To prepare doxorubicin-loaded N-octyl-N'-succinyl chitosan polymeric micelle (DOX-OSC) and study the biodistribution of DOX-OSC in mice, DOX-OSC was prepared by dialysis method. By using doxorubicin injection (DOX-INJ) as control, DOX-OSC and DOX-INJ were administered to mice through caudal vein at a dose of 5 mg x kg(-1) body weight. The RP-HPLC method was established to determine the DOX levels in the plasma and other tissues of mice. The tissues distribution and targeting efficiency were evaluated by pharmacokinetic parameters (AUC, MRT) and targeting parameters (Re, Ce and Te). The drug loading and entrapment efficiency of DOX-OSC were (35.8 +/- 0.4)% and (75.3 +/- 1.1)%, respectively. The diameter and zeta potential of DOX-OSC were (174 +/- 12) nm and (-37.1 +/- 3.0) mV, respectively. The transmission electron microscope result showed DOX-OSC with spherical shape. The biodistribution results showed that the concentration of DOX of both DOX-OSC and DOX-INJ decreased rapidly in blood after iv administration. While free DOX levels in blood at 12-96 h were not detectable for DOX-INJ, in contrast, DOX level in blood at 96 h was still found for DOX-OSC. In contrast to DOX-INJ group, DOX-OSC showed a higher targeting efficiency in the liver and spleen. The AUCs of DOX in the liver and spleen were 20.0 and 47.4 times and the MRT were 11.2 and 37.2 times, respectively. And the levels of DOX-OSC in the heart and kidney tissues were significantly reduced. And the drug distribution of DOX-OSC in the heart and kidney tissues were 17.0% and 11.4%, respectively. Hence, DOX-OSC shows an excellent drug loading capabilities and a higher targeting efficiency in the liver and spleen. That the levels of DOX-OSC in the heart and kidney tissues are significantly reduced, might improve the treatment efficacy of DOX and decrease the side effects.
Animals ; Antibiotics, Antineoplastic ; administration & dosage ; pharmacokinetics ; Area Under Curve ; Chitosan ; analogs & derivatives ; chemistry ; Doxorubicin ; administration & dosage ; pharmacokinetics ; Drug Carriers ; Drug Delivery Systems ; Female ; Liver ; metabolism ; Male ; Mice ; Micelles ; Particle Size ; Polymers ; Spleen ; metabolism ; Tissue Distribution

This study was aimed to investigate the activation of P38MAPK/STAT3 and expression of telomerase reverse transcriptase during sodium nitroprusside (SNP) inducing apoptosis of human leukemia cell line K562 and to explore the molecular mechanisms of SNP-inducing apoptosis in K562 cells. The K562 cell were treated with different concentrations of SNP and were cultured for different time. Cell apoptosis was analysed by cell morphology, DNA agarose gel electrophoresis, DNA content, and Annexin-V/PI labeling method. The TdT-mediated dUTP nick end labeling (TUNEL) assay was used to quantitate the in situ cell apoptosis. The expressions of phosphorylated p38MAPK or STAT3 were analysed by flow cytometry, while the expression of hTERT mRNA in transcriptional level was measured by fluorescence quantitative RT-PCR. The results showed that SNP inhibited K562 cell growth. The K562 cell apoptosis was confirmed by typical cell morphology and DNA fragment, peak of sub-G1 phase, TUNEL and Annexin-V/PI labeling. A majority of K562 cells were arrested in G0/G1 phase. After treatment with SNP at 0.5-3.0 mmol/L, the expression of phosphorylated-P38MAPK and phosphorylated-STAT3 increased first and decreased afterwards. Incubation of K562 cell with SNP (2 mmol/L) could increase the expression of phosphorylated-P38MAPK and phosphorylated-STAT3 at 12 hours and 24 hours respectively, and down-regulated at 72 hours and 48 hours. SNP could decrease the expression of hTERT-mRNA in time-and dose-dependent manner. It is concluded that SNP can significantly induce K562 cells apoptosis, its mechanism may be related to the activation of P38MAPK and suppression of phosphorylated-STAT3 and hTRET-mRNA.
Apoptosis ; drug effects ; Humans ; K562 Cells ; Nitroprusside ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; STAT3 Transcription Factor ; genetics ; metabolism ; Telomerase ; biosynthesis ; genetics ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism

BACKGROUNDDuring recent years, the incidence of serious infections caused by opportunistic fungi has increased dramatically due to alterations of the immune status of patients with hematological diseases, malignant tumors, transplantations and so forth. Unfortunately, the wide use of triazole antifungal agents to treat these infections has lead to the emergence of Aspergillus spp. resistant to triazoles. The present study was to assess the in vitro activities of five antifungal agents (voriconazole, itraconazole, posaconazole, amphotericin B and caspofungin) against different kinds of Aspergillus spp. that are commonly encountered in the clinical setting.

METHODSThe agar-based Etest MIC method was employed. One hundred and seven strains of Aspergillus spp. (5 species) were collected and prepared according to Etest Technique Manuel. Etest MICs were determined with RPMI agar containing 2% glucose and were read after incubation for 48 hours at 35°C. MIC(50), MIC(90) and MIC range were acquired by Whonet 5.4 software.

RESULTSThe MIC(90) of caspofungin against A. fumigatus, A. flavus and A. nidulans was 0.094 µg/ml whereas the MIC(90) against A. niger was 0.19 µg/ml. For these four species, the MIC(90) of caspofungin was the lowest among the five antifungal agents. For A. terrus, the MIC(90) of posaconazole was the lowest. For A. fumigatus and A. flavus, the MIC(90) in order of increasing was caspofungin, posaconazole, voriconazole, itraconazole, and amphotericin B. The MIC of amphotericin B against A. terrus was higher than 32 µg/ml in all 7 strains tested.

CONCLUSIONSThe in vitro antifungal susceptibility test shows the new drug caspofungin, which is a kind of echinocandins, has good activity against the five species of Aspergillus spp. and all the triazoles tested have better in vitro activity than traditional amphotericin B.

Amphotericin B ; pharmacology ; Antifungal Agents ; pharmacology ; Aspergillus ; drug effects ; Echinocandins ; pharmacology ; Itraconazole ; pharmacology ; Lipopeptides ; Microbial Sensitivity Tests ; Pyrimidines ; pharmacology ; Triazoles ; pharmacology ; Voriconazole