Drug delivery platform utilizing hydrogel pumping mechanism

A drug delivery platform is provided for delivering a controlled infusion of a drug to an individual. The drug delivery platform includes a reservoir for receiving the drug therein and a pressure source engageable with the reservoir. The pressure source is movable between a first configuration and a second configuration wherein the pressure source exerts a pressure on the reservoir to urge the drug therefrom. An output conduit is provided for transmitting the drug into the individual. An actuation mechanism is operatively connected to the pressure source and the output conduit. The actuation mechanism is movable between a non-actuated position and an actuated position wherein pressure source moves from the first configuration to the second configuration and wherein the input of the output conduit communicates with the drug and the output end of the output conduit is receivable in the individual.

FIELD OF THE INVENTION

This invention relates generally to microfluidic devices, and in particular, to a drug delivery platform utilizing a hydrogel pumping mechanism to provide controlled infusion of a drug to an individual.

BACKGROUND AND SUMMARY OF THE INVENTION

As is known, the pharmaceutical industry has had limited success overcoming the challenges of delivering pharmaceuticals to patients. The oral ingestion of pharmaceuticals is considered the safest, most convenient and most economical method of drug administration. As compared to present alternatives, patient acceptance and adherence to a dosing regimen is typically higher among orally delivered pharmaceuticals. However, the oral delivery of many pharmaceuticals is not possible because the pharmaceuticals are either too large or too electrically charged to pass through the small intestine to reach the bloodstream. In addition, many pharmaceuticals which are unable to withstand the environment of the digestive tract or to penetrate the dermis need to be injected into the patient (e.g. insulin, proteins).

In order to overcome the problems associated with orally delivered pharmaceuticals, transdermal drug delivery patches have been developed. Transdermal drug delivery patches incorporate a medication and are intended to adhere to the skin of an individual. Molecules of the medication pass through the skin and into the bloodstream of the individual thereby delivering a specific dose of medication. While functional for their intended purposes, these patches have certain inherent limitations. By way of example, since the skin is a very effect barrier, existing transdermal drug delivery patches can only be used to deliver small molecule drugs such as nicotine and birth control. Alternatively, other transdermal technologies have been developed that utilize pressurized gas or voltage to move larger drug molecules across the skin barrier into the bloodstream. Again, while functional for their intended purposes, use of these technologies are limited to smaller volume injections and may have the undesired effect of altering the medications supplied to individuals. Therefore, a transdermal drug delivery device that provides controlled infusion of a drug to an individual without the use of pressurized gas or voltage would constitute a significant advancement in the art.

Therefore, it is a primary object and feature of the present invention to provide a drug delivery device that provides controlled infusion of a drug to an individual without the use of pressurized gas or voltage.

It is a further object and feature of the present invention to provide a drug delivery device that provides controlled infusion of a drug to an individual while maximizing the volume of drug delivered.

It is a still further object and feature of the present invention to provide a drug delivery device that provides controlled infusion of a drug to an individual that is simple to utilize and inexpensive to manufacture.

In accordance with the present invention, a drug delivery platform is provided for delivering a controlled infusion of a drug to an individual. The drug delivery platform includes a reservoir for receiving the drug therein and a pressure source engageable with the reservoir. The pressure source is movable between a first configuration and a second configuration wherein the pressure source exerts a pressure on the reservoir to urge the drug therefrom. An output conduit is provided for transmitting the drug into the individual. An actuation mechanism is operatively connected to the pressure source and the output conduit. The actuation mechanism is movable between a non-actuated position and an actuated position wherein pressure source moves from the first configuration to the second configuration and wherein the input of the output conduit communicates with the drug and the output end of the output conduit is receivable in the individual.

The pressure source includes a hydrogel that expands in response to a predetermined stimulus, such as a fluid. The drug delivery platform further includes an initiation fluid wherein the actuation mechanism includes an initiation conduit having an input and output. The input of the initiation conduit communicates with the initiation fluid and the output of the initiation conduit communicates with the pressure source in response to the actuation mechanism in the actuated position. A barrier is positioned between the initiation fluid and the pressure source. The barrier defines a channel network communicating with the pressure source and having an input that communicates with the output of the initiation conduit in response to the actuation mechanism in the actuated position. A fluid diverter may be provided to direct fluid from the output of the initiation conduit to the channel network. The channel network includes a plurality of circular, concentric channels.

The actuation mechanism includes a biasing structure for urging the actuation mechanism towards the non-actuated position. The reservoir has first and second ends and includes an output adjacent the first end. The pressure source is positioned adjacent to the second end of the reservoir.

In accordance with a further aspect of the present invention, a drug delivery platform is provided for delivering a controlled infusion of a drug to an individual. The drug delivery platform includes an initiation fluid and a reservoir for receiving the drug therein. A pressure source is engageable with the reservoir. The pressure source is movable between a first configuration and a second configuration wherein the pressure source exerts a pressure on the reservoir to urge the drug therefrom. An output conduit has an input and output, and an initiation conduit has an input and output. An initiation button is operatively connected to the output and initiation conduits. The initiation button is movable between a non-actuated position and an actuated position. With initiation button in the non-actuated position, the input of the initiation conduit is isolated from the initiation fluid and the output of the initiation conduit is isolated from the pressure source. In addition, the input of the output conduit is isolated from the drug and the output of the conduit is isolated from the individual. With the initiation button in the actuated position, the input of the initiation conduit communicates with the initiation fluid and the output of the initiation conduit communicates with the pressure source, and the input of the output conduit communicates with the drug and the output of the output conduit is receivable in the individual.

A barrier may be positioned between the initiation fluid and the pressure source. The barrier defines a channel network communicating with the pressure source and has an input that communicates with the output of the initiation conduit in response to the initiation button in the actuated position. A fluid diverter directs fluid from the output of the initiation conduit to the channel network. The channel network may include a plurality of circular, concentric channels.

The drug delivery platform includes a biasing structure for urging the initiation button towards the non-actuated position. The reservoir has first and second ends and includes an output adjacent the first end. The pressure source is positioned adjacent the second end of the reservoir.

In accordance with a still further aspect of the present invention, a drug delivery platform is provided for delivering a controlled infusion of a drug to an individual. The drug delivery platform includes a reservoir for receiving the drug therein. The reservoir has a first end and a second end. An expansion structure is positioned over the first end of the reservoir. The expansion structure has a first configuration and an expanded second configuration wherein the expansion structure exerts a pressure on the reservoir to urge the drug therefrom. An output conduit is movable between a retracted position and an extended position. An actuation mechanism is operatively connected to the expansion structure and the output conduit and is movable between a non-actuated position and an actuated position. The expansion structure moves from the first configuration to the second configuration in response to the actuation mechanism moving to the actuated position. The output conduit moves from the retracted position to the extended position to deliver the drug to the individual therethrough in response to actuation mechanism moving to the actuated position.

The expansion structure includes a hydrogel that expands in response to a predetermined stimulus, such as an initiation fluid. The actuation mechanism includes an initiation conduit having an input and output. The input of the initiation conduit communicates with the initiation fluid and the output of the initiation conduit communicates with the hydrogel in response to the actuation mechanism in the actuated position.

A barrier is positioned between the initiation fluid and the expansion structure. The barrier defines a channel network communicating with the expansion structure and having an input that communicates with the output of the initiation conduit in response to the actuation mechanism in the actuated position. A fluid diverter directs fluid from the output of the initiation conduit to the channel network. The channel network includes a plurality of circular, concentric channels and the actuation mechanism includes a biasing structure for urging the actuation mechanism towards the non-actuated position.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring toFIG. 1, a drug delivery platform in accordance with the present invention is generally designated by the reference numeral10. It is intended for drug delivery platform10to be affixed to an individual, as hereinafter described, to provide a controlled infusion of a drug to the individual. As best seen in FIGS.2and5-7, drug delivery platform10includes base12having a generally circular body portion13and an ear portion15projecting radially from the outer periphery of body portion13. Guide passageways17and19extend through ear portion15of base12to accommodate corresponding guide pins21and23, respectively, for reasons hereinafter described. Base12further includes a generally flat lower surface14and an upper surface16. Adhesive pad18includes an upper surface20affixed to lower surface14of base12in any conventional manner and a lower surface22having an adhesive thereon for interconnecting drug delivery platform10to an individual at a user desired location.

Upper surface16of body portion13of base12includes a generally circular recess24adapted for receiving bladder26therein. Generally circular groove27extends about the outer periphery of recess24and is adapted for receiving enlarged outer end30aof lip30of bladder26. Shoulder28extends radially inward from inner edge27aof groove27for supporting lip30of bladder26. Upper surface16of ear portion of base includes concave-shaped recess34adapted for receiving output end36of bladder26. Needle passageway25,FIGS. 3-4, interconnects concave-shaped recess34and lower surface14of base12. In addition, circular recess38extends into upper surface16of ear portion15of base12and defines generally cylindrical support post39. Support post39in recess38is adapted for receiving lower end40of spring42thereon, for reasons hereinafter described. Support post39may extend beyond upper16of ear portion15of base12to align the various components of drug delivery platform10of the present invention.

Drug delivery platform10further includes a pressure source such as hydrogel disc44. Hydrogel disc44includes an upper surface46and a lower surface48interconnected by outer periphery47. Hydrogel disc44is positionable on upper surface50of bladder26at a location adjacent end52opposite output end36of bladder26, for reasons hereinafter described. It is contemplated for hydrogel disc44to expand in response to a predetermined stimulus such as exposure to a fluid or the like.

Drug delivery platform10further includes a middle insert56having a lower surface60receivable on upper surface16of base12so as to capture bladder26and hydrogel disc44therebetween and an upper surface60. Middle insert56is further defined by a generally circular body portion62having an ear portion64projecting radially from the outer periphery thereof. Guide passageways63and65extend through ear portion64of middle insert56to accommodate corresponding guide pins21and23, respectively, for reasons hereinafter described. Needle passageway67and spring passageway66also extend through ear portion64of middle insert56between upper and lower surfaces58and60, respectively. Needle passageway67is axially aligned with concave-shaped recess34in upper surface16of base12, while spring passageway66is axially aligned with circular recess38extending into upper surface16of ear portion15of base12. Spring passageway66has a diameter sufficient to accommodate spring42, for reasons hereinafter described.

As best seen in FIGS.2and8-10, lower surface60of body portion62of middle insert56includes a generally circular recess68terminating at inner terminal surface80. Generally circular groove70extends about the outer periphery of recess68and is adapted for receiving enlarged edge30aof lip30of bladder26,FIGS. 5-7. Shoulder72extends radially inward from inner edge70aof groove70. Lower surface60of ear portion64of middle insert56further includes concave-shaped recess74extending radially outwardly from inner edge72aof shoulder72. Concave-shaped recess74is adapted for receiving output end36of bladder26. Needle passageway76extends between upper surface58of middle insert56and concave-shaped output recess74, for reasons hereinafter described.

Terminal surface80of recess68in body portion62of middle insert56includes defined by concentric inner and outer, generally circular, flow channels82aand82b, respectively. Recessed portion84of terminal surface80extends about and is radially spaced from outer flow channel82b. A plurality of spokes86a-86eextend from a common point88located at the center of inner flow channel82aso as to interconnect recessed portion84of terminal surface80with inner and outer flow channels82aand82b, respectively. Recessed portion84of terminal surface80communicates with a needle passageway90through input channel92. Needle passageway90, in turn, communicates with concave-shaped recess94in upper surface58of ear portion64of middle insert56. Flow diverter96projects from recessed portion84of terminal surface80at a location between input92and outer flow channel82b. In the depicted embodiment, flow diverter96is generally crescent-shaped. However, other shapes are possible without deviating from the scope of the present invention.

Referring specifically toFIGS. 9-10, a plurality of circumferentially spaced ledges100a-100eproject from terminal surface80of middle insert56. Inner edges102a-102bof ledges100a-100e, respectively, are intended to align hydrogel disc44captured between bladder26and middle insert56of drug delivery platform10, as hereinafter described.

Referring back to FIGS.2and5-7, upper surface58of body portion62of middle insert56includes a generally circular recess106adapted for receiving bladder108therein. Shoulder110extends about the outer periphery of recess106and is adapted for receiving peripheral edge112of bladder108thereon. Recess106communicates with concave-shaped recess94, which in turn, is adapted for receiving output end114of bladder108.

Cover116is receiveable on upper surface58of middle insert56. Cover116includes an upper surface132and a lower surface120. Cover116is further defined by a generally circular body portion121and an ear portion123projecting radially from the outer periphery of body portion121. Lower surface120of body portion121has a recess122therein adapted for receiving bladder108. Shoulder124extends about the outer periphery of recess122and is adapted for engaging peripheral edge112of bladder108. In addition, lower surface120of ear portion123of cover116includes a concave-shaped recess128for accommodating output end114of bladder108. Needle passageway130extends between concave-shaped recess128in lower surface120of cover116and upper surface132of cover116, for reasons hereinafter described.

Ear portion123of cover116further includes guide passageways133and135extending therethrough for accommodating corresponding guide pins21and23, respectively, for reasons hereinafter described. Needle passageway138and spring passageway140also extend through ear portion123of cover116between upper and lower surfaces132and120, respectively. Needle passageway138is axially aligned with concave-shaped recess94in upper surface58of middle insert56, while spring passageway140is axially aligned with spring passageway66through ear portion64of middle insert56and with circular recess38extending into upper surface16of ear portion15of base12. Spring passageway140has a diameter sufficient to accommodate spring42, for reasons hereinafter described.

In order to actuate drug delivery platform10, initiation button142is provided. Initiation button142includes a generally flat base144having an upper surface146and a lower surface148. Guide wall150depends from the outer periphery of base142and extends about the outer periphery of ear portion123of cover116. Guide wall150includes recess152therein so as to allow base portion144of initiation button142to partially overlap upper surface132of cover116. Guide pins21and23depend from lower surface148and are slidably received in corresponding guide passageways133and135, respectively, to guide movement of initiation button142between a non-actuated position,FIGS. 3 and 5, and an actuated position, FIGS.4and6-7. It is noted that initiation button142may include third guide pin137,FIGS. 3-4, for further guiding movement of initiation button142between the non-actuated and actuated positions. Cover116further includes first and second, generally tubular, needle supports156and158, respectively, depending from lower surface148of base144. First needle support156is adapted for receiving upper end160of initiation needle162. First needle support156is axially aligned with and has a diameter less than needle passageway130through cover116. As best seen inFIGS. 5-7, initiation needle162includes an output163at lower end166thereof and an input164centrally located between upper end160and lower end166thereof.

Second needle support158is adapted for receiving upper end168of output needle170. Referring toFIGS. 3-4, output needle170includes an output172at lower end174thereof and an input176at a location between upper end168and lower end174thereof. Output needle170extends through needle passageway138in cover116; needle passageway67through middle insert56; output end36of bladder26; and needle passageway25through base12. It can be appreciated that the outer surface of output needle170and output end36of bladder26form a fluid-tight relationship for maintaining a drug in bladder26when drug delivery device is not actuated, as hereinafter described.

Initiation button142further includes a generally tubular spring retainer178depending from lower surface148of base144and adapted for receiving upper end180of spring42therein. Spring42passes through spring passageway140in cover116; spring passageway66in middle insert56; and into recess38in base12about support post39. As described, it can appreciated that initiation button142is movable between the first non-actuated position,FIGS. 3 and 5, and the second actuated position, FIGS.4and6-7, against the bias of spring42.

In operation, the drug delivery platform10is assembled as heretofore described wherein bladder108is filled with a fluid to which hydrogel disc44is responsive and bladder26is filled with a predetermined drug. Lower surface22of adhesive pad18is affixed to an individual at a desired location so as to interconnect drug delivery platform10to the individual. Referring toFIGS. 3 and 5, with initiation button142in its non-actuated state, input164of initiation needle162is isolated from output end114of bladder108and such that output163of initiation needle162is isolated from input192to recess surface84of terminal surface80of middle insert56. In addition, with initiation button142in the non-actuated position, input176of output needle170is isolated from output end36of bladder26and output172of output needle170is isolated from the individual to which the drug in bladder26is to be administered.

Referring back toFIGS. 4 and 6, in order to actuate a drug delivery platform10, initiation button142is pressed against the bias of spring42such that initiation needle162pierces output end114of bladder108. As a result, input164of initiation needle162communicates with the interior of bladder108via output end114and output163of initiation needle162communicates with input channel92of recessed portion84of terminal surface80in middle insert56. In addition, with initiation button142in the actuated position, input176of output needle170communicates with the interior of bladder26through output end36and output172of output needle170is received within the individual to which the drug is to be administered.

Referring toFIG. 7, with initiation button142in the actuated position, fluid flows from the interior of bladder108into initiation needle162through input164thereof. The fluid exits initiation needle162through output163and flows onto recessed portion84of terminal surface80through input channel92. Flow diverter96causes the fluid to flow about the entirety of recessed portion84of terminal surface80into spokes86a-86b, thereby directing the fluid into flow channels82aand82b. Thereafter, the fluid is distributed onto a substantial portion of upper surface46of hydrogel disc44and about the outer periphery thereof. In response, hydrogel disc44expands thereby providing pressure onto bladder26. Flow diverter96acts to prevent hydrogel disc44from expanding in such a manner as to block input channel92and prevent additional fluid from flowing onto recessed portion84of terminal surface80therethrough. As heretofore described, hydrogel disc44is positioned adjacent end52of bladder26such that expansion of hydrogel disc44urges the drug within bladder56toward output end36thereof. Under pressure, the drug flows from the output end36of bladder26into output needle70through input176thereof. Thereafter, the drug exits output needle170through output172and is dispensed into the individual.

It can be appreciated that since the rate of expansion of hydrogel disc44controls the flow rate of the drug from bladder26into the individual, the desired delivery profiles such as bolus injections, constant infusion, delayed onset or the like are possible simply by altering the chemistry of hydrogel disc44. It can also be appreciated the output172of output needle170can be replaced with a microneedle array or like without deviating from the scope of the present invention.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing and distinctly claiming the subject matter that is regarded as the invention.