Pharmacokinetics, tissue distribution and magnetic resonance's response characterstics of folic acid-O-carboxymethyl chitosan ultrasmall superparamagnetic iron oxide nanoparticles in mice and rats / 药学学报

Folic acid-O-carboxymethyl chitosan ultrasmall superparamagnetic iron oxide nanoparticles (FA-OCMCS-USPIO-NPs) are a novel molecular targeting MR contrast agent. This paper reperts the pharmacokinetics and magnetic resonance response characteristics of FA-OCMCS-USPIO-NPs in normal rats and mice, and discussed its distributing regularity in animals, providing basis for tumor targeting imaging. O-phenanthroline method was used to determine iron content in rats' plasma and mice's organs following high and low doses of nanoparticles injected through tail vein, and the blood concentration-time curve was drawn, the calculated t1/2 of two groups were greater than 7 h. The results of tissue distribution showed that only a small part of nanoparticles were swallowed by the liver and spleen, while none in the heart, lung and kidney. At the same times, the phagocytosis of nanoparticles did not change with the dose. The results of MRI showed that renal excretion occurred 4 hours after injection, and signal to noise ratio (SNR) of liver and kidney returned to normal levels 24 hours after injection. There were no nanoparticles in the lungs. So a part of nanoparticles escaped from phagocytosis of liver and spleen, and it owned lower toxicity and longer half-life. indicated its use for tumor-targeting imaging. All of these indicated its use for tumor-targeting imaging.

Pharmacokinetics of amphotericin B in the cerebrospinal fluid during continuous intrathecal administration for treatment of cryptococcal neoformans meningitis / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the pharmacokinetics of amphotericin B (AMB) in the cerebrospinal fluid (CSF) during continuous intrathecal administration of AMB for treatment of cryptococcal neoformans meningitis (CNM).</p><p><b>METHODS</b>The concentration of AMB in the CSF was measured using reversed phase high performance liquid chromatography (RP-HPLC) in 3 patients receiving continuous intrathecal infusion of AMB for CNM.</p><p><b>RESULTS</b>AMB concentrations in the CSF of the 3 patients exceeded the minimal inhibitory concentration (MIC) of AMB against Cryptococcus neoformans. The concentration-time curve showed that AMB concentration in the CSF underwent obvious variations on the first day of intrathecal infusion and after additional AMB doses, but maintained a stable level (0.61-1.21 µg/ml) on the next day.</p><p><b>CONCLUSION</b>[corrected] Continuous intrathecal administration of AMB can enhance the drug concentration in the CSF and maintain a stable and effective drug level for treatment of CNM.</p>

Preparation and characterization of superparamagnetic iron oxide nanoparticles / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the physical and magnetic properties of superparamagnetic iron oxide (SPIO) nanoparticle prepared in our laboratory and evaluate its possibility for use as contrast agents in magnetic resonance imaging (MRI).</p><p><b>METHODS</b>The SPIO nanoparticle was obtained by means of classical coprecipitation in dextran solution and its size determined by electron microscopy and photon-correlation spectroscopy. The iron content was determined by phenanthroline photometry, and T(2) values as well as relaxivity evaluated with a clinical MR system at 1.5T.</p><p><b>RESULTS</b>Dextran-coated magnetite particles with a hydrodynamic diameter of 85.9 nm were prepared. The iron core size was 15 nm and the formation of Fe(3)O(4) crystal in SPIO nanoparticles was confirmed by X-ray diffraction (XRD) analysis. These particles possessed some characteristics of superparamagnetic and show a smaller spin-spin relaxation, with relaxivity and saturation magnetization of 0.1567 mmol(-1)/ms(-1) and 80 emu/g Fe, respectively.</p><p><b>CONCLUSIONS</b>A stable SPIO nanoparticle with a dextran coating have been developed, and in vitro evaluation of its physical and magnetic properties suggests its potential for use as the contrast agent in MRI.</p>

Sampling of exhaled gas after intravenous administration of octafluoropropane-containing human albumin micropheres in dogs / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop a method for quantitative collection of exhaled gas in anesthetized dogs at given time following intravenous administration of octafluoropropane (OFP)-containing human albumin micropheres for assessing the gas kinetics of OFP.</p><p><b>METHODS</b>OFP-containing albumin micropheres were administered intravenously at 0.4, 0.8 and 1.2 ml/kg, respectively, in anesthetized and ventilated dogs. The exhaled air samples were analyzed by gas chromatography-tandem mass spectrometry (GC-MS-MS).</p><p><b>RESULTS</b>The correlation curve between the area under curve (AUC) and administered dose was roughly linear (Y=1162.5X-417.38, r square=0.949 9). The total recovery rate was (119.49-/+27.62)% which was not significantly different from the rate of 100% (P>0.05). GC-MS-MS was accurate, sensitive, precise and applicable for OFP determination.</p><p><b>CONCLUSION</b>The sampling method is useful for characterizing OFP pharmacokinetics in dogs, and also applicable for studying the pharmacokinetics of other gas-containing drugs.</p>