Sustained-release Drug Delivery System of Trazodone Hydrochloride Based on Electrospray Technology: Preparation, Characterization, In vitro and In vivo Evaluation

Electrospray technology is a process capable of forming monodisperse drug nano/microparticles with enhanced solubility or sustained-release effects. This study aimed to fabricate a sustained-release drug delivery system containing trazodone hydrochloride (TZN-SRDDS) by combining electrospray technology with functional carriers (Soluplus®, Carbopol 940, HPMC K4M, and Lecithin) for solubility improving, drug release prolonging and bioavailability enhancing. The optimized TZN-SRDDS exhibited a spherical morphology, with a particle size of (3.456 ± 0.448) μm, a polydispersity index (PDI) of (0.456 ± 0.024), and a zeta potential of (-17.291 ± 2.351) mV. This system showed a high encapsulation efficiency (97.12 ± 1.82%) and maintained good stability for up to 30 days. In vitro release studies indicated that TZN-SRDDS followed first-order kinetics in pH 1.2 hydrochloric acid solution and the Higuchi model in pH 6.8 phosphate-buffered saline (PBS), with the cumulative release rate increased to (80.81 ± 4.26%); both release profiles exhibited a certain sustained-release effect. Cytotoxicity assays confirmed that TZN-SRDDS was non-toxic at concentrations below 2.6 mg/mL, and the formulation showed a relatively sustained cellular uptake effect. Pharmacokinetic studies in rats showed that the time to reach peak concentration (T max ) of TZN-SRDDS was extended from 0.25 h to 1 h, its half-life (t 1/2 ) was increased from (1.15 ± 0.17) h to (6.71 ± 0.39) h, resulting in a relative bioavailability of 374.64%. This study achieved the synergistic goals of drug solubilization, sustained-release delivery, and enhanced bioavailability. It provides new technical references for the development of pH-sensitive drug formulations using electrospray technology and also expands the research on the development of sustained-release formulations of trazodone hydrochloride.