Preparation and characterization of genipin-cross-linked silk fibroin/chitosan sustained-release microspheres

Abstract

We report the effects of distinct concentrations of genipin and silk fibroin (SF):chitosan (CS) ratios on the formation of SF–CS composite microspheres. We selected microspheres featuring an SF:CS ratio of 1:1, encapsulated various concentrations of bovine serum albumin (BSA), and then compared their encapsulation efficiency and sustained-release rate with those of pure CS microspheres. We determined that the following five groups of microspheres were highly spherical and featured particle sizes ranging from 70 μm to 147 μm: mass ratio of CS:SF =1:0.5, 0.1 g or 0.5 g genipin; CS:SF =1:1, 0.05 g or 1 g genipin; and CS:SF =1:2, 0.5 g genipin. The microspheres prepared using 1:1 CS:SF ratio and 0.05 g genipin in the presence of 10 mg, 20 mg, and 50 mg of BSA exhibited encapsulation efficiencies of 50.16%±4.32%, 56.58%±3.58%, and 42.19%±7.47%, respectively. Fourier-transform infrared spectroscopy (FTIR) results showed that SF and CS were cross-linked and that the α-helices and random coils of SF were converted into β-sheets. BSA did not chemically react with CS or SF. Moreover, thermal gravimetric analysis (TGA) results showed that the melting point of BSA did not change, which confirmed the FTIR results, and X-ray diffraction results showed that BSA was entrapped in microspheres in a noncrystalline form, which further verified the TGA and FTIR data. The sustained-release microspheres prepared in the presence of 10 mg, 20 mg, and 50 mg of BSA burst release 30.79%±3.43%, 34.41%±4.46%, and 41.75%±0.96% of the entrapped BSA on the 1st day and cumulatively released 75.20%±2.52%, 79.16%±4.31%, and 89.04%±4.68% in 21 days, respectively. The pure CS microspheres prepared in the presence of 10 mg of BSA burst release 39.53%±1.76% of BSA on the 1st day and cumulatively released 83.57%±2.33% of the total encapsulated BSA in 21 days. The SF–CS composite microspheres exhibited higher sustained release than did the pure CS microspheres, and thus these composite microspheres might function as a superior drug carrier.

Preparation, characterization, and in vivo evaluation of intranasally administered liposomal formulation of donepezil

“…The surface morphology of the liposomes was studied using scanning electron microscopy (Zeiss EVO LS10, Cambridge, UK). 20 Samples were fixed on stubs using both side adhesive carbon tape (SPI Supplies, West Chester, PA, USA) and coated under vacuum with gold in a Q150R sputter coater unit obtained from Quorum Technologies Ltd. (East Sussex, UK) in an argon atmosphere at 20 mA for 120 seconds. After mounting, the samples were viewed and photographed.…”

Optimization, formulation, and characterization of multiflavonoids-loaded flavanosome by bulk or sequential technique

“…Simultaneously, total mass of the carrier (PC) lipid matrix was obtained. Thus the % of DL was determined using the following formula: 25,27 DL% Amount of loaded flavonoids Total mass of the matrix = × 100 0 (3)…”

Anti-tumor Effect of Quercetin Loaded Chitosan Nanoparticles on Induced Colon Cancer in Wistar Rats

“…In our study, the LE% was obtained as ~96%, so in the CS NPs the CS:Qu weight ratio can influence the rate of drug entrapment in CS N/MPs. 36 Additionally, the type of crosslinking (chemical, physical or dual crosslinking), 37 hybridation of CS with polyanionic/polymeric complementaries, 35 type of hybridation (blending, coating or both of them) 31 are the other important factors that can influence/enhance on the loading and encapsulation efficiency in drug delivery systems.…”