Devices, systems, kits and methods for increasing the
skin's permeability controlled by measured
skin electrical parameter are described herein. They may be used for transdermal
drug delivery and / or
analyte extraction or measurement. The controlled abrasion device contains (i) a hand piece, (ii) an
abrasive tip, (iii) a
feedback control mechanism, (iv) two or more electrodes, and (v) an electrical motor. Preferably the
feedback control mechanism is an
internal feedback control mechanism. In this embodiment, the
abrasive tip contains two electrodes, i.e. both the source
electrode and the return
electrode. In another embodiment, the
feedback control mechanism is an external feedback control. In the preferred embodiment for external feedback control, the device contains a co-axial or concentric arrangement of the two electrodes. In this embodiment, the
abrasive tip contains the source
electrode and the return electrode is located at the proximal end of the hand piece. The abrasive tip can be made of any material with a surface that can abrade
skin. The material can be conductive or non-conductive. The controlled abrasion device may be provided in a kit, where the kit contains the device, one or more abrasive tips, optionally with a
wetting fluid. The method for increasing the skin's permeability requires applying the controlled abrasion device to a portion of the skin's surface for a short period of time. The desired level of
skin impedance, and thus the resulting permeability of the treated site, can be set at a predetermined value. Alternatively, the level of
skin impedance can be selected based on the desired level of skin integrity, the subject's
sensation of discomfort, or the duration of the application. The device contains a control mechanism which uses an appropriate
algorithm or
signal processing on the
conductivity information provided by the electrodes to determine when the desired level of
skin permeability has been reached. Once the desired level has been reached, the abrasion device is removed and either a
drug delivery composition or device or an
analyte sensor is applied to the treated site.