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Influence of array interspacing on the force required for successful microneedle skin penetration: theoretical and practical approaches

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posted on 22.12.2014 by Ololade Olatunji, Diganta Das, Martin J. Garland, Luc Belaid, Ryan F. Donnelly
Insertion behaviour of microneedle (MN) arrays depends upon the mechanical properties of the skin and, MN geometry and distribution in an array. In addressing this issue, this paper studies MN array insertion mechanism into skin and provides a simple quantitative basis to relate the insertion force with distance between two MNs. The presented framework is based on drawing an analogy between a beam on an elastic foundation and mechanism of needle insertion, where insertion force is separated into different components. A theoretical analysis indicates that insertion force decreases as interspacing increases. For a specified skin type, insertion force decreased from 0.029 to 0.028N/MN when interspacing at MN tip was increased from 50μm (350μm at MN base) to 150μm (450μm at MN base). However, dependence of insertion force seems to decrease as the interspacing is increased beyond 150μm. To assess the validity of the proposed model, a series of experiments was carried out to determine the force required for skin insertion of MN. Experiments performed at insertion speed of 0.5 and 1.0mm/s yielded insertion force values of 0.030 and 0.0216N, respectively, for 30μm interspacing at MN base (330μm interspacing at tip) and 0.028 and 0.0214N, respectively, for 600μm interspacing at MN base (900μm interspacing at tip). Results from theoretical analysis and finite element modelling agree well with experimental results, which show MN interspacing only begins to affect insertion force at low interspacing (<150μm interspacing at MN base). This model provides a framework for optimising MN devices, and should aid development of suitable application method and determination of force for reliable insertion into skin. © 2013 Wiley Periodicals, Inc.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Journal of Pharmaceutical Sciences

Volume

102

Issue

4

Pages

1209 - 1221

Citation

OLATUNJI, O. ... et al, 2013. Influence of array interspacing on the force required for successful microneedle skin penetration: theoretical and practical approaches. Journal of Pharmaceutical Sciences, 102 (4), pp. 1209 - 1221.

Publisher

© Wiley Periodicals, Inc. and the American Pharmacists Association

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2013

Notes

This is the accepted version of the following article: OLATUNJI, O. ... et al, 2013. Influence of array interspacing on the force required for successful microneedle skin penetration: theoretical and practical approaches. Journal of Pharmaceutical Sciences, 102 (4), pp. 1209 - 1221, which has been published in final form at: http://dx.doi.org/10.1002/jps.23439

ISSN

0022-3549

eISSN

1520-6017

Language

en

Exports