Hydrogel-forming microarray patches combined with powder-based reservoir for labetalol hydrochloride transdermal delivery

Hypertension is the most common pregnancy disorder and can lead to life-threatening conditions for both mother and fetus. However, managing this condition with oral and intravenous labetalol can be challenging, highlighting the need for alternative delivery methods. This study presents, for the first time, the development of novel powder-based reservoirs incorporated with hydrogel-forming microarray patches (MAPs) to facilitate the transdermal delivery of labetalol hydrochloride (HCl). A holder, created from poly(propylene) using a 3D printer, was designed to house labetalol HCl powder, which was then combined with hydrogel-forming MAPs. This novel system improved the insertion profile of MAPs into Parafilm® layers and excised full-thickness neonatal porcine skin, achieving up to 85 % of needle height penetration without compromising needle integrity (only 8 % height reduction after applying 32 N of force). The current holder design was able to load 50 mg of labetalol HCl and allowed for single or multiple injections of deionised water to dissolve the powder and facilitate permeation through dermatomed neonatal porcine skin in in vitro studies using a Franz cell setup. The results showed that this powder-based reservoir design delivered labetalol HCl more effectively over 24 h compared to directly compressed tablets. Additionally, poly(vinyl alcohol)/poly(vinyl pyrrolidone)/citric acid-based hydrogel-forming MAPs delivered more labetalol HCl than Gantrez® S-97/poly(ethylene glycol)-based MAPs (9 mg vs. 5 mg) in 24 h. This novel system holds promise for improving the delivery of compounds in a simple manner, though further design modifications for one-step application are needed.