Nanomedicine strategies for sustained, controlled, and targeted treatment of cancer stem cells of the digestive system.

Cancer stem cells (CSCs) constitute a small proportion of the cancer cells that have self-renewal capacity and tumor-initiating ability. They have been identified in a variety of tumors, including tumors of the digestive system. CSCs exhibit some unique characteristics, which are responsible for cancer metastasis and recurrence. Consequently, the development of effective therapeutic strategies against CSCs plays a key role in increasing the efficacy of cancer therapy. Several potential approaches to target CSCs of the digestive system have been explored, including targeting CSC surface markers and signaling pathways, inducing the differentiation of CSCs, altering the tumor microenvironment or niche, and inhibiting ATP-driven efflux transporters. However, conventional therapies may not successfully eradicate CSCs owing to various problems, including poor solubility, stability, rapid clearance, poor cellular uptake, and unacceptable cytotoxicity. Nanomedicine strategies, which include drug, gene, targeted, and combinational delivery, could solve these problems and significantly improve the therapeutic index. This review briefly summarizes the ongoing development of strategies and nanomedicine-based therapies against CSCs of the digestive system.

[Research progress of layer-by-layer self-assembly technique in drug delivery].

Now the layer-by-layer self-assembling (LbL) technique has become an attention-getting reparative methodology for ultrathin film formation. Many scientists in different academic areas including bioengieering, medical science, drug controlled release, optoelectronics dive into this technology. Among of them, carriers with structures which can be flexibly controlled are more useful since functional structure units can be assembled in layer-by-layer fashion, which is simplicity, chemical mildness, concealment, can achieve targeted drug delivery and so on. In this review, we have discussed the advantage, development, influential factors and applications of LbL. We have focused on reviewing the applications and perspective of nanoparticles, microgels and capsules were both fabricated via the LbL assembling at drug delivery.

[Preparation and properties of Talpha1 loaded injectable sustained release microspheres].

To prepare thymosin alpha-1 (Talpha) loaded injectable sustained release microspheres and to evaluate its release behavior, bioactivities in vitro as well as its pharmacodynamics in vivo, Talpha1 loaded microspheres was prepared with poly ( lactic-co-glycolic acid) (PLGA) as carrier material by double emulsion (W/O/W) method. Physical and chemical properties of microspheres, such as mean diameter, The release behavior and its influencing factors were morphology and drug loading were evaluated. evaluated by HPLC determination. The bioactivity of Talpha1 in the course of encapsulation process and in vitro release ware evaluated by CCK-8 method. The ratio of CD4+/CD8+ in blood was determined with flow cytometry and the pharmacodynamics of Ta, loaded microspheres was evaluated by the change of CD4+/ CD8+. Microspheres with good shape and dispersive quality were prepared. The drug entrapment efficiency of two optimizing prescriptions containing 5% NaCl and 10% glucose as outer water phase were 87. 8% and 90. 2% , respectively. The cumulated release in one month is up to 90%. The bioactivity of Talpha was conserved with glucose as outer water phase, but in the course of in vitro release, the specific activity of Talpha in the microspheres decreased a little. Talpha microspheres can increase significantly the immunity of immuno-suppressed rats. Talpha can be encapsulated in injectable microspheres to yield one-month continuous release when using biodegradable polymers PLGA as carrier material, and this technique will have a favorable perspective in the near future.

[Long-acting injectable microspheres of glucagon-like peptide-1].

AIM: To prepare glucagon-like peptide-1 (GLP-1) loaded long-acting injectable microspheres and to evaluate their in vitro release behavior as well as its pharmacodynamics. METHODS: GLP-1 loaded microspheres were prepared with poly (lactic-co-glycolic acid) (PLGA) as carrier materials by dowble emulsion (W/O/W) method. Physical and chemical characteristics of microspheres, such as mean diameter, morphology and drug loading were evaluated. The in vitro release behavior and its influencing factors were determined by HPLC, also the bioactivity of GLP-1 in the course of encapsulation process and in vitro release were evaluated by in vivo animal experiments. The effect of reducing plasma glucose about GLP-1 microspheres were evaluated on the diabetes mice. RESULTS: Microspheres with good shape and dispersive quality were prepared. The drug entrapment efficiency was more than 80%. The accumulated release in one month is up to 85% and the release equation is in accord with zero-class release model. The bioactivity of GLP-1 was conserved with glutin as inner water phase, but in the course of in vitro release, the specific activity of CLP-1 in the microspheres decreased a little. GLP-1 microspheres can decrease the plasma glucose significantly and the effect can go on for one month. CONCLUSION: GLP-1 can be encapsulated in injectable microspheres to yield one-month continuous release when using biodegradable polymers PLGA as carrier material, and this technique will have a favorable perspective in the near future.