Chinese quince seed gum and poly (N,N-diethylacryl amide-co-methacrylic acid) based pH-sensitive hydrogel for use in drug delivery.

In this investigation, a variety of innovative pH-sensitive polymers consisting of Chinese quince seed gum (CQSG) and poly (N,N-diethylacryl amide-co-methacrylic acid) were synthesized via free radical polymerization for controlled drug delivery. The resultant hydrogel polymers were characterized by scanning electron microscopy and X-ray diffraction, analyzed by Fourier-transform infrared spectroscopy, and confirmed with thermogravimetry. Results suggested the hydrogel polymers were composed of CQSG chains physically entangled in poly (N,N-diethylacryl amide-co-methacrylic acid) networks. Swelling properties of these hydrogels were strongly affected by the contents of CQSG and crosslinkers. The drug delivery applications of the hydrogels were evaluated using bovine serum albumin (BSA) as a model drug in vitro release. It was determined that BSA release from the hydrogels was pH-sensitive under simulated gastrointestinal conditions. All of these attributes imply that the new proposed CQSG/poly (N,N-diethylacryl amide-co-methacrylic acid) hydrogel polymers can be used as a good medium for oral delivery of proteinaceous drugs.

Structural Characterization of Lignin in Fruits and Stalks of Chinese Quince.

Chinese quince (Chaenomeles sinensis) is used in food and pharmaceutical products, but it is seldom eaten as a raw fruit due to its astringent, woody flesh. The structural characterization of lignin fractions from Chinese quince was very important to investigate the structure-activity relationships of lignin. In this investigation, to characterize the structure of lignin in Chinese quince fruits, the milled wood lignin sample was isolated from the fruits (FMWL) and the chemical structure of FMWL was investigated by sugar analysis, FT-IR, GPC, pyrolysis-GC/MS analysis, UV spectra analysis, thermogravimetric analysis (TGA), and advanced NMR spectroscopic techniques. In addition, the lignin fraction from the stalk of Chinese quince (SMWL) was also prepared for comparison to obtained more information of lignin structure in the fruits. The results showed that the two lignin fractions isolated from fruit and stalk of Chinese quince exhibited different structural features. The two MWL samples were mainly composed of ß-O-4 ether bonds, ß-5 and ß-ß' carbon-carbon linkages in the lignin structural units. Compared to the SMWL, the FMWL fraction had the higher S/G ratio and more carbohydrates linkages. The predominant carbohydrates associated with FMWL and SMWL fractions were glucans-type hemicelluloses and xylan-type hemicelluloses, respectively. Understanding the structure of lignin could give insight into the properties of the lignin and enable the food processing industry to separate lignin more efficiently.