Construction of composite nanoparticles of β-cyclodextrin and corn starch encapsulating 5-hydroxytryptophan for sustained release and sleep improvement in vivo.

5-Hydroxytryptophan (5-HTP) is a functional food ingredient widely recognized for its sleep-enhancing properties, but it has a short elimination half-life in vivo, resulting in suboptimal pharmacokinetic performance. In this study, we developed a composite nanoparticles system based on β-cyclodextrin and corn starch using the anti-solvent precipitation method for the encapsulation and sustained release of 5-HTP. The nanoparticles were characterized using laser particle size analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and evaluation of their digestive properties in simulated gastrointestinal fluids. We further evaluated their effects on the pharmacokinetic profile and distribution of 5-HTP in rats, including serum, gut, and brain, demonstrating a significant extension of the drug elimination half-life and improved bioavailability. In an insomnia mouse model, administration of the composite nanoparticles system significantly alleviated behavioral abnormalities and circadian rhythm disorder induced by sleep deprivation. This study provides a solid theoretical basis and technical support for the efficient application of 5-HTP in functional foods.