title: Microneedle-assisted permeation of lidocaine carboxymethylcellulose with gelatine co-polymer hydrogel.
abstract: OBJECTIVE
  Lidocaine hydrochloride (LidH) was formulated in sodium carboxymethyl cellulose/ gelatine (NaCMC/GEL) hydrogel and a 'poke and patch' microneedle delivery method was used to enhance permeation flux of LidH.
  
  
  METHODS
  The microparticles were formed by electrostatic interactions between NaCMC and GEL macromolecules within a water/oil emulsion in paraffin oil and the covalent crosslinking was by glutaraldehyde. The GEL to NaCMC mass ratio was varied between 1.6 and 2.7. The LidH encapsulation yield was 1.2 to 7% w/w. LidH NaCMC/GEL was assessed for encapsulation efficiency, zeta potential, mean particle size and morphology. Subsequent in vitro skin permeation studies were performed via passive diffusion and microneedle assisted permeation of LidH NaCMC/GEL to determine the maximum permeation rate through full thickness skin.
  
  
  RESULTS
  LidH 2.4% w/w NaCMC/GEL 1:1.6 and 1:2.3 respectively, possessed optimum zeta potential. LidH 2.4% w/w NaCMC/GEL 1:2.3 and 1:2.7 demonstrate higher pseudoplastic behaviour. Encapsulation efficiency (14.9-17.2%) was similar for LidH 2.4% w/w NaCMC/GEL 1:1.6-1:2.3. Microneedle assisted permeation flux was optimum for LidH 2.4% w/w NaCMC/GEL 1:2.3 at 6.1 μg/ml/h.
  
  
  CONCLUSIONS
  LidH 2.4% w/w LidH NaCMC/GEL 1:2.3 crossed the minimum therapeutic drug threshold with microneedle skin permeation in less than 70 min.
authors.affiliation: Department of Chemical Engineering, Loughborough University, Loughborough, LE11 3TU, UK.
authors.forename: Atul
authors.initials: A
authors.lastname: Nayak
authors.forename: Diganta B
authors.initials: DB
authors.lastname: Das
authors.forename: Goran T
authors.initials: GT
authors.lastname: Vladisavljević
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D005780:Gelatin / Q000737:chemistry*; D020100:Hydrogels; D008012:Lidocaine / Q000493:pharmacokinetics*; D009339:Needles; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D014783:Viscosity
chemical_list: D020100:Hydrogels; D011108:Polymers; D005780:Gelatin; D008012:Lidocaine; D002266:Carboxymethylcellulose Sodium