Nanoparticle-Mediated Delivery of Artesunate from Artemisia annua Extracts: Formulation and In Vitro Characterisation

Artemisinin-based compounds, derived primarily from Artemisia annua, form the backbone of frontline malaria treatment in Nigeria. However, poor oral bioavailability and rapid elimination of artesunate present pharmacokinetic challenges that limit its clinical efficacy. Polymeric nanoparticle-based delivery systems offer a strategy for enhancing bioavailability and prolonging plasma residence time. This study formulates artesunate-loaded chitosan nanoparticles derived from Artemisia annua plant extract and characterises them for pharmaceutical and biopharmaceutical performance. Artesunate was isolated from dried A. annua leaves sourced from cultivated farms in Plateau State, North Central Nigeria, and encapsulated in chitosan nanoparticles using ionic gelation. Nanoparticle characterisation included particle size analysis, zeta potential, polydispersity index, encapsulation efficiency, and in vitro drug release profile in simulated gastric and intestinal fluids. The stability of the formulation was assessed under accelerated storage conditions at 40 degrees C and 75% RH over three months. Nanoparticles showed mean particle size of 214 nm, polydispersity index of 0.21, and zeta potential of +28.4 mV, indicating good colloidal stability. Encapsulation efficiency was 78.6%. In vitro release demonstrated sustained artesunate delivery over 24 hours with an initial burst phase. Stability testing confirmed maintained physicochemical parameters for three months. These results support the feasibility of chitosan nanoparticle delivery for artesunate and recommend further in vivo pharmacokinetic and antimalarial efficacy studies. Keywords: artesunate, nanoparticles, chitosan, Artemisia annua, drug delivery