HA/PLA Composite Nanoparticles for Enhanced Oral Bioavailability of Capsaicin: Fabrication, Characterization and in vitro‐in vivo Evaluation.

In this paper, hydroxylapatite (HA) nanoparticles were constructed through the ultrasound‐assisted dispersion method. Using scanning electron microscopy (SEM), we studied the preparation methods of HA nanoparticles, and spherical HA nanoparticles with a size of about 50 nm were prepared. Besides, we constructed the HA/PLA composite nanoparticles with polylactic acid (PLA) as the material. The effects of different composite proportions on the HA/PLA composite nanoparticles were investigated before Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), Transmission electron microscope (TEM), and SEM, were applied to preliminary evaluate the effects of the above‐mentioned nanoparticles on capsaicin release. Through an in vitro study, we found that the release rate of the drug could be influenced by various release media and different compounding ratios (of HA and PLA). Furthermore, the pharmacokinetics study of capsaicin powder and capsaicin‐loaded HA/PLA composite nanoparticles demonstrated marked increased Cmax, prolongation of Tmax to 8 h, increased T1/2 and mean retention time (MRT) by 6.7 and 5.6 times respectively, coupled with 9240.2 % increase in relative bioavailability. Of note, HA/PLA composite nanoparticles showed good biocompatibility and exhibited good long‐term controlled release carriers, coupled with the ability to improve the solubility and bioavailability of a lipophilic drug. [ABSTRACT FROM AUTHOR]