Probing nanoliposomes using single particle analytical techniques: effect of excipients, solvents, phase transition and zeta potential

There has been a steady increase in the interest towards employing nanoliposomes as colloidal drug delivery systems, particularly in the last few years. Their biocompatibility nature along with the possibility of encapsulation of lipid-soluble, water-soluble and amphipathic molecules and compounds are among the advantages of employing these lipidic nanocarriers. A challenge in the successful formulation of nanoliposomal systems is to control the critical physicochemical properties, which impact their in vivo performance, and validating analytical techniques that can adequately characterize these nanostructures. Of particular interest are the chemical composition of nanoliposomes, their phase transition temperature, state of the encapsulated material, encapsulation efficiency, particle size distribution, morphology, internal structure, lamellarity, surface charge, and drug release pattern. These attributes are highly important in revealing the supramolecular arrangement of nanoliposomes and incorporated drugs and ensuring the stability of the formulation as well as consistent drug delivery to target tissues. In this article, we present characterization of nanoliposomal formulations as an example to illustrate identification of key in vitro characteristics of a typical nanotherapeutic agent. Corresponding analytical techniques are discussed within the context of nanoliposome assessment, single particle analysis and ensuring uniform manufacture of therapeutic formulations with batch-to-batch consistency.

Selective cytotoxicity of green synthesized silver nanoparticles against the MCF-7 tumor cell line and their enhanced antioxidant and antimicrobial properties

Introduction

Silver nanoparticles (AgNPs) are of great interest due to their unique and controllable characteristics. Different synthesis methods have been proposed to produce these nanoparticles, which often require elevated temperatures/pressures or toxic solvents. Thus, green synthesis could be a replacement option as a simple, economically viable and environmentally friendly alternative approach for the synthesis of silver nanoparticles.

Methods

Here, the potential of the walnut green husk was investigated in the production of silver nanoparticles. An aqueous solution extracted from walnut green husk was used as a reducing agent as well as a stabilizing agent. Then, the synthesized nanoparticles were characterized with respect of their anticancer, antioxidant, and antimicrobial properties.

Results

Results showed that the synthesized nanoparticles possessed an average size of 31.4 nm with a Zeta potential of -33.8 mV, indicating high stability. A significant improvement in the cytotoxicity and antioxidant characteristics of the green synthesized Ag nanoparticles against a cancerous cell line was observed in comparison with the walnut green husk extract and a commercial silver nanoparticle (CSN). This could be due to a synergistic effect of the synthesized silver nanoparticles and their biological coating. AgNPs and the extract exhibited 70% and 40% cytotoxicity against MCF-7 cancerous cells, respectively, while CSN caused 56% cell death (at the concentration of 60 µg/mL). It was observed that AgNPs were much less cytotoxic when tested against a noncancerous cell line (L-929) in comparison with the control material (CSN). The free radical scavenging analysis demonstrated profound anti-oxidant activity for the synthesized nanoparticles in comparison with the extract and CSN. It was also detected that the synthesized AgNPs possess antibacterial activity against nosocomial and standard strains of both Gram-positive and Gram-negative bacteria (minimum inhibitory concentration =5-30 µg/mL).

Conclusion

These findings imply that the synthesized nanoparticles using green nanotechnology could be an ideal strategy to combat cancer and infectious diseases.

Impact of Particle Size and Polydispersity Index on the Clinical Applications of Lipidic Nanocarrier Systems

Lipid-based drug delivery systems, or lipidic carriers, are being extensively employed to enhance the bioavailability of poorly-soluble drugs. They have the ability to incorporate both lipophilic and hydrophilic molecules and protecting them against degradation in vitro and in vivo. There is a number of physical attributes of lipid-based nanocarriers that determine their safety, stability, efficacy, as well as their in vitro and in vivo behaviour. These include average particle size/diameter and the polydispersity index (PDI), which is an indication of their quality with respect to the size distribution. The suitability of nanocarrier formulations for a particular route of drug administration depends on their average diameter, PDI and size stability, among other parameters. Controlling and validating these parameters are of key importance for the effective clinical applications of nanocarrier formulations. This review highlights the significance of size and PDI in the successful design, formulation and development of nanosystems for pharmaceutical, nutraceutical and other applications. Liposomes, nanoliposomes, vesicular phospholipid gels, solid lipid nanoparticles, transfersomes and tocosomes are presented as frequently-used lipidic drug carriers. The advantages and limitations of a range of available analytical techniques used to characterize lipidic nanocarrier formulations are also covered.

Radiation Cross-linked Polyethylene Foam: Preparation and Properties

The ability of some additives to increase the efficiency of polyethylene (PE) cross-linking is studied. The results confirm that additives are effective especially at low doses. Formulations of radiation cross-linked PE foam are used, and optimum conditions for the foaming process to prepare desirable final products are obtained. In addition, different properties of the foam, such as tensile properties, density, water absorption, thermal conductivity, and cellular structure, are determined in relation to blowing agent concentration. Finally, a PE foam formula with desirable properties is introduced.

The management of dental waste in dental offices and clinics in Shiraz, Southern Iran

BACKGROUND

Dental waste can be hazardous to humans and the environment.

OBJECTIVE

To determine the current status of dental waste management in private and public dental clinics and private dental offices in Shiraz, southern Iran.

METHODS

This cross-sectional study was conducted at the Shiraz University of Medical Sciences from February through June 2013. A stratified random sampling method was used to study 86 private offices, 14 private clinics and 10 public clinics. Types of waste studied included mercury and amalgam, lead foil packets, sharps, infectious tissues and fluids, pharmaceuticals and domestic waste materials. Compliance with established standards by the monitored dental offices and clinics and public clinics were compared.

RESULTS

89.1% of dental offices and clinics disposed their infectious waste with domestic waste. Only 60% of centers used standard method for sharps disposal. None of the dental centers disposed their pharmaceutical waste and x-ray fixer waste by standard methods. Less than 10% of centers recycled the amalgam and lead foil pockets waste to the manufacture.

CONCLUSION

Government agencies should establish monitoring programs for all dental offices and clinics to identify noncompliant activity and enforce recommended regulations.

How do nurses manage their occupational exposure to cytotoxic drugs? A descriptive survey in chemotherapy settings, Shiraz, Iran

Occupational exposure to cytotoxic drugs is a global concern. We conducted this cross-sectional study in 2012 to describe the adverse effects experienced by nurses working in one of chemotherapy facilities affiliated to Shiraz University of Medical Sciences, Shiraz, southern Iran, and their proper use of personal protective equipment and educational programs. The frequency of side effects reported by participants was noticeably high. Approximately, 60% of the nurses used all personal protective equipment. There were air conditioner ventilation systems in all facilities, but they were not standard. Clinics did not have any dedicated room. Lack of adequate training was noticeable among all participants. We concluded that establishment of safety regulations, health care workers safety surveillance systems as well as continuous training for nurses are of paramount importance.

Abstract P1-07-16: Liver derived epithelial cells as source of false positive circulating tumor cells in early breast cancer

The MAINTRAC technique as introduced by our coworkers from Jena (RBC lysis, fluorometric detection and analysis on Olympius ScanR) detects more circulating epithelial cells than techniques using enrichment. Also cells with a low EPCAM expression are detected and not only the typical cells with bright expression found after immunomagnetic enrichment. The relative cheapness and reproducibility allows frequent monitoring during and after therapy Using 3 colour detection (EPCAMfitc, DAPI, Vimentin PE) living and dead circulating epithelial cells in EMT, or cells in EMT with stemcell markers (EPCAMfitc, Vimentin-PE, CD44PacBlue) can be detected. In early breast cancer (n = 135) cells can be found in 60% of patients and in 40% higher cell counts (>100 ml are detectable. A control population(n = 100) showed low numbers in 98% (e.g (<100 CECin 1 ml blood). Expression of the mesenchymal marker (vimentin) ranges between 10 and 40% with different expression. CD44 shows also a wide range of expression. Two main cell types can be distinguished: type 1 shows generalized but weaker expression patterns and a second type with very bright dotted expression. The clinical relevance of these subsets is not known and their behavior under therapy has not been analysed in depth yet. In advanced breast cancers high cell counts were detectable in most patients with a less agressive disease course. In the rapidly progressing unfavorable subtypes (TN and Her2+. HRneg) less or none cells were found. During crossvalidation in non cancer patients we found high cell numbers in several forms of liver affections (n = 108). The expression patterns of markers on these cells were not differing from those in cancer patients. So this same cell type merging EMT, stemcell an hypoxic stress markers is detectable in advanced and early breast cancer (n = 40) and in benign disease. These cells disappear or decrease after response to chemo or anti-hormonal therapy in cancer or antioxidant therapy in NAFLD. We believe that the evasion of these cells is driven by the same force in cancer as in non cancer conditions. We suggest that this are the wellknown hypoxic and hyperacidic conditions causing epithelial mesenchymal transition. Cancer cell hijack this functions occurring normally under these conditions to survive and to facilitate evasion. More comprehensive analysis (four colour analysis on the AMNIS Flowsight) is needed and should show differences in expression patterns of liver derived epithelial cells (LDEC) and real tumor derived epithelial cells (TDEC). Further clarification of these phenomena should give new insights of the biological events in early disease and the possibilities and reliability of “fluid biopsy”.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-07-16.

Precautions for health care workers to avoid hepatitis B and C virus infection

The burden of exposure to blood-borne pathogens (such as hepatitis B and C viruses) is considerable for health care workers. Hepatitis virus transmission requires a non-immune host, an infectious source, and skin or mucous membrane injury. These three aspects are the main fields for preventional interventions. We reviewed major recent studies on this topic to identify precautions health care workers should take to avoid hepatitis B (HBV) and C virus (HCV) infections. Accordingly, this review looks at aspects of epidemiology, risk factors, economy, knowledge, attitudes, practice, and ethics of HBV and HCV that affect health care workers. The risk of transmission depends on the load of pathogen, infectious characteristics and exposure frequency. Health care workers skill levels and the specific hospital department involved appear to be the most important factors in the exposure of health care workers to blood-borne pathogens. However, many health care workers surveyed, believed that educational programs about standard precautions in their setting were not adequate. Obviously, more detailed studies will be needed to clarify risks and opportunities for health care workers precautions aimed at avoiding HBV and HCV infection, especially in emerging health research communities.