutical product, said treatment module being configured to activate, for example, using radiofrequency, said product and being arranged so as to be detachably fixed to a support defined by a receptacle containing said product. Such a treatment module allows the product to be activated, in particular in situ, i.e., in this case on the body of the user, notably with the aim of optimising the effectiveness of the applied product and/or of improving the penetration of the product into the body of the user.
Document JP2011194175 discloses a cosmetic device that comprises an RF (Radio Frequency) transmitter and a pair of RF electrodes. A control device delivers a control signal to the RF transmitter. The RF transmitter comprises, for example, an inverter that converts direct current originating from a battery (not shown) into a high-frequency current (alternating current). The RF transmitter supplies a high-frequency current converted on the basis of the control signal to the RF electrode. When the RF electrodes are placed against the skin, the skin becomes an electrical resistor that connects between the RF electrodes. This electrically closes the circuit with the RF transmitter and the RF electrode in order to allow the high-frequency current to flow through the circuit. As skin is in the path of the circuit, particularly between the two RF electrodes, radiofrequency current can be delivered to the skin. The electrical energy is consumed in the form of thermal energy in the skin, which acts as an electrical resistor, allowing the skin to be heated, with a view to promoting the diffusion of cosmetic agents within the skin.
A requirement remains for benefiting from a method for improving the effectiveness of radiofrequency devices in cosmetics.
The aim is to provide multiple advantages to non-ablative and/or high-frequency microcurrent RF technology by improving the mode of action, notably by selecting formulas with properties for coupling active agents for which the RF signal will also act as a skin penetration booster.
Another aim of the invention is to determine the types of active agents that are able to add, or even form, a synergy with the biological effects of collagen remodelling directly induced by the RF signal.

Definition of the invention

The present invention addresses this requirement by means of a method for non-therapeutic, cosmetic treatment of skin, comprising:
applying a cosmetic composition to a target area of the skin comprising a non-polymeric cosmetic active agent having a molecular weight ranging from 100 Da to 700 Da,
exposing the target area of the skin to a series of pulses of an electric current, with the pulses having a frequency ranging between 100 kHz and 100 MHz and the electric current being supplied by a bipolar radiofrequency cosmetic device having at least one electrode and at least one counterelectrode.
The combined action of the pulse at a frequency ranging between 100 kHz and 100 MHz and of the cosmetic composition comprising the non-polymeric cosmetic active agent has the effect of significantly promoting the penetration of such active agents in order to increase their effectiveness, notably when the composition is applied simultaneously with the RF treatment, compared with a topical application of the same composition applied alone or compared with the RF treatment implemented alone, i.e., without the cosmetic composition.
This involves delivering thermal energy to the skin using a radiofrequency generator, notably within a range compatible with both professional and domestic use (for example, a non-invasive application head, limited heating of the skin surface, with a sensor and an ON-OFF switch to ensure good tolerance/lack of routine side effects).
The method can be intended for domestic or professional use, for example, in a beauty salon.
In particular, the time needed to carry out the steps is short. Therefore, the method is perfectly suited for daily domestic use, for example, during a lunch break.
The method can be repeated several times, preferably several times a month, with the period between two applications preferably ranging from 1 day to 15 days, more preferably from 1 to 7 days, and even more preferably from 1 to 2 days.
Preferably, the target area has an equivalent diameter that is less than or equal to 1 cm.
Preferably, the target area has an equivalent diameter that is greater than 0.1 mm, or even greater than 0.5 mm, notably greater than 1 mm.
Cosmetic composition
Step b) can be carried out after step a). Preferably, step b) and step a) are carried out simultaneously.
Step a) of applying the cosmetic composition can be carried out only once over the same target area.
As a variant, step a) of applying the cosmetic composition can be repeated several times over the same target area, for example, between 2 and 200 times.
Application step a) can be carried out between 1 and 5 times a day over the same target area.
The cosmetic composition can be applied at least once a day for at least 6 days, preferably at least twice a day for at least 7 days, notably for at least 14 days, better still for at least 21 days, even better still for at least 28 days, better still for at least 35, 42, 49 or 56 days.
The cosmetic composition comprises at least one non-polymeric cosmetic active agent with a molecular weight ranging from 100 Da to 700 Da, notably selected from the following list.
Preferred active agents with a molecular weight ranging from 100 Da to 700 Da
2,4-diamino-6-piperidino pyrimidine-3-oxide or “Minoxidil” described in US-4,139,619 and US-4,596,812,
Aminexil or 2,4-diaminopyrimidine 3-oxide, described in WO 96/09048,
Xanthine derivatives such as diethylaminoethyl theophylline hydrochloride and caffeine.
In particular, the composition according to the invention comprises an active agent content with a molecular weight ranging from 100 Da to 700 Da ranging from 0.01 % to 10 %, and preferably from 0.1 % to 5 % by weight, relative to the total weight of the composition.
Additional active agents and adjuvants
The cosmetic composition can comprise one or more additional active agents and/or one or more of the adjuvants commonly used in the cosmetics field.
The cosmetic composition further comprises a physiologically acceptable medium. Such a medium is considered to be physiologically acceptable when it does not cause any tingling, tautness or discomfort that is unacceptable for the user.
Galenical forms
A composition used according to the invention can be provided in any galenical form normally used in the cosmetics field.
More specifically, this composition is intended for topical application. Preferably, such a composition is not intended to be rinsed off after application.
A composition according to the invention is preferably intended to be applied to skin.
Preferably, the skin is the skin of the face and/or of the body, in particular of the face and/or of the hands, preferably of the face, and more specifically of the forehead and/or of the alae of the nose and/or of the chin, the commissures of the lips and the eyes.
A composition alternatively can be in the form of a face and/or body care or makeup product, and can be packaged, for example, in the form of a cream in a jar or a fluid in a tube or a pump bottle or a dropper bottle.
Radiofrequency pulse
Step b) can be carried out only once over the same target area.
As a variant, step b) can be repeated several times over the same target area, notably several times a month.
Step b) can be repeated in order to cover an entire inhomogeneous surface of the skin.
The exposure step b) can be carried out between 1 and 20 times over a period of two months.
The period between two repetitions of step b) can range between 1 and 15 days, notably between 1 and 7 days, between 1 and 2 days or even every day.
Such durations provide a high level of performance for the treatment over a relatively short time period compared to the prior art.
The method, notably step b), can be executed using a portable device, notably known under the reference RF Ultrasonic Device, model EH-XR10® marketed by Panasonic, or the Newa® device marketed by EndyMed.
The light pulses preferably have a constant duration. In a variant, the pulses have a variable duration. Two consecutive light pulses of ranks n and n+1 thus can have different respective durations.
The energy emitted per pulse (for 5 kOhms) preferably ranges between 0.6 mJ and 70 mJ. The device can be configured to emit radiofrequencies for a certain predefined operating duration, and then to switch off automatically.
The total light power received by the area to be treated during a pulse advantageously ranges between 0.067 W and 0.67 W.
The distance between the device and the area to be treated can range between 0 cm and 100 cm, better still between 0 and 1 or 2 cm.
Assembly
A further aim of the invention, in addition to the above, is an assembly for carrying out the method described above, comprising a radiofrequency cosmetic device generating electrical pulses at a frequency ranging between 100 kHz and 100 MHz and a cosmetic composition comprising a non-polymeric cosmetic active agent having a molecular weight ranging from 100 Da to 700 Da.
The assembly can be marketed in the same packaging, notably comprising an instruction guide allowing the user to implement the method according to the invention.

Preferred embodiments

Preferably, the method according to the invention has one or more of the following features, taken alone or in combination:
the electric current has a voltage amplitude ranging from 70 V to 200 V, and an intensity ranging from 0.1 mA to 10 mA,
the pulses each having a duration (t_pulse) ranging between 0.2 ms and 1 s, with a rest interval (T_off) between them ranging between 1 ms and 1,000 ms,
the supplied current has a duty cycle (tpulse/(tpulse+Toff)) varying from 2 % to 98 %, where tpulse designates the duration of a pulse and Toff designates the interval between two successive pulses,
the surface area of the one or more electrodes (2) in contact with the keratin materials varies from 0.1 to 20 cm2,
the device is hand-held,
it comprises topical application of the composition to the target area before applying the electric current and/or during said application,
it involves manually moving the one or more electrodes of the device over the target area while subjecting the target area to said pulses of electric current,
the target area of the skin is exposed for a duration ranging between 2 minutes and 10 minutes,
the pulses have a pulse duration T_on ranging between 2 ms and 1,000 ms,
the electric current density applied by the electrode ranges from 0.2 mA/cm2 to 50 mA/cm2,
the non-polymeric active agent comprises a hydrophilic or lipophilic group,
the non-polymeric active agent has a logP ranging from -5 to 4,
the non-polymeric active agent is selected from among compounds derived from pyrimidine or xanthine,
the non-polymeric active agent is selected from among 2,4-diamino-6-piperidino pyrimidine-3-oxide, 2,4-diaminopyrimidine 3-oxide, theophylline, caffeine or a mixture thereof.
The value of a logP represents the partition coefficient of a compound. It can be determined according to the method described in the article by Meylan and Howard entitled, “Atom / Fragment contribution method for estimating octanol-water partition coefficient”, J. Pharm. Sci., 84, 83-92 (1995). This value also can be computed using commercially available software that determines the value of logP on the basis of the structure of the molecule. By way of an example, the Epi-Win software of the US Environmental Agency can be cited.

Description of the figures

is a schematic diagram of the method according to the invention implemented with the Newa® device marketed by EndyMed,
is a schematic diagram of the method according to the invention implemented with the RF Ultrasonic Device, model EH-XR10®, marketed by Panasonic,
describes the experimental protocol for preparing samples,
[Fig. 4],
[Fig. 4] shows the cutaneous absorption of caffeine after 1 hour (in µg/cm²),
,
shows the cutaneous absorption of minoxidil after 1 hour (in µg/cm²).

Example

The devices used in this example are the Newa® commercial devices marketed by EndyMed and the RF Ultrasonic Device, model EH-XR10®, marketed by Panasonic.
The composition used is described in table 1.
The composition in gel form is prepared on the basis of the weight proportions described below. The percentages are provided by weight relative to the total weight of the composition. The percentage of active materials (AM) is also indicated where necessary.

The molecular weight MW is expressed in Da.

Compounds	Amount (g)	Properties
CAFFEINE (1,3,7-TRIMETHYL XANTHINE) ANHYDROUS called “caffeine”	0.5	MW: 194 logP: -0.07
2,4-DIAMINO 6-PIPERIDINO PYRIMIDINE N-OXIDE called “minoxidil”	0.5	MW: 209 LogP: 0.87
ACRYLATES/C-10-C30 ALKYL ACRYLATE CROSSPOLYMER	3	--
NON-DENATURED 96° ETHYL ALCOHOL	40	--
2 METHYLPENTANE-2,4-DIOL	15	--
DEIONISED WATER	qs 100	--

As shown in figures 1 and 2, the periphery of a human skin sample 1 is attached to a Franz cell 2, so that an exposure surface 3 is exposed to the radiofrequencies. Specific operating conditions are assigned to each device. The RF is applied remotely, and the sample is then placed on a Franz cell.
The following skin samples are prepared:
“Passive”: The sample is only treated with the composition.
“Stripped”: The sample is treated by stripping.
“Newa”: Skin treated with the Newa® device and the composition for 1 minute. The composition is then left on the skin for 1 hour.
“Panasonic”: Skin co-treated with the Panasonic (Radiofrequency + Ultrasound mode) device and with the composition for 1 minute. The composition is then left on the skin for 1 hour.
The detailed protocol is shown in .
[Fig. 4] shows the absorption profile of caffeine in the stratum corneum (SC), the epidermis (epidermis), the dermis (dermis), as well as the cumulative absorption in the stratum corneum, the epidermis and the dermis.
shows the absorption profile of minoxidil in the stratum corneum (SC), the epidermis (epidermis), the dermis (dermis), as well as the cumulative absorption in the stratum corneum, the epidermis and the dermis.
In order to measure the absorption profiles of caffeine and minoxidil, the analysis device is used under the following operating conditions: LC-MS/MS coupling is used to quantify the caffeine and the minoxidil in the skin compartments in order to establish the absorption profile. The two molecules are analysed using the same analytical method, the mobile phases of which are methanol and a mixture of water + 0.1 % of formic acid by weight, the stationary phase is a 50 mm long, 2.1 mm diameter C18 column with 2.7 µm particles. The ionisation source used is positive ESI. In order to obtain an optimal chromatographic result, injection is carried out at a gradient.
Finally, a more than twofold increase was observed: for minoxidil, which hardly penetrates for topical application, there was a more than twentyfold increase, and for caffeine there was a more than fivefold increase.

Claims

Method for non-therapeutic, cosmetic treatment of skin, comprising:
applying a cosmetic composition to a target area of the skin comprising a non-polymeric cosmetic active agent having a molecular weight ranging from 100 Da to 700 Da,

exposing the target area of the skin to a series of pulses of an electric current, with the pulses having a frequency ranging between 100 kHz and 100 MHz and the electric current being supplied by a bipolar radiofrequency cosmetic device having at least one electrode and at least one counterelectrode.
Method according to Claim 1, the electric current having a voltage amplitude ranging from 70 V to 200 V and an intensity ranging from 0.1 mA to 10 mA.
Method according to any one of the preceding claims, the pulses each having a duration (t_pulse) ranging between 0.2 ms and 1 s, with a rest interval (T_off) between them ranging between 1 ms and 1,000 ms.
Method according to any one of the preceding claims, the supplied current having a duty cycle (tpulse/(tpulse+Toff)) varying from 2 % to 98 %, where tpulse designates the duration of a pulse and Toff designates the interval between two successive pulses.
Method according to any one of the preceding claims, the surface area of the one or more electrodes (2) in contact with the keratin materials varying from 0.1 to 20 cm2.
Method according to any one of the preceding claims, the device being hand-held.
Method according to any one of the preceding claims, comprising topical application of the composition to the target area before applying the electric current and/or during said application.
Method according to any one of the preceding claims, comprising manually moving the one or more electrodes of the device over the target area while subjecting the target area to said pulses of electric current.
Method according to any one of the preceding claims, the exposure of the target area of the skin being carried out for a duration ranging between 2 minutes and 10 minutes.
Method according to any one of the preceding claims, the pulses having a pulse duration T_on ranging between 2 ms and 1,000 ms.
Method according to any one of the preceding claims, the electric current density applied by the electrode ranging from 0.2 mA/cm2 to 50 mA/cm2.
Method according to any one of the preceding claims, the non-polymeric active agent comprising a hydrophilic or lipophilic group.
Method according to any one of the preceding claims, the non-polymeric active agent having a logP ranging from -5 to 4.
Method according to any one of the preceding claims, the non-polymeric active agent being selected from among compounds derived from pyrimidine or xanthine.
Method according to any one of the preceding claims, the non-polymeric active agent being selected from among 2,4-diamino-6-piperidino pyrimidine-3-oxide, 2,4-diaminopyrimidine 3-oxide, theophylline, caffeine or a mixture thereof.
Assembly for carrying out the method according to any one of the preceding claims, comprising a radiofrequency cosmetic device generating electrical pulses at a frequency ranging between 100 kHz and 100 MHz and a cosmetic composition comprising a non-polymeric cosmetic active agent having a molecular weight ranging from 100 Da to 700 Da.