Tip-loaded dissolving microneedles for transdermal delivery of donepezil hydrochloride for treatment of Alzheimer’s disease

Getting Drugs Across Biological Barriers

“…Hollow needles are often conduits for a non-pressurized drug reservoir. Solid ones are used to merely create microscopic channels within the tissue; drug can be dry-coated onto premade needles, [161] or incorporated within a dissolvable or biodegradable needle (made of materials such as hydroxy-propyl-methylcellulose [162] and poly-lactide-co-glycolide [PLGA] [111] ) and eluted upon skin insertion.…”

“…Microneedles can deliver macromolecules and hydrophilic small molecules, including hormones, [111, 158] hydrophilic drugs, [153, 162] genetic material (DNA, siRNA), [111–112] and vaccines. [110–111] The drug molecules delivered via microneedles can enter the systemic circulation by absorption into capillaries in the dermis.…”

“…Donepezil hydrochloride, for example, has been encapsulated within dissolvable needles and eluted into the blood stream for the treatment of Alzheimer’s Disease. [162] In another example, silicon microneedle arrays have delivered a cholesterol-modified housekeeping gene ( Gapdh ) siRNA across the SC in vivo. [112] Greater plasma concentrations have been reported using microneedles than those obtained by oral administration for the same dose.…”

“…[112] Greater plasma concentrations have been reported using microneedles than those obtained by oral administration for the same dose. [162] …”

“…[111] Pain could be addressed by optimizing the needle dimensions to avoid nerve endings. [111, 161–162] There is an upper limit of drug loading per needle, beyond which needle breakage can occur. [111] Therefore, microneedles are considered most appropriate for highly potent drugs.…”