POWER PACK FOR AN AUTOINJECTOR
A power pack, for use in an autoinjector to deliver a drug from a container at an injection rate includes a power pack body configured to hold a liquefied gas and a flow regulator, the power pack body further including at least one outlet through which some of the liquefied gas can exit the power pack in a gaseous state such that, during use, the flow regulator will control a rate of exit flow such that the liquefied gas in the canister is maintained at substantially its vapor pressure, while the gas leaving the outlet applies an adaptively changing force to the drug in the container so that delivery of the drug will occur at about a constant injection rate.
1 . A power pack for use in an autoinjector to deliver a drug from a container at an injection rate, the power pack comprising:
a power pack body having a canister therein configured to hold a liquefied gas, and a flow regulator, the power pack body further including at least one outlet through which some of the liquefied gas in the canister can exit the power pack in a gaseous state such that, during use, the flow regulator will control a rate of exit flow so that the liquefied gas in the canister is maintained at substantially its vapor pressure, while the gas leaving the outlet applies an adaptive force to the drug in the container in a controlled manner such that:
i) the adaptive force will be constant at a constant injection rate,
ii) the adaptive force will increase, if the injection rate slows to below the constant injection rate, and
iii) the adaptive force will decrease, as the injection rate increases from below the constant injection rate towards the constant injection rate.
2 . The power pack of claim 1 , wherein the liquefied gas is a propellant.
3 . The power pack of claim 2 , wherein the propellant includes a hydrocarbon.
4 . The power pack of claim 1 , wherein, prior to use, the liquefied gas occupies about 50% of the canister's volume.
5 . The power pack of claim 2 , wherein, prior to use, the liquefied gas occupies between about 25% and about 45% of the canister's volume.
6 . The power pack of claim 5 , wherein, prior to use, the liquefied gas occupies between about 30% and about 40% of the canister's volume.
7 . The power pack of claim 1 wherein, prior to use, the liquefied gas in the canister is at a pressure of between about 17 psi and about 850 psi.
8 . The power pack of claim 7 , wherein the liquefied gas comprises one or more of:
nitrous oxide (N 2 O), n-butane, isobutane, propane, R134a or dimethyl ether (DME).
9 . The power pack of claim 5 , wherein the liquefied gas comprises one or more of:
nitrous oxide (N2O), n-butane, isobutane, propane, R134a or dimethyl ether (DME).
10 . The power pack of claim 1 , wherein the at least one outlet comprises multiple openings through which the gaseous state will pass.
11 . The power pack of claim 10 , wherein the multiple openings are holes.
12 . The power pack of claim 1 , wherein the constant injection rate is a rate which will result in delivery of a dose of the drug in greater than about 5 seconds.
13 . The power pack of claim 12 , wherein the constant injection rate will result in delivery of a dose of the drug in between about 5 seconds and about 10 seconds.
14 . The power pack of claim 13 , wherein the regulator includes at least one of:
a permeable membrane or a solid porous material.
15 . The power pack of claim 14 , wherein the regulator comprises the permeable membrane and, wherein the permeable membrane is at least one of:
a plastic membrane, a fiber membrane, or a microporous film.
16 . The power pack of claim 14 , wherein the regulator comprises the solid porous material and wherein the solid porous material is at least one of: a sintered porous metal, a porous metal foam, a porous ceramic, or a porous ceramic foam.
17 . The power pack of claim 1 wherein, the power pack is further configured such that:
iv) the adaptive force will decrease, if the injection rate speeds up to above the constant injection rate, and
v) the adaptive force will then increase, as the injection rate decreases from above the constant injection rate towards the constant injection rate.
18 . The power pack of claim 1 , wherein the outlet is coupled to an exhaust end of the canister and the outlet is dimensioned to closely correspond with, and fit into, an interior surface of the container so as to form a sealed connection therebetween during use.
19 . The power pack of claim 1 , wherein the outlet is coupled to an exhaust end of the canister and the outlet is dimensioned to closely correspond with, and envelop, an exterior surface of the container so as to form a sealed connection therebetween during use.
20 . A power pack, for use in an autoinjector to deliver a drug from a container at an injection rate, the power pack comprising:
a power pack body configured to hold a liquefied gas,
the power pack body further including a flow regulator and at least one outlet through which some of the liquefied gas can exit the power pack in a gaseous state such that, during use, the flow regulator will control a rate of exit flow such that the liquefied gas in the canister is maintained at substantially its vapor pressure, while the gas leaving the outlet will apply an adaptively changing force to the drug in the container so that delivery of the drug will occur at about a constant injection rate, the power pack body further configured such that, when the constant injection rate changes to a deviated injection rate, the adaptively changing force applied by the gas leaving the outlet will adjust to modify the deviated injection rate towards the constant injection rate.