Patent Publication Number: US-2023149637-A1

Title: Fluid reservoir cap with gas trapping filter and associated retaining feature

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to U.S. Provisional Application No. 63/278,969, filed Nov. 12, 2021, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments of the subject matter described herein relate generally to fluid infusion devices for delivering a medication fluid to the body of a user. More particularly, embodiments of the subject matter relate to the use of a gas trapping filter in the medication fluid flow path. 
     BACKGROUND 
     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&#39;s skin to deliver an infusion fluid to the body. Alternatively, the hollow tubing may be connected directly to the patient&#39;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. 
     BRIEF SUMMARY 
     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. 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the subject matter may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures. 
         FIG.  1    is a simplified block diagram representation of an embodiment of a fluid delivery system; 
         FIG.  2    is a plan view of an exemplary embodiment of a fluid delivery system that includes a fluid infusion device and an infusion set; 
         FIG.  3    is a perspective view of an exemplary embodiment of a fluid delivery system that includes a fluid infusion device designed to be affixed to the skin of the user; 
         FIG.  4    is a schematic representation of a portion of a fluid conduit assembly; 
         FIG.  5    is an exploded and partially phantom view of a connector assembly suitable for use with a fluid conduit; 
         FIG.  6    is an exploded perspective view of an embodiment of a fluid conduit assembly that is realized as a cap for a fluid reservoir; 
         FIG.  7    is an exploded perspective view of another embodiment of a fluid conduit assembly that is realized as a cap for a fluid reservoir; 
         FIG.  8    is a perspective view of an exemplary embodiment of a fluid reservoir cap; 
         FIG.  9    is a side view of the fluid reservoir cap shown in  FIG.  8   ; 
         FIG.  10    is an exploded perspective view of the fluid reservoir cap shown in  FIG.  8   ; 
         FIG.  11    is a top view of the fluid reservoir cap shown in  FIG.  8   ; 
         FIG.  12    is a cross-sectional view of the fluid reservoir cap taken across line A-A of  FIG.  11   ; 
         FIG.  13    is a top perspective view of an exemplary embodiment of a fluid reservoir cap having retaining features integrated therein for retaining a filter; 
         FIG.  14    is a top perspective view of another exemplary embodiment of a fluid reservoir cap having retaining features integrated therein for retaining a filter; 
         FIG.  15    is a partially exploded perspective view of an exemplary embodiment of a fluid reservoir cap having rectangular shaped filters; and 
         FIG.  16    is a top view of the fluid reservoir cap shown in  FIG.  15   . 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
     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, U.S. Pat. Nos. 4,562,751; 4,678,408; 4,685,903; 5,080,653; 5,505,709; 5,097,122; 6,485,465; 6,554,798; 6,558,351; 6,659,980; 6,752,787; 6,817,990; 6,932,584; and 7,621,893; which are herein incorporated by reference. 
       FIG.  1    is a simplified block diagram representation of an embodiment of a fluid delivery system  100 , which can be utilized to administer a medication fluid such as insulin to a patient. The fluid delivery system  100  includes a fluid infusion device  102  (e.g., an infusion pump) and a fluid conduit assembly  104  that is coupled to, integrated with, or otherwise associated with the fluid infusion device  102 . The fluid infusion device  102  includes a fluid reservoir  106  or an equivalent supply of the medication fluid to be administered. The fluid infusion device  102  is operated in a controlled manner to deliver the medication fluid to the user via the fluid conduit assembly  104 . Although not depicted in  FIG.  1   , the fluid delivery system  100  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  104 . 
     The fluid infusion device  102  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.  2    is a plan view of an exemplary embodiment of a fluid delivery system  200  that includes a portable fluid infusion device  202  and a fluid conduit assembly that takes the form of an infusion set component  204 . For this particular embodiment, the infusion set component  204  can be coupled to the fluid infusion device  202  as depicted in  FIG.  2   . The fluid infusion device  202  accommodates a fluid reservoir (hidden from view in  FIG.  2   ) for the medication fluid to be delivered to the user. 
     The illustrated embodiment of the infusion set component  204  includes, without limitation: a tube  210 ; an infusion unit  212  coupled to the distal end of the tube  210 ; and a connector assembly  214  coupled to the proximal end of the tube  210 . The fluid infusion device  202  is designed to be carried or worn by the patient, and the infusion set component  204  terminates at the infusion unit  212  such that the fluid infusion device  202  can deliver fluid to the body of the patient via the tube  210 . The fluid infusion device  202  may leverage a number of conventional features, components, elements, and characteristics of existing fluid infusion devices. For example, the fluid infusion device  202  may incorporate some of the features, components, elements, and/or characteristics described in U.S. Pat. Nos. 6,485,465 and 7,621,893, the relevant content of which is incorporated by reference herein. 
     The infusion set component  204  defines a fluid flow path that fluidly couples the fluid reservoir to the infusion unit  212 . The connector assembly  214  mates with and couples to the neck region of the fluid reservoir, establishing the fluid path from the fluid reservoir to the tube  210 . The connector assembly  214  (with the fluid reservoir coupled thereto) is coupled to the housing of the fluid infusion device  202  to seal and secure the fluid reservoir inside the housing. Thereafter, actuation of the fluid infusion device  202  causes the medication fluid to be expelled from the fluid reservoir, through the infusion set component  204 , and into the body of the patient via the infusion unit  212  at the distal end of the tube  210 . Accordingly, when the connector assembly  214  is installed as depicted in  FIG.  2   , the tube  210  extends from the fluid infusion device  202  to the infusion unit  212 , which in turn provides a fluid pathway to the body of the patient. For the illustrated embodiment, the connector assembly  214  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. 
       FIG.  3    is a perspective view of another exemplary embodiment of a fluid delivery system  300  that includes a fluid infusion device  302  designed to be affixed to the skin of the user. The fluid infusion device  302  includes two primary components that are removably coupled to each other: a durable housing  304 ; and a base plate  306 . The fluid infusion device  302  also includes or cooperates with a removable/replaceable fluid reservoir (which is hidden from view in  FIG.  3   ). For this particular embodiment, the fluid reservoir mates with, and is received by, the durable housing  304 . In alternate embodiments, the fluid reservoir mates with, and is received by, the base plate  306 . 
     The base plate  306  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  308  into the body of the patient. The cannula  308  functions as one part of the fluid delivery flow path associated with the fluid infusion device  302 . In this regard, the cannula  308  may be considered to be one implementation of the fluid conduit assembly  104  shown in  FIG.  1    (or a portion thereof). 
       FIG.  3    depicts the durable housing  304  and the base plate  306  coupled together. For this particular embodiment, the durable housing  304  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  304  and the base plate  306  are cooperatively configured to accommodate removable coupling of the durable housing  304  to the base plate  306 . The removable nature of the durable housing  304  enables the patient to replace the fluid reservoir as needed. 
     The fluid delivery systems  200 ,  300  described here are merely two exemplary embodiments that can include a fluid conduit assembly outfitted with a gas trapping filter. In this regard,  FIG.  4    is a schematic representation of a portion of a fluid conduit assembly  400  having a gas trapping filter  402  positioned therein. It should be appreciated that the fluid conduit assembly  400  has been simplified for ease of illustration. In practice, the fluid conduit assembly  400  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  400  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  400  is suitably configured to accommodate the delivery of a medication fluid such as insulin. The fluid conduit assembly  400  includes a structure  404  (or structures) defining a flow path  406  for the medication fluid. In  FIG.  4   , the structure  404  is depicted in cross section, and it resembles a tube. Alternatively, the structure  404  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  404  includes, forms a part of, or is realized as a reservoir cap for a fluid infusion device (see  FIG.  6   ). In some embodiments, the structure  404  includes, forms a part of, or is integrated with an infusion set for a fluid infusion device. In this regard, the gas trapping filter  402  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  404  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  404  is implemented as a feature of the fluid infusion device. These and other deployments of the fluid conduit assembly  400  are contemplated by this disclosure, and the particular examples presented here are not intended to be limiting or exhaustive. 
     The flow path  406  is defined by the interior space of the structure  404 . The gas trapping filter  402  may be coupled to the structure  404  and positioned in the flow path  406  such that the medication fluid passes through the gas trapping filter  402  during fluid delivery operations.  FIG.  4    depicts a straightforward scenario where the gas trapping filter  402  physically obstructs the flow path  406 , such that the medication fluid is not diverted around the gas trapping filter  402 . In other embodiments, there can be additional fluid flow paths that allow some of the medication fluid to bypass the gas trapping filter  402 . 
     The gas trapping filter  402  is formed from a suitable material, composition, or element such that the medication fluid can easily pass through the gas trapping filter  402  during fluid delivery operations. The gas trapping filter  402  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  402  can be partially or predominantly hydrophilic while exhibiting some amount of hydrophobicity. In practice, the gas trapping filter  402  can exhibit up to fifty percent hydrophobicity without adversely impacting the desired performance. For example, the gas trapping filter  402  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  402  also serves to filter particulates from the medication fluid during fluid delivery operations. Accordingly, the gas trapping filter  402  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 0.45 to 5.00 microns, which is suitable for most medical applications. Non-limiting examples of suitable materials for the gas trapping filter  402  include: polyacrylate; polyurethane; nylon; cellulose acetate; polyvinyl alcohol; polyethylene 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  402  can be treated to enhance the hydrophilic characteristics if so desired. In certain embodiments, the gas trapping filter  402  includes or is fabricated from a polyvinyl alcohol composition having a pore size within the range of 0.1 mm to 5.0 mm, e.g., an average of about 0.35 millimeter or 350 microns. 
     One function of the gas trapping filter  402  is to inhibit the downstream flow of air bubbles. Depending on the particular composition and configuration of the gas trapping filter  402 , air bubbles  410  (depicted as small circles in the flow path  406  upstream of the gas trapping filter  402 ) can be blocked by the gas trapping filter  402  and/or retained within the gas trapping filter  402  as the liquid medication flows downstream. Thus, the gas trapping filter  402  may be realized as a gas impermeable membrane or material that also exhibits good hydrophilic properties. In some embodiments, the gas trapping filter  402  can be fabricated from material having micro-cavities formed therein for trapping and retaining gas bubbles from the medication fluid.  FIG.  4    illustrates a scenario where the air bubbles  410  are removed from the medication fluid. Accordingly, no air bubbles  410  are present in the medication fluid that resides downstream from the gas trapping filter  402 . 
     Another benefit of the gas trapping filter  402  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  402  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  402  can be selected with a desired pore size to accommodate filtering of particulates having an expected size. 
     In some embodiments, the gas trapping filter  402  also serves to absorb and/or adsorb certain substances, chemicals, or suspended elements from the medication fluid. For example, the gas trapping filter  402  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  402  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  402 . 
     In particular embodiments, the gas trapping filter  402  also serves as a drug depot during operation of the fluid delivery system. To this end, the gas trapping filter  402  can include a drug, medicine, chemical, or composition impregnated therein (or coated thereon, or otherwise carried by the gas trapping filter  402 ). A quantity of the drug is released into the medication fluid as the fluid flows through the gas trapping filter  402  during a fluid delivery operation. The wavy lines  414  in  FIG.  4    schematically depict the drug after it has been released into the downstream medication fluid. In practice, the drug carried by the gas trapping filter  402  will eventually be depleted unless the gas trapping filter  402  or the fluid conduit assembly  400  is replaced before depletion. The drug carried by the gas trapping filter  402  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  402  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  402  can be treated with an anticoagulant such as Heparin or Dextran. As another example, the gas trapping filter  402  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  402  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. 
     Although  FIG.  4    shows a single component that serves as the gas trapping filter  402 , an embodiment of the fluid conduit assembly  400  can utilize a plurality of physically distinct elements that collectively function as the gas trapping filter  402 . For example, the gas trapping filter  402  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.  5    is an exploded and partially phantom view of a fluid connector assembly  500  suitable for use with a fluid conduit assembly. The illustrated embodiment of the fluid connector assembly  500  functions to physically and fluidly couple an upstream section of tubing  502  to a downstream section of tubing  504 . The fluid connector assembly  500  includes a first connector  506  (which is physically and fluidly coupled to the upstream section of tubing  502 ) that mates with a second connector  508  (which is physically and fluidly coupled to the downstream section of tubing  504 ). The first connector  506  includes a hollow needle  510  that provides a fluid flow path from the upstream section of tubing  502 . The second connector  508  includes a septum  512  that receives the hollow needle  510  when the first connector  506  engages the second connector  508 . When the two connectors  506 ,  508  are engaged and locked together, the medication fluid can flow from the upstream section of tubing  502 , through the hollow needle  510 , and into the downstream section of tubing  504 . 
     One or both of the connectors  506 ,  508  can be provided with a gas trapping filter having the characteristics and functionality described previously. For this particular embodiment, a unitary gas trapping filter  516  is integrated in the second connector  508 . The gas trapping filter  516  is located within the body of the second connector  508 , and it resides downstream from the septum  512 . During a fluid delivery operation, the medication fluid exits the hollow needle  510 , enters the second connector  508  (e.g., into a space that is upstream from the gas trapping filter  516 ), and is forced through the gas trapping filter  516  before it passes into the downstream section of tubing  504 . The gas trapping filter  516  may be fabricated from material or compositions described above with reference to the gas trapping filter  402 . In certain embodiments, the gas trapping filter  516  includes or is fabricated from a polyvinyl alcohol composition having a pore size within the range of 0.1 mm to 5.0 mm, e.g., an average of about 0.35 millimeter or 350 microns. 
     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.  6    is an exploded perspective view of a fluid conduit assembly that is realized as a cap or a connector assembly  600  for a fluid reservoir. In this regard, the connector assembly  600  is generally configured as described above for the connector assembly  214  shown in  FIG.  2   . Accordingly, the connector assembly  600  may be provided as component of a disposable infusion set. 
     The illustrated embodiment of the connector assembly  600  generally includes, without limitation: a body section  602 ; a flow path defined in the body section  602 ; a length of tubing  604  extending from the body section  602 ; and a gas trapping filter  606 .  FIG.  6    depicts the body section  602  separated into two constituent parts: a lower body section  602   a;  and an upper body section  602   b.  The lower body section  602   a  can be affixed to the upper body section  602   b  (for example, by sonic welding or using an adhesive) after installing the gas trapping filter  606  into a retaining cavity  610  formed within the lower body section  602   a.  In alternative embodiments, the body section  602  can be fabricated as a one-piece component by molding a suitable material while encapsulating the gas trapping filter  606  inside the body section  602 . The gas trapping filter  606  may be fabricated from material or compositions described above with reference to the gas trapping filter  402 . In certain embodiments, the gas trapping filter  606  includes or is fabricated from a polyvinyl alcohol composition having a pore size within the range of 0.1 mm to 5.0 mm, e.g., an average of about 0.35 millimeter or 350 microns. 
     The lower body section  602   b  is suitably configured to receive a fluid reservoir, e.g., by a threaded engagement, a snap fit, tabs, or the like. The tubing  604  is physically and fluidly coupled to the upper body section  602   b  such that the tubing  604  is in fluid communication with the flow path. This allows the tubing  604  to carry fluid from the body section  602  during a fluid delivery operation. The flow path, much of which is hidden from view in  FIG.  6   , 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  602   a,  which is upstream of the gas trapping filter  606 ; and an internal space, chamber, or conduit  614  of the upper body section  602   b,  which is downstream of the gas trapping filter  606 . The flow path continues into the tubing  604 , which is connected to the upper body section  602   b.    
     The gas trapping filter  606  is secured within the body section  602  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.  6   ). The distal end of the hollow needle terminates at a location that is upstream of the gas trapping filter  606 . This positioning ensures that the medication fluid can be filtered and otherwise treated by the gas trapping filter  606  before it exits the connector assembly  600 . As explained above, the gas trapping filter  606  is suitably configured to reduce the amount of air bubbles in the downstream medication fluid, and to reduce the amount of particulates in the downstream medication fluid. 
       FIG.  7    is an exploded perspective view of another embodiment of a fluid conduit assembly  700  that is realized as a cap for a fluid reservoir. The assembly  700  shares some elements and features with the assembly  600  and, therefore, common elements and features will not be redundantly described here in the context of the assembly  700 . As mentioned previously, the connector assembly  700  may be provided as component of a disposable infusion set. 
     The illustrated embodiment of the connector assembly  700  generally includes, without limitation: a body section  602  (having a lower body section  602   a  and an upper body section  602   b ); a venting membrane  702 ; a hollow needle  704 ; a gas trapping filter  706 ; and a membrane  708 . These components can be assembled together in the manner generally described above for the assembly  600 . 
     The venting membrane  702  can be affixed to the upper interior surface of the lower body section  602   a  such that the venting membrane  702  covers one or more vent holes  710  formed in the top portion of the lower body section  602   a.  The vent holes  710  facilitate venting of the reservoir chamber that resides in the housing of the fluid infusion device (see, for example,  FIG.  2   ). The hollow needle  704  can be affixed to the lower body section  602   a  such that the downstream end  712  of the hollow needle  704  resides below or within the gas trapping filter  706  after the fluid conduit assembly  700  is fabricated. The positioning of the downstream end  712  is important to ensure that the medication fluid is forced through the gas trapping filter  706  during fluid delivery operations. The membrane  708  can be affixed within a cavity formed in the upper body section  602   b  (the cavity is hidden from view in  FIG.  7   ). The membrane  708  is at least partially hydrophilic to allow the medication fluid to pass during fluid delivery operations. In certain embodiments, the membrane  708  has a smaller pore size than the gas trapping filter  706 . For example, the membrane  708  may have a pore size within the range of about 0.1 μm to about 10 μm. 
     The gas trapping filter  706  is secured within the body section  602  such that it is positioned in the flow path of the medication fluid. For the illustrated embodiment, the gas trapping filter  706  may be positioned between the membrane  708  and the downstream end  712  of the hollow needle  704 . In certain embodiments, the gas trapping filter  706  is realized as a foam, sponge, or felt fiber composite material. Although not always required, the material used for the gas trapping filter  706  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 filter  706  has a pore size within the range of about one to 100 microns, and preferably within the range of about 20 to 40 microns. In accordance with certain embodiments, a sponge-based gas trapping filter  706  has a pore size within the range of about 20 to 1000 microns. The gas trapping filter  706  may be fabricated from material or compositions described above with reference to the gas trapping filter  402 . In certain embodiments, the gas trapping filter  706  includes or is fabricated from a polyvinyl alcohol composition having a pore size within the range of 0.1 mm to 5.0 mm, e.g., an average of about 0.35 millimeter or 350 microns. Regardless of its composition and configuration, the gas trapping filter  706  is suitably configured to reduce the amount of air bubbles in the downstream medication fluid, and to reduce the amount of particulates in the downstream medication fluid. 
       FIG.  8    is a perspective view of an exemplary embodiment of a fluid reservoir cap  800 ,  FIG.  9    is a side view of the cap  800 ,  FIG.  10    is an exploded perspective view of the cap  800 ,  FIG.  11    is a top view of the cap  800 , and  FIG.  12    is a cross-sectional view of the cap  800  as taken along line A-A of  FIG.  11   . The cap  800  is similar to the connector assembly  600  and the fluid conduit assembly  700  described above. The cap  800 , however, is fabricated with a one-piece primary body section rather than an upper body section and a lower body section. 
     At least one suitably shaped, sized, and configured gas trapping filter  802  is retained within a neck region  804  of the cap  800 . For the illustrated embodiment, two gas trapping filters  802  are stacked within the neck region  804 . The illustrated embodiment of the cap  800  also includes: a venting membrane  806 ; a hollow needle  808 ; and a membrane  810  (as described above for the other embodiments). The cap  800  also includes an insert  812  that is inserted into the neck region  804  (see  FIG.  12   ). When the cap  800  is assembled, the gas trapping filters  802  and the membrane  810  are located between an interior base section of the neck region  804  and a bottom section of the insert  812 . 
     The gas trapping filters  802  may be fabricated from material or compositions described above with reference to the gas trapping filter  402 . In certain embodiments, each gas trapping filter  802  includes or is fabricated from a polyvinyl alcohol composition having a pore size within the range of 0.1 mm to 5.0 mm, e.g., an average of about 0.35 millimeter or 350 microns. In certain embodiments, the membrane  810  has a smaller pore size than the gas trapping filters  802 . For example, the membrane  810  may have a pore size within the range of about 0.1 μm to about 10 μm. 
     During manufacturing of the cap  800 , the gas trapping filters  802  should be oriented as shown in  FIG.  12   —aligned with each other, and vertically stacked without any gap between them. However, fabrication and assembly processes may cause one or both gas trapping filters  802  to shake, vibrate, shift, rotate, move, or otherwise become mis-oriented. To address this scenario, the cap  800  can be fabricated with integrated retaining features that are shaped, sized, arranged, and otherwise configured to keep the gas trapping filters  802  in a stationary position after they have been installed within the neck region  804  of the cap  800 . At least one retaining feature can be implemented to inhibit movement, shifting, or dislodging of the gas trapping filters  802  within the cap  800 . 
       FIG.  13    is a top perspective view of an exemplary embodiment of a fluid reservoir cap  900  having retaining features  902  integrated therein for retaining at least one filter (not shown). For clarity and ease of illustration, the cap  900  is shown without its associated filter(s), hollow needle, membrane, or insert.  FIG.  13    depicts a hole  904  that accommodates the hollow needle and/or fluid flow. The hole  904  is formed within the interior base section of the neck region  906  of the cap  900 . For this particular embodiment, the retaining features  902  are realized as two projections that extend radially inward toward the hole  904 , although only one projection or more than two projections can be utilized. The projections are configured to compress a portion of the filter(s) to retain the filter(s) in the desired position and/or to guide at least one filter during assembly and/or to hold at least one filter in place after assembly. The retaining features  902  may include ridges (as shown), nubs, and/or textured surfaces that provide additional friction to hold the filter(s) when installed. The shape, contour, and dimensions of the retaining features  902  may vary from one embodiment to another, as appropriate for the particular shape, size, and configuration of the cap  900  and the filter(s). 
       FIG.  14    is a top perspective view of another exemplary embodiment of a fluid reservoir cap  1000  having retaining features  1002  integrated therein for retaining at least one filter (not shown). For clarity and ease of illustration, the cap  1000  is shown without its associated filter(s), hollow needle, membrane, or insert.  FIG.  14    depicts a hole  1004  that accommodates the hollow needle. The hole  1004  is formed within the interior base section of the neck region  1006  of the cap  1000 . For this particular embodiment, the retaining features  1002  are realized as three narrow block-shaped projections that extend radially inward toward the hole  1004 , although only one projection or more than two projections can be utilized. The retaining features  1002  may include ridges, nubs, and/or textured surfaces that provide additional friction to hold the filter(s) when installed. The shape, contour, and dimensions of the retaining features  1002  may vary from one embodiment to another, as appropriate for the particular shape, size, and configuration of the cap  1000  and the filter(s). 
       FIG.  15    is a partially exploded perspective view of an exemplary embodiment of a fluid reservoir cap  1100  having rectangular shaped gas trapping filters  1102 , and  FIG.  16    is a top view of the fluid reservoir cap  1100 . As explained above with reference to  FIGS.  8 - 12   , the cap  1100  includes an insert  1104  that retains the gas trapping filters  1102  inside a neck region  1106  of the cap  1100 . 
     The gas trapping filters  1102  may be fabricated from material or compositions described above with reference to the gas trapping filter  402 . In certain embodiments, each gas trapping filter  1102  includes or is fabricated from a polyvinyl alcohol composition having a pore size within the range of 0.1 mm to 5.0 mm, e.g., an average of about 0.35 millimeter or 350 microns. 
       FIG.  16    is a top perspective view of the cap  1100 . For clarity and ease of illustration,  FIG.  16    depicts the cap  1100  without its associated filter(s), hollow needle, membrane, or insert.  FIG.  16    depicts a hole  1110  that accommodates the hollow needle and/or fluid flow. The hole  1110  is formed within the interior base section of the neck region  1106  of the cap  1100 . For this particular embodiment, a retaining feature  1114  for the filter(s) is realized as a rectangular-shaped cavity that is shaped and sized to match the outer dimensions of the filter(s). The cavity is defined by four sidewalls that extend to support the outer walls of the filter(s) when the cap  1100  is assembled. The sidewalls hold the filter(s) in position and inhibit rotation of the filter(s). The sidewalls may include ridges, nubs, and/or textured surfaces that provide additional friction to hold the filter(s) when installed. The shape, contour, and dimensions of the cavity may vary from one embodiment to another, as appropriate for the particular shape, size, and configuration of the cap  1100  and the filter(s). 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope defined by the claims, which includes known equivalents and foreseeable equivalents at the time of filing this patent application.