ABSTRACT
Objective: To prepare Naja atra neurotoxin (NT) loaded dissolving microneedles (DMNs-NT), and investigate the physicochemical properties and in vitro transdermal properties. Methods: DMNs-NT was prepared by a two-step centrifugation method. The ratio of CS and PVP K30, the water content of the matrix solution, and the backing layer material were optimized by the indexes of formability and mechanical strength of the microneedles and flexibility of the backing layer. The drug loading content was determined by HPLC, and the morphological characteristics were observed under an optical microscope, and the stability was also examined. Franz diffusion cell was used to investigate its in vitro skin permeation characteristics. Results: Through the single-factor exploration, we confirmed that the optimal prescription technique for DMNs-NT preparation was a 1:1 ratio of CS and PVP k30, a 5:4 ratio of matrix material and water, with CMC as the backing layer material. The DMNs-NT had a pyramidal shape with a smooth surface and a length of approximately 500 μm. The drug loading content of per tablet was (15.4 ± 0.5) μg. The drug was located in the upper part of the needle. DMNs-NT had good stability within 3 months. The results of in vitro skin permeation assay showed that the cumulative penetration of NT in DMNs-NT could reach 95.8% in 4 h, while NT solution barely penetrated the skin, which proved that it had a good promoting effect on NT transdermal delivery. Conclusion: In this study, DMNs-NT had good mechanical properties and good skin penetration, which realized the transdermal drug delivery of macromolecular drugs.
ABSTRACT
This study was aimed at the transport across blood-brain barrier (BBB) of polysorbate-80 modified neurotoxin loaded polybutylcyanoacrylate nanoparticle (P-80-NT-NP) and its cytotoxicity. An in vitro model of BBB using rat brain microvascular endothelial cells (rBMECs) was established. The cytotoxicity of P-80-NT-NP was measured by the MTT assays, where neurotoxin (NT), nanoparticle (NP), neurotoxin nanoparticle (NT-NP) as control, and the permeability of P-80-NT-NP was determined by using of Millicell insert coculture with rBMECs and fluorescence spectrophotometry. MTT results showed that NT, NP, NT-NP and P-80-NT-NP were avirulent to rBMECs when the concentration of NT was lower than 200 ng x mL(-1). But the cytotoxicity of NP, NT-NP and P-80-NT-NP would be augmented accordingly as concentration increased (P < 0.01), causing obvious reductions of cell survival rate, with no significant difference between them (P > 0.05). When the concentration of NT was 150 ng x mL(-1), the permeability on rBMECs of P-80-NT-NP and NT-NP were both significantly higher than that of NT (P < 0.01), and the permeability of P-80-NT-NP was greater than that of NT-NP (P < 0.05). In conclusion, polysorbate-80 modified neurotoxin nanoparticles can transport across the BBB, while concentration of NT is greater than 200 ng x mL(-1), P-80-NT-NP has a little cytotoxicity against rBMECs.