A study published in Dermatologic Surgery (December 2020) investigated how timing of topical application, needle length and device type affects penetration in device-assisted drug delivery procedures.
The researchers harvested skin from cosmetic surgeries and treated it with black ink either before or after treatment with a microneedling pen (MP), roller or fractional ablative CO2 laser; the skin was then incubated for different time intervals. After one and three hours, the ink applied prior to MP treatment penetrated the skin deeper than the ink applied after MP. Ink applied prior to MP also showed deeper penetration than ink applied before or after treatment with a roller.
When comparing penetration of ink applied prior to MP vs. fractional ablative CO2 laser, MP treatment caused a lateral extension of the ink beyond the microchannels with increased ink penetration over time. CO2 laser demonstrated ink localization within microthermal zones without time-dependent increases in depth after 30 minutes. Ink penetration increased by .06mm per 1 mm increase in needle length.
Overall, the ink applied before MP resulted in deeper penetration with the channels exhibiting increased penetration with lateral extension of the product over time.
Read the full study here.