Monitoring the Effect of Transdermal Drug Delivery Patches on the Skin Using Terahertz Sensing

Abstract

Water content of the skin is an important parameter for controlling the penetration rate of chemicals through the skin barrier; therefore, for transdermal patches designed for drug delivery to be successful, the effects of the patches on the water content of the skin must be understood. Terahertz (THz) spectroscopy is a technique which is being increasingly investigated for biomedical applications due to its high sensitivity to water content and non-ionizing nature. In this study, we used THz measurements of the skin (in vivo) to observe the effect of partially and fully occlusive skin patches on the THz response of the skin after the patches had been applied for 24 h. We were able to observe an increase in the water content of the skin following the application of the patches and to identify that the skin remained hyper-hydrated for four hours after the removal of the fully occlusive patches. Herein, we show that THz spectroscopy has potential for increasing the understanding of how transdermal patches affect the skin, how long the skin takes to recover following patch removal, and what implications these factors might have for how transdermal drug patches are designed and used.

Moisture-cured solvent free silylated poly(ether-urea) pressure-sensitive adhesives (PSAs) for use as skin adhesives for application in transdermal drug delivery (TDD)

“…In another study, the PUXL variant patches were analysed using Terahertz (THz) spectroscopy to assess their impact on skin hydration levels. [48][49][50] Patches with nonpermeable backing materials seemed to hydrate the skin more compared to permeable woven ones in a hydration event that starts the first 30 min of patch application and lasts for 24 h. Finally, preliminary wearability events using PUXL placebo formulations on human skin have also been conducted with most of the variants demonstrating acceptable overall performance.…”

Quantitative evaluation of transdermal drug delivery patches on human skin with in vivo THz-TDS

“…Prior to the start of the study, all subjects were informed of the experiments and gave their signed consent. To provide further insight into the significance of the observations in the previous work [ 10 ] on the effects of the patches on the skin, woven and film based patches were applied on the volar forearms of the 19 subjects.…”

“…Therefore, it is essential to study the influence of TDD patches on skin hydration in order to have better control and understanding of the drug delivery rate. Additionally, analysing the recovery of skin after removing the patches can provide supporting information on the frequency of applying patches and switching the application area [ 10 ].…”

“…To acquire a more comparable result to the actual dynamic process in skin during TDD, in vivo THz measurements on human skin need to be studied. Lindley-Hatcher et al have conducted in vivo THz point scan on volar forearm to investigate the changes induced in the skin by TDD patches with different backing materials and PG concentrations [ 10 ]. The study focused on how different types of patches can influence the drug delivery rate through the changes in skin hydration and skin’s response to occlusion.…”

Defect-rich graphene-coated metamaterial device for pesticide sensing in rice

“…It is well known that THz wave is the last part of the electromagnetic wave to be explored. Since the absorption of THz wave is dominated by the excitation of intramolecular and intermolecular vibrations, 12 some chemicals such as drugs, 13,14 pesticide, 15 and carbohydrate 16 show ngerprint absorption peaks in THz band. To enhance the interaction between molecule and THz wave, the localized resonances excited by metamaterials which show an intense enhanced electromagnetic eld near the metallic structures are utilized.…”