COATED MICRONEEDLES FOR TRANSDERMAL DELIVERY :COATED MICRONEEDLES FOR TRANSDERMAL DELIVERY H.S. Gill, M.R. Prausnitz., Journal of Controlled Release, Vol. 117; 227–237; 2007 Mohana Marimuthu 200840090


PRESENTATION OVERVIEW :PRESENTATION OVERVIEW INTRODUCTION DISCUSSION OF THE RESULTS MICRONEEDLE FABRICATION METHODS MICRONEEDLE COATING METHODS DELIVERY FROM COATED MICRONEEDLES CONCLUSION PERSPECTIVE ON THIS ARTICLE


INTRODUCTION :INTRODUCTION Biopharmaceuticals - pharmaceutical therapies Parenteral delivery - patient complaince due to needle phobic Hypodermic needles Microneedles Transdermal patches


INTRODUCTION :INTRODUCTION 4 modes of delivery 1. Piercing microneedle + application of drug patches 2. Coated microneedle 3. Encapsulated biodegradable microneedle 4. Injecting drug through hollow microneedles molecular weight drugs Solid state-long term stability Vaccine delivery into skin


INTRODUCTION :INTRODUCTION Essential characters of coating process: Uniform coating Limit deposition onto microneedle Avoid temperature High drug loading Good adhesion of coating solution aqueous coating solution Rapid or controlled – dissolution kinetics


INTRODUCTION :INTRODUCTION Coating processes -dip coating – micron scale-used -roll coating not used -spray coating


INTRODUCTION :INTRODUCTION


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS 1. Microneedle fabrication methods Laser-cutting – stainless steel Diferent geometrics “pocketed” microneedles – 20 µm Forms of barbes and serrated edges Bench-scale apparatus – cut & polished – two 50 needle arrays/hr.


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS 2. Microneedle coating methods Coat by dipping into aqueous Drug solution – no surface coverage 1% carboxymethylcellulose - viscosity enhancer, 0.5% Lutrol F-68 NF - surfactant


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS Simple dipping process Contamination of microneedles substrate due to capillary force Capillary effect – bridging of coating solution between adjacent microneedles Dip coating device – dip holes with dimension similar to individual microneedles


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS Single, in-plane and out-of-plane Microneedle Requires – less volumes of coating solution – 10 µl to 100 µl Vent holes – prevent air bubbles Evaporation of coating solution – solid deposits – block dip-coating holes – avoid by syringe.


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS 3. Delivery from coated microneedles No residue on skin surface - bioavailability Vitamin B – upto 2.6µg / Microneedle Vaccine delivery – potent immune response Storage - antigen stability Eliminate cold-chain storage


DISCUSSION OF THE RESULTS :DISCUSSION OF THE RESULTS


CONCLUSION :CONCLUSION Coating methods Pressure sensitive adhesive patches Dip-coating approaches – control surface tension First time – organic and inorganic microparticles, viruses were coated In vitro study – cadaver skin In vivo study – uncoated microneedle in human subjects


CONCLUSION :CONCLUSION


PERSPECTIVE ON THIS ARTICLE :PERSPECTIVE ON THIS ARTICLE Simple versatile, controllable method to coat microneedles with protein, DNA, viruses and microparticles for rapid delivery into the skin be smaller, cheaper, pain-free and more convenient with a wide range of biomedical and other applications. Future of drug delivery-influenced by microfabrication technologies.


Slide 20:animation microneedle


QUESTIONS? :QUESTIONS?