HK1176852B - A liquid receiving bottle with drop by drop dispensing head - Google Patents

Description

Liquid-containing bottle with drop-wise dispensing head

Technical Field

The present invention relates to the design and production of containers for packaging and for the controlled dispensing (dispensing, conveying) of liquids. The main novel feature of the present invention relates to a head for dispensing a liquid from a reservoir of a bottle, said reservoir having an elastically deformable wall which can be reversibly restored to its original configuration by sucking air into said bottle after dispensing a dose of liquid, in particular with the aim of dispensing dropwise.

The invention has preferred, but not limiting, application in the field of pharmaceutical liquid compositions, in particular in ophthalmic applications. In this field, the problems of purity and precision of the dispensed product are of utmost importance. Very similar requirements can be found, for example, in cosmetology or dermatology, in particular with regard to the precision of the dispensing site of the extruded drops, if necessary in relation to the intended dose to be administered.

Background

More specifically, the subject of the invention is a packaging bottle with a reservoir having a reversibly elastically deformable wall and a head for dispensing a liquid through a drop-counting end piece projecting outside the bottle and comprising an antibacterial filter membrane that protects the liquid contained in said reservoir from contaminants coming from the outside environment. In bottles industrially manufactured by the applicant, in particular according to the french patent application published under number FR2872137, such a membrane is placed between the reservoir for the liquid inside the bottle and the dispensing end piece at the base of the channel for expelling the drops, across the duct for the flow of the liquid, and this same duct also serves as an inlet for the re-expansion of the bottle by external air entering after each dispensing operation in order to replace the liquid previously expelled.

This operation may be achieved by using the antibacterial filter membrane as a bifunctional membrane which is partly hydrophilic and partly hydrophobic, similar to membranes which may for example be made of polyethersulfone based polymers. The unique feature of these membranes is that they allow to pass through themselves alternately or preferably by the aqueous liquid in the bottle or preferably by air from the outside, depending on the pressure difference between the pressure present on the side of the membrane facing the reservoir and the pressure present on the other side of the membrane facing the dispensing channel.

The presence of such a membrane, which on the one hand allows the passage of the liquid in the dispensing direction under the effect of the pressure exerted by the user on the walls of the reservoir and on the other hand allows the passage of air from the outside into the reservoir in the opposite direction when the pressure of the bottle is released after the dispensing of the drops of liquid, is one factor that makes it possible to package ophthalmic liquids in multi-dose bottles without having to incorporate preservatives in their components.

However, correct operation of the multi-dose bottle so formed requires precise control of droplet generation, which, as described in the patents already cited, in bottles made by the applicant requires the use of a dispensing head having an insert spanning the liquid flow between the reservoir and the membrane, the insert having a hollow body containing a porous (more precisely microporous) pad serving as a liquid flow regulator. Thus, the pad is positioned downstream of the reservoir and upstream of the bifunctional membrane in the direction of liquid flow from the reservoir to the dispensing end piece. Advantageously, the pad is made of a material having hydrophobic properties.

Although such bottles are satisfactory in many cases, the use of such bottles poses particular problems for drop-wise operations when it comes to packaging solutions having surface-active properties. In this case, to avoid reliance on preservatives, single dose packaging ampoules are preferred for these problems, but have disadvantages in terms of product consumption (leaving an excess of contents wasted per use). In particular, the problem of poor quality of droplet formation is encountered with ophthalmic formulations containing active ingredients which are themselves of surface-active nature or surface-active additives which act as emulsifiers (e.g. polysorbates, glycerol, glycol ricinoleates) or other excipients, for example some viscosity agents or lubricants of the polyvinyl alcohol derivative family or of the polyethylene glycol family.

The source of the present invention is that it appears that the drop-wise dispensing in this case is hampered by the fact that: foam is formed upon exiting the porous pad and the operation of the hydrophobic/hydrophilic dual function membrane is disrupted when a biphasic liquid/gas mixture is able to come into contact therewith.

Disclosure of Invention

To solve the above-mentioned problems and achieve substantially the same effect, in the case of drop-by-drop dispensing, as already seen in the case of non-foaming liquids, the efforts are then no longer directed to the flow conditions of the liquid as it is expelled from the bottle, but to the conditions of air admission after each dispensing operation. In this way, a constructive form of the dispensing head is achieved, which tends to prevent air from staying inside the porous pad (porous buffer), each passage of air remaining in the pad being responsible for the formation of foam in the liquid, which then passes through the pad in the opposite direction.

According to the invention, it is proposed that the insert forming the dispensing head is mounted with the periphery of its body sealingly in the neck of the reservoir (container), with the base of the body extending beyond the porous pad, which enters the bottle, forming therein a star-shaped pattern of passages that direct air radially to the periphery of the bottle. This passage has the effect of distributing the air evenly over the entire cross section of the bottle above the surface of the liquid still contained in the reservoir, while promoting the suction of the air extracted from the porous pad, by virtue of the section of the passage being widely open (open) so as not to cause a pressure loss at this location. In addition, advantageously, the same base of the insert forms, beyond these radial passages, a central tab (tablet-like portion, small disk-like portion) which prevents air from blowing directly onto the surface of the liquid along the general axis of rotation of the bottle.

In addition to the above, the invention advantageously provides that, in the body of the insert, the porous pad is spaced from the bifunctional membrane by an axial height, allowing the blisters leaving the pad to break over the full range before reaching the membrane, even in the case of formulations with surface-active characteristics. This prevents any risk of foam formation in the discharged droplets. This ensures that the membrane is covered by a thin film of liquid that does not contain air when the droplets are extracted. It will be noted that the hydrophobic part of the membrane then represents the critical point, since the flow rate of air over the hydrophobic part is much greater than the flow rate of liquid over the hydrophilic part, with equal surface areas. In formulations without surface active features, the bubbles collapse immediately upon formation away from the porous pad under the pressure exerted on the bottle body. On the other hand, the foaming solution promotes the formation of bubbles of larger size, which are characterized in that they can deform before being able to collapse, which makes them have a longer life inside the dispensing head.

By avoiding the destructive effect of the biphasic mixture in the discharged liquid and the consequent malfunction of the bifunctional membrane, the invention makes it possible to ensure repeatability of the liquid volume of each drop of liquid dispensed at each dispensing operation and the composition of this liquid. In the case of ophthalmic drops, there are two fundamental factors observed by patients for prescribing a dose to be administered. These advantages offered by the present invention are obtained while maintaining the conditions of correct operation associated with the flow conditions of the liquid, in particular when working with air flowing into the reservoir inside the bottle at its inlet, and therefore passing upstream through the porous pad in the direction of flow of the liquid.

More precisely, the bottle designed to package the liquid to be dispensed dropwise according to the invention advantageously has the following characteristics which can be considered individually or in any technically realizable combination. It comprises a reservoir with an elastically deformable wall which can be reversed by letting air enter the reservoir through a dispensing head (head) through which the liquid is dispensed under the effect of the pressure exerted on the wall, the dispensing head comprising an insert with a hollow body through which the dispensing head is mounted in a sealed manner in the neck of the bottle and communicates with the reservoir. The dispensing head comprises an end piece extending the head to the outside of the bottle, the end piece being traversed by a central channel leading to an orifice for discharging the liquid. The dispensing head also comprises an antibacterial (anti-bacterial) filtering membrane made partially hydrophilic and partially hydrophobic, mounted on the base (bottom) of the end piece between the end piece and the insert. The filter membrane allows liquid to pass through it in the dispensing direction and allows the required air to pass through the filter membrane into the bottle in the opposite direction after liquid dispensing to compensate. The insert contains a porous pad for regulating the flow (flux) on the path of the liquid pushed from the reservoir to the discharge channel (when the internal volume is reduced under the action of the pressure manually exerted on the wall of the bottle). The pad, advantageously made of hydrophobic material, is arranged in an axial position downstream of the reservoir and upstream of a chamber itself delimited downstream by a filter membrane arranged upstream of the end piece, across the passage formed by the central recess of the pad. "upstream" and "downstream" are defined herein with respect to the direction of flow of the liquid when it is dispensed, i.e. from the packaging reservoir to the channel for expelling the droplets.

According to the invention, the insert with a hollow body advantageously ends at its end directed towards the reservoir at a distance from the inner periphery of the bottle at a seat formed by a longitudinal arch supporting a central tab having a diameter smaller than the inner diameter of the insert, so as to form the reservoir receiving the liquid at rest at its inner space. The shape of the insert leaves a considerable open space for the passage of the liquid leaving the reservoir to reach the dispensing head and above all it forms a wide open passage in the bottle in the radial direction, which makes it easier for compensation air sucked through the porous pad to enter between two liquid discharge operations, while immediately distributing this air over the entire cross section of the bottle, including in the vicinity of the peripheral wall of the bottle.

The arch of the base of the insert advantageously takes the shape of a longitudinal lug folded radially at the bottom end to support the central tab portion and connect it to the external ring of the body. This shape gives the insert good strength against compression at its base. This provides the insert with good mechanical strength in the longitudinal direction to prevent bending. This makes it possible to guide the assembly when it is put in place by inserting it along the axis of the bottle neck by longitudinal pressure, while imparting mechanical strength. It also makes it possible to hold the porous pad, which may slide towards the reservoir of the bottle during handling. Furthermore, this helps to provide a differentiation to the assembly elements of the dispensing head during storage and transport of these elements when they are loose in the bag before they are fitted in the bottle. In the industrial manufacture of eyewashes (eyedrops) where it is necessary to separate the said tops, which are thus snapped together, the space requirement of the insert bases (domes and central tabs) prevents the two dispensing heads from being coupled together by the penetration of the end piece of one dispensing head into the central channel of the insert of the other dispensing head, thus preventing any stresses that would be generated.

The bottle provided with a dispensing head according to the invention is extremely advantageous in terms of regulating and controlling the volume of the drops expelled, because of the particular structure of the seat of the insert, placed in the neck of the reservoir and containing the flow-regulating microporous pad. This construction allows in particular an easy return of air into a reservoir for storing liquid located at a distance from the membrane after each dispensing operation. This smoothing of the flow of air and liquid reduces the amount of air bubbles in the liquid that flows out to the membrane when dispensing droplets of liquid, particularly surfactant liquid. Moreover, this gives the appropriate distance necessary for the collapse of the bubbles, which are present at the interface of the outlets of the pad when the liquid flow carries the air that remains absorbed in the pad between the two expulsion operations, for the intermediate chamber between the porous pad and the membrane. It can be considered that such a chamber has for the exiting liquid flow the function of a flow regulating pad, which is complementary to the flow regulating function of the material pad, and the function of being distributed in the transverse direction before passing through the membrane if the membrane has an even distribution of hydrophilic and hydrophobic areas. Furthermore, since the chamber forms an air cushion, it also functions as a cross-sectional distribution when operating on the air inlet between the end piece that lets air in and the outer surface of the material mat that creates good conditions for air entry. This facilitates dispensing of a uniform dose of liquid. As already known, this chamber also keeps the membrane dry between two dispensing operations when the container rests in its normal position, i.e. on its base, receiving inside it the residual liquid that has not been drained.

The invention also satisfies the following features which can be applied individually or in technically feasible combinations, according to preferred embodiments in industrial practice.

According to an advantageous feature of the invention, the arches are three in number and are placed at equal distances from each other, so that the passage interface provided for the air to enter the bottle is widely open, while providing good firmness to the base of the insert body.

For the purpose of preventing any pressure loss of the air flow entering the bottle, in a preferred embodiment of the invention, the arch has a height of between 1mm and 5mm, preferably between 2mm and 4 mm.

A hydrophobic microporous pad located in the body portion regulates the liquid flow, occupies the entire cross section of the body portion, and generates a pressure loss through the microporous pad. In this way, it facilitates the controlled dispensing of liquid doses. It also prevents the flow of liquid contained in the reservoir when no pressure is exerted on the walls of the reservoir.

According to an advantageous feature of the invention, the pad is designed to trap a minimum amount of air in the pores of the pad.

The porosity (porosity) of the pad is suitable for the (air) inflow and the (liquid) outflow without causing too large a pressure loss, and it is also necessary to ensure a size sufficient for the bubbles to be able to easily collapse before reaching the surface of the membrane.

Thus, in a preferred embodiment of the invention, the hydrophobic microporous pad has an equivalent (equivalent) porosity of between 20 μm and 120 μm.

The pad is preferably made of low density polyethylene, which imparts hydrophobic properties to the pad, so that the pad is non-absorbent. However, its microporous nature allows the liquid to pass through the pad under a sufficient pressure differential-generated between the reservoir and the outside by the pressure exerted by the user on the deformable wall of the reservoir. The nature of the pad is such that it does not interact with the formulation of the liquid, more specifically with the active ingredient.

To obtain the chamber height (distance between the top surface of the pad and the membrane) necessary to cause the bubbles to collapse before reaching the membrane, one can address the longitudinal thickness (height) and/or arrangement of the pad.

According to an advantageous feature of the invention, the pad has a longitudinal thickness which is large enough to create a pressure loss capable of preventing the liquid from wetting the membrane before the first use of the bottle, in order to prevent deterioration of the membrane, while being small enough to ensure that the chamber between the pad and the membrane has a considerable height. Thus, when the bottle is used, the bubbles that may form on the top surface of the pad, i.e. on the surface directed towards the chamber, have a complete chance of rupturing within the chamber without the risk of reaching the bifunctional membrane. Thus shielding the bifunctional membrane from these gas bubbles.

According to a preferred embodiment of the invention the height of the chamber, i.e. the distance between the top surface of the porous pad and the membrane, is more than 2 mm. Preferably, the height is greater than or equal to about 3 mm. Again preferably, the height has a value between 4mm and 10mm, in particular between 5mm and 9 mm.

The longitudinal thickness of the pad after insertion into the insert is preferably in the range between 0.3mm and 0.8 mm. The pad is compressed when put into the hollow body and the thickness of the pad can be reduced by 50%. The pad is positioned in the insert so that the chamber downstream (in the direction of liquid flow) above the pad is high enough-as defined above-to allow bubbles that may form in the liquid leaving the pad to break before reaching the membrane.

The bifunctional membrane itself is a conventional membrane. For example, it is made of a polymer based on a polyamide resin or on a polyether sulfone resin. The membrane is rendered substantially hydrophilic in character to selectively allow liquid to pass through during a dispensing operation. The membrane is made partially hydrophobic on a portion of its surface, which portion thus selectively allows the air to flow from the outside to the reservoir after each dispensing operation, by structural modification, in particular by grafting in the presence of a radical reaction initiator. This treatment is carried out in particular on an intermediate band occupying 20% to 50% of its surface, located on the whole path of the liquid. The membrane also preferably has an average pore size of about 0.1 μm to 0.2 μm in order to perform an antibacterial function by filtration, thereby protecting the liquid still present in the bottle from any biological contamination from the outside.

According to an advantageous feature of the invention, the insert with the hollow body is designed to be forced into the neck of the bottle by pressure on the longitudinal axis. It is preferably assembled within the container by a close contact fit (nesting, joggling).

The central tab portion, which is supported by the arch and is spaced a distance from the main portion of the insert, advantageously serves to provide strength during the forced insertion of the insert into the neck of the container during manufacture of the container. This is very useful when the method for manufacturing the insert is implemented by plastic injection, as it makes it possible to position the injection point at this level and prevent sealing problems due to mold flash on the periphery of the insert body.

In a preferred embodiment of the invention, the insert body is resiliently deformable at its periphery to make it easier to place in place by being forced into the neck of the container. The insert body comprises a ring of larger diameter on the top edge, which rests on the top edge of the neck of the container to ensure good positioning of the insert in the neck. The ring also advantageously serves as a bearing surface for pushing the insert into the neck during assembly.

The insert is preferably fitted with at least one O-ring, preferably with a plurality of O-rings distributed axially, on the outer surface, so as to ensure that the contact between the insert and the neck of the container is hermetic. These O-rings, also called grooves (gordon), form in particular an integral component with the insert.

As with the other elements forming the container according to the invention, the insert is advantageously made by moulding and then assembled together.

The container according to the invention also offers the following advantages which may have been described in the applicant's patents, in particular in patent publication FR2872137, which are related to the presence of: a memory having a reversibly deformable wall; an antibacterial filtering membrane; a flow-regulating mat and a chamber interposed between the membrane and the flow-regulating mat. In particular, the reversibly deformable wall ensures optimal utilization of all the liquid contained in the reservoir; the reservoir keeps the discharge capacity intact during successive dispensing operations by letting in air that restores the discharge pressure to its initial value after each discharge operation. The membrane protects the liquid contained in the reservoir from external contamination. It also constitutes the cause of pressure loss, which is added to the pressure loss created by the microporous pad, in order to improve the regulation of the liquid flow and to ensure that no leakage from the reservoir occurs when no pressure is applied to the walls of the reservoir.

In addition to its effectiveness in controlling the volume of drops dispensed, preserving the liquid in the reservoir and optimizing the use of the total volume of liquid, the container according to the invention has the following advantages: simple structure, limited production costs and is completely suitable for the application field of consumable products, can be discarded after use, and is very easy for the consumer to use.

As mentioned above, the invention applies more particularly to bottles for packaging and dispensing liquids, in particular eye washes, containing compounds with surface-active properties.

The invention can be applied to all fields in which drop-counting bottles are used, in particular in any case in which the product to be dispensed is a foamed product containing surface-active properties that promote the formation of bubbles.

The invention also relates to a dispensing head as described above, designed to be fitted to a reservoir with elastic walls of a drop counter bottle.

Drawings

The present invention will now be described more fully with reference to fig. 1-3, in the context of preferred features and advantages thereof. In the drawings:

figure 1 shows a bottle according to the invention in axial section;

FIG. 1A shows the bottle of FIG. 1 in exploded axial cross-section;

figure 2 shows in perspective an insert of the dispensing head of the bottle of figure 1 with a hollow body; and

fig. 3 shows the insert of fig. 2 in a top view.

Detailed Description

In fig. 1 and 1A, a container for packaging a liquid to be dispensed dropwise is shown in the form of a bottle designed more particularly for packaging an eyewash. The elements of the container are typically constructed of a plastic compatible with the application to hold the ophthalmic solution. They are made in particular of polymers of the polyethylene family.

The bottle comprises a liquid storage reservoir 2, the cylindrical peripheral wall of the reservoir 2 being reversibly elastically deformable to allow a user to dispense the liquid 1 by manual squeezing and then to spontaneously return to its original shape by the ingress of air when the squeezing is released. Make-up air for each drop of expelled liquid enters along the reverse path of the discharge through the dispensing head occupying the neck of the bottle. There is no other air inlet, in particular no pressure equalizing hole through the base of the neck and the wall of the bottle. The cylindrical peripheral wall has a narrowed portion (narrowing portion) 20 at its free end, from which the neck 10 projects (extends).

The dispensing head for dispensing the liquid drop by drop comprises an insert 4 of hollow body placed inside the neck 10 of the bottle, a dispensing end piece (or nozzle) 5, and optionally, as shown here, a removable cap 6 for closing the end piece, usually screwed around the neck of the bottle. The head also comprises a porous pad 8 contained in the insert 4 and an antibacterial film 7 placed at the base of the end piece 5.

An antimicrobial filter membrane 7, which is partially hydrophilic and partially hydrophobic, is arranged upstream of the end piece 5 in the direction of flow of the liquid from the reservoir to the dispensing end piece, to protect the liquid 1 by filtering out external contaminants, in particular bacteria. The membrane 7 is freely supported in operation by being pressed against the seat of the end-piece 5. The membrane 7 is attached at its periphery by heat sealing between a peripheral ring of the seat (here, this peripheral ring has a projection which is reduced during the sealing operation between the two parts) and an interacting support surface located on the terminal face of the insert 4. The membrane is made of, for example, polyethersulfone which is partially hydrophobically treated on a portion of its surface. The film has a porosity of about 0.1 μm to 0.2 μm. The seat of the end piece, which has the shape of a concave disc fitted inside the hollow body 4, has on its inner surface microchannels 3 which make it easier for the liquid to drain towards the discharge opening.

The insert 4 has a substantially cylindrical shape, in this case with an internal diameter of about 1cm, which is flared at the top end portion to a diameter of about 1.5cm, forming an interacting bearing surface provided with fins 16 for supporting the membrane 7 when it is squeezed between the insert and the end piece. In this example, the body of the insert (the base formed by the arch and the tab) has a height of about 1.5 cm. The insert accommodates in its inner recess a microporous pad 8 made of hydrophobic material having a cylindrical shape closely conforming to the recess. The microporous mat is made in particular of a felt with polyethylene filler. The presence of this microporous pad has the effect of regulating the flow of the liquid to be dispensed and of preventing the liquid from flowing from the reservoir 2 to the end piece 5 when the walls of the container are not compressed, whereby the flow rate of the liquid to be dispensed can be regulated. The pad 8 is arranged upstream of the membrane 7 at a distance from the membrane in the direction of flow of the liquid from the reservoir to the dispensing end piece, so that an intermediate chamber 9 is arranged between the pad and the membrane. This chamber 9 allows in particular the bubbles of dispensed liquid to break before reaching the membrane 7. The chamber also makes it possible to collect the residual liquid that has not been drained.

The pad 8 has an equivalent porosity of about 100 μm. In this case, the pad 8 also has a height of about 0.5cm, i.e. equal to about 33% of the height of the body of the insert, when it is in place in the insert 4 and in a compressed state. The pad had a height of about 1cm before being inserted therein. The pad is placed in the bottom of the insert body so that the chamber 9 between the pad and the membrane 7 has a considerable height, in this case a height of about 6 mm. Air bubbles may be trapped in the pad after air is drawn in with the operation of expelling one droplet, said bubbles being of a size such that they can be ruptured in the intermediate chamber 9 before reaching the dual-function chamber when they are expelled from the pad simultaneously with the liquid during the subsequent operation of dispensing the liquid.

The insert 4 comprises, at its base and at the end directed towards the inside of the reservoir containing the liquid, as shown in more detail in figure 2, a central tab 11 having a diameter much smaller than the diameter of the cylindrical body portion of the insert, in this case about 0.4 cm. The small piece is supported by a longitudinal arch 13. These arches are in the form of lugs, relatively long and specifically oriented in the longitudinal direction, which engage together at one end with the cylindrical portion of the insert 4 and are bent radially towards the axis of the insert at the opposite end, so as to support the tab portion 11 centred on this axis.

The arches 13 are sufficiently high to arrange wide open passages between them, allowing the air entering the reservoir of the bottle to flow through the axial ducts of the dispensing head. This height is in particular equal to approximately 3.5 mm. The lugs forming the arch each have a total length of about 5 mm. These arches provide about 0.40cm of space at the base of the insert³From which air escapes mainly in radial direction around the axis of the assembly. It will be appreciated that it is important that the passages formed between the arches allow, on the one hand, the liquid to flow from the reservoir to the outside via the pad, so that the base does not hinder the liquid distribution, and on the other hand that they make it possible to direct the returning air towards the walls of the reservoir. The returning air is thus directed radially on the wall and not directly on the liquid still present in the reservoir. For this purpose, the central small piece has the shape of a disc whose diameter is large enough to block the passage of air originating from the pad in the axial direction, thus being directed in towards the wall of the reservoirAir entering the reservoir. As can be seen from fig. 1, it is particularly advantageous that the central tab is located at a narrow portion 20 of the bottle where the peripheral wall is not substantially vertical when the insert is mounted in the neck of the bottle. The incoming air, which after being blocked by the tab portion is deflected radially, reaches this inclined portion of the peripheral wall of the bottle, so that it does not hit said wall head-on, but is guided along this wall in a laminar manner towards the liquid still present in the reservoir.

As can be seen in fig. 3, the arches 13 are three in number and are arranged equidistant from each other, so as to ensure the firmness of this portion of the insert, in particular in terms of resistance to compression in the longitudinal direction. It will be appreciated that the number of arches and their arrangement may be different when they are arranged as open passages for liquid flow to drain them and for air return.

The central tab 11 makes it easier to force the insert into the neck 10 of the bottle. The central patch portion includes a point 12 at its center and on its outer surface, which point is from the point of injection of the polymer to form the assembly. The central tab portion acts as a stop when the insert is inserted into the neck of the bottle, while making it possible to facilitate the axial guidance of the insert by means of the arch. It prevents the porous pad from being damaged and falling off during the bulk transport of the dispensing heads provided with the end piece. Its presence is also useful as part of a preferred method for producing the insert by injection molding. It includes at 12 the locus of points at which the polymer is injected into the mould. This prevents the injection point, which may be located on the outside of the insert, from forming a leak that is detrimental to the necessary seal between the insert and the neck of the bottle.

The insert 14 is formed on its top edge with a peripheral ring 14 of larger diameter, in this case about 2cm in diameter. This ring acts as a stop allowing the insert 4 to be properly positioned in the neck 10 of the bottle during assembly.

During assembly, the insert 4 is loaded into the neck 10 of the bottle by force fitting. This fit is achieved due to the slight elastic deformability of the material forming the insert. This fit is achieved by a circular O-ring 15, called a groove, arranged on the outer periphery of the insert. The seal is preferably formed integrally with the insert in the same step as that carried out by moulding. These seals ensure a contact seal with the inner wall of the neck 10. They also provide guidance of the insert when assembled by axial compression, resulting in a tight contact fit overall without risk of angular positioning.

The bottle of the invention was tested with a small amount of solution containing an emulsifying active ingredient in an emulsifier with surface active properties in order to verify the calibrated uniformity of the solution droplets expelled according to the chamber height for a given insert and a given porous pad configuration that meet the above specifications. The calibration uniformity of the droplets was verified by weighing ten expelled droplets and repeating each test three times. These tests show that the volume of the ejected droplets varies by less than 10% for a chamber having a height of at least 3mm, and that in practice the droplets retain sufficient mass in most cases. For a height of 6mm, the results are better, with a variation of less than 5%.

The foregoing description clearly illustrates how the invention achieves the objectives set by itself. In particular, the present invention provides a container of the type having an air inlet and a bifunctional filtering membrane for packaging and dispensing liquids, in particular ophthalmic liquids, which ensures good uniformity of dispensing, while in particular preventing the presence of air in the dispensed liquid, even if the liquid has surface-active characteristics. The present invention makes it possible to control the correct calibration of the drops and the repeatability of the doses dispensed, in order to ensure the correct efficacy of the drug and to ensure that there are no side effects that may be caused by improper dosing. The invention is of course not, however, limited to the embodiments that have been specifically described, but on the contrary extends to any variant obtained by equivalent means.

Claims (10)

1. A drip dispensing bottle comprising a reservoir (2) having an elastically deformable wall, which is reversible by allowing air to enter the reservoir via a dispensing head through which liquid is dispensed under the action of a pressure exerted on the wall, wherein the dispensing head comprises an insert having a hollow body, a dispensing end piece which is an extension of the body and is pierced by a central channel leading to a discharge opening, and a partially hydrophilic and partially hydrophobic bifunctional antimicrobial filter membrane mounted across the insert at the base of the end piece so as to allow the passage of liquid in a dispensing direction and the passage of air in the opposite direction which is required to enter as a compensation after the dispensing of the liquid, the insert comprising a hollow body allowing on the one hand the sealed mounting of the dispensing head in the neck of the bottle by its periphery, on the other hand, allowing the dispensing head to communicate with the reservoir through an internal recess thereof, in which a porous pad (8) is housed for regulating the flow of liquid through it towards the membrane, said porous pad being axially spaced from the membrane,

characterized in that the insert (4) comprises a base portion which extends the body beyond the porous pad in a direction opposite to the dispensing end piece, the base of the insert entering into the reservoir and forming a longitudinal arch (13) the end of which opposite the insert is radially curved towards the axis of the insert to support a central tab (11), the passages provided between said longitudinal arches being open to radial flow towards the periphery of the reservoir, for air entering the bottle after having passed through the pad, the central tab portion having a disc shape or disc shape, the central panel portion is centered on the axis of the insert and the axis of the bottle, leaving an open space, for the air to reach radially from the dispensing head, around the central tab, to the peripheral wall of the bottle, while forming an obstacle to the direct axial jet leaving the insert.

2. Bottle according to claim 1, characterized in that the insert (4) is mounted in the neck (10) of the bottle with its base extending to the narrowing (20) of the peripheral wall of the bottle in order to direct the incoming air in laminar flow along the wall, which is directed radially to the peripheral wall of the bottle due to the obstruction of the central tab.

3. Bottle according to claim 1 or 2, characterized in that the insert (4) is assembled into the bottle by force-fitting inside the neck (10) of the bottle and comprises, at its top edge, a ring (14) of larger diameter which abuts against the top edge of the neck (10) of the bottle to ensure good positioning of the insert (4) in the neck (10).

4. Bottle according to claim 1 or 2, characterized in that said arches (13) are three in number, arranged at equal angular distances from each other around the axis of the neck of the bottle.

5. Bottle according to claim 1 or 2, characterized in that said arch (13) has a height of between 1mm and 5 mm.

6. Bottle according to claim 1 or 2, characterized in that the porous pad is a microporous pad made of hydrophobic material, in the form of a felt having an equivalent pore size between 20 μ ι η and 120 μ ι η.

7. Bottle according to claim 1 or 2, characterized in that the distance between the top surface of the porous pad (8) and the membrane (7) is greater than 2 mm.

8. Bottle according to claim 7, characterized in that the distance between the top surface of the porous pad (8) and the membrane (7) is between 4mm and 10 mm.

9. Bottle according to claim 1 or 2, characterized in that the porous pad (8) is made of low density polyethylene.

10. Bottle according to claim 1 or 2, characterized in that the outer surface of the insert (4) is provided with a plurality of axially distributed O-rings.