Chen Xiguang

Effect of UV-B radiation on ingesting and nutritional selecting behavior of rotifer Brachionus urceus

Effect of UV-B radiation on ingesting and nutritional selecting behavior of the roifer Brachionus urceus on 5 species of micro-algae were studied under controlled laboratory conditions. Results showed that enhanced UV-B radiation significantly inhibited ingesting of the rotifer B. urceus when it was fed with 5 species of micro-algae (p<0.05). The ingesting selectivity rate varied with the UV-B radiation enhancement when it was fed with 5 species micro-algal mixture. Results indicated that the enhanced UV-B radiation could affect ingesting and nutritional selectivity of B. urceus.

Preparation and in vitro release performance of sustained-release captopril/Chitosan-gelatin net-polymer microspheres

The captopril/Chitosan-gelatin net-polymer microspheres (CTP/CGNPMs) were prepared using Chitosan (CTS) and gelatin (GT) by the methods of emulsification, cross-linked reagent alone or in combination and microcrystalline cellulose (MCC) added in the process of preparation of microspheres, which aimed to eliminate dose dumping and burst phenomenon of microspheres for the improvement of the therapeutic efficiency and the decrease of the side effects of captopril (CTP). The results indicated that CTP/CGNPMs had a spherical shape, smooth surface and integral structure inside but no adhesive phenomena in the preparation. The size distribution ranged from 220 μm to 280 μm. The CTP release test in vitro demonstrated that CTP/CGNPMs played the role of retarding the release of CTP compared with ordinary CTP tablets. The release behaviors of CGNPMS were influenced by preparation conditions such as experimental material ratio (EMR) and composition of cross linking reagents. Among these factors, the EMR (1/4), CLR (FA+SPP) and 0.75% microcrystalline cellulose (MCC) added to the microspheres constituted the optimal scheme for the preparation of CTP/CGNPMs. The ER, DL and SR of CTP/CGNPMs prepared according to the optimal scheme were 46.23±4.51%, 9.95±0.77% and 261±42%, respectively. The CTP/CGNPMs had the good characteristics of sustained release of drug and the process of emulsification and cross-linking were simple and stable. The CGNPMs are likely to be an ideal sustained release formulation for water-soluble drugs.

Preparation and characterizationin vitro of sustained-release captopril/Chitosan-gelatin net-polymer microspheres (Cap/CGNPMs)

The captopril/Chitosan-gelatin net-polymer microspheres (Cap/CGNPMs) were prepared using Chitosan (CS) and gelatin (Gel) by the methods of emulsification. A cross linked reagent alone or in combination with microcrystalline cellulose (MCC) was added in the process of preparation of microspheres to eliminate dose dumping and burst phenomenon of microspheres for the improvement of the therapeutic efficiency and the decrease of the side effects of captopril (Cap). The results indicate that Cap/CGNPMs have a spherical shape, smooth surface morphology and integral inside structure and no adhesive phenomena and good mobility, and the size distribution is mainly from 220 to 280 μm. Researches on the Cap release test in vitro demonstrate that Cap/CGNPMs are of the role of retarding release of Cap compared with Cap ordinary tablets (COT), embedding ratio (ER), drug loading (DL), and swelling ratio (SR), and release behaviors of CGNPMS are influenced by process conditions of preparation such as experimental material ratio (EMR), composition of cross linking reagents. Among these factors, the EMR(1/4), CLR (FOR+TPP) and 0.75% microcrystalline cellulose (MCC) added to the microspheres are the optimal scheme to the preparation of Cap/CGNPMs. The Cap/CGNPMs have a good characteristic of sustained release of drug, and the process of emulsification and cross-linking process is simple and stable. The CGNPMs is probable to be one of an ideal sustained release system for water-soluble drugs.