A three-dimensional
porous MoS2/chitosan (MoS2/CS) aerogel with
excellent mechanical strength and stability was
constructed in this work through anchoring MoS2 to the
surface of the CS aerogel. It is found that the MoS2/CS
aerogel can effectively recover gold from thiosulfate solution via
direct in situ reduction of Au(I) to Au0 under sunlight,
thus realizing the one-step recovery of gold, which greatly benefits
the development of thiosulfate leaching for gold extraction. Furthermore,
according to the results of photocurrent, ultraviolet–visible
absorption, and atomic absorption spectrophotometry, it has been found
that the reduction of the MoS2/CS aerogel to Au(I) is mainly
consisted of photoreduction and chemical reduction, where photoreduction
plays a dominant role, primarily because of the narrow band gap and
higher conduction band edge of the MoS2/CS aerogel as well
as the strong reducibility of photogenerated electrons.
Nanosuspensions (NS) can enhance the saturation solubility and dissolution velocity of poorly soluble drugs. PEG as a non-ionic surfactant plays an important role in surface modification of nanoparticles for prolonging in vivo circulation. In this study, anti-solvent precipitation method was introduced to prepare gambogenic acid nanosuspensions (GNA-NS) with PVPK30 and PEG2000 as stabilizers to settle the disadvantages of GNA. The obtained nanoparticles were spherical with a mean particle size of 183.7 nm and a zeta potential of À22.8 mV.The entrapment efficiency and drug loading of the resultant formulation were 97.3 and 29.73%. X-ray diffraction analysis confirmed the amorphous phase of GNA in NS. Fourier transform infrared indicated there may be hydrogen bond interaction between the drug and excipients. After lyophilization of GNA-NS, the freeze-dried powder displayed sufficient longterm physical stability at 4 and 25 C. In comparison to GNA solution, in vitro studies of GNA-NS showed much slower release and higher cytotoxicity in HepG2 cells. What's more, the pharmacokinetic study in rats revealed that the AUC 0-1 and t 1/2 of GNA-NS were increased 2.63-and 1.77-fold than that of the reference formulation. Taken together, in vitro/in vivo evaluations showed NS would be an effectively strategy to change the poor aqueous solubility and prolong the half-life for GNA. The GNA-NS with enhanced bioavailability and drug efficacy provided a promising delivery system for the application of GNA.
KeywordsCytotoxicity, gambogenic acid, in vivo pharmacokinetics, in vitro release, nanosuspensions History
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