Novel magnetic embolic MRI imageable particles with anticancer drug release for transcatheter arterial embolization and magnetic ablation.

The aim of the study is to prepare embolic hydroxyl ethyl cellulose (HEC)-polyvinyl prolidone (PVP)-magnetic particles suitable for transcatheter arterial chemoembolization (TACE) procedures, drug delivery, and magnetic hyperthermia. Two different sizes (microsized and nanosized) of iron oxide particles were used to prepare the embolic particles to investigate the embolization and drug delivery properties. Iron oxides were linked with PVP via bridging flocculation process, then outermost layer of the linked particles was coated with HEC in order to load drugs to particles and reach size requirements for a successful TACE procedure. Size of each particle was calibrated to the range that allows easy injections through microcatheters (40-500 µm). The results showed that the size of the final embolic particles reached around 70 µm with 82 W/g specific absorption rate (SAR) values for nano-iron oxide particles and 45 µm with 77 W/g SAR values for micro-iron oxide particles, which are quite suitable for TACE applications. Furthermore, an anticancer drug doxorubicin (DOX) was successfully loaded onto these particles in order to achieve localized chemotherapy at the tumor site. Particles produced in this study, loaded DOX successfully and prolonged drug release time, performed similarly to pure DOX at higher concentration treatments against human breast cancer cell lines, were heatable under applied alternating magnetic fields. In addition, in vivo embolization studies performed using a rabbit renal embolization model, indicated that these particles were easily delivered through microcatheters and were able to embolize the target.

Raw and Purified Clay Minerals for Drug Delivery Applications.

In this study, the aim was to prepare drug-releasing clay mineral particles using raw (CaMt) and purified (PMt) montmorillonite and to compare and determine the effects of purification on the properties of montmorillonite. Montmorillonite clay minerals are used in several pharmaceutical and cosmetic products due to their many favorable properties, such as cation exchange capacity, adsorption capability, high specific surface area, and biocompatibility. Recently, several types of clay minerals have been widely studied for drug delivery applications due to their unique properties. The purification of montmorillonite is considered as a potentially useful step which may decrease the toxicity of impurities but which may increase the adsorption capacity of the montmorillonite. However, the effects on the toxicity and drug-release properties of purified montmorillonite have never been compared to that of raw montmorillonite. Montmorillonite was purified through decomposition of carbonates, dissolution of hydroxides, oxidation of organic materials, dialysis, and sedimentation. The raw and the purified montmorillonite were characterized using XRD, FTIR, and cation exchange capacities. Then, the cytotoxicity of raw and purified montmorillonite on normal hFOB cells was investigated to assess their biocompatibility in vitro. Finally, the efficacy of montmorillonite as a drug-delivering agent was investigated in vitro using cytotoxicity assays with the MCF7 cell line. The antitumor drug doxorubicin was loaded onto particles through electrostatic forces at 97.99% for CaMt and 96.79% for PMt. The drug-loading efficiency and release behavior of both clay minerals were determined. Results showed that both raw and purified montmorillonite did not significantly reduce the viability of normal cells at low concentrations (<500 µg/mL). At high concentrations, both raw and purified montmorillonite showed significant toxicity and the effect of impurities on toxicity were also more pronounced. Although drug loading was successful for both clay minerals there were differences in their controlled drug-release behavior. Doxorubicin-loaded raw and purified clay minerals significantly reduced MCF7 cell viability similar to pure DOX.

Comparison of ionic polymers in the targeted drug delivery applications as the coating materials on the Fe3O4 nanoparticles.

The objective of the study was to obtain multifunctional core shell nanostructures of superparamagnetic iron oxide nanoparticles (Fe3O4) coated with various ionic biopolymers that can optimize toxicity to healthy cells, colloidal instabilities and drug loading capacities. These nanostructures can also allow drug delivery to tumor tissue because of their magnetic properties, accumulation and drug release at tumor site could be controlled by means of an external magnetic field. The impact of the biopolymers with different ionic properties to final core shell structures were investigated and compared in terms of their colloidal properties, cytotoxicities, drug adsorption and drug delivery capacities. Besides, the effect of the surface charges on the healthy cells and cancer cells is very important factor affecting toxicity and drug delivery. The results showed that the drug delivery agents coated with cationic biopolymers with cationic surface properties significantly reduced cancer cell viability compared to the anionic and nonionic polymer coatings even though their drug loading capacities were found to be the lowest.

Colloidal properties and in vitro evaluation of Hydroxy ethyl cellulose coated iron oxide particles for targeted drug delivery.

In this study, superparamagnetic iron oxide (Fe3O4) nanoparticles were prepared for the targeted drug delivery applications by controlling the colloidal properties with a cellulosic polymer that is Hydroxy ethyl cellulose (HEC). Fe3O4 particles were treated with HEC in a variable range of polymer concentration. Rheological, electrokinetic, magnetorheological and morphological properties of the dispersions were investigated to have stable and fully covered surfaces of Fe3O4 particles by coating with HEC and obtaining non-toxic biocompatible multifunctional magnetic particles. Fully coated HEC and iron-oxide particles were characterized thermally, magnetically and tested for toxicity in vitro. Then Doxorubicin hydrochloride (DOX), which is an anticancer drug widely used for cancer therapies, was loaded onto nanoparticles and their drug loading efficiency was determined. Finally, effects of DOX-loaded particles on the cancer cells were examined to report a nano drug system which can potentially open up new possibilities in the design of therapeutic agents. Results indicated that the synthesized nanoparticles in this study could be suitable to magnetically manipulated targeted delivery systems, imaging, magnetic hyperthermia treatments.

Effect of cationic surfactant adsorption on the rheological and surface properties of bentonite dispersions.

In this study, the adsorption, bridging, and intercalation effects of a cationic surfactant, benzyldimethyltetradecyl ammonium chloride (BDTDACl), on bentonite clay suspensions was investigated. The adsorption, rheological behaviors, and colloidal properties of the clay dispersions were determined as a function surfactant concentration. Adsorption isotherms were obtained using the batch-equilibrium technique. The rheological behavior of the clay suspensions was obtained by shear stress-shear rate measurements within 0-350 s-1 shear rates. The structure of the composite particles was analyzed by using X-ray diffraction analysis and it was found that the expansions of basal d-spacings are less than 16.80 A, suggesting a monolayer structure.