Publications in July 2010
In July several outstanding articles about chitosan had been published around the world. All in all 122 articles were released in 67 different journals. With regard to the number of publications the leading countries are China (31), the USA (20) and South Korea (10).
|Top 5 Themes||Publications||Top 5 Journals||Publications|
|Pharmaceutical Preparation||112||International Journal of biological macromolecules||7|
|Evaluation Studies as Topic||30||International Journal of pharmaceutics||6|
|Nanoparticles||26||Journal of material science- Materials in medicine||5|
Tissue engineering / wound dressing
In July 2010, 26 articles about Chitosan / Tissue and 17 about tissue engineering have been published.
1.: Preparation, fabrication and biocompatibility of novel injectable temperature-sensitive chitosan/glycerophosphate/collagen hydrogels
Song K., Qiao M., Liu T., Jiang B., Macedo H.M., Ma X., Cui Z.; J Mater Sci Mater Med. 2010 Jul 18. [Epub ahead of print]
This paper investigates a novel chitosan based hydrogel with excellent properties in terms of tissue engineering. The hydrogel consist of chitosan (2.2% (v/v), beta-glycerophosphate (50% (w/w)) andcollagen (2 mg/ml). At a body temperature the hydrogels get a jelly texture within 12 minutes. The study examined the properties of the hydrogel by usingan adipose tissue-derived stem cell culture (ADSC). Using inverted and scanning electron microscopy the cellular growth and the formation of the C/GP/Co hydrogel was observed. The inner structure of the gel had a porous spongy structure. The ADSCs, which have been seeded into the hydrogel, displayed a normal adherent cell morphology and very high cellular viability after 7 days. Further Live/Dead, Viability/Cytotoxicity tests confirm the great biocompatibility of C/GP/Co gels. In conclusion the injectable temperature-sensitive C/GP/Co hydrogels possess excellent properties as a scaffold for tissue engineering.
2.: Osteoblastic induction on calcium phosphate cement-chitosan constructs for bone tissue engineering
Weir, M D, Xu, H H; Journal of biomedical materials research.Part A, Vol. 94 (1): 223-33, 2010
The object of this research was to examine mechanical properties of calcium phosphate cement (CPC), Chitosan and the human bone morphogenicprotein-2 (rhBMP-2) in terms of bone substitution and regeneration. CPC is moduable and osteoconductive, but has relatively low resorption- and bone ingrowth rates. In combination with chitosan an increase in strength and toughness was detected. This report investigated additionally the osteoblastic effect of the rhBMP-2 in combination withCPC-chitosan. rhBMP-2 plays an important role in the development of bone and cartilage structures. Using of MC3T3-E1 cells, cell-viability tests showed that the CPC-chitosan compound was stronger and tougher than the CPC control. Furthermore the osteoblastic induction was determined by measuring the activity of APL (alkaline phosphatase) after 14 day. The enzyme activity was about two times higher for the CPC/Chitosan/rhBMP-2 composite, while conventional CPC conducted the lowest APL activity. The flexural strength of the bone substitution increased to double, when CPC contained 15% (mass fraction) chitosan. In addition the fracture toughnessincreased as well. Due to these ideal features the CPC-chitosan composite is a promising scaffold for bone repair and may be useful as an injectable delivery vehicle for osteoinductive growth factors.
3.: Physical, antibacterial and antioxidant properties of chitosan films incorporated with thyme oil for potential wound healing applications
Altiok D., Altiok E., Tihminlioglu F.; J Mater Sci Mater Med. 2010 Jul; 21(7):2227-36. Epub 2010 Apr 7
This paper investigated chitosan films for wound dressing, in which thyme oil is incorporated. Those films were prepared by using solvent casting method. Several tests have been conducted, investigating the antimicrobial and antioxidant activity, water vapor permeability, oxygen transmission rate and mechanical properties.Antimicrobial tests, carried out on gram positive and negative bacteria, showed that a minimum concentration of 1.2 % (v/v) thyme oil exhibit antibacterial activity. Furthermore this concentration has the highest antioxidant activity due to carvacrol within the oil. In Addition an increase of water vapor permeability and oxygen transmission rate was detected. In contrast mechanical properties decreased with thyme oil incorporation. In conclusion, an incorporation of thyme oil into chitosan films enhances the positive properties of chitosan wound dressing in terms of antibacterial activity and permeability.
26 articles have been published about the usage of chitosan nanoparticles for delivery systems.
4.: Acyl modified chitosan derivatives for oral delivery of insulin and curcumin
Shelma R., Sharma C.P.; J Mater Sci Mater Med. 2010 Jul;21(7):2133-40. Epub 2010 Apr 8
Polymeric nanoparticles of chitosan are promising candidates for advanced drug delivery applications. This study investigated the bioadhesive properties of acyl derivatives of chitosan. The N-acylation of chitosan with various fatty acids chlorides (hexanoyl-, lauroyl- and oleoyl-chlorides) increases the hydrophobic character and the adhesive properties of the biopolymer. Depending on the length of the acryl chain and the degree of substitution the derivatives differs in their solubility. The drug release at different pH was tested for hydrophilic and hydrophobic drugs.This study reported a strong interaction between those chitosan derivatives and mucin. Oleoyl-chloride-chitosan has higher mucoadhesion ability than modified chitosan with lower fatty acid groups. Using L-929 cell lines, the modified chitosan nanoparticles provided a sustained release of hydrophobic drugs and are not toxic.
5.:One-step preparation of chitosan solid nanoparticles by electrospray deposition
Zhang, Shaoling, Kawakami, Kohsaku; International journal of pharmaceutics, 2010
Using electrospray procedure, solid chitosan/ acetic acid solution micro- and nanoparticles have been generated. The electrospray behavior was strongly affected by the viscosity and conductivity of the chitosan solution. To stabilize the electrospray, the viscosity needed to be increased, while the conductivity has to be low. This can be achieved by adding ethanol. By decreasing the concentration of chitosan and acetic acid, smaller nanoparticles could be obtained. Additionally the flow rate was decreased as well. Finally the average diameter of chitosan nanoparticles could be reduced to 124nm, suggesting the electrospray method as a promising device to generate solid micro- and nanoparticles.
6.:Synthesis and characterization of low-toxic amphiphilic chitosan derivatives and their application as micelle carrier for antitumor drug
Huo M., Zhang Y., Zhou J., Zou A., Yu D., Wu Y., Li J., Li H.; Int J Pharm. 2010 Jul 15;394(1-2):162-73. Epub 2010 May 8
Amphiphilic chitosan derivatives were synthesized as drug carriers for water-insoluble paclitaxel (PTX), which is used in cancertherapy as a mitotic inhibitor. An amphiphilic character has been created by attaching long alkyl chains (hydrophobic moieties) and glycol groups (hydrophilic moieties) to chitosan. The chemical structure of the generated N-octyl-O-glycol chitosan derivate (OGC) was characterized by FTRI, (1)H nuclear magnetic resonance, and elemental analysis.Furthermore several safety studies including acute toxicity, organ toxicity, hemolysis, hypersensitivity and maximum tolerated dose, have been done,showing advantages of PTX-loaded OGC micelles compared to the normal application. The blank OGC micelles are found to be less toxic thanCremophor EL vehicle, which is used for intravenous applications of water-insoluble drugs.The stability and drug-loading capacity of OGC micelles significantly depend on the degree of alkyl chains. OGCs seem to be a promising drug carrier for injectable chemo-therapeutic agents like PTX.
7.:Co-delivery of PDTC and doxorubicin by multifunctional micellar nanoparticles to achieve active targeted drug delivery and overcome multidrug resistance
Fan L., Li F., Zhang H., Wang Y., Cheng C., Li X., Gu C.H., Yang Q., Wu H., Zhang S.; Biomaterials. 2010 Jul; 31(21):5634-42. Epub 2010 Apr 28
To overcome multidrug resistance (MDR) against doxorubicin (DOX), micellar nanoparticles of folate-chitosan (FA-CS) have been investigated for drug delivery.Pyrrolidinedi-thiocarbamate (PDTC) was co-encapsulated together with DOX. PDTC is an antioxidants and metabolic inhibitors of a variety of biological reactions and can be used in cancer therapy.Tests revealed that the drug release was pH dependent. At neutral or alkalescent pH, a slow and sustained release occurred, while at a weak acidic pH the release was much faster. To achieve a good stability of the nanoparticles in the blood stream, a lower critical aggregation concentration (CAC) was used. Furthermore the cellular uptake efficiency was enhanced by a lower IC50 of DOX-loaded FA-CS nanoparticles. The co-delivery of PDTC and DOX seems to help overcoming the MDR of DOX, besides the folate-receptor mediated endocytosis process. This co-delivery system may have important clinical implications against liver cancers.
8.: Molecular imprinted macroporous chitosan coated mesoporous silica xerogels for hemorrhage control
Dai C., Liu C., Wei J., Hong H., Zhao Q.; Biomaterials.2010 Jul 23. [Epub ahead of print]
In this study, a new hemostatic compound has been developed consisting of macroporous chitosan, which coats a core out of mesoporous silica xerogel beads (CSSX). The compound is constructed by using modified sol-gel process and PEG molecular imprinting technique. To optimize the hemostatic effect several in vivo and in vitro tests have been conducted, showing the highest efficiency when CSSX is prepared with 2% chitosan and 5% PEG. CSSX beads seem to accelerate the contact activation pathway of coagulation cascade significantly and thus promote hemostasis. In Addition no cytotoxicity orexothermic reactions have been observed even after 7 days of the application. Therefore CXXS beads seem to be a safe hemostatic system with a high potential for a topical hemostatic agent.
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