(509g) Electrospun Patch for Transdermal Delivery of Contraceptive Hormone

There has been great interest in making contraceptive hormone transdermal patches thinner and smaller. Recently, the patch sizes, crystallinity and site of administration make significant challenges for current available transdermal patch designs. Herein, we report levonorgestel (LNG)-loaded electrospun transdermal patches which are expected to release a predetermined amount of LNG over the well-defined period of time required by contraceptive and hormone replacement treatments. The diameter and thickness of fiber developed patches allows discreet placement into the skin. The electrospun fibers consisted of biodegradable polycaprolactone (PCL) in which contraceptive hormone LNG were encapsulated to replace the daily usage of a typical birth control pill. We characterized the electrospun patch by fiber morphology, thermal properties, crystallinity, chemical drug-polymer interaction, saturation solubility, and LNG release from electrospun patch. Scanning electron microscope (SEM) showed uniform, randomly oriented with large interconnected voids of drug-loaded patch. Thermogravimetric analysis (TGA) confirmed LNG had thermal stability in the temperature range required for LNG-loaded PCL electrospun patches. DSC suggested that LNG was dispersed in the electrospun fibers at the molecular level without an interaction between the LNG and PCL. FTIR and X-ray results can be justified by the fact that chloroform is an ideal solvent for the deposition of solid PCL. Pretreatment of skin with metal microneedles to create micropores across the skin’s stratum corneum barrier indicated the successful insertion can increase the skin permeability which leads to higher drug delivery efficiency of electrospun patches in vitro. In vivo study of LNG delivery systems in female hairless rats controlled the release of LNG for at least once-weekly dosing from both untreated control and metal-loaded microneedles. We therefore showed that electrospinning patches can create transport pathways large enough to increase efficacy of lower doses from highly porous and surface area fibers into the skin.