title: The role of microneedles for drug and vaccine delivery.
abstract: BACKGROUND
  Transdermal drug delivery offers a number of advantages for the patient, not only due to its non-invasive and convenient nature, but also due to factors such as avoidance of first-pass metabolism and prevention of gastrointestinal degradation. It has been demonstrated that microneedles (MNs) can increase the number of compounds amenable to transdermal delivery by penetrating the skin's protective barrier, the stratum corneum, and creating a pathway for drug permeation to the dermal tissue below.
  
  
  METHODS
  MNs have been extensively investigated for drug and vaccine delivery. The different types of MN arrays and their delivery capabilities are discussed in terms of drugs, including biopharmaceutics and vaccines. Patient usage and effects on the skin are also considered.
  
  
  CONCLUSIONS
  MN research and development is now at the stage where commercialisation is a viable possibility. There are a number of long-term safety questions relating to patient usage which will need to be addressed moving forward. Regulatory guidance is awaited to direct the scale-up of the manufacturing process alongside provision of clearer patient instruction for safe and effective use of MN devices.
authors.affiliation: Queen's University Belfast, School of Pharmacy , 97 Lisburn Road, Belfast, BT9 7BL , UK.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Quinn
authors.forename: Mary-Carmel
authors.initials: MC
authors.lastname: Kearney
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Courtenay
authors.forename: Maelíosa T C
authors.initials: MT
authors.lastname: McCrudden
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Donnelly
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D016503:Drug Delivery Systems / Q000295:instrumentation*; D004817:Epidermis / Q000187:drug effects; D006801:Humans; D009339:Needles; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D004364:Pharmaceutical Preparations; D014612:Vaccines
keywords: drug delivery; microneedle; skin; transdermal; vaccine