Patent Description:
Certain diseases or conditions may be treated, according to modern medical techniques, by delivering a medication fluid or other substance to the body of a patient, either in a continuous manner or at particular times or time intervals within an overall time period. For example, diabetes is commonly treated by delivering defined amounts of insulin to the patient at appropriate times. Some common modes of providing insulin therapy to a patient include delivery of insulin through manually operated syringes and insulin pens. Other modern systems employ programmable fluid infusion devices (e.g., continuous insulin infusion devices such as insulin pumps) to deliver controlled amounts of insulin or other drugs to a patient.

A fluid infusion device suitable for use as an insulin pump may be realized as an external device or an implantable device, which is surgically implanted into the body of the patient. External fluid infusion devices include devices designed for use in a generally stationary location (for example, in a hospital or clinic), and devices configured for ambulatory or portable use (to be carried by a patient). External fluid infusion devices may establish a fluid flow path from a fluid reservoir to the patient via, for example, a suitable hollow tubing. The hollow tubing may be connected to a hollow fluid delivery needle that is designed to pierce the patient's skin to deliver an infusion fluid to the body. Alternatively, the hollow tubing may be connected directly to the patient's body through a cannula or set of micro-needles.

It is desirable to reduce the amount of air bubbles in a medication fluid before delivering the fluid to the patient. Small bubbles may be introduced into the medication fluid during a reservoir filling operation, for example, when the fluid reservoir is filled from a vial using a syringe. Although patients are instructed to eliminate air from a filled reservoir, some micro bubbles may remain.

Accordingly, it is desirable to have an assembly, system, or component that is designed to mitigate the effects of air bubbles within a medication fluid flow path. In addition, it is desirable to have an assembly, system, or component that reduces the presence of air bubbles in a fluid flow path while also filtering particulates and/or unwanted substances from the medication fluid. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. <CIT> discloses a drip infusion device having an inlet tube leading to a chamber having a liquid permeable membrane leading to an outlet tube and a gas permeable membrane leading to a gas vent.

In one aspect of the invention, claim <NUM> defines a fluid conduit assembly. In a further aspect, claim <NUM> defines a fluid delivery system. Disclosed herein is a fluid conduit assembly for delivery of a medication fluid. An exemplary embodiment of the fluid conduit assembly includes a structure defining a flow path for the medication fluid and a gas trapping filter coupled to the structure. The gas trapping filter is positioned in the flow path to filter particulates from the medication fluid and retain gas bubbles from the medication fluid.

A fluid delivery system is also disclosed herein. An exemplary embodiment of the system includes: a fluid infusion pump to provide a medication fluid; a fluid conduit assembly coupled to the fluid infusion pump; and a gas trapping filter. The fluid conduit delivers the medication fluid to a user, and the fluid conduit assembly defines a flow path for the medication fluid. The gas trapping filter is positioned in the flow path to filter particulates from the medication fluid and retain gas bubbles from the medication fluid.

Also disclosed herein is a fluid conduit assembly for delivery of a medication fluid. An exemplary embodiment of the fluid conduit assembly includes a body section to receive a fluid reservoir, and a flow path defined in the body section. The flow path carries fluid from the fluid reservoir when the body section is coupled to the fluid reservoir. The fluid conduit assembly also has a length of tubing extending from the body section and in fluid communication with the flow path. The length of tubing carries fluid from the body section during a fluid delivery operation. The fluid conduit assembly also has a partially or predominantly hydrophilic gas trapping filter positioned in the flow path. to filter particulates from the medication fluid and retain gas bubbles from the medication fluid.

One embodiment of the present invention comprises a cap for a reservoir of a medicinal fluid which provides a fluid flow path for the medicinal fluid to tubing used to deliver said fluid to a user; said cap comprising: a lower body section configured to be able to engage with the reservoir and having an axial bore to conduct the medicinal fluid from the reservoir, an upper body section having an axial bore for connection at one end to the tubing, the axial bore of the upper body section being in fluid communication with the axial bore of the lower body section to receive the medication fluid via an internal chamber; wherein a gas trapping filter is housed within the internal chamber and configured to retain gas bubbles thereby preventing said gas from leaving the internal chamber.

The gas trapping filter may be adapted to have one or more of the following additional functions: a. filter out particulates; b. adsorb or absorb silicone oil; c. form a depot of a drug such that the drug is released into the medicinal fluid as it passes through. Particularly where the gas trapping filter is adapted to filter out particulates, it can have a pore size within the range of <NUM> to <NUM> microns. The gas trapping filter may comprise a hydrophilic sponge, felt or fiber composite material. If the gas trapping filter is of felt it preferably has a pore size in the range <NUM>-<NUM> micrometres, more preferably <NUM> to <NUM> micrometres. If the gas trapping filter is of sponge it preferably has a pore size in the range <NUM> micrometres to <NUM> millimetre.

The lower body section and the upper body section may be integral with one another. Whether or not the body sections are integral the lower body section may include an upstream hollow needle disposed axially within the axial bore and in fluid communication with the internal chamber upstream of the gas trapping filter for piecing a septum in the reservoir and conducting the medicinal fluid therefrom to the internal chamber. The gas trapping filter may comprise a discrete or an integrally formed cylindrical component axially disposed in the internal chamber and having a ratio of diameter to height of greater than unity, preferably <NUM>:<NUM> or greater. If discrete the gas trapping filter may be is held in the internal chamber by a first annular flange forming part of the lower body section, and second annular flange forming part of the upper body section, at least one of said annular flanges also sealing against margins of respective major surfaces of the gas trapping filter ensuring that the flow of medication fluid is through a central region of the filter.

On the other hand, the gas trapping filter may comprise a discrete cylindrical component axially disposed in the internal chamber and having a ratio of diameter to height of less than or equal to unity. In this case there may be provided a hydrophilic membrane separating the internal chamber from the bore of the upper body section. In all cases the upper body section may be a manual grip radially outwardly from the gas trapping filter enabling the cap to readily be turned by hand about its longitudinal axis. Such a cap can form part of a disposible fluid delivery assembly comprising a reservoir of the medicinal fluid, wherein the cap is further being provided with thread or bayonet fitting for detachably mounting the reservoir in an infusion pump, whereby the assembly can be detached for disposal by turning the cap via said manual grip.

In a further embodiment, the invention provides a fluid delivery system for delivering a medicinal fluid to a user comprising: an infusion pump including a reservoir of the medicinal fluid, said reservoir having a cap as described above; a length of tubing connected at a proximal end to the axial bore of the upper body section of the cap, and at a distal end to an infusion unit having a canula to enable fluid from the reservoir to be infused into the body of the user during operation of the pump.

The present invention according to a further embodiment provides a fluid conduit assembly for a medication fluid comprising: a first connector having a bore for connection at one end to an upstream tubing; a second connector having a bore for connection at one end to a downstream tubing; the first and second connectors being detachably couplable, such that when coupled the respective bores are in fluid communication allowing flow of the medication fluid from the upstream tubing to the downstream tubing via the said coupled bores; wherein one of the first and second connectors contains a hollow needle and the other contains a septum, and when the first and second connectors are coupled the needle pierces the septum thereby providing the said fluid communication between the bores of the said respective connectors; a gas trapping filter disposed in the bore of the second connector to retain gas bubbles and hinder such bubbles from traveling with the medication fluid into the downstream tubing. The gas trapping filter is adapted to have one or more of the following additional functions: a. filter out particulates; b. adsorb or absorb silicone oil; c. form a depot of a drug such that the drug is released into the medicinal fluid as it passes through. The gas trapping filter may is mold inside the bore of the second connector forming an integral component therewith. The fluid conduit assembly may further include a second gas trapping filter disposed in the bore of the first connector to detain gas bubbles in the medication fluid entering the fluid conduit assembly from the upstream tubing. In this case the second gas trapping filter may be adapted to have one or more of the following additional functions: a. filter out particulates; b. adsorb or absorb silicone oil; c. form a depot of a drug such that the drug is released into the medicinal fluid as it passes through. In all of embodiments the gas trapping filter may be of a predominantly hydrophilic material optionally exhibiting up to <NUM>% hydrophobicity.

The subject matter described here relates to certain assemblies, components, and features of a fluid infusion system of the type used to treat a medical condition of a patient. The fluid infusion system is used for infusing a medication fluid into the body of a user. The non-limiting examples described below relate to a medical device used to treat diabetes (more specifically, an insulin pump), although embodiments of the disclosed subject matter are not so limited. Accordingly, the medication fluid is insulin in certain embodiments. In alternative embodiments, however, many other fluids may be administered through infusion such as, but not limited to, disease treatments, drugs to treat pulmonary hypertension, iron chelation drugs, pain medications, anti-cancer treatments, medications, vitamins, hormones, or the like. Moreover, the gas trapping filter described below could be utilized in the context of other fluid delivery systems if so desired.

For the sake of brevity, conventional features and technologies related to infusion system operation, insulin pump and/or infusion set operation, and other functional aspects of the fluid infusion system (and the individual operating components of the system) may not be described in detail here. Examples of infusion pumps and/or related pump drive systems used to administer insulin and other medications may be of the type described in, but not limited to, <CIT>; <CIT>;<CIT>; <CIT>;<CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

<FIG> is a simplified block diagram representation of an embodiment of a fluid delivery system <NUM>, which can be utilized to administer a medication fluid such as insulin to a patient. The fluid delivery system <NUM> includes a fluid infusion device <NUM> (e.g., an infusion pump) and a fluid conduit assembly <NUM> that is coupled to, integrated with, or otherwise associated with the fluid infusion device <NUM>. The fluid infusion device <NUM> includes a fluid reservoir <NUM> or an equivalent supply of the medication fluid to be administered. The fluid infusion device <NUM> is operated in a controlled manner to deliver the medication fluid to the user via the fluid conduit assembly <NUM>. Although not depicted in <FIG>, the fluid delivery system <NUM> also includes a gas trapping filter that is positioned in the fluid flow path. In certain embodiments, the gas trapping filter is located within the fluid flow path defined by the fluid conduit assembly <NUM>.

The fluid infusion device <NUM> may be provided in any desired configuration or platform. In accordance with one non-limiting embodiment, the fluid infusion device is realized as a portable unit that can be carried or worn by the patient. In this regard, <FIG> is a plan view of an exemplary embodiment of a fluid delivery system <NUM> that includes a portable fluid infusion device <NUM> and a fluid conduit assembly that takes the form of an infusion set component <NUM>. For this particular embodiment, the infusion set component <NUM> can be coupled to the fluid infusion device <NUM> as depicted in <FIG>. The fluid infusion device <NUM> accommodates a fluid reservoir (hidden from view in <FIG>) for the medication fluid to be delivered to the user.

The illustrated embodiment of the infusion set component <NUM> includes, without limitation: a tube <NUM>; an infusion unit <NUM> coupled to the distal end of the tube <NUM>; and a connector assembly <NUM> coupled to the proximal end of the tube <NUM>. The fluid infusion device <NUM> is designed to be carried or worn by the patient, and the infusion set component <NUM> terminates at the infusion unit <NUM> such that the fluid infusion device <NUM> can deliver fluid to the body of the patient via the tube <NUM>. The fluid infusion device <NUM> may leverage a number of conventional features, components, elements, and characteristics of existing fluid infusion devices. For example, the fluid infusion device <NUM> may incorporate some of the features, components, elements, and/or characteristics described in <CIT>and<CIT>.

The infusion set component <NUM> defines a fluid flow path that fluidly couples the fluid reservoir to the infusion unit <NUM>. The connector assembly <NUM> mates with and couples to the neck region of the fluid reservoir, establishing the fluid path from the fluid reservoir to the tube <NUM>. The connector assembly <NUM> (with the fluid reservoir coupled thereto) is coupled to the housing of the fluid infusion device <NUM> to seal and secure the fluid reservoir inside the housing. Thereafter, actuation of the fluid infusion device <NUM> causes the medication fluid to be expelled from the fluid reservoir, through the infusion set component <NUM>, and into the body of the patient via the infusion unit <NUM> at the distal end of the tube <NUM>. Accordingly, when the connector assembly <NUM> is installed as depicted in <FIG>, the tube <NUM> extends from the fluid infusion device <NUM> to the infusion unit <NUM>, which in turn provides a fluid pathway to the body of the patient. For the illustrated embodiment, the connector assembly <NUM> is realized as a removable reservoir cap (or fitting) that is suitably sized and configured to accommodate replacement of fluid reservoirs (which are typically disposable) as needed.

Although not visible in <FIG> the fluid delivery system <NUM> includes a gas trapping filter in the connector assembly <NUM> preferably immediately downstream of the reservoir. This traps any bubbles which may inadvertently enter the fluid pathway when the fluid reservoir is replaced. The filter itself can, but need not be, itself independently replaceable such that when the reservoir is replaced the filter can be removed from the cap / connector assembly <NUM> and replaced separately.

Another gas trapping filter may be included in the infusion unit <NUM> just downstream of the point when the tubing <NUM> enters the infusion unit, i.e. beyond the distal end of the tubing. With this second filter any gas that manages to pass the first filter is prevented from entering the patient. It is also envisaged that one of the filters be omitted. Either or both filters may be constructed to act as a particulate filter. Accumulated particles in the filter are disposed of by filter replacement.

<FIG> is a perspective view of another exemplary embodiment of a fluid delivery system <NUM> that includes a fluid infusion device <NUM> designed to be affixed to the skin of the user. The fluid infusion device <NUM> includes two primary components that are removably coupled to each other: a durable housing <NUM>; and a base plate <NUM>. The fluid infusion device <NUM> also includes or cooperates with a removable/replaceable fluid reservoir (which is hidden from view in <FIG>). For this particular embodiment, the fluid reservoir mates with, and is received by, the durable housing <NUM>. In alternate embodiments, the fluid reservoir mates with, and is received by, the base plate <NUM>.

The base plate <NUM> is designed to be temporarily adhered to the skin of the patient using, for example, an adhesive layer of material. After the base plate is affixed to the skin of the patient, a suitably configured insertion device or apparatus may be used to insert a fluid delivery needle or cannula <NUM> into the body of the patient. The cannula <NUM> functions as one part of the fluid delivery flow path associated with the fluid infusion device <NUM>. In this regard, the cannula <NUM> may be considered to be one implementation of the fluid conduit assembly <NUM> shown in <FIG> (or a portion thereof).

<FIG> depicts the durable housing <NUM> and the base plate <NUM> coupled together. For this particular embodiment, the durable housing <NUM> contains, among other components, a drive motor, a battery, a threaded drive shaft for the fluid reservoir, one or more integrated circuit chips and/or other electronic devices (not shown). The durable housing <NUM> and the base plate <NUM> are cooperatively configured to accommodate removable coupling of the durable housing <NUM> to the base plate <NUM>. The removable nature of the durable housing <NUM> enables the patient to replace the fluid reservoir as needed.

The fluid delivery systems <NUM> shown in <FIG> has a gas trapping filter in the fluid path leading from its internal reservoir (not shown) to the cannula <NUM>. Typically, the gas trapping filter will be immediately upstream of the point where the cannula <NUM> exits through the base plate <NUM>. Preferably the filter is replaceable at least when the reservoir is replaced. The gas trapping filter in the <FIG> arrangement may also be configured to be able to detain particulates.

It is also envisaged that a gas trapping filter may be situated at an intermediate position in a length of fluid conduit. In this regard, <FIG> is a schematic representation of a portion of a fluid conduit assembly <NUM> having a gas trapping filter <NUM> positioned therein. It should be appreciated that the fluid conduit assembly <NUM> has been simplified for ease of illustration. In practice, the fluid conduit assembly <NUM> may be realized in any of the fluid delivery systems described here, and/or in other fluid delivery systems not specifically described in detail here. For example, the fluid conduit assembly <NUM> may be implemented as, or form a part of, a fluid infusion set, a connector assembly, a fluid reservoir, a fluid reservoir cap, a chamber or internal feature of an infusion pump, or the like.

The fluid conduit assembly <NUM> is suitably configured to accommodate the delivery of a medication fluid such as insulin. The fluid conduit assembly <NUM> includes a structure <NUM> (or structures) defining a flow path <NUM> for the medication fluid. In <FIG>, the structure <NUM> is depicted in cross section, and it resembles a tube. Alternatively, the structure <NUM> can be a section of a fluid connector (such as a two-part detachable connector), an internal feature of an infusion device, a portion of a fluid reservoir coupler, or the like. In certain embodiments, the structure <NUM> includes, forms a part of, or is realized as a reservoir cap for a fluid infusion device (see <FIG>). In some embodiments, the structure <NUM> includes, forms a part of, or is integrated with an infusion set for a fluid infusion device. In this regard, the gas trapping filter <NUM> can be integrated with the delivery cannula hub or housing that is located at or near the downstream end of the infusion set. In yet other embodiments, the structure <NUM> includes, forms a part of, or is realized as a fluid connector, such as a LUER LOK fitting or connector. In certain embodiments, the structure <NUM> is implemented as a feature of the fluid infusion device. These and other deployments of the fluid conduit assembly <NUM> are contemplated by this disclosure, and the particular examples presented here are not intended to be limiting or exhaustive.

The flow path <NUM> is defined by the interior space of the structure <NUM>. The gas trapping filter <NUM> may be coupled to the structure <NUM> and positioned in the flow path <NUM> such that the medication fluid passes through the gas trapping filter <NUM> during fluid delivery operations. <FIG> depicts a straightforward scenario where the gas trapping filter <NUM> physically obstructs the flow path <NUM>, such that the medication fluid is not diverted around the gas trapping filter <NUM>. In other embodiments, there can be additional fluid flow paths that allow some of the medication fluid to bypass the gas trapping filter <NUM>.

The gas trapping filter <NUM> is formed from a suitable material, composition, or element such that the medication fluid can easily pass through the gas trapping filter <NUM> during fluid delivery operations. The gas trapping filter <NUM> can be formed from a hydrophilic, semi-hydrophilic, partially hydrophilic, or predominantly hydrophilic material. Although a truly hydrophilic material may be ideal, the material used for the gas trapping filter <NUM> can be partially or predominantly hydrophilic while exhibiting some amount of hydrophobicity. In practice, the gas trapping filter <NUM> can exhibit up to fifty percent hydrophobicity without adversely impacting the desired performance. For example, the gas trapping filter <NUM> may include or be fabricated from a hydrophilic membrane, a hydrophilic sponge material, or a hydrophilic foam material. As explained below, the gas trapping filter <NUM> preferably also serves to filter particulates from the medication fluid during fluid delivery operations. Accordingly, the gas trapping filter <NUM> preferably has a pore size that is small enough to inhibit the flow of particulates. In certain embodiments, the pore size is within the range of about <NUM> to <NUM> microns, which is suitable for most medical applications. Non-limiting examples of suitable materials for the gas trapping filter <NUM> include: polyacrylate; polyurethane; nylon; cellulose acetate; polyvinyl alcohol; polyethelene foam; polyvinyl acetate; polyester fiber felt; polyester (PET); polysulfone; polyethyl sulfone; collagen; polycaprolactone; or the like. It should be appreciated that the material or materials used to fabricate the gas trapping filter <NUM> can be treated to enhance the hydrophilic characteristics if so desired.

One function of the gas trapping filter <NUM> is to inhibit the downstream flow of air bubbles. Depending on the particular composition and configuration of the gas trapping filter <NUM>, air bubbles <NUM> (depicted as small circles in the flow path <NUM> upstream of the gas trapping filter <NUM>) can be blocked by the gas trapping filter <NUM> and/or retained within the gas trapping filter <NUM> as the liquid medication flows downstream. Thus, the gas trapping filter <NUM> may be realized as a gas impermeable membrane or material that also exhibits good hydrophilic properties. In some embodiments, the gas trapping filter <NUM> can be fabricated from material having micro-cavities formed therein for trapping and retaining gas bubbles from the medication fluid. <FIG> illustrates a scenario where the air bubbles <NUM> are removed from the medication fluid. Accordingly, no air bubbles <NUM> are present in the medication fluid that resides downstream from the gas trapping filter <NUM>.

Another benefit of the gas trapping filter <NUM> relates to the volume accuracy of the fluid delivery system. In certain implementations, syringe pumps are calibrated to deliver a specified volume in response to a controlled mechanical actuation (e.g., movement of the syringe plunger in response to controlled rotation of an electric motor). Reducing or eliminating air from the fluid delivery path increases the accuracy of the volume calibrations.

In certain embodiments, the gas trapping filter <NUM> also serves to filter particulates from the medication fluid such that the particulate count of the downstream medication fluid is reduced. As mentioned above, the material used to fabricate the gas trapping filter <NUM> can be selected with a desired pore size to accommodate filtering of particulates having an expected size.

In some embodiments, the gas trapping filter <NUM> also serves to absorb and/or adsorb certain substances, chemicals, or suspended elements from the medication fluid. For example, the gas trapping filter <NUM> may include material that is configured or treated to absorb/adsorb lubricating or manufacturing oil that is associated with the manufacturing, assembly, or maintenance of one or more components of the fluid delivery system. In this regard, a fluid reservoir for insulin can be fabricated with a trace amount of silicone oil that serves as a lubricant for the plunger of the reservoir. Accordingly, the gas trapping filter <NUM> can include a material, layer, or treatment that reduces, traps, or otherwise removes some or all of the silicone oil from the medication fluid as it passes through the gas trapping filter <NUM>.

In particular embodiments, the gas trapping filter <NUM> also serves as a drug depot during operation of the fluid delivery system. To this end, the gas trapping filter <NUM> can include a drug, medicine, chemical, or composition impregnated therein (or coated thereon, or otherwise carried by the gas trapping filter <NUM>). A quantity of the drug is released into the medication fluid as the fluid flows through the gas trapping filter <NUM> during a fluid delivery operation. The wavy lines <NUM> in <FIG> schematically depict the drug after it has been released into the downstream medication fluid. In practice, the drug carried by the gas trapping filter <NUM> will eventually be depleted unless the gas trapping filter <NUM> or the fluid conduit assembly <NUM> is replaced before depletion. The drug carried by the gas trapping filter <NUM> can be selected to address the needs of the particular patient, fluid delivery system, medication fluid, etc. In accordance with the exemplary insulin infusion system described here, the gas trapping filter <NUM> is impregnated with a drug that treats the patient site to extend the useful life of the fluid infusion set. For example, the gas trapping filter <NUM> can be treated with an anticoagulant such as Heparin or Dextran. As another example, the gas trapping filter <NUM> can be impregnated or infused with an anti-proliferative drug such as Rapamycin. It should be appreciated that these examples are neither exhaustive nor restrictive, and that the gas trapping filter <NUM> can be impregnated, treated, or infused with any drug that may be appropriate and suitable for the particular medical condition, fluid delivery system, or application.

Similarly any of the gas trapping filters to be described in detail below with reference to <FIG> can also include a drug as described above.

Although <FIG> shows a single component that serves as the gas trapping filter <NUM>, an embodiment of the fluid conduit assembly <NUM> can utilize a plurality of physically distinct elements that collectively function as the gas trapping filter <NUM>. For example, the gas trapping filter <NUM> can be fabricated from different materials that are selected for their properties and characteristics (gas trapping, oil absorption, oil adsorption, particulate filtering). Moreover, certain embodiments of the fluid delivery system can be outfitted with multiple gas trapping filters located in different sections of the fluid flow path. For example, one filter component can be positioned at or near the fluid reservoir, and another filter component can be positioned at or near the distal end of the fluid infusion set. These and other practical implementations are contemplated by this disclosure.

As mentioned above, the fluid conduit assembly that carries the gas trapping filter can be realized in a number of different forms. For example, the fluid conduit assembly may include or be realized as a fluid connector, where the gas trapping filter is integrated in the fluid connector. In this regard, <FIG> is an exploded and partially phantom view of a fluid connector assembly <NUM> suitable for use with a fluid conduit assembly. The illustrated embodiment of the fluid connector assembly <NUM> functions to physically and fluidly couple an upstream section of tubing <NUM> to a downstream section of tubing <NUM>. The fluid connector assembly <NUM> includes a first connector <NUM> (which is physically and fluidly coupled to the upstream section of tubing <NUM>) that mates with a second connector <NUM> (which is physically and fluidly coupled to the downstream section of tubing <NUM>). The first connector <NUM> includes a hollow needle <NUM> that provides a fluid flow path from the upstream section of tubing <NUM>. The second connector <NUM> includes a septum <NUM> that receives the hollow needle <NUM> when the first connector <NUM> engages the second connector <NUM>. When the two connectors <NUM>, <NUM> are engaged and locked together, the medication fluid can flow from the upstream section of tubing <NUM>, through the hollow needle <NUM>, and into the downstream section of tubing <NUM>.

One or both of the connectors <NUM>, <NUM> can be provided with a gas trapping filter having the characteristics and functionality described previously. For this particular embodiment, a unitary gas trapping filter <NUM> is integrated in the second connector <NUM>. The gas trapping filter <NUM> is located within the body of the second connector <NUM>, and it resides downstream from the septum <NUM>. During a fluid delivery operation, the medication fluid exits the hollow needle <NUM>, enters the second connector <NUM> (e.g., into a space that is upstream from the gas trapping filter <NUM>), and is forced through the gas trapping filter <NUM> before it passes into the downstream section of tubing <NUM>.

By positioning a gas trapping filter inside the connector, particularly the connector adjacent the downstream tubing <NUM> it is able to retain and/or absorb / adsorb any small amounts of air that may be introduced by closure of the connector, thus preventing this air from entering the downstream tubing <NUM>.

As another example, a fluid conduit assembly configured as described herein may include or be realized as an infusion set for a fluid infusion pump, where the gas trapping filter is integrated in the infusion set. In this regard, <FIG> is an exploded perspective view of a fluid conduit assembly that is realized as a cap or a connector assembly <NUM> for a fluid reservoir. In this regard, the connector assembly <NUM> is generally configured as described above for the connector assembly <NUM> shown in <FIG>. Accordingly, the connector assembly <NUM> may be provided as component of a disposable infusion set.

The illustrated embodiment of the connector assembly <NUM> generally includes, without limitation: a body section <NUM>; a flow path defined in the body section <NUM>; a length of tubing <NUM> extending from the body section <NUM>; and a gas trapping filter <NUM>. <FIG> depicts the body section <NUM> separated into two constituent parts: a lower body section 602a; and an upper body section 602b. The lower body section 602a can be affixed to the upper body section 602b (for example, by sonic welding or using an adhesive) after installing the gas trapping filter <NUM> into a retaining cavity <NUM> formed within the lower body section 602a. In alternative embodiments, the body section <NUM> can be fabricated as a one-piece component by molding a suitable material while encapsulating the gas trapping filter <NUM> inside the body section <NUM>.

The lower body section 602a is suitably configured to receive a fluid reservoir, e.g., by a threaded engagement, a snap fit, tabs, or the like. The tubing <NUM> is physically and fluidly coupled to the upper body section 602b such that the tubing <NUM> is in fluid communication with the flow path. This allows the tubing <NUM> to carry fluid from the body section <NUM> during a fluid delivery operation. The flow path, much of which is hidden from view in <FIG>, may be defined by: a hollow needle that penetrates a septum of the fluid reservoir; an internal space, chamber, or conduit of the lower body section 602a, which is upstream of the gas trapping filter <NUM>; and an internal space, chamber, or conduit <NUM> of the upper body section 602b, which is downstream of the gas trapping filter <NUM>. The flow path continues into the tubing <NUM>, which is connected to the upper body section 602b.

The gas trapping filter <NUM> is secured within the body section <NUM> such that it is positioned in the flow path of the medication fluid. During a fluid delivery operation, the medication fluid is forced out of the fluid reservoir and into the hollow needle (not shown in <FIG>). The distal end of the hollow needle terminates at a location that is upstream of the gas trapping filter <NUM>. This positioning ensures that the medication fluid can be filtered and otherwise treated by the gas trapping filter <NUM> before it exits the connector assembly <NUM>. As explained above, the gas trapping filter <NUM> is suitably configured to reduce the amount of air bubbles in the downstream medication fluid, and optionally can reduce the amount of particulates in the downstream medication fluid.

The <FIG> arrangement in which the gas trapping filter is configured as a round "pill" shape. In other words a cylinder axially aligned with the retaining cavity and with a diameter to height ration greater than unity. The <FIG> arrangement has a diameter to height ration of <NUM>:<NUM>.

The gas trapping filter of the <FIG> arrangement can be composed of any of the materials listed above for the gas trapping filter of the <FIG> arrangement, or any combination thereof.

An advantage of the <FIG> arrangement is that the gas trapping filter presents a large surface area in both the upstream and the downstream directions than the cross-sectional area of the tubing <NUM>. With this configuration the filter has a large working area, and also a large capacity to hold gas and, if required, particulates. As the filter is part of a disposable part of the apparatus as a whole, i.e. the cap or connector assembly for the fluid reservoir which is, in turn, connected via a tubing to the infusion unit, the device need only have a fairly short life, thus no provision need be made for the removal of the gas collected or of any particulate material that may have accumulated.

Another advantage is the filter is situated at a position in the flow path where a high wall rigidity is provided as the cap needs to be manually gripped and turned to undo the reservoir from the infusion pump. Thus a greater diameter can be provided, and the gas trapping filter can be housed within this manual grip section, thus protecting it from damage.

<FIG> is an exploded perspective view of another embodiment of a fluid conduit assembly <NUM> that is realized as a cap for a fluid reservoir. The assembly <NUM> shares some elements and features with the assembly <NUM> and, therefore, common elements and features will not be redundantly described here in the context of the assembly <NUM>. As mentioned previously, the connector assembly <NUM> may be provided as component of a disposable infusion set.

The illustrated embodiment of the connector assembly <NUM> generally includes, without limitation: a body section <NUM> (having a lower body section 602a and an upper body section 602b); a venting membrane <NUM>; a hollow needle <NUM>; a gas trapping filter <NUM>; and a reservoir membrane <NUM>. These components can be assembled together in the manner generally described above for the assembly <NUM>.

The venting membrane <NUM> can be affixed to the upper interior surface of the lower body section 602a such that the venting membrane <NUM> covers one or more vent holes <NUM> formed in the top portion of the lower body section 602a. The vent holes <NUM> facilitate venting of the reservoir chamber that resides in the housing of the fluid infusion device (see, for example, <FIG>). The hollow needle <NUM> can be affixed to the lower body section 602a such that the downstream end <NUM> of the hollow needle <NUM> resides below or within the gas trapping filter <NUM> after the fluid conduit assembly <NUM> is fabricated. The positioning of the downstream end <NUM> is important to ensure that the medication fluid is forced through the gas trapping filter <NUM> during fluid delivery operations. The reservoir membrane <NUM> can be affixed within a cavity formed in the upper body section 602b (the cavity is hidden from view in <FIG>). The reservoir membrane <NUM> is at least partially hydrophilic to allow the medication fluid to pass during fluid delivery operations.

The gas trapping filter <NUM> is secured within the body section <NUM> such that it is positioned in the flow path of the medication fluid. For the illustrated embodiment, the gas trapping filter <NUM> may be positioned between the reservoir membrane <NUM> and the downstream end <NUM> of the hollow needle <NUM>. The gas trapping filter for example the filter <NUM> in the <FIG> arrangement or the filter <NUM> in the <FIG> arrangement may be is realized as a foam, sponge, or felt fiber composite material. Although not always required, the material used for the gas trapping filters <NUM> and <NUM> may include, without limitation: polyvinyl acetate (PVA); polyvinyl alcohol; polyester (PET); polycarbonate; polyurethane; polyethyl sulfone; collagen; polycaprolactone; or any combination thereof. In accordance with certain embodiments, a felt-based gas trapping filters <NUM> and <NUM> have a pore size within the range of about one to <NUM> microns, and preferably within the range of about <NUM> to <NUM> microns. A sponge-based gas trapping filter <NUM> or <NUM> may have a pore size within the range of about <NUM> to <NUM> microns. Regardless of their composition and configuration, the gas trapping filters <NUM> and <NUM> are suitably configured to reduce the amount of air bubbles in the downstream medication fluid, and preferably also to reduce the amount of particulates in the downstream medication fluid.

Claim 1:
A fluid conduit assembly for delivery of a medication fluid, the fluid conduit assembly comprising:
a structure (<NUM>, <NUM>, <NUM>, <NUM>) defining a flow path (<NUM>) for the medication fluid; and
a gas trapping filter ( <NUM>, <NUM>, <NUM>) coupled to the structure and positioned in the flow path to filter particulates from the medication fluid and retain gas bubbles from the medication fluid;
wherein the gas trapping filter (<NUM>, <NUM>, <NUM>) is fabricated from material having microcavities formed therein for trapping and retaining gas bubbles from the medication fluid.