title: Microneedle-assisted transdermal delivery of Zolmitriptan: effect of microneedle geometry, in vitro permeation experiments, scaling analyses and numerical simulations.
abstract: OBJECTIVE
  The present study was aimed to investigate the effect of salient microneedle (MN) geometry parameters like length, density, shape and type on transdermal permeation enhancement of Zolmitriptan (ZMT).
  
  
  METHODS
  Two types of MN devices viz. AdminPatch®arrays (ADM) (0.6, 0.9, 1.2 and 1.5 mm lengths) and laboratory fabricated polymeric MNs (PM) of 0.6 mm length were employed. In the case of PMs, arrays were applied thrice at different places within a 1.77 cm2skin area (PM-3) to maintain the MN density closer to 0.6 mm ADM. Scaling analyses was done using dimensionless parameters like concentration of ZMT (Ct/Cs), thickness (h/L) and surface area of the skin (Sa/L2).
  
  
  RESULTS
  Micro-injection molding technique was employed to fabricate PM. Histological studies revealed that the PM, owing to their geometry/design, formed wider and deeper microconduits when compared to ADM of similar length. Approximately 3.17- and 3.65-fold increase in ZMT flux values were observed with 1.5 mm ADM and PM-3 applications when compared to the passive studies. Good correlations were observed between different dimensionless parameters with scaling analyses. Numerical simulations, using MATLAB and COMSOL software, based on experimental data and histological images provided information regarding the ZMT skin distribution after MN application.
  
  
  CONCLUSIONS
  Both from experimental studies and simulations, it was inferred that PM were more effective in enhancing the transdermal delivery of ZMT when compared to ADM.
  
  
  CONCLUSIONS
  The study suggests that MN application enhances the ZMT transdermal permeation and the geometrical parameters of MNs play an important role in the degree of such enhancement.
authors.affiliation: a Department of Pharmaceutics , KVSR Siddahrtha College of Pharmaceutical Sciences , Vijayawada , India.
authors.forename: Chandra Teja
authors.initials: CT
authors.lastname: Uppuluri
authors.affiliation: a Department of Pharmaceutics , KVSR Siddahrtha College of Pharmaceutical Sciences , Vijayawada , India.
authors.forename: Jyothirmayee
authors.initials: J
authors.lastname: Devineni
authors.affiliation: b Department of Chemical Engineering , Loughborough University , Loughborough , UK.
authors.forename: Tao
authors.initials: T
authors.lastname: Han
authors.affiliation: b Department of Chemical Engineering , Loughborough University , Loughborough , UK.
authors.forename: Atul
authors.initials: A
authors.lastname: Nayak
authors.affiliation: c Department of Engineering and Informatics , University of Bradford , Bradford , UK.
authors.forename: Kartik J
authors.initials: KJ
authors.lastname: Nair
authors.affiliation: c Department of Engineering and Informatics , University of Bradford , Bradford , UK.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Whiteside
authors.affiliation: b Department of Chemical Engineering , Loughborough University , Loughborough , UK.
authors.forename: Diganta B
authors.initials: DB
authors.lastname: Das
authors.affiliation: a Department of Pharmaceutics , KVSR Siddahrtha College of Pharmaceutical Sciences , Vijayawada , India.
authors.forename: Buchi N
authors.initials: BN
authors.lastname: Nalluri
mesh_terms: D000279:Administration, Cutaneous; D016503:Drug Delivery Systems / Q000379:methods*; D008845:Microinjections / Q000379:methods*; D009339:Needles; D023303:Oxazolidinones / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D010539:Permeability; D012869:Skin Absorption; D014363:Tryptamines / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D023303:Oxazolidinones; D014363:Tryptamines; C089750:zolmitriptan
keywords: Histological sections; Zolmitriptan; microneedle geometry; microneedles; numerical simulations; scaling analyses