Development of Minoxidil-Loaded Calcium Citrate Nanoparticles

Abstract

Minoxidil (MNX) treatment for androgenetic alopecia is limited by poor aqueous solubility and solvent-induced irritation. This study synthesised aqueous-based calcium citrate nanoparticles (CaCit NPs) using a simple precipitation method to encapsulate MNX. We evaluated the physical stability and optimised the formulation using various stabilisers. SEPIMAX™ ZEN proved to be a superior stabiliser compared to sodium carboxymethyl cellulose (CMC) and Tween 80. The optimised system yielded spherical MNX-CaCit NPs with a diameter of approximately 300 nm, achieving 74.6% encapsulation efficiency and 10.2% drug loading. The formulation demonstrated excellent physical stability at 4, 25, and 40 °C over 3 weeks. In vitro drug release studies showed advantageous burst release profiles at both pH 7.4 and 5.6. Finally, cellular uptake and ex vivo porcine skin penetration studies validated successful transfollicular delivery at the hair root area. This MNX−CaCit system offers a stable and target-specific platform for alopecia treatments.