Terahertz Wave Propagation in a Nanotube Conveying Fluid Taking into Account Surface Effect.

In nanoscale structure sizes, the surface-to-bulk energy ratio is high and the surface effects must be taken into account. Surface effect plays a key role in accurately predicting the vibration behavior of nanostructures. In this paper, the wave behaviors of a single-walled carbon nanotube (CNT) conveying fluid are studied. The nonlocal Timoshenko beam theory is used and the surface effect is taken into account. It is found that the fluid can flow at a very high flow velocity and the wave propagates in the terahertz frequency range. The surface effects can significantly enhance the propagating frequency. This finding is different from the classical model where the surface effect is neglected.

Phospholipid deformable vesicles for buccal delivery of insulin.

To investigate the possibility of the enhancing effect of deformable vesicles on buccal delivery of insulin, two kinds of vesicles with and without the presence of sodium deoxycholate (deformable vesicles and conventional vesicles) were prepared by reverse phase evaporation methods. The liposomal entrapment efficiency was determined by column chromatography. The particle size and morphology of the vesicles were also evaluated. The hypoglycemic effects, insulin concentrations, and residual amounts of insulin deposited in the buccal membrane after buccal administration of insulin vesicles to rabbits were investigated. Compared with subcutaneous administration of insulin solution, the relative pharmacological bioavailability and the relative bioavailability of buccal administration of insulin vesicles were determined. The results showed that the entrapment efficiencies of the deformable and conventional vesicles were 18.87+/-1.78% (n=3) and 22.07+/-2.16% (n=3), respectively. The particle sizes of the deformable and conventional vesicles were 42.5+/-20.5 nm and 59.7+/-33.8 nm, respectively. There were no significant differences in appearance between the two types of vesicle. Compared with subcutaneous administration of insulin solution, the relative pharmacological bioavailability and the relative bioavailability in the insulin-deformable vesicles group were 15.59% and 19.78%, respectively, which were higher than in the conventional insulin vesicles (p<0.05), blank deformable vesicles and insulin mixture groups (p<0.05). Deformable vesicles have an enhancing effect on buccal delivery of insulin and may be a better carrier than conventional vesicles for buccal delivery of protein drugs.

[In vitro and in vivo study of two kinds of long-circulating solid lipid nanoparticles containing paclitaxel].

AIM: To prepare long-circulating solid lipid nanoparticles containing paclitaxel with stearic acid, and investigate the in vitro and in vivo characterization of nanoparticles. METHODS: The method of "emulsion evaporation-solidification at low temperature" was used to prepare the stearic acid solid lipid nanoparticles containing paclitaxel. Its morphology was examined by transmission electron microscope. The HPLC method for determination of paclitaxel in nanoparticles or serum samples was established. The release of paclitaxel in vitro and the pharmacokinetics after i.v. bolus injection to mice were studied. RESULTS: The mean diameter of Brij78-SLN and F68-SLN is (103.5 +/- 29.2) nm and (220 +/- 98) nm, respectively. The nanoparticles release paclitaxel slowly and linearly, within 24 h, Brij78-SLN and F68-SLN release 8% and 20% of total drug, respectively. Long-circulation nanoparticles was found to stay in the blood circulation, with T 1/2 beta 10.1 h of F68-SLN, and T 1/2 beta 4.88 h of Brij78-SLN more than one commercialized paclitaxel injection, T 1/2 beta 1.3 h. CONCLUSION: Stearic acid might be a new drug carrier material in the future.