Brain targeting of venlafaxine via intranasal transbilosomes thermogel for improved management of depressive disorder.

The current research aimed to design and optimize hyaluronic acid-coated transbilosomes containing venlafaxine (VLF-HA-TBLs) for nose-to-brain delivery for improved management of depressive disorder. Venlafaxine-loaded transbilosomes (VLF-TBLs) were developed according to the film hydration procedure, optimized for maximum efficiency using the quality by design-based Box-Behnken design (BBD), and then coated with hyaluronic acid (HA). The optimized VLF-HA-TBLs were subjected to in vitro characterization, integrated into a thermolabile gel, and then exposed to in vivo evaluation studies. The results revealed that the VLF-HA-TBLs formulation exhibited acceptable size (185.6 ± 4.9 nm), surface charge (-39.8 ± 1.7 mV), and entrapment efficiency (69.6 ± 2.6 %). The morphological study revealed that nanovesicles were spherical and displayed a consistent size distribution without particle aggregation. It also showed improved ex vivo nasal diffusion and a prolonged release profile. In addition, the formulated VLF-HA-TBLs were stable under the studied conditions and tolerable when applied intranasally. Compared to the intranasal administration of VLF solution (VLF-SOL), the biodistribution analysis showed that VLF-HA-TBLs delivered intranasally had a relative bioavailability of 441 % in the brain and 288 % in plasma. Moreover, the intranasal delivery of VLF-HA-TBLs demonstrated much higher bioavailability (512 %) in the brain compared to VLF-SOL administered intravenously. Collectively, it could be possible to infer that HA-TBLs might be an effective nanocarrier to administer VLF to the brain via the nasal route.