Design and formulation of fast-dissolving microneedles for the rapid transdermal delivery of lorazepam.

Abstract

This study investigates lorazepam-loaded dissolving microneedles (LMNs) as a fast-acting and minimally invasive treatment for status epilepticus. The LMNs were developed using a micro-moulding technique with an optimised combination of PVP K30, Dextran 40 and Pullulan. Their stability was confirmed through Fourier transform infra-red (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The Parafilm^® membrane insertion test demonstrated 100% penetration efficiency, verifying their ability to effectively pierce the skin. Scanning electron microscopy (SEM) imaging revealed well-defined microneedles with precise dimensions (800 µm height, 200 µm base and 500 µm pitch). The LMNs rapidly dissolved in the subdermal layer of porcine skin. An ex vivo drug diffusion study showed that 3-5% of the encapsulated lorazepam was released within 30 min, with a cumulative release of 79.3% over 24 h. An acute dermal irritation study confirmed the biocompatibility and skin tolerance of the LMNs. Additionally, an in vivo anti-convulsant efficacy study in Albino Wistar rats subjected to maximal electroshock seizures demonstrated significant anticonvulsant effects (p < .05), confirming efficient systemic delivery of lorazepam. These findings highlight LMNs as a rapid-acting, non-invasive transdermal drug delivery system for managing status epilepticus, particularly in ambulatory care settings.