Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) hydrogels loaded with soybean peptide (SPE) were fabricated via a freeze-thaw method. These hydrogels conquer barriers in simulated gastric fluid (SGF), and then release SPE in simulated intestinal fluid (SIF). The results of in vitro SPE release from these hydrogels showed that in SGF only a little of the SPE released, but in SIF the SPE was completely released. The released SPE had scavenging rates for DPPH and ABTS free radicals of 41.68 and 31.43 %. The pharmacokinetic model of SPE release from the hydrogels in SIF was studied. When the hydrogels are moved from SGF to SIF, the sorption of the shrinkage hydrogel network is entirely controlled by stress-induced relaxations. There are swollen and shrunken regions during SPE release. For SPE release into the SIF, SPE has to be freed from the weak bonds in the swollen regions by changes in the conformation of CMC and PVA. The release rate of SPE was found to be governed by the diffusion and swelling rate of the shrinkage hydrogel network. The Korsmeyer-Peppas equation diffusion exponents (n) for SPE release from the hydrogels are >2.063, indicating a super case II transport. These data demonstrate CMC/PVA hydrogels have potential applications in oral peptide delivery.
In this work, a novel sustained released system (VCSB-Zn(II)) for zinc supplements was built by vanillin-chitosan Schiff base (VCSB) chelated with Zn 2+ to improve the zinc trace element utilization ratio. Samples were characterized by FT-IR, 1 H NMR, XRD, SEM, and TGA. The results showed that VCSB exhibited a more excellent chelation capacity of Zn 2+ than chitosan. The chelation capacity of VCSB was about 1.7 times more than that of chitosan, corresponding to 50.96 mg/g and 29.91 mg/g, respectively. Furthermore, VCSB-Zn(II) showed excellent sustained released performance at simulated gastric fluid because of the acid slow-dissolving ability. And the higher the C N content of VCSB, the higher the cumulative release rate ( R i ) of Zn 2+ , the highest R i reached 77.81%. The sustained released curves were described by the first-order and Korsmeyer-Peppas equation, which described the Zn 2+ sustained released performance caused by the dissolution of VCSB-Zn(II) and Fick diffusion. This Zn 2+ sustained released system shows great potential in the application in the field of trace elements supplements for animals.
Salicylaldimine, furfuralimine and benzaldehyde imine were adopted to modify mesoporous silica (MCM) respectively denoted as Sal-MCM, Fur-MCM and Ben-MCM before loading methyl eugenol (Me) for pesticide delivery. Me was adsorbed by Schiff base mesoporous silica without destructing regular hexagonal pore structure verified by the characterization results. DSC result implied that Me in amorphous state which was distributed in the pores of the mesoporous silica. The loading content of Me-Sal-MCM, Me-Fur-MCM and Me-Ben-MCM 67.89%, 73.34% and 73.84% which was higher than Me-MCM without modification (67.35%).Because the electrostatic interaction and π-π interaction between Schiff base and Me strengthened the adsorption capacity of the carrier. And the electrostatic interaction played a more important role in interaction between Me and Schiff base modified mesoporous silica. As a result, Schiff base modified sustained release system also has significantly longer sustained release time with a sequence of Me-Sal-MCM > Me-Ben-MCM > Me-Fur-MCM in release speed in negative correlation with the electric potential sequence. The behaviors of their sustained release performance can be fitted by First order kinetic model before Schiff base modification. After modification, their sustained release behaviors were consistent with Korsmeyer-Peppas equation with non-Fickian diffusion mechanism indicating that main impact on the release process after modification was no longer mainly controlled by the difference of the concentration. Finally, the highest lure rate of the modified MCM (Me-Fur-MCM) equals to the 73% of the pure Me due to its highest BET surface area and strongest interaction with Me among the three Schiff base modified samples. Therefore, the environment-friendly slow-release bio pesticide with long service life was prepared to reduce the damage on the environment caused by pesticide.
危险品化学品经营许可证（带存储）