Apparatus and method for piercing skin with microprotrusions
A method and device are described for applying a microprotrusion member ( 44 ) including a plurality of microprotrusions ( 90 ) to the stratum corneum with impact. The method and device are used to improve transport of an agent across the skin for agent delivery or sampling. The applicator ( 10, 60, 80 ) causes the microprotrusion member ( 44 ) to impact the stratum corneum with a certain amount of impact determined to effectively pierce the skin with the microprotrusions ( 90 ). The preferred applicator ( 10, 60, 80 ) impacts the stratum corneum with the microprotrusion member ( 44 ) with an impact of at least 0.05 joules per cm 2 of the microprotrusion member ( 44 ) in 10 msec or less.
1. A method of transferring an agent through the stratum corneum of a subject, comprising the steps of: providing a microprotrusion member having one or more stratum corneum-piercing microprotrusions; placing said microprotrusion member proximate a skin site on the subject; applying a hold down force to cause the stratum corneum to be stretched; striking said microprotrusion member with an impact force, whereby said microprotrusion member imparts an energy on impact with the stratum corneum in the range of approximately 0.05-0.3 joules per cm 2 of said microprotrusion member over a penetration period no greater than 10 milliseconds, and whereby at least one of said stratum corneum-piercing microprotrusions forms a microslit through the stratum corneum of the subject; and delivering or sampling or transferring the agent through said microslits microslit.
2. A method of transferring an agent through the stratum corneum of a subject, comprising the steps of: providing a microprotrusion member having one or more stratum corneum-piercing microprotrusions; applying a hold down force to cause the stratum corneum to be stretched; striking said microprotrusion member with an impact force, whereby said microprotrusion member imparts an energy on impact with the stratum corneum in the range of approximately 0.1-0.3 joules per cm 2 of said microprotrusion member over a penetration period in the range of 1-10 milliseconds, and whereby at least one of said stratum corneum-piercing microprotrusions forms a microslit through the stratum corneum of the subject; and transferring the agent through said microslit.
3. A method of transferring an agent through the stratum corneum of a subject, comprising the steps of: providing a microprotrusion member having one or more stratum corneum-piercing microprotrusions; providing an impact applicator adapted to provide a first impact force; placing said microprotrusion member proximate a skin site on the subject; placing said impact applicator proximate said skin site in operational relationship with said microprotrusion member; applying a hold down force to cause the stratum corneum to be stretched; actuating said impact applicator to impart said first impact force to said microprotrusion member, whereby said microprotrusion member imparts an energy on impact with the stratum corneum in the range of 0.1-0.3 joules per cm 2 of said microprotrusion member over a penetration period in the range of 1-10 milliseconds, and whereby at least one of said stratum corneum-piercing microprotrusions forms a microslit through the stratum corneum of the subject; and transferring the agent through said microslit.