Improved piercing of microneedle arrays in dermatomed human skin by an impact insertion method

• Published in: Journal of controlled release Vol. 128; no. 1; pp. 80 - 88
• Main Authors: Verbaan, F.J., Bal, S.M., van den Berg, D.J., Dijksman, J.A., van Hecke, M., Verpoorten, H., van den Berg, A., Luttge, R., Bouwstra, J.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 22.05.2008; Elsevier
• Subjects: Biological and medical sciences; Chromatography, High Pressure Liquid; Electric applicator; Fluorescein-5-isothiocyanate - administration & dosage; Fluorescent Dyes - administration & dosage; General pharmacology; Human skin; Humans; In vitro transport; Injections, Subcutaneous - instrumentation; Injections, Subcutaneous - methods; Medical sciences; Microinjections - instrumentation; Microinjections - methods; Microneedles; Nanoparticles - administration & dosage; Needles; Organometallic Compounds - administration & dosage; Organophosphorus Compounds - administration & dosage; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Skin; Human skin; Microneedles; Electric applicator; In vitro transport; Human; Pharmaceutical technology; Skin; Transport; In vitro; Microneedle
• ISSN: 0168-3659; 1873-4995
• DOI: 10.1016/j.jconrel.2008.02.009

An electrical applicator was designed, which can pierce short microneedles into the skin with a predefined velocity. Three different shapes of microneedles were used, namely 300 μm assembled hollow metal microneedle arrays, 300 μm solid metal microneedle arrays and 245 μm hollow silicon microneedle arrays. The latter are available as 4 × 4, 6 × 6 and 9 × 9 arrays. When using a velocity of 1 or 3 m/s reproducible piercing of dermatomed and full thickness human skin was evident from the appearance of blue spots on the dermal side of the skin after Trypan Blue treatment and the presence of fluorescently labeled particles in dermatomed skin. Manual piercing did not result in the appearance of blue spots. Transport studies revealed that i) piercing of microneedles with a predefined velocity into human skin resulted in a drastic enhancement of the Cascade Blue (CB, Mw 538) transport, ii) A higher piercing velocity resulted in a higher CB transport rate, iii) The CB transport rate was also dependent on the shape of the microneedles and iv) no difference in transport rate was observed between 4 × 4, 6 × 6 and 9 × 9 hollow silicon microneedle arrays.