Response surface optimization, Ex vivo and In vivo investigation of nasal spanlastics for bioavailability enhancement and brain targeting of risperidone

Transnasal brain drug targeting could ensure better drug delivery to the brain through the olfactory pathway. Risperidone bioavailability is 66% in extensive metabolizers and 82% in slow metabolizers. The aim of this study is to investigate the ability of the nanovesicular spanlastics to effectively deliver risperidone through the nasal route to the brain and increase its bioavailability. Spanlastics formulae, composed of span and polyvinyl alcohol, were designed based on central composite statistical design. The planned formulae were prepared using ethanol injection method. The prepared formulae were characterized by testing their particle size, polydispersity index, zeta potential and encapsulation efficiency. The optimized formula having the lowest particle size, polydispersity index, the highest zeta potential and encapsulation efficiency was subjected to further investigations including characterization of its rheological properties, elasticity, transmission electron microscopy, in vitro diffusion, ex vivo permeation, histopathology and in vivo biodistribution. The optimized formula was composed of 5mg/mL span and 30mg/mL polyvinyl alcohol. It showed significantly higher transnasal permeation and better distribution to the brain, when compared to the used control regarding the brain targeting efficiency and the drug transport percentage (2.16 and 1.43 folds increase, respectively). The study introduced a successful and promising formula to directly and effectively carry the drug from nose to brain.

Investigating the cubosomal ability for transnasal brain targeting: In vitro optimization, ex vivo permeation and in vivo biodistribution

The aim of this study was to enhance the risperidone delivery to the brain through the transnasal route via optimization of cubosomal gel. Cubosomes were prepared using glycerol mono-oleate (GMO), Pluronic F127 (PF127) and Tween 80 (T80). The prepared formulae were characterized by testing their particle size, polydispersity index, zeta potential, entrapment efficiency, in vitro drug release and transmission electron microscopy. Central composite design was planned for the formulae optimization and the selected formula (containing PF127 with concentration 15 mg/g GMO and T80 with concentration of 20mg/L) was re-prepared in presence of gelling polymer (gellan gum or polyox). The optimal cubosomal gel (containing 0.4% w/v polyox) had been subjected to ex-vivo permeation, histopathological evaluation and in vivo biodistribution studies. It showed significantly higher transnasal permeation and better distribution to the brain, when compared to the used control (drug solution and/or suspension). Finally, the cubosomal gel could be considered as a promising carrier for brain targeting of CNS acting drugs through the transnasal route.