The transient precorneal retention time and low penetration capacity into intraocular tissues are the key obstacles that hinder the ophthalmic drug delivery of many therapeutic compounds, especially for drugs with poor solubility and permeability. To break the stalemate, N-acetyl-L-cysteine functionalized chitosan copolymer (CS-NAC), which exhibit marked bioadhesion and permeation enhancing effect, was synthesized. The curcumin encapsulated NLC (CUR-NLC) was produced and optimized followed by surface absorption of CS-NAC. After coating, changed particle size from 50.76 ± 2.21 nm to 88.64 ± 1.25 nm and reversed zeta potential from −20.38 ± 0.39 mV to 22.51 ± 0.34 mV was observed. The in vitro CUR release from NLC was slower than that of CUR-NLC and chitosan hydrochlorides (CH) coated NLC due to the inter and/or intramolecular disulfide formation of thiomers on the surface of nanocarriers. The modification also significantly enhanced transcorneal penetration compared with CH-NLC and the uncoated ones. The effect on bioadhesion and precorneal retention were evaluated by in vivo imaging technique and ocular pharmacokinetics studies revealing that the clearance of the formulations was significantly delayed in the presence of CS-NAC and the effect was positively related to the degree of thiolation. In summary, CS-NAC-NLC presented a series of notable advantages for ophthalmic drug application.

The purpose of this work was to explore the particle size reduction effect of carvedilol on dissolution and absorption. Three suspensions containing different sized particles were prepared by antisolvent precipitation method or in combination with an ultrasonication process. The suspensions were characterized for particle size, surface morphology, and crystalline state. The crystalline form of carvedilol was changed into amorphous form after antisolvent precipitation. The dissolution rate of carvedilol was significantly accelerated by a reduction in particle size. The intestinal absorption of carvedilol nanosuspensions was greatly improved in comparison with microsuspensions and solution in the in situ single-pass perfusion experiment. The in vivo evaluation demonstrated that carvedilol nanosuspensions and microsuspensions exhibited markedly increased C max (2.09- and 1.48-fold) and AUC 0− t (2.11- and 1.51-fold), and decreased T max (0.34- and 0.48-fold) in contrast with carvedilol coarse suspensions. Moreover, carvedilol nanosuspensions showed good biocompatibility with the rat gastric mucosa in in vivo gastrointestinal irritation test. The entire results implicated that the dissolution rate and the oral absorption of carvedilol were significantly affected by the particle size. Particle size reduction to form nanosized particles was found to be an efficient method for improving the oral bioavailability of carvedilol.

The ionic liquid catalyst [TEAPS]5PW10V2O40 exhibited good activity and reusability in the esterification process owing to its acidity and thermoregulated properties.

The influencing factors of ammonia content and centrifugal speed on ammonium rhenate recovery from waste superalloy were systematically analyzed. It was found that proper ammonia content and centrifugal speed could promote crystal growth and a higher purity of ammonium rhenate was obtained. Moreover, the XRD patterns showed that excessive ammonia content and inappropriate centrifugal speed restrained the growth of (101) crystal plane and (112) crystal plane, which caused the crystal structural regularity and relative crystallinity to attenuate. The microscopic morphology and purity of the crystal also changed.

A novel molybdenum- and vanadium-substituted quaternary heteropoly acid H5SiW9Mo2VO40[Formula: see text][Formula: see text][Formula: see text]13H2O has been synthesized and characterized by IR, UV, TG-DTA and XRD. The proton conductive performance was studied by the electrochemical impedance spectroscopy (EIS), which demonstrated that H5SiW9Mo2VO40[Formula: see text][Formula: see text][Formula: see text]13H2O shows excellent proton conduction performance with proton conductivity reaching [Formula: see text][Formula: see text]S[Formula: see text]cm[Formula: see text] at 60∘C and 80% relative humidity. In the temperature range of measurements, conductivity enhances with higher temperature. The proton conductive mechanism of this new heteropoly acid is the vehicle mechanism due to the activation energy of 31.91[Formula: see text]kJ [Formula: see text] mol[Formula: see text].