Application of Validated UV Spectrophotometric and Colorimetric Method to Quantify Minoxidil in the Development of Trilayer Dissolving Microneedle: Proof of Concept in Ex Vivo and In Vivo Studies in Rats

The study aimed to develop, confirm, and validate the analysis of Minoxidil (MNX) using UV–Vis Spectrophotometry for the treatment of Alopecia Areata (AA). The researchers developed a Trilayer Dissolving Microneedle (TDMN) as a new drug delivery system for MNX, which minimizes side effects from oral and topical administration. The UV–Vis Spectrophotometry method was validated based on selectivity, linearity, accuracy and precision, Detection Limit (DL) and Quantification Limit (QL), and dilution integrity parameters. The results met the requirements and qualifications according to International Conference Harmonization (ICH) standards. This method was then applied to evaluate extraction recovery, ex vivo permeation, ex vivo dermatokinetics, and in vivo studies. The study concluded that the UV–Vis Spectrophotometry method is a viable and effective way to analyze MNX in the skin tissue of rats with AA.