Biomimetic synthesis and evaluation of histidine-derivative templated chiral mesoporous silica for improved oral delivery of the poorly water-soluble drug, nimodipine.

In this study, spherical shaped chiral mesoporous silica nanoparticles (CMS) was biomimetic synthesized using histidine derivatives (C16-L-histidine) as template via the sol-gel reaction and employed as poorly water-soluble drug nimodipine (NMP) carrier. Characteristics of CMS and its application as drug carrier were intensively investigated and compared with MCM41. Then NMP was respectively loaded into CMS and MCM41 with the drug: carrier weight ratio of 2:1. Structural features of NMP before and after drug loading were systemically characterized. The results demonstrated that hydrogen bonds were formed between NMP and carriers during the drug loading process. After drug loading, crystalline state of NMP effectively converted into modification L and amorphous state, and the first form turned out to be easily removed by washing. On the other hand, drug dissolution rate was significantly improved after drug loading, and the best result came from NMP-C3 sample. It was able to release 17.83% of drug within 60 min, which was 6.8-fold higher than the release amount of pure NMP. Undoubtedly, NMP-C3 presented the highest relative bioavailability (386.22%), and the best therapeutic effect. Meanwhile, CMS improved the brain distribution of NMP in vivo.