Abstract:
An infusion system comprises a disposable wearable infusion device having a body arranged to be adhered to a patient&#39;s skin and a reservoir for holding a liquid medicament to be infused into the patient. The infusion system further comprises a filler device arranged to be detachably received by the infusion device and to provide a positive pressure directly to the liquid medicament to transfer a volume of the liquid medicament to the infusion device reservoir.

Description:
BACKGROUND OF THE INVENTION 
     Tight control over the delivery of insulin in both type I diabetes (usually juvenile onset) and type II diabetes (usually late adult onset), has been shown to improve the quality of life as well as the general health of these patients. Insulin delivery has been dominated by subcutaneous injections of both long acting insulin to cover the basal needs of the patient and by short acting insulin to compensate for meals and snacks. Recently, the development of electronic, external insulin infusion pumps has allowed the continuous infusion of fast acting insulin for the maintenance of the basal needs as well as the compensatory doses (boluses) for meals and snacks. These infusion systems have shown to improve control of blood glucose levels. However, they suffer the drawbacks of size, cost, and complexity. For example, these pumps are electronically controlled and must be programmed to supply the desired amounts of basal and bolus insulin. This prevents many patients from accepting this technology over the standard subcutaneous injections. 
     Hence, there is a need in the art for a convenient form of insulin treatment which does not require significant programming or technical skills to implement to service both basal and bolus needs. Preferably, such a treatment would be carried out by an infusion device that is simple to use and mechanically driven negating the need for batteries and the like. It would also be preferable if the infusion device could be directly attached to the body and not require any electronics to program the delivery rates. The insulin is preferably delivered through a small, thin-walled tubing (cannula) through the skin into the subcutaneous tissue similar to technologies in the prior art. 
     While the idea of such a simple insulin delivery device is compelling, many obstacles must be overcome before such a device may become a practical realty. One problem resides in insulin supply. Patients vary greatly on the amount of insulin their device must carry to provide treatment over a fixed time period of, for example, three days. This is one environment where one size does not fit all. Another problem is with cannula deployment to support insulin delivery. Cannula deployment to support delivery of the insulin beneath the patient&#39;s skin must be made easy and convenient. This is not as easy as it seems because cannula deployment, as generally and currently performed in the art, requires insertion of a cannula carrying needle into the patient and then retraction of only the needle to leave the cannula in place beneath the patient&#39;s skin. 
     Still further, medical devices, such as IV pumps, insulin pumps and the like, designed to deliver liquid medicaments to patients by means of intravascular, intramuscular or interstitial injection are subject to problems due to difficulties in filling with the medicament prior to use. Specifically, the process of transferring a liquid medicament from a storage vial to the drug delivery device can be both difficult and error prone. The difficulty can be caused by the need to maintain sterility of the contacting surfaces, and the logistics of using an intermediate transfer device such as a syringe. Errors can be caused by miss-measurement of fluids and by the inadvertent introduction of air into the drug delivery device. While the difficulties can be inconvenient, the errors can result in more serious problems such miss-dosing. The consequences of incorrect treatment due to miss-dosing can vary from minor to serious. In the case of insulin delivery, incorrect dosing can lead to acute hypoglycemia or chronic hyperglycemia. 
     One currently proposed method of preparing a disposable insulin delivery device for use includes transferring insulin from a liquid medicament vial to the insulin delivery device. As proposed, this may be accomplished with a syringe and mounted needle by first drawing an amount of air into the syringe equal to the amount of insulin that will be withdrawn from the vial. Next, the vial septum is pierced with the needle and air is injected from the syringe into the vial, thus pressurizing the vial. The desired amount of insulin is then withdrawn from the vial into the syringe and thereafter, the needle is withdrawn from the vial. Next, the syringe is held in a vertical orientation to allow entrapped air to rise to the top. The syringe plunger is then gently advanced until the air has been ejected and a small amount of fluid is expressed from the syringe. The septum on the medicament delivery device is then pierced with the syringe to access the device reservoir and the insulin is injected into the reservoir. Lastly, the reservoir is inspected for air bubbles and those larger than 1 mm in diameter are removed by reinserting the syringe needle and aspirating the bubble. 
     This foregoing procedure is subject to error during the syringe filling and degassing steps, and during the reservoir filling step. Error during either step can result in excess air injected into the medicament delivery device. Excess air in the reservoir of the medicament delivery device can adversely affect the amount of insulin delivered to the patient during use, thereby compromising treatment. 
     Hence, there is a need for an improved filling device and method that will reduce the complications and potential errors associated with transferring a medicament from a storage vial to a drug delivery device. As will be seen subsequently, the present invention addresses these and other issues. 
     SUMMARY OF THE INVENTION 
     In one embodiment the invention provides an infusion system comprising a disposable wearable infusion device having a body arranged to be adhered to a patient&#39;s skin and a reservoir for holding a liquid medicament to be infused into the patient. The system further comprises a filler device arranged to be detachably received by the infusion device and to provide a positive pressure directly to the liquid medicament to transfer a volume of the liquid medicament to the infusion device reservoir. 
     The filler device may be arranged to receive a vial of the liquid medicament. The filler device may be arranged to transfer a set volume of the liquid medicament from the vial to the infusion device reservoir. The filler may further include a chamber that receives the liquid medicament from the vial before the liquid medicament is transferred to the infusion device reservoir. 
     The filler may include a piston and a piston chamber to meter a predetermined volume of the medicament to the reservoir. Alternatively, the filler may include a peristaltic pump. The filler may further include a vent that vents the liquid medicament to atmospheric pressure. 
     In another embodiment, the invention provides a method comprising the steps of providing a disposable infusion device adapted to adhere to a patient&#39;s skin and having a reservoir for holding a liquid medicament to be infused into the patient, coupling a medicament filler to the infusion device reservoir, and filling the infusion device reservoir with the liquid medicament. The reservoir may be filled by providing a positive pressure with the medicament filler directly to the medicament. 
     The coupling step may comprise detachably joining the medicament filler to the infusion device. The filling step may further comprise providing the medicament filler with a vial of the liquid medicament. The method may comprise the further step of venting the liquid medicament to atmospheric pressure. The method may comprise the further step of transferring the liquid medicament to an intermediate chamber before transferring the liquid medicament to the infusion device reservoir. 
     The filling step may include providing a piston and a piston chamber, filling the piston chamber with the liquid medicament, and causing the piston to act upon the liquid medicament within the piston chamber. 
     In a further embodiment, the invention provides a filler device for filling a reservoir of a disposable wearable infusion device with a liquid medicament. The filler device comprises an outlet arranged to be detachably received by the infusion device and a pump that provides a positive pressure directly to the liquid medicament to transfer a volume of the liquid medicament to the infusion device reservoir. 
     The device may further comprises a device body defining a cavity, and the cavity may be arranged to receive a vial of the liquid medicament. The filler device may be further arranged to transfer a set volume of the liquid medicament from the vial to the infusion device reservoir. 
     The pump may comprise a piston and a piston chamber. The piston may act upon the liquid medicament within the piston chamber to meter a predetermined volume of the liquid medicament to the reservoir. 
     Alternatively, the pump may be a peristaltic pump. The device may further comprise a vent that vents the liquid medicament to atmospheric pressure. The device may further comprise a chamber that receives the liquid medicament before the liquid medicament is transferred to the infusion device reservoir. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further features and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify identical elements, and wherein: 
         FIG. 1  is a perspective view of an infusion system including a medicament filling apparatus according to a first embodiment of the present invention; 
         FIG. 2  is a sectional side view illustrating details of the filling apparatus of  FIG. 1 ; 
         FIG. 3  is a perspective view of an infusion system and medicament filling apparatus according to a second embodiment of the present invention; 
         FIG. 4  is a perspective view of an infusion system and medicament filling apparatus according to a further embodiment of the present invention; 
         FIG. 5  is side view illustrating details of the filling apparatus  FIG. 4 ; 
         FIG. 6  is a sectional side view of a medicament filling apparatus according to a still further embodiment of the present invention; 
         FIG. 7  is a sectional side view illustrating the apparatus of  FIG. 6  after receiving a vial of liquid medicament; 
         FIG. 8  is a sectional side view illustrating the apparatus of  FIG. 6  after transferring a desired amount of the liquid medicament from the vial to an intermediate chamber in accordance with an embodiment of the present invention; and 
         FIG. 9  is a sectional side view of the apparatus of  FIG. 6  after transferring the desired amount of liquid medicament from the intermediate chamber to a reservoir of a disposable wearable infusion device according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , it is a perspective view of an infusion system  10  according to a first embodiment of the present invention. The system  10  generally comprises a wearable disposable infusion device  12  and a liquid medicament filling device  14 . 
     The infusion device  12  generally includes a housing  16 , at least one actuator button  18 , a fill port  20 , and a reservoir  24 . The device is preferably arranged to receive a cannula (not shown) after it is filled with liquid medicament, such as insulin, to be administered to the wearer of the device  12 . The actuator button  18  may be one of two actuator buttons which require concurrent actuation to cause the liquid medicament to be delivered. This arrangement helps to prevent accidental dosing. The fill port  20  may include a septum (not shown) that may be pierced by a needle  22  carried by the filling device  14  during the filling of device reservoir  24 . This serves to promote sterility during the filling process. To these and other ends, the infusion device may take a form as shown, and described, for example, in U.S. application Ser. No. 11/604,166, filed Nov. 22, 2006 for DISPOSABLE INFUSION DEVICE FILLING APPARATUS AND METHOD, which application is owned by the assignee of the present invention and incorporated herein by reference in its entirety. 
     The filling device  14  generally includes a generally cylindrical housing  30 , a vent tube  32 , an actuator  34 , and a metering pump  36 . The metering pump  36  includes a first one-way valve  38 , a second one-way valve  40 , a needle  42 , a piston chamber  44 , and a piston  46 . 
     The housing  30  has a cavity  31  dimensioned to receive a vial  48  containing the insulin or other liquid medicament. When the vial  48  is received within the housing  30 , the end cap  50  of the vial  48  is pierced first by the vent tube  32  and then by the needle  42 . The length of the vent tube  32  is selected so that when the vial  48  is fully received within the housing  30 , the end of the vent tube  32  extends above the liquid medicament. The vent tube  32  thus permits the liquid medicament to flow freely from the vial  48 , through the one-way valve  38 , and into the chamber  44  of the metering pump  36 . 
     The metering pump  36  is shown in greater detail in  FIG. 2 . When the actuator  34  is depressed, the piston  46  is caused to exert a direct positive pressure on the liquid medicament within the piston chamber  44  to displace a set volume or known quantity of the liquid medicament from the piston chamber  44 . The set volume or known quantity of displaced liquid medicament flows through the one-way valve  40 , and through the needle  22  into the reservoir  24 . Hence, the number of times that the actuator  36  is depressed determines the amount of liquid medicament transferred form the vial  48  to the reservoir  24  of the device  12 . This enables the reservoir  24  to be filled with a precise and desired amount liquid medicament. The valve  40  is preferably a drip-less, excellent flow, low volume valve. To that end, the valve  40  may be a swabable luer valve of the type known in the valve art. 
     In use, the needle  22  is attached to the one-way valve  40  of the metering pump  36 . Next, the vial  48  of liquid medicament is placed in the housing  30  and the filling device  14  is releaseably joined with the infusion device  12 . Next, the actuator  34  is depressed the number of times required to transfer the desired quantity of the liquid medicament from the vial to the fill port  20  and thus the reservoir  24  of the infusion device  12 . When the desired quantity of liquid medicament has been transferred to the device  12 , the filling device  14  is removed from the infusion device  12 , the needle  22  is removed from the one-way valve  22 , and the filling device  14  is placed in sterile storage with the vial  48  remaining in the housing  30 . Such storage supports multiple use of the filling device. 
       FIG. 3  is a perspective view of an infusion system  110  comprising an infusion device  112  and a medicament filling device  114  according to a second embodiment of the present invention. As in the previous embodiment, the infusion device  112  generally includes a housing  116 , at least one actuator button  118 , a fill port  120 , and a reservoir (not shown). The device is preferably arranged to receive a cannula (not shown) after it is filled with liquid medicament, such as insulin, to be administered to the wearer of the device  112 . The actuator button  118  may again be one of two actuator buttons which require concurrent actuation to cause the liquid medicament to be delivered. As before, this arrangement helps to prevent accidental dosing. The fill port  120  may be dimensioned to receive a fill tube  122  carried by the filling device  114  during the filling of device reservoir. 
     The filling device  114  includes a syringe  136 , a first one-way valve  138 , a second one-way valve  140 , and a transfer tube  142 . The transfer tube  142  couples the interior of the vial  148  to the one-way vale  138 . This permits the liquid medicament to be drawn from the vial  148  as the piston  144  of the syringe  136  is withdrawn through movement of the actuator  134 . The actuator movement is represented by arrows  132 . As the piston  146  is withdrawn, a chamber  144  is formed of a known volume that is filled with the liquid medicament. The medicament may flow freely due to the vacuum release or vent tube  132 . 
     When the chamber  144  is expanded to hold a desired or set volume of the liquid medicament, the actuator  134  is moved in the other direction to cause the piston  146  to exert a direct positive pressure on the liquid medicament. The liquid medicament thus flows from the syringe chamber  144  through the fill tube  122  and into the fill port  120  of the device  112 . When the volume of the chamber  144  has been diminished completely, the known or set volume of liquid medicament has been transferred to the device  112 . 
       FIG. 4  is a perspective view of an infusion system  210  and medicament filling device  214  according to a further embodiment of the present invention. The system  210  may include the infusion device  12  of the embodiment of  FIG. 1 , previously described. 
     The filling device  214  generally includes a generally cylindrical housing  230 , a vent tube  232 , an actuator  234 , and a metering pump  236 . The metering pump  236  is in the form of a peristaltic pump. 
     The housing  230  has a cavity  231  dimensioned to receive a vial  248  containing the insulin or other liquid medicament. When the vial  248  is received within the housing  230 , the end cap  250  of the vial  248  is pierced first by the vent tube  232  and then by the needle  242 . Again, the length of the vent tube  232  is selected so that when the vial  248  is fully received within the housing  230 , the end of the vent tube  232  extends above the liquid medicament. The vent tube  232  thus vents the vial to atmospheric pressure to permit the liquid medicament to flow freely from the vial  248 . 
     The peristaltic metering pump  236  is shown in greater detail in  FIG. 5 . Here it may be seen that the peristaltic pump  236  includes a plurality of radially extending rotating fingers  246 . The fingers  246  rotate about a toothed hub  244 . The teeth of the toothed hub  244  are driven by the teeth of a toothed drive member  242  connected to the actuator  234 . A transfer tube  240  conducts the liquid medicament from the vial  248  to the fill port  20  of the device  12 . The fingers  246  are rotated when the actuator  234  is depressed. The ends of the rotating fingers engage the transfer tube  240  to push the liquid medicament long to the fill port  20 . Each depression of the actuator  234  meters a set volume of the liquid medicament to the fill port  20 . Hence again, the number of actuator depressions determines with precision the volume of liquid medicament transferred to the fill port  20 . Also, in this embodiment, the liquid medicament, although receiving direct positive pressure from the peristaltic pump, is never actually touched by pump mechanism. 
       FIGS. 6-9  show a medicament filling apparatus  314  according to a still further embodiment of the present invention. As shown on  FIG. 6 , the device  314  includes a plunger  344  that reciprocates on a frame  343 . Seal rings  341  provide a seal between the plunger  344  and the frame  343 . On top of the plunger  344  is a ring  330  that defines a cavity  331  for receiving a vial of liquid medicament. The device  314  also includes a vent tube  332  and a transfer tube  342 . One-way valve  338 , as will be seen subsequently, permits the liquid medicament to be transferred to an intermediate chamber when the plunger  344  is withdrawn. Another one-way valve  340  permits the liquid medicament to flow from the aforementioned intermediate chamber into the fill tube  322 . The fill tube  322  has an end  323  that is received by the infusion device fill port. The device  314  further has a protective cap  350  that protect the fill tube  322  during device storage. 
       FIG. 7  shows the device  314  after the ring has received the vial  348  of liquid medicament. It may be noted the vent tube  332  is venting the vial  348  to atmospheric pressure above the liquid medicament. 
     In  FIG. 8 , the plunger  344  has been withdrawn causing liquid medicament to flow from the vial  348 , through transfer tube  342  and one-way valve  238 , into the intermediate chamber  337  formed by the withdrawal of the plunger  344 . The extent in which the plunger  344  is withdrawn and the volume of liquid medicament to be transferred, is set by spacer  347 . The spacer  347  comprises two rings joined by a stepped incline. Depending upon which relative directions the rings are rotated with respect to each other, the spacer is widened or narrowed to control the travel of the plunger, and hence the volume of liquid medicament transferred to the intermediate chamber. Here, the volume so transferred is seen at  345 . 
     In  FIG. 9 , the protective cap  350  has been removed and the filling device  314  has been coupled to an infusion device  312  for filling the reservoir  324  of the device  312 . The plunger  344  has been brought to its initial position thus completely reducing the intermediate chamber. This has caused through direct positive, the liquid medicament to have flowed from the intermediate chamber, through the one-way valve  322  and fill to tube  322  into the reservoir  324  of the infusion device  312 . The filling of the infusion device reservoir is now complete and the protective cover  350  may be once again placed on the filling device for storage. 
     While particular embodiments of the present invention have been shown and described, modifications may be made, and it is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention as defined by those claims.