Lidocaine permeation from a lidocaine NaCMC/gel mi

Authors: Atul Nayak Liam Short Diganta B Das

Publish Date: 2015/04/21

Volume: 5, Issue: 4, Pages: 372-386

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Abstract

Common local anaesthetics such as lidocaine are administered by the hypodermic parenteral route but it causes pain or anxiety to patients Alternatively an ointment formulation may be applied which involves a slow drug diffusion process In addressing these two issues this paper aims to understand the significance of the ‘poke and patch’ microneedle MN treatment on skin in conjunction to the lidocaine permeation and in particular the vertical depth averaged and horizontal eg lateral permeation profiles of the drug in the skin The instantaneous pharmacokinetics of lidocaine in skin was determined by a skin denaturation technique coupled with Franz diffusion cell measurements of the drug pharmacokinetics All pharmacokinetic profiles were performed periodically on porcine skin Three MN insertion forces of 39 79 and 157 N were applied on the MN to pierce the skin For the smaller force 39 N post MNtreated skin seems to provide an ‘optimum’ percutaneous delivery rate A 102fold increase in lidocaine permeation was observed for a MN insertion force of 39 N at 025 h and similarly a 54fold increase in permeation occurred at 05 h compared to passive diffusional delivery It is shown that lidocaine permeates horizontally beyond the area of the MNtreated skin for the smaller MN insertion forces namely 39 and 79 N from 025 to 075 h respectively The lateral diffusion/permeation of lidocaine for larger MNtreated force namely 157 N in this work seems to be insignificant at all recorded timings The MN insertion force of 157 N resulted in lidocaine concentrations slightly greater than control passive diffusion but significantly less than 39 and 79 N impact force treatments on skin We believe this likelihood is due to the skin compression effect that inhibits diffusion until the skin had time to relax at which point lidocaine levels increase

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