Preparation and performance of pravastatin sodium-loaded chitosan microspheres / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare pravastatin sodium-loaded chitosan microspheres to allow sustained drug release.</p><p><b>METHODS</b>The drug-loaded chitosan microspheres were prepared by using genipin as the cross-linker. The influences of molecular weight of chitosan, volume ratio of oil and water, reaction temperature, and stirring speed on the formation of chitosan microspheres were investigated. The morphology of the microspheres was observed using scanning electron microscopy. The encapsulation efficiency, swelling ratio under different pH conditions, and in vitro drug release were measured.</p><p><b>RESULTS</b>The in vitro release of pravastatin sodium could last for at least 31 days. The drug release rate varied with the reaction condition. The drug entrapment efficiency of the microsphere was 54.7%. The optimal processing conditions were as follows: chitosan viscosity of 200-400 mPa·s, oil-water proportion of 10:1, stirring speed of 850 r/min, and reaction temperature at 40 degrees celsius;.</p><p><b>CONCLUSION</b>The pravastatin sodium-loaded microspheres show good sustained drug release property, and the drug release rate can be modified by controlling the cross-linking time.</p>

Live cell fluorescent imaging and cytotoxicity assessment of pH fluorescent probe based on styrylcyanine dyes / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare a pH fluorescence probe based on styrylcyanine dyes for live cell imaging.</p><p><b>METHODS</b>The Probe 1 was prepared by reaction of 4-pyridinecarboxaldehyde with 1,1,2-trimethylbenz[e]indole. The influence of pH on the fluorescent properties was examined, and the cell viability was examined using cell counting kit-8. The Probe 1 was used as a pH fluorescence probe in living cell.</p><p><b>RESULTS</b>Probe 1 emitted green fluorescence under neutral and basic conditions but orange fluorescence under acid condition. Probe 1 selectively stained the cytoplasmic regions of living cells without significantly affecting the cell viability.</p><p><b>CONCLUSION</b>The pH-sensitive fluorescent probe prepared based on styrylcyanine possesses good ability of cell membrane permeation for live cell fluorescent imaging.</p>

Fingerprints of Radix Glycyrrhizae by HPLC / 中草药

Objective To establish the HPLC fingerprints of Radix Glycyrrhizae. Methods The RP-HPLC method was used, Zorbax SB C_ 18 column (250 mm?4.6 mm, 5 ?m) was employed; the acetonitrile-1.2% acetic acid (gradient elution) was used as mobile phase, analytic time was 70 min, and detective wavelength was at 254 nm. Results The HPLC fingerprints of Radix Glycyrrhizae were set up. The result showed that 38 peaks were common in different sources. The results of method validation met technical standard of fingerprints. Conclusion The method is stable and reliable with a good reproducibility and provides a reference standard for the quality control of Radix Glycyrrhizae.