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Nic_Mokhoff
For the curious, the original technical paper on Purdue researchers' ...
Nic_Mokhoff
Variation in body temperature and temperature in the environment are issues that ...
Purdue pump uses body heat to deliver drugs
Nicolas Mokhoff
9/1/2010 2:40 AM EDT
MANHASSET, NY -- Purdue University researchers have developed a pump for drug-delivery patches that might use arrays of "microneedles" to deliver a wider range of medications using the body's heat to transfer the drugs.
"We have developed a simple pump that's activated by touch from the heat of your finger and requires no battery," said Babak Ziaie, professor of electrical and computer engineering and biomedical engineering.
The liquid is contained in a pouch separated from the drug by a thin membrane made of a rubberlike polydimethylsiloxane polymer, which is used as diaphragms in pumps.
The dispenser consists of stacked PDMS layers mounted on a silicon substrate and operates based on the evaporation and condensation of a low boiling point liquid. Therefore, there is no need for a heater or a battery, since the only required source of energy is the heat provided by skin contact.
The pump contains a liquid that boils at body temperature so that the heat from a finger's touch causes it to rapidly turn to a vapor, exerting enough pressure to force drugs through the microneedles.
Current "transdermal" patches use small hydrophobic molecules that can be absorbed through the skin. "Most new drugs are large molecules that won't go through the skin. And a lot of drugs, such as those for treating cancer and autoimmune disorders, you can't take orally because they aren't absorbed into the blood system through the digestive tract," according to Ziaie. "It takes 20 to 30 seconds."
Ziaie has tested prototypes with liquid fluorocarbons, which are used as refrigerants and also in semiconductor manufacturing.
"You need a relatively large force, a few pounds per square inch, to push medications through the microneedles and into the skin," Ziaie said.
Findings indicate prototypes using the fluorocarbon HFE-7000 exerted 4.87 psi and another fluorocarbon, FC-3284, exerted 2.24 psi.
Researchers built a prototype device with 14mm×14 mm×8mm dimensions.
The work has been supported with funding from the National Science Foundation.
Research findings are detailed in a paper being presented during the 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences on Oct. 3-7 at University of Groningen in The Netherlands.
"We have developed a simple pump that's activated by touch from the heat of your finger and requires no battery," said Babak Ziaie, professor of electrical and computer engineering and biomedical engineering.
The liquid is contained in a pouch separated from the drug by a thin membrane made of a rubberlike polydimethylsiloxane polymer, which is used as diaphragms in pumps.
The dispenser consists of stacked PDMS layers mounted on a silicon substrate and operates based on the evaporation and condensation of a low boiling point liquid. Therefore, there is no need for a heater or a battery, since the only required source of energy is the heat provided by skin contact.
The pump contains a liquid that boils at body temperature so that the heat from a finger's touch causes it to rapidly turn to a vapor, exerting enough pressure to force drugs through the microneedles.
Current "transdermal" patches use small hydrophobic molecules that can be absorbed through the skin. "Most new drugs are large molecules that won't go through the skin. And a lot of drugs, such as those for treating cancer and autoimmune disorders, you can't take orally because they aren't absorbed into the blood system through the digestive tract," according to Ziaie. "It takes 20 to 30 seconds."
Ziaie has tested prototypes with liquid fluorocarbons, which are used as refrigerants and also in semiconductor manufacturing.
"You need a relatively large force, a few pounds per square inch, to push medications through the microneedles and into the skin," Ziaie said.
Findings indicate prototypes using the fluorocarbon HFE-7000 exerted 4.87 psi and another fluorocarbon, FC-3284, exerted 2.24 psi.
Researchers built a prototype device with 14mm×14 mm×8mm dimensions.
The work has been supported with funding from the National Science Foundation.
Research findings are detailed in a paper being presented during the 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences on Oct. 3-7 at University of Groningen in The Netherlands.
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DrQuine
9/1/2010 9:31 AM EDT
This is an interesting concept - but does not address the fact that human environments span temperature ranges above and below "body" temperature. My finger temperature today in a comfortable room, according to my laser pyrometer, is 92 to 94 degrees (peripheral temperatures are lower than the "core" temperature of 98.6). How will this drug delivery system work in Phoenix where the temperature is forecast to be 108 (F) tomorrow? On a broader scale, could body temperature or movements be used to power biomedical electrical devices?
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hm
9/1/2010 11:54 AM EDT
Yes, this novel concept of employing body heat to deliver drug is quite interesting. It is good to know it generally works in laboratory environment. However, its trial on actual real life environment will need few more new concepts to improvise it. As it is for humane health reliability of pump is of prime importance. As mentioned DrQuine, it must adapt to environment conditions from northern Canada to desserts’ of middle-east. It may also need some form measurement verification/calibration (or embedded intelligence) that only said amount of dose is delivered and it should not leak except for pumped into body. One another question is – how do you refill this pump?
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Nic_Mokhoff
9/1/2010 12:40 PM EDT
Variation in body temperature and temperature in the environment are issues that need to be addressed further before commercialization of course; I do think that the temperature variation is "negligent" at the "local" level where the pump pushes the medication thru the skin. The researchers explain this way: "The pump contains a liquid that boils at body temperature so that the heat from a finger's touch causes it to rapidly turn to a vapor, exerting enough pressure to force drugs through the microneedles.
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Nic_Mokhoff
9/1/2010 1:39 PM EDT
For the curious, the original technical paper on Purdue researchers' achievements is here: http://i.cmpnet.com/eetimes/ZiaiePatches.pdf
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