Microneedle applicator

Abstract

A microneedle applicator comprising an application head (T) provided with several microneedles (N) and a motor (M1) for vibrating the microneedles (N), the application head (T) defining a base surface (S) from which the microneedles (N) protrude, characterized in that the base surface (S) and the microneedles (N) are made in one piece of plastic, each microneedle (N) comprising a base (1) emerging from the base surface (S), a frustoconical portion (2) extending from the base (1), and a plate (3) terminating the frustoconical portion (2). (See Figure 2b for abbreviations.)

Description

Title of the invention: Microneedle applicator

[0001] The present invention relates to a microneedle applicator for applying a fluid product to the skin and facilitating its penetration into the upper layer of the epidermis. The invention's field of application is cosmetics, not tattooing. The aim is to enhance the effectiveness of a cosmetic treatment on the skin, not to color the skin.

[0002] Conventionally, this type of cosmetic applicator comprises an application head defining a base surface from which microneedles protrude. A motor, often electric, is used to vibrate the microneedles, either alone or with the base surface. A fluid reservoir may be connected to the application head by a fluid outlet. The reservoir may or may not be integrated into the applicator. Documents FR3110854, FR3110855, and FR3119546 describe such microneedle applicators with a fluid reservoir.

[0003] In general, microneedles are made of metal, while the rest of the application head is made of plastic, so the application head is not recyclable.

[0004] The object of the present invention is to provide an application head that is easily recyclable and biocompatible with the skin and the fluid products to be applied.

[0005] To achieve this goal, the present invention provides that the base surface and the microneedles are made in a single piece of plastic material, each microneedle comprising a base emerging from the base surface, a frustoconical part extending in line with the base and a plate terminating the frustoconical part.

[0006] In fact, the entire application head can be made in one piece from plastic material, so that it is recyclable.

[0007] The base has two functions, on the one hand increasing the strength of the micro-needle and on the other hand facilitating filling during injection.

[0008] The taper angle can be on the order of 7° to 15° with respect to the vertical axis of revolution. Preferably, it is 7°.

[0009] The platform is preferably flat, that is to say without hollows or bumps. While being flat, it may however be inclined or, on the contrary, horizontal.

[0010] Advantageously, the microneedles have a height of approximately 0.4 mm to 0.7 mm, measured from the base surface to the platform.

[0011] Plastic microneedles are taller and thicker than metal microneedles. They can be likened to small spikes. They thus ensure a better mechanical strength and avoids the risk of breakage in the skin, while maintaining identical performance.

[0012] Advantageously, the base has a height of approximately 0.2 mm to 0.3 mm. It can be said that the base represents nearly half the height of the microneedle or more.

[0013] Advantageously, the base has a maximum diameter of approximately 0.8 mm to 1 mm at its connection to the base surface. Preferably, this connection is without breakage or step.

[0014] Advantageously, the base has a minimum diameter of approximately 0.44 mm to 0.49 mm at its connection to the frustoconical portion. Preferably, this connection is without breaks or notches, which implies that the maximum diameter of the frustoconical portion is equal to the minimum diameter of the base.

[0015] Advantageously, the base is curved with a radius of approximately 0.2 mm to 0.3 mm. The base can then also be described as a "filler". This particular flared shape, comparable to that of a sand pile or a volcano, ensures great strength.

[0016] Advantageously, the frustoconical portion has a diameter of approximately 0.4 mm at its connection to the plate. Preferably, this connection can be in the form of a more or less sharp edge or even in the form of a small fillet.

[0017] Advantageously, the frustoconical part has a height of approximately 0.1 mm to 0.4 mm.

[0018] Advantageously, the microneedles have a density of 10 to 50 per cm² and preferably 22 to 44 per cm². As a general rule, the higher the density, the taller the microneedles can be, and vice versa. More precisely, when the needle height and shape are identical, a higher density results in shallower penetration, and vice versa. Similarly, when the needle density is constant and their shape is identical, a greater needle height corresponds to deeper penetration, and vice versa. With identical needle density and height, a larger conical angle results in shallower penetration, and vice versa. Adjusting these parameters allows for targeting different penetration depths, thus facilitating adaptation to various types of treatments, skin types, and body areas, while ensuring optimal resistance of the plastic needles.

[0019] Advantageously, the application head is made by injection / molding of polypropylene, advantageously having a rigidity E of 1850 MPa. Moreover, the polypropylene is of a biocompatible type, in that it is inert with respect to the action of the fluid product on the skin to be treated.

[0020] According to a particularly advantageous embodiment, the plates together define a dome shape. The dome is preferably rounded and relatively flat. Advantageously, the application head defines an outer periphery and a center, with the microneedles having increasing heights from the outer periphery to the center. Alternatively, the microneedles may all have the same height but protrude from a convex base surface. The axis and orientation of the needles then follow the same direction as the vibration axis, thus avoiding any shear stress on the needles. According to another embodiment, the base surface could be molded flat and then deformed to give it a convex shape. The deformation could be carried out while hot as it exits the mold. In this case, the axis and orientation of the needles would diverge, resulting in shear stress on the peripheral needles.

[0021] For example, an application head can be designed with 31 micro-needles (or spikes) having a height of 0.7 mm, with a base of 0.3 mm in height, a maximum diameter of 1 mm, a minimum diameter of 0.49 mm and a radius of 0.3 mm, with a frustoconical part of 0.4 mm in height, a minimum diameter of 0.4 mm and a flat, non-inclined platform.

[0022] One can also design an application head with 16 micro-needles (or spikes) having a height of 0.4 mm, with a base of 0.2 mm in height, 0.8 mm in maximum diameter, 0.44 mm in minimum diameter and a radius of 0.2 mm, with a frustoconical part of 0.2 mm in height, a minimum diameter of 0.4 mm and a flat, non-inclined platform.

[0023] An application head can also be designed with 31 micro-needles (or spikes) of 0.43 mm to 0.7 mm in height, with bases of 0.3 mm in height, 1 mm maximum diameter, 0.49 mm minimum diameter and a radius of 0.3 mm, with frustoconical parts of 0.13 mm to 0.4 mm in height, a minimum diameter of 0.4 mm and inclined flat dome-shaped platforms.

[0024] Still other designs are conceivable within the framework of the invention.

[0025] Advantageously, the application head forms a window opening at the base surface, this window receiving a fluid product outlet conduit connected to a fluid product reservoir. This is notably the case in the applicators of the aforementioned documents FR3110854, FR3110855 and FR3119546. The head, made entirely of plastic, preferably polypropylene, may include means for fixing it in a housing of the applicator, for example, tabs or snap-on profiles.

[0026] The spirit of the invention lies in providing a recyclable and biocompatible application head made of plastic, preferably high-rigidity polypropylene, with solid micro-needles or pins forming an enlarged base and a part Truncated cone. The dome-shaped configuration of the micro-needles or spikes allows for more uniform penetration without edge effect.

[0027] The invention will now be described more fully with reference to the accompanying drawings which give, by way of non-limiting examples, several embodiments of the invention.

[0028] In the figures:

[0029] [Fig. 1a] Fig. 1a is a vertical cross-sectional view through an applicator in the disassembled state,

[0030] [Fig.lb] The [Fig.lb] is an enlarged view of the application head,

[0031] [Fig. 2a] Fig. 2a is an enlarged perspective view of the application head of the [Fig.lb]

[0032] [Fig. 2b] Fig. 2b is a top perspective view of the applicator [Fig.la], showing the application head,

[0033] [Fig. 3a] Figures 3a and 3b are top and side views of a head application according to a second embodiment of the invention,

[0034] [Fig.3b] cf [Fig.3a]

[0035] [Fig. 4a] Figures 4a and 4b are top and side views of a head application according to a third embodiment of the invention,

[0036] [Fig.4b] cf [Fig.4a]

[0037] [Fig. 5a] Figures 5a and 5b are top and side views of a head application according to a fourth embodiment of the invention, and

[0038] [Fig.5b] cf [Fig.5a]

[0039] [Fig. 6] Figure 6 is a top perspective view of an application head according to a fifth embodiment of the invention.

[0040] The applicator of the invention is purely cosmetic, or even dermatological, excluding tattooing. It combines two treatment methods: the distribution of a cosmetic product, which may be a cream, ointment, lotion, serum, etc., and the perforation of the epidermis, without touching the dermis, by means of micro-needles. Depending on the nature of the cosmetic product and the desired result, the cosmetic product is applied before, at the same time as, or after the micro-perforation. The applicator of the invention is primarily intended for home use, in that the user will use the applicator on themselves. However, it can also be used professionally.

[0041] Reference will first be made to Figures 1a and 1b to describe in very general terms a microneedle applicator that can be equipped with the application head of the invention. The applicator in Figures 1a and 1b is broadly similar to that described in document FR3110854. This applicator comprises two separate modules, namely a first module M and a second module C1, which are connectable and The two modules can be easily and quickly disconnected by the user, for example, by applying torque and / or a push / pull between them. When the two modules are assembled, the applicator has a general pen-like shape with a longitudinal X-axis. The applicator can be held like a pen, between the thumb and middle finger with the index finger resting on the applicator.

[0042] The first module M contains a motor M1, which is preferably an electric motor. It may be a small rotary motor that drives a shaft M10 in rotation. The motor M1 is powered by a battery M2 and controlled by electronics M3, which manages the rotational speed of the shaft M10, the sequences and durations of motor activation, etc. An external activation button M21 allows the user to switch the applicator on. The free end of the shaft M10 is capped with a wobbly cap M4, which forms an inclined cam surface M40. The rotation of the shaft M10 causes this inclined cam surface to rotate in rotation, thus describing a rotary wobble motion.

[0043] The first module M also includes a piston M5 that moves axially back and forth. The piston M5 forms an inclined lower face M50 which is engaged with the inclined cam surface M40 of the wobble cap M4. The piston M5 is prevented from rotating, so that the inclined lower face M50 remains stationary, while the inclined cam surface M40 is driven in rotation by the motor ML1. It follows that the piston M5 is driven in axial displacement due to the wobble contact between the cam surface M40 and the inclined face M50. The piston M5 includes a transmission head M51, located opposite the inclined face M50, which therefore moves axially back and forth when the motor ML1 is activated. The piston M5 can be guided axially within the connecting end M6 so as to prevent it from rotating. We can therefore say that the M5 piston slides axially back and forth in the M6 ​​connection fitting.The axial stroke of the M5 piston is limited downwards by the M4 ratcheting cap and upwards by the M6 ​​connecting tip. The M5 piston is therefore clamped between the M4 cap and the M6 ​​tip with a purely axial degree of freedom, imposed by the M4 ratcheting cap. The piston stroke can be increased or decreased by moving the M12 selector slider, which moves the M4 ratcheting cap relative to the M6 ​​connecting tip, which remains fixed.

[0044] It is understood that this first module M contains expensive organs and components, which are intended to be kept for a prolonged period.

[0045] The second module Cl comprises an outer casing C17 forming a central window Cl8 at its upper end. The central window Cl8 can form an axial guide cylinder C181. The casing C17 comprises a lateral window C19 for receiving the RIO actuation unit of the R reservoir, as will be seen below.

[0046] The second module Cl comprises an application head T forming a base surface S on which microneedles N are arranged. The base surface S is traversed by a fluid product outlet O, which may be central or offset. Several fluid product outlets may also be provided, for example arranged in a circle. The fluid product outlet may also be located at the periphery of the stage P.

[0047] The application head T also includes a support ring B to which a transmission rod Cil is attached, extending axially in a centered manner. The transmission rod Cil includes a contact lug C12 intended to make firm contact with the transmission head M51 of the first module M.

[0048] The second module Cl also includes a connecting sleeve D, for example by snap-fitting. The sleeve D also includes an annular flange DI 1 which forms a central passage D12, through which the transmission rod Cl 1 passes. The contact heel C12 is disposed in the sleeve D, with a return spring S bearing between the heel C11 and the flange DI 1, so that the plate P is forced inwards towards the window Cl8.

[0049] The second module Cl also includes a cosmetic fluid product reservoir RI which is connected to the fluid product outlet O by a supply conduit RI 1. The reservoir RI includes an actuation wall RIO which is accessible through the side window C19 of the casing C17. The actuation wall RIO is deformable, either elastically or permanently.

[0050] The second module Cl, due to its simplicity of design and its passivity (no electrical or electronic components), constitutes an inexpensive entity, which can be considered as a replaceable cartridge or refill.

[0051] Figures 2a and 2b show in detail the application head T of the applicator of Figures 1a and 1b. It can be seen that the base surface S has a central window F and that the support ring B forms flexible tabs B2 which are provided with snap-fit ​​profiles Bl, projecting outwards. The head T can thus be attached and snapped into the axial guide cylinder C181 of the housing C17, as can be seen in [Fig. 2a]. The supply conduit RI1 is engaged in the window F and even protrudes slightly. The fluid product outlet O can be said to be surrounded by the micro-needles or pins N.

[0052] The base surface S thus has an annular shape, preferably flat. However, it is conceivable that the base surface could be slightly curved or convex.

[0053] All the microneedles N are identical here: thirty-one can be provided. Each microneedle N comprises a base 1 emerging from the base surface S, a frustoconical portion 2 extending from the base 1, and a plate 3, which terminates the frustoconical section 2. As an example, the microneedles N have a total height of 0.7 mm from the base surface S. The base 1 has a height of 0.3 mm, a maximum diameter of 1 mm at its junction with the base surface S, a minimum diameter of 0.49 mm at its junction with the frustoconical section 2, and describes a profile with a radius of 0.3 mm. The frustoconical section has a height of 0.4 mm, a maximum diameter of 0.49 mm at its junction with the base 1, and a minimum diameter of 0.4 mm at its junction with the platform 3. The platform 3 is flat and not inclined.

[0054] Figures 3a and 3b show in detail an application head Tl, which could be fitted to the applicator of figures 1a and 1b, instead of the head T of figures 2a and 2b. In this embodiment, the head Tl can be identical to that of the head T, except at the level of the micro-needles N, which comprise three different models, namely Np, Ni and Nm, classified by increasing heights. Np microneedles are those located on the outer periphery of the base surface S. Nm microneedles are those located directly around the central window F. Ni microneedles are located between the Np and Nm microneedles. For example, one could use thirteen Np microneedles, ten Ni microneedles, and eight Nm microneedles. As an example, the Np microneedles can have a height of 0.40 mm to 0.50 mm, advantageously 0.45 mm.Ni microneedles can have a height of 0.50 mm to 0.62 mm, advantageously 0.58 mm. Nm microneedles can have a height of 0.6 mm to 0.70 mm, advantageously 0.70 mm. The base 1 of all Np, Ni, and Nm microneedles is identical. It has a height of 0.3 mm, a maximum diameter of 1 mm at its junction with the base surface S, a minimum diameter of 0.49 mm at its junction with the frustoconical portion 2, and describes a profile with a radius of 0.3 mm. The frustoconical portions of Np, Ni, and Nm microneedles have progressively increasing heights. The height of the frustoconical portion 2 of Np microneedles is approximately 0.1 mm to 0.2 mm, advantageously 0.15 mm. The height of the truncated conical section 2 of the Ni microneedles is approximately 0.2 mm to 0.32 mm, advantageously 0.28 mm. The height of the truncated conical section 2 of the Nm microneedles is approximately 0.3 mm to 0.4 mm, advantageously 0.4 mm.It can also be noted that the plates 3 of the Np and Ni microneedles are inclined outwards, while the plates 3 of the Nm microneedles are flat or horizontal.

[0055] The increasing heights of the microneedles from the outside inward cause their plates 3 to together define a dome shape, which is pierced in its center. The dome is not very pronounced: it can be said to be flattened. The orientations of the plates (inclined for Np and Ni and flat for Nm) further improve this dome shape, which avoids pronounced edge effects.

[0056] Figures 4a and 4b show an application head T2, which lacks a central window. This head T2 is designed to be mounted on a microneedle applicator that does not dispense a fluid product. This embodiment is similar to that of Figures 2a and 2b. All the microneedles N are identical: thirty-one can be used. Each microneedle N comprises a base 1 emerging from the base surface S, a frustoconical portion 2 extending in line with the base 1 and a plate 3 terminating the frustoconical portion 2. As an example, the microneedles N have a total height of 0.7 mm from the base surface S. The base 1 has a height of 0.3 mm, a maximum diameter of 1 mm at its junction with the base surface S, a minimum diameter of 0.49 mm at its junction with the frustoconical portion 2 and describes a profile with a radius of 0.3 mm.The truncated cone section has a height of 0.4 mm, a maximum diameter of 0.49 mm at its junction with the base 1 and a minimum diameter of 0.4 mm at its junction with the plate 3. The plate 3 is flat and not inclined.

[0057] Figures 5a and 5b show an application head T3, which lacks a central window. This head T3 is designed to be mounted on a microneedle applicator that does not dispense a fluid product. This embodiment is similar to that shown in Figures 3a and 3b. The microneedles comprise four different models, namely Np, Nil, Ni2, and Nm, arranged in ascending order of height. The Np microneedles are those located on the outer periphery of the base surface S. The Nm microneedles are those located directly around the central window F. The Nil and Ni2 microneedles are located between the Np and Nm microneedles.

[0058] For example, fifteen Np microneedles, ten Nil microneedles, five Ni2 microneedles, and one Nm microneedle can be provided. As an example, the Np microneedles can have a height of 0.43 mm to 0.48 mm. The Nil microneedles can have a height of 0.58 mm to 0.60 mm. The Ni2 microneedles can have a height of 0.67 mm to 0.68 mm. The central Nm microneedle can have a height of 0.7 mm. The base 1 of all the Np, Nil, Ni2, and Nm microneedles is identical. It has a height of 0.3 mm, a maximum diameter of 1 mm at its junction with the base surface S, a minimum diameter of 0.49 mm at its junction with the frustoconical portion 2, and describes a profile with a radius of 0.3 mm.The truncated conical sections of the Np, Nil, Ni2, and Nm microneedles have varying heights, increasing from the outside in, which means that their three platforms together define a dome shape that is both flattened and complete, since the Nm microneedle with its flat platform is located at the center. The orientations of the platforms (inclined for Np and Nil, and flat for Ni2) are also varied. for Nm) further improve this full dome shape, which avoids the effects of sharp edges.

[0059] In [Fig. 6], an application head T4 is shown, which also lacks a central window. This embodiment is distinguished by the reduced height of the Ns microneedles, which is only 0.4 mm. Furthermore, there are only sixteen Ns microneedles, instead of thirty-one in previous embodiments. All the Ns microneedles are identical here. The base 1 has a height of 0.2 mm, a maximum diameter of 0.8 mm, a minimum diameter of 0.44 mm, and a radius of 0.2 mm. The frustoconical portion 2 has a height of 0.2 mm, a minimum diameter of 0.4 mm, and a flat, not inclined, platform 3.

[0060] It can be seen in the figures that the density of the Ns microneedles is lower than that of the previous embodiments, which have thirty-one microneedles, instead of sixteen here. This reduced density is compensated for by the reduced height of the Ns microneedles to provide a skin penetration capacity that is substantially similar to that of the previous embodiments, which have more microneedles with greater heights.

[0061] As an indication, the density of microneedles is about 44 per cm2 for the embodiments of figures 2a to 5b and only about 22 per cm2 for the embodiment of [Fig.6].

[0062] In all embodiments, the application heads T, T1, T2, T3, and T4 are made in one piece, preferably by injection molding of plastic material, advantageously polypropylene, preferably having a stiffness E of 1850 MPa. Other manufacturing processes, such as 3D printing, sintering, punching, pressing, etc., are also possible. However, it remains a requirement that the chosen process does not leave any plastic residue on and / or in the user's skin.

[0063] In all embodiments, the taper angle of the frustoconical portion 2 can be on the order of 7° to 15° with respect to the vertical axis of revolution. Preferably, it is 7°. The frustoconical portion connects to the base 1 continuously, without any step or edge.

[0064] Thanks to the invention, an application head for a microneedle applicator is provided, the plastic microneedles having an optimal design, with a curved base 1 representing approximately half or more of the total height of the microneedle and a frustoconical portion 2 representing approximately half or less of the total height of the microneedle. Even when the height of the frustoconical portion 2 varies, as is the case in the embodiments of Figures 3a, 3b and 5a, 5b, the height of the base 1 remains constant.

Claims

Demands

1. A microneedle applicator comprising an application head (T; T1; T2; T3; T4) provided with several microneedles (N; Np, Ni, Nm; Np, Nil, Ni2, Nm; Ns) and a motor (M1) for vibrating the microneedles (N; Np, Ni, Nm; Np, Nil, Ni2, Nm; Ns), the application head (T; T1; T2; T3; T4) defining a base surface (S) from which the microneedles (N; Np, Ni, Nm; Np, Nil, Ni2, Nm; Ns) protrude, characterized in that the base surface (S) and the microneedles (N; Np, Ni, Nm; Np, Nil, Ni2, Nm; Ns) are made in a single piece of plastic material, each microneedle (N; Np, Ni, Nm; Np, Nil, Ni2, Nm; Ns) comprising a base (1) emerging from the base surface (S), a truncated conical part (2) which extends in the continuation of the base (1) and a plate (3) which terminates the truncated conical part (2).

2. Applicator according to claim 1, wherein the microneedles (N) have a height of approximately 0.4 mm to 0.7 mm, measured from the base surface (S) to the tray (3).

3. Applicator according to claim 1 or 2, wherein the base (1) has a height of approximately 0.2 mm to 0.3 mm.

4. Applicator according to any one of the preceding claims, wherein the base (1) has a maximum diameter of approximately 0.8 mm to 1 mm at the point where it connects to the base surface (S).

5. Applicator according to any one of the preceding claims, wherein the base (1) has a minimum diameter of approximately 0.44 mm to 0.49 mm at the point where it connects to the truncated conical part (2).

6. Applicator according to any one of the preceding claims, wherein the base (1) is curved with a radius of approximately 0.2 mm to 0.3 mm.

7. Applicator according to any one of the preceding claims, wherein the frustoconical part (2) has a diameter of approximately 0.4 mm at the point where it connects to the plate (3).

8. Applicator according to any one of the preceding claims, wherein the frustoconical part (2) has a height of approximately 0.1 mm to 0.4 mm.

9. Applicator according to any one of the preceding claims, wherein the microneedles (N; Np, Ni, Nm; Np, Nil, Ni2, Nm; Ns) have a density of 10 to 50 per cm2 and preferably of 22 to 44 per cm2.

10. Applicator according to any one of the preceding claims, wherein the application head (T; T1; T2; T3; T4) is made by injection / molding of polypropylene, advantageously having a stiffness E of 1850 MPa.

11. Applicator according to any one of the preceding claims, wherein the plates (3) together define a dome shape.

12. Applicator according to claim 11, wherein the application head (T1; T3) defines an outer periphery and a center, the microneedles (Np, Ni, Nm; Np, N1, Ni2, Nm) having increasing heights going from the outer periphery to the center.

13. Applicator according to any one of the preceding claims, wherein the application head (T; Tl) forms a window (F) which opens at the level of the base surface (S), this window (F) receiving at least one fluid product outlet conduit (RI 1) connected to a fluid product reservoir (RI).

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