Patent Publication Number: US-2020282132-A1

Title: Subcutaneous infusion device for injecting medicinal substances

Description:
CROSS REFERENCE 
     The present application is a 35 U.S.C. § 371 National Stage application which claims priority to International Application No. PCT/US2015/022494 filed on Mar. 25, 2015 under 35 U.S.C. §§ 119(a) and 365(b), which claims priority to a U.S. provisional patent application Ser. No. 61/971,966 filed on Mar. 28, 2014 under 35 U.S.C. § 119(e); both of which applications are incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure generally relates to devices for injecting medicinal substances, and more particularly relates to a medical fluid delivery device for subcutaneously administering viscous liquid medicines into the body of a user. 
     Subcutaneous infusion devices are well known in the medical arts for use in the administration of a selected medicinal substance to a desired infusion site located underneath the skin of a patient or user. Commonly included in such infusion device is a tubular cannula or catheter that is supported by and protrudes from a hub for receiving the medicinal substance via a delivery tubing. Typically, the hub includes a small needle that is inserted just under the surface of the skin, and remains in place for up to several days. 
     More specifically, such infusion devices provide an alternative to intravenous delivery of medicines and allow the medicinal substance to be administered through a layer of skin immediately below the dermis and epidermis. As is known in the art, such use of the subcutaneous infusion devices decreases the number of times the patient must have an injection to receive frequently administered medicines. Although not all medicines can be administered through such infusion devices, they are an effective and convenient way to administer medicinal substances without having to impose multiple injections on the patient. 
     However, some medicinal substances are highly viscous (i.e., in the range of 3-10 cP or centipoise) and are delivered at high flow rates, and conventional subcutaneous infusion devices are not designed to deliver the highly viscous substance at these flow rates. As a result, a build-up of excessive delivery pressure during the delivery of such substances is likely to occur, and clogging may occur in the needle or its adjacent areas during infusion. Further, because the needle used in the infusion device is typically bent about 90 degrees, the risk of kinking is relatively high at or near the bent portion of the needle. 
     Another issue of conventional infusion devices is that movement of the hub can cause the needle to break during use. Foldable gripping wings are typically attached to the hub for securely holding the needle when inserting the needle straight into the desired infusion site at a 90 degree angle relative to the skin surface. Specifically, the wings are folded back away from the needle and pinched together between two fingers. At times, the folded wings slide against each other during the insertion step, making the insertion of the needle rather challenging. Further, if the needle is made of a smaller diameter, the needle is not supported firmly and causes it to break during use. 
     Therefore, there is a need for improving subcutaneous infusion devices to facilitate a more stable retention of the needle on the skin during the insertion step, and for reducing flow resistance of highly viscous substance during the delivery step. 
     SUMMARY 
     The present disclosure is directed to a medical fluid delivery device for subcutaneously administering viscous liquid medicines into the body of a user or patient. The present infusion device is designed to reduce a pressure drop (or flow resistance) that occurs during the delivery step of the viscous liquid or solution into a subcutaneous space of the user&#39;s skin. As described in further detail below, the present infusion device delivers the viscous liquid at a higher flow rate than the conventional devices due to the geometry of a hub and a needle. 
     One aspect of the present infusion device is that low flow resistance is achieved for high viscosity liquids (e.g., 3-20 cP) in flow rates ranging 40 to 400 ml/hr (or milliliter/hour) during subcutaneous delivery. Specifically, a 24G (or gauge) needle having a thin tubular wall is provided for accommodating the viscous liquid, and a mid-region of the needle is slightly bent at a predetermined radius of curvature, such that the mid-region surrounds a support region located at an outer end of the hub. 
     Another important aspect is that the present infusion device provides secure placement of the needle that reduces disturbance to the desired infusion site, and enhances comfort during infusion. A plurality of substantially diagonally disposed ribs is provided on a bottom side of the hub for preventing unwanted movement of the hub while worn by the user. More specifically, the diagonal bottom ribs are angled in such a manner that a forward movement toward the sharp end of the needle is prevented while a backward movement away from the sharp end of the needle is allowed. Furthermore, the diagonal pattern also stabilizes the hub for lateral disturbances after installation of the needle. This arrangement reduces shear and/or normal stress on the bent portion of the needle. 
     Yet another aspect of the present device is that a top side of the hub includes at least two ribs, each one of which is respectively located on a left wing and a right wing of the hub. Each rib is asymmetrically disposed on the wings, such that when the wings are folded back away from the needle and pinched together, the two ribs prevent twisting and/or sliding of the wings relative to each other during an insertion of the needle into the skin. Accordingly, the needle remains stable and straight during the insertion, preventing a breakage of the needle due to undesirable movement of the wings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top perspective view of the present infusion device featuring a winged hub having top ribs; 
         FIG. 2  is a vertical cross-section taken along the line  2 - 2  of  FIG. 1  and in the direction generally indicated; 
         FIG. 3  is a top view of the present hub featuring angled bottom ribs; 
         FIG. 4  is a vertical cross-section taken along the line  4 - 4  of  FIG. 3  and in the direction generally indicated; 
         FIG. 5  is a front view of the winged hub folded away from a needle in preparation of an insertion of the needle into an infusion site; 
         FIG. 6  is a perspective view of the present infusion device being inserted into the infusion site; 
         FIG. 7  is a perspective view of the present infusion device during infusion; and 
         FIG. 8  is an enlarged perspective view of the winged hub after the needle is inserted into the infusion site. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-2 , the present subcutaneous infusion device is generally designated  10  and is designed for subcutaneously delivering a medicinal substance below the dermis and epidermis. An exemplary medicinal substance may include nutritional products and Chinese herbal medicinal products. It is contemplated that the device  10  is disposable. Included in the device  10  is a luer cap  12  configured for receiving the liquid at one end, and at an opposite end, is attached to a female luer connector  14  using complementary helically threaded portions for threadably fastening the cap and connector together. For carrying a viscous liquid medicine to an infusion site, a flexible elongated tube  16  is attached at one end to the female luer connector  14 , and at an opposite end to a foldable hub  18  having a left or first wing  20  and a right or second wing  22 . 
     An exemplary length of the tube  16  is approximately 24 inches, but it is also contemplated that any length of tube can be utilized to suit different applications. Regulating a flow of the viscous liquid medicine in the tube  16  is achieved by transversely adjusting a slide clamp  24  relative to a longitudinal axis of the tube. As an example, a movable release slot  26  is provided in a center of the slide clamp  24  such that the clamp can transition between an occluding position and a non-occluding position by selectively sliding the release slot relative to the tube  16 . 
     In a preferred embodiment, the winged hub  18  is molded, as by injection molding or the like, such that the hub and its connecting elements are integrally formed. However, it is also contemplated that the hub  18  is attachable to the connecting elements by chemical adhesives, solvent boding, ultrasonic welding or other conventional fastening techniques. More specifically, the hub  18  is attached at one end to the tube  16 , and at an opposite end to a needle  28 , which is slidably fitted into and safeguarded by a needle protector  30  when not in use. It is contemplated that after the hub  18  is molded, the needle  28  is assembled onto the hub  18  using an adhesive. Alternatively, the hub  18  may be over-molded over the needle  28 . 
     An exemplary needle size is approximately 24G for ensuring comfort during infusion, and an exemplary needle length may be one of 6, 9, or 12 mm (or millimeter) depending on an application. Preferably, the needle  28  has a thin tubular wall for accommodating the viscous liquid medicine. 
     An important aspect of the present hub  18  is that each of the foldable left and right wings  20 ,  22  of the hub has at least one top rib  32 ,  34  extending along an entire longitudinal length of a corresponding wing. Each top rib  32 ,  34  is disposed on an upper surface  36  of the corresponding wing  20 ,  22 , such that when the wings are folded, the top ribs  32 ,  34  are directly in contact with the upper surface  36  of a corresponding opposite wing. As a result, the top rib  32  disposed on the left wing  20  engages the upper surface  36  of the right wing  22 , and conversely the top rib  34  disposed on the right wing  22  engages the upper surface  36  of the left wing  20 . 
     As illustrated in an exemplary  FIGS. 1 and 5  embodiment, a left or first top rib  32  is asymmetrically disposed from a right or second top rib  34  such that the first top rib  32  is juxtaposed with the second top rib  34  when the wings  20 ,  22  are folded back away from the needle  28  and pinched together ( FIG. 5 ). More specifically, the first top rib  32  is spaced in parallel from an elongated center section  38  of the hub  18  at a first predetermined distance D A  ( FIG. 1 ), but the second top rib  34  is spaced in parallel from the center section at a second predetermined distance D B  ( FIG. 1 ), where the first distance D A  is different from the second distance D B . 
     For example, as best shown in the  FIG. 5  embodiment, the first distance D A  is longer than the second distance D B , and the first rib  32  goes over the second rib  34  such that the ribs  32 ,  34  are adjacently positioned with each other when the wings  20 ,  22  are folded back. As a result, this particular configuration of the top ribs  32 ,  34  prevents the wings  20 ,  22  from twisting or sliding relative to each other, thereby reducing the risk of breakage of the needle  28  during the insertion of the needle into the skin. 
     Returning now to  FIGS. 1-2 , a first insertion opening  40  at a first end of the center section  38  is configured for accommodating insertion of the needle  28 , and a second insertion opening  42  at a second opposite end of the center section in fluid communication with the tube  16  is configured for accommodating insertion of the tube. In a preferred embodiment, the tube  16  is inserted into the first insertion opening  40  approximately half a length of the center section  38  to reduce a total length of the needle  28  ( FIG. 2 ). 
     Both openings  40 ,  42  provide a passage way for the delivery of the liquid medicine. This passage way provides low flow resistance for high viscosity liquids (e.g., 3-20 cP) in flow rates ranging 40 to 400 ml/hr during subcutaneous delivery without dropping a fluid pressure more than 10 psi (or pounds per square inch). More specifically, an exemplary 24G stainless needle  28  having the thin tubular wall is configured for accommodating the viscous liquid medicine, and a mid-region  44  of the needle  28  is slightly bent at a predetermined radius of curvature (e.g.,  0 . 125 ″ typically and not less than 0.060″ or more than 0.200″), such that the mid-region of the needle surrounds a support region  46  located at or near the first insertion opening  40  of the center section  38 . 
     It is preferred that the mid-region  44  of the needle  28  is bent gradually at an angle of 45 to 90 degrees (nominally close to 90 degrees), such that the support region  46  buttresses against the bent mid-region of the needle. A sharp end of the needle  28  extends outwardly from the first insertion opening  40  of the center section  38  so that the sharp end of the needle is disposed transverse to a longitudinal axis of the center section. Consequently, the support region  46  reduces the risk of needle breakage, and provides integrated support for the bent mid-region  44  not only during the insertion of the needle  28  into the skin but also while being attached to the user&#39;s body. 
     Referring now to  FIGS. 2-4 and 8 , a plurality of substantially diagonally disposed bottom ribs  48   a ,  48   b  is provided on a lower or bottom surface  50  of each wing  20 ,  22  for preventing unwanted movement of the hub  18  during use. It is preferred that the bottom ribs  48   a ,  48   b  are generally evenly spaced in parallel, and extend along a full diagonal length of a corresponding wing  20 ,  22 . The bottom ribs  48   a ,  48   b  are angled or slanted in such a manner that a forward movement toward the sharp end of the needle  28  is prevented, while a backward movement away from the sharp end of the needle is allowed. This particular arrangement reduces shear and/or normal stress on the bent mid-region  44  of the needle  28  during use. 
     In a preferred embodiment, both the first and second wings  20 ,  22  of the hub  18  have the bottom ribs  48   a ,  48   b  positioned on the lower surface  50  at an angle of approximately 45 degrees relative to the longitudinal axis of the center section  38 . An important aspect of the ribs  48   a ,  48   b  is, however, that each bottom rib  48   a  disposed on the lower surface  50  of the first wing  20  is inclined or sloped upwardly from a left side of the first wing to a right side of the first wing toward the center section  38 . In a mirrored orientation, each bottom rib  48   b  disposed on the lower surface  50  of the second wing  22  is declined or sloped downwardly from a left side of the second wing adjacent the center section  38  to a right side of the second wing. As a whole, the bottom ribs  48   a ,  48   b  are constructed and arranged in a chevron or herringbone pattern, thereby preventing unwanted movement of the hub  18  while being attached to the user&#39;s body. 
     This enhanced friction provided by the ribs  48   a ,  48   b  prevents slippage of the hub  18  from the skin during use. While diagonally arranged ribs  48   a ,  48   b  are shown for illustration purposes, any type of knurling or textured ribs, ridges, grooves, or bumps are contemplated for disposition as a friction formation on the lower surface  50  of the wings  20 ,  22  for enhancing friction in this manner. Further, the angular orientation and/or spacing of the ribs  48   a ,  48   b  is variable to suit the situation. 
     Referring now to  FIGS. 5-7 , an exemplary use of the present infusion device is illustrated in greater detail. Before inserting the needle  28  into the skin, the user folds the wings  20 ,  22  back away from the needle  28  and pinches the wings together between two fingers. Then, the user subsequently removes the needle protector  30  from the needle  28 , and discards the protector ( FIG. 5 ). In preparation of the insertion, the user pinches an inch of the cleansed skin at the desired infusion site, and inserts the needle  28  with a darting motion, straight into the infusion site at a 90 degree angle ( FIG. 6 ). Next, the user checks a needle placement with a syringe  52  by pulling a plunger  54  backward. If blood is seen in the syringe  52 , then the present device  10  is removed and discarded in case of a disposable device. Otherwise, the user repeats the process of preparing the present device  10  and the infusion site. If no blood is seen in the syringe  52 , the user secures the needle  28  in place, and starts infusion as directed by a healthcare professional ( FIGS. 7-8 ). 
     While a particular embodiment of the present infusion device has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the present disclosure in its broader aspects and as set forth in the following claims.