title: Microneedle Coating Techniques for Transdermal Drug Delivery.
abstract: Drug administration via the transdermal route is an evolving field that provides an alternative to oral and parenteral routes of therapy. Several microneedle (MN) based approaches have been developed. Among these, coated MNs (typically where drug is deposited on MN tips) are a minimally invasive method to deliver drugs and vaccines through the skin. In this review, we describe several processes to coat MNs. These include dip coating, gas jet drying, spray coating, electrohydrodynamic atomisation (EHDA) based processes and piezoelectric inkjet printing. Examples of process mechanisms, conditions and tested formulations are provided. As these processes are independent techniques, modifications to facilitate MN coatings are elucidated. In summary, the outcomes and potential value for each technique provides opportunities to overcome formulation or dosage form limitations. While there are significant developments in solid degradable MNs, coated MNs (through the various techniques described) have potential to be utilized in personalized drug delivery via controlled deposition onto MN templates.
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. rita.haj-ahmad@sunderland.ac.uk.
authors.forename: Rita
authors.initials: R
authors.lastname: Haj-Ahmad
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. hashimkhan15@googlemail.com.
authors.forename: Hashim
authors.initials: H
authors.lastname: Khan
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. sohail_arshad79@yahoo.com.|Department of Pharmacy, Bahauddin Zakariya University, Multan 60800, Pakistan. sohail_arshad79@yahoo.com.
authors.forename: Muhammad Sohail
authors.initials: MS
authors.lastname: Arshad
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. m.rasekh@alumni.ucl.ac.uk.
authors.forename: Manoochehr
authors.initials: M
authors.lastname: Rasekh
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. amjad_husein@hotmail.com.|College of Pharmacy, University of the Punjab, Lahore 54000, Pakistan. amjad_husein@hotmail.com.
authors.forename: Amjad
authors.initials: A
authors.lastname: Hussain
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. SWalsh@dmu.ac.uk.
authors.forename: Susannah
authors.initials: S
authors.lastname: Walsh
authors.affiliation: State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China. xiang.li@zju.edu.cn.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China. mwchang@zju.edu.cn.|Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China. mwchang@zju.edu.cn.
authors.forename: Ming-Wei
authors.initials: MW
authors.lastname: Chang
authors.affiliation: School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK. zahmad@dmu.ac.uk.
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Ahmad
keywords: coating process; coatings; drug delivery; films; microneedles; particles