Influence of histidine on the release of all-trans retinoic acid from self-assembled glycol chitosan nanoparticles

Objective: In this study, the influence of N-acetyl histidine (NAHis) on the all-trans retinoic acid (ATRA) release from the NAHis-conjugated self-assembled glycol chitosan (GC) nanoparticles was investigated. Methods: NAHis was conjugated to GC as a hydrophobic moiety to prepare the self-assembled nanoparticles, and ATRA was incorporated into the inner core of the NAHisGC nanoparticles. The ATRA release from NAHisGC nanoparticles was performed at 37°C in a phosphate-buffered saline buffer (pH 5.5 or 7.4) for 48 hours. Results: At a pH of 5.5, less than 20 (ww) of total loading amount of ATRA was released from the nanoparticles after 48 hours. In contrast, two times greater amount of ATRA was released at a pH of 7.4. The ATRA release rate from the NAHisGC nanoparticles was significantly slower at a pH of 5.5 than at a pH of 7.4. Conclusion: The release profiles of ATRA that was incorporated into the NAHisGC nanoparticles were controlled by the NAHis content in the GC nanoparticles.