Microneedle pretreatment enhances the percutaneous permeation of hydrophilic compounds with high melting points
Jessica Stahl1, Mareike Wohlert, Manfred Kietzmann
1Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, Hannover 30559, Germany. xjessica.stahl@tiho-hannover.de
Background:
Two commercially available microneedle rollers with a needle length of 200 μm and 300 μm were selected to examine the influence of microneedle pretreatment on the percutaneous permeation of four non-steroidal anti-inflammatory drugs (diclofenac, ibuprofen, ketoprofen, paracetamol) with different physicochemical drug characteristics in Franz-type diffusion cells. Samples of the receptor fluids were taken at predefined times over 6 hours and were analysed by UV-VIS high-performance liquid-chromatography. Histological examinations after methylene blue application were additionally performed to gather information about barrier disruption.
Results:
Despite no visible pores in the stratum corneum, the microneedle pretreatment resulted in a twofold (200 μm) and threefold higher (300 μm) flux through the pretreated skin samples compared to untreated skin samples for ibuprofen and ketoprofen (LogK(ow) > 3, melting point < 100°C). The flux of the hydrophilic compounds diclofenac and paracetamol (logK(ow) < 1, melting point > 100°C) increased their amount by four (200 μm) to eight (300 μm), respectively.
Conclusion:
Commercially available microneedle rollers with 200-300 μm long needles enhance the drug delivery of topically applied non-steroidal anti-inflammatory drugs and represent a valuable tool for percutaneous permeation enhancement particularly for substances with poor permeability due to a hydrophilic nature and high melting points.
