RESUMEN
Objective To prepare asenapine maleate microemulsion gel(ASPM-Emulgel)and evaluate its brain targeting by nasal administration.Methods The prescription composition and dosage of asenapine maleate microemulsion(ASPM-Emul)was determined according to the equilibrium solubility of asenapine maleate(ASPM)in different oils,emulsifiers,co-emulsifiers and the compatibility results of excipients,and ASPM-Emul was prepared into a gel with carbomer 940 as the gel matrix.The particle size distribution and microstructure of ASPM-Emul were investigated.The in vitro release rates and permeability in sheep nasal mucosa of ASPM-Emul and ASPM Emulgel were compared using the Franz diffusion cell method.The nasal ciliary toxicity of ASPM-Emulgel was investigated using the in vivo toad maxillary model method.Brain targeting of ASPM-Emulgel by nasal administration in rats was evaluated.Results According to the results of equilibrium solubility and compatibility,Maisine 35-1,Tween 80 and Transcutol P were selected as the oil phase,emulsifier and co-emulsifier of ASPM-Emul,respectively,with the ratio of 4 ∶ 4 ∶ 2.ASPM-Emul was a light blue semi-transparent microemulsion with a particle size of(73.6±7.4)nm.The microemulsion was regularly spherical and uniformly dispersed under transmission electron microscopy.The results of in vitro release and permeation showed that the release rate of ASPM-Emul was relatively fast,while the release rate of ASPM-Emulgel remained stable.However,the permeability of the two formulations in sheep nasal mucosa was basically similar.ASPM-Emul and ASPM-Emulgel showed no significant toxicity to nasal cilia of toad.Compared with the tail vein ASPM group,the drug content in the brain of ASPM-Emul and ASPM-Emulgel significantly increased after nasal administration,both exhibiting significant brain targeting,and the drug targeting efficiency(DTE)of ASPM-Emulgel was higher.Conclusion The preparation of ASPM into microemulsion gel can significantly improve the brain targeting after nasal administration,and is expected to improve the clinical therapeutic effect of ASPM.