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(This maybe old news but I just read about them.)
Patches Instead of Injections
by Kathrin Wildemann published: 2011-01-25
A soluble microneedle patch simplifies the self-administration of the human growth hormone for patients and maintains the full activity of the hormone.
Almost all children and many adults, too, know: Syringes are mean, scary and painful. But until now, the hypodermic needle is the only way to administrate many biopharmaceuticals, and patients who need those drugs on a regular basis have no choice but to overcome their apprehension of syringes. The miniaturization of needles for drug and vaccine delivery offers a solution – microneedles measure only a few hundreds micrometers, long enough to penetrate the skin’s permeability barrier but short enough to cause no pain. Recently, researchers have even gone one step further: They developed microneedles that dissolve inside the skin, releasing the drug and leaving nothing behind but the patch they were attached to. Compared to hypodermic needles, the soluble microneedle patches are not only easier to administer but can also prevent accidents with needles and infections caused by reuse of needles, a problem particularly in developing countries.
One group of patients that have to deal with hypodermic needles regularly are children with disturbance of growth: Their therapy includes subcutaneous injection of human growth hormone (hGH) several times a week – usually for months or even years. In the journal Small, Jeong Woo Lee et al. from the Georgia Institute for Technology, USA, now present a soluble microneedle patch for hGH: In an aqueous and mild-temperature process, they encapsulated the hormone in microneedles composed of carboxymethylcellulose and trehalose. These needles dissolve almost completely inside the skin of hairless rats, leaving behind only blunt stubs on the patches. In vitro tests show that the encapsulated hGH maintains its activity completely. However, in experiments with rats, the bioavailabilty of hGH administered via the patch reaches only 70% compared to the subcutaneous injection of the hormone; almost one fifth of the initial dose remains in the undissolved stubs on the patch. Apart from a slight, transient erythema and a decreased permeability barrier of the skin for two days, the patches have no side effects.
The study shows that, in the case of hGH, soluble microneedle patches could soon provide a safe alternative to hypodermic needles. Only the somewhat lower bioavalability and the slow recovery of the skin’s permeability barrier constitute shortcomings – but the authors presume that those can be overcome easily by optimizing the solubility of the matrix material and by localizing the drug in the tips of the microneedles.
Patches Instead of Injections
by Kathrin Wildemann published: 2011-01-25
A soluble microneedle patch simplifies the self-administration of the human growth hormone for patients and maintains the full activity of the hormone.
Almost all children and many adults, too, know: Syringes are mean, scary and painful. But until now, the hypodermic needle is the only way to administrate many biopharmaceuticals, and patients who need those drugs on a regular basis have no choice but to overcome their apprehension of syringes. The miniaturization of needles for drug and vaccine delivery offers a solution – microneedles measure only a few hundreds micrometers, long enough to penetrate the skin’s permeability barrier but short enough to cause no pain. Recently, researchers have even gone one step further: They developed microneedles that dissolve inside the skin, releasing the drug and leaving nothing behind but the patch they were attached to. Compared to hypodermic needles, the soluble microneedle patches are not only easier to administer but can also prevent accidents with needles and infections caused by reuse of needles, a problem particularly in developing countries.
One group of patients that have to deal with hypodermic needles regularly are children with disturbance of growth: Their therapy includes subcutaneous injection of human growth hormone (hGH) several times a week – usually for months or even years. In the journal Small, Jeong Woo Lee et al. from the Georgia Institute for Technology, USA, now present a soluble microneedle patch for hGH: In an aqueous and mild-temperature process, they encapsulated the hormone in microneedles composed of carboxymethylcellulose and trehalose. These needles dissolve almost completely inside the skin of hairless rats, leaving behind only blunt stubs on the patches. In vitro tests show that the encapsulated hGH maintains its activity completely. However, in experiments with rats, the bioavailabilty of hGH administered via the patch reaches only 70% compared to the subcutaneous injection of the hormone; almost one fifth of the initial dose remains in the undissolved stubs on the patch. Apart from a slight, transient erythema and a decreased permeability barrier of the skin for two days, the patches have no side effects.
The study shows that, in the case of hGH, soluble microneedle patches could soon provide a safe alternative to hypodermic needles. Only the somewhat lower bioavalability and the slow recovery of the skin’s permeability barrier constitute shortcomings – but the authors presume that those can be overcome easily by optimizing the solubility of the matrix material and by localizing the drug in the tips of the microneedles.
