Davoud Asgari

Synthesis, characterization, and in vitro evaluation of novel polymer-coated magnetic nanoparticles for controlled delivery of doxorubicin.

Poly (N-isopropylacrylamide-methyl methacrylic acid, PNIPAAm-MAA)-grafted magnetic nanoparticles were synthesized using silane-coated magnetic nanoparticles as a template for radical polymerization of N-isopropylacrylamide and methacrylic acid. Properties of these nanoparticles, such as size, drug-loading efficiency, and drug release kinetics, were evaluated in vitro for targeted and controlled drug delivery. The resulting nanoparticles had a diameter of 100 nm and a doxorubicin-loading efficiency of 75%, significantly higher doxorubicin release at 40°C compared with 37°C, and pH 5.8 compared with pH 7.4, demonstrating their temperature and pH sensitivity, respectively. In addition, the particles were characterized by X-ray powder diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. In vitro cytotoxicity testing showed that the PNIPAAm-MAA-coated magnetic nanoparticles had no cytotoxicity and were biocompatible, indicating their potential for biomedical application.

Specific targeting of cancer cells by multifunctional mitoxantrone-conjugated magnetic nanoparticles

Abstract We report on the synthesis of bifunctional mitoxantrone (MTX)-grafted magnetic nanoparticles (MNPs) modified by dopamine-polyethylene glycol-folic acid (DPA-PEG-FA) for targeted imaging and therapy of cancer. MNPs (∼7–10 nm) were synthesized using the thermal decomposition reaction of Fe(acac)3. Bromoacetyl (BrAc) terminal polyethylene glycol dopamine (DPA-PEG-BrAc) was synthesized and treated with ethylene diamine to form bifunctional PEG moiety containing dopamine at one end and amino group at the other end (i.e. DPA-PEG-NH2). It was then reacted with Fe3O4 nanoparticles (NPs) to form Fe3O4-DPA-PEG-NH2 NPs. The activated folic acid (FA) was chemically coupled to Fe3O4-DPA-PEG-NH2, forming Fe3O4-DPA-PEG-FA. MTX was then conjugated to Fe3O4-DPA-PEG-FA, forming Fe3O4-DPA-PEG-FA-MTX. Physicochemical characteristics of the engineered MNPs were determined. The particle size analysis and electron microscopy showed an average size of ∼35 nm for Fe3O4-DPA-PEG-FA-MTX NPs with superparamagnetic behavior. FT-IR spectrophotometry analysis confirmed the conjugation of FA and MTX onto the MNPs. Fluorescence microscopy, cytotoxicity assay and flow cytometry analysis revealed that the engineered Fe3O4-DPA-PEG-FA-MTX NPs were able to specifically bind to and significantly inhibit the folate receptor (FR)-positive MCF-7 cells, but not the FR-negative A549 cells. Based upon these findings, we suggest the Fe3O4-DPA-PEG-FA-MTX NPs as an effective multifunctional-targeted nanomedicine toward simultaneous imaging and therapy of FR-positive cancers.

Targeted Fluoromagnetic Nanoparticles for Imaging of Breast Cancer MCF-7 Cells

PURPOSE To achieve simultaneous imaging and therapy potentials, targeted fluoromagnetic nanoparticles were synthesized and examined in human breast cancer MCF-7 cells. METHODS Fe3O4 nanoparticles (NPs) were synthesized through thermal decomposition of Fe(acac)3. Then, magnetic nanoparticles (MNPs) modified by dopamine-poly ethylene glycol (PEG)-NH2; finally, half equivalent fluorescein isothiocyanate (FITC) and half equivalent folic acid were conjugated to one equivalent of it. The presence of Fe3O4-DPA-PEG-FA/FITC in the folate receptor (FR) positive MCF-7 cells was determined via fluorescent microscopy to monitor the cellular interaction of MNPs. RESULTS FT-IR spectra of final compound confirmed existence of fluorescein on folic acid grafted MNPs. The Fe3O4-DPA-PEG-FA/FITC NPs, which displayed a size rang about 30-35 nm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were able to actively recognize the FR-positive MCF-7 cells, but not the FR-negative A549 cells. CONCLUSION The uniform nano-sized Fe3O4-DPA-PEG-FA/FITC NPs displayed great potential as theranostics and can be used for targeted imaging of various tumors that overexpress FR.

MODIFIED SYNTHESIS OF ERLOTINIB HYDROCHLORIDE

PURPOSE An improved and economical method has been described for the synthesis of erlotinib hydrochloride, as a useful drug in treatment of non-small-cell lung cancer. METHOD Erlotinib hydrochloride was synthesized in seven steps starting from 3, 4-dihydroxy benzoic acid. In this study, we were able to modify one of the key steps which involved the reduction of the 6-nitrobenzoic acid derivative to 6-aminobenzoic acid derivative. An inexpensive reagent such as ammonium formate was used as an in situ hydrogen donor in the presence of palladium/charcoal (Pd/C) instead of hydrogen gas at high pressure. RESULT This proposed method proceeded with 92% yield at room temperature. Synthesis of erlotinib was completed in 7 steps with overall yield of 44%. CONCLUSION From the results obtained it can be concluded that the modified method eliminated the potential danger associated with the use of hydrogen gas in the presence of flammable catalysts. It should be mentioned that the catalyst was recovered after the reaction and could be used again.

Synthesis, Characterization and in vitro Anti-Tumoral Evaluation of Erlotinib-PCEC Nanoparticles

BACKGROUND Development of a nanosized polymeric delivery system for erlotinib was the main objective of this research. MATERIALS AND METHODS Poly caprolactone-polyethylene glycol-polycaprolactone (PCEC) copolymers with different compositions were synthesized via ring opening polymerization. Formation of triblock copolymers was confirmed by HNMR as well as FT-IR. Erlotinib loaded nanoparticles were prepared by means of synthesized copolymers with solvent displacement method. RESULTS Physicochemical properties of obtained polymeric nanoparticles were dependent on composition of used copolymers. Size of particles was decreased with decreasing the PCL/PEG molar ratio in used copolymers. Encapsulation efficiency of prepared formulations was declined by decreasing their particle size. Drug release behavior from the prepared nanoparticles exhibited a sustained pattern without a burst release. From the release profiles, it can be found that erlotinib release rate from polymeric nanoparticles is decreased by increase of CL/PEG molar ratio of prepared block copolymers. Based on MTT assay results, cell growth inhibition of erlotinib has a dose and time dependent pattern. After 72 hours of exposure, the 50% inhibitory concentration (IC50) of erlotinib hydrochloride was appeared to be 14.8 μM. CONCLUSIONS From the obtained results, it can be concluded that the prepared PCEC nanoparticles in this study might have the potential to be considered as delivery system for erlotinib.

Simultaneous Determination of 6-Mercaptopurine and its Oxidative Metabolites in Synthetic Solutions and Human Plasma using Spectrophotometric Multivariate Calibration Methods

INTRODUCTION 6-Mercaptopurine (6MP) is an important chemotherapeutic drug in the conventional treatment of childhood acute lymphoblastic leukemia (ALL). It is catabolized to 6-thiouric acid (6TUA) through 8-hydroxo-6-mercaptopurine (8OH6MP) or 6-thioxanthine (6TX) intermediates. METHODS High-performance liquid chromatography (HPLC) is usually used to determine the contents of therapeutic drugs, metabolites and other important biomedical analytes in biological samples. In the present study, the multivariate calibration methods, partial least squares (PLS-1) and principle component regression (PCR) have been developed and validated for the simultaneous determination of 6MP and its oxidative metabolites (6TUA, 8OH6MP and 6TX) without analyte separation in spiked human plasma. Mixtures of 6MP, 8-8OH6MP, 6TX and 6TUA have been resolved by PLS-1 and PCR to their UV spectra. RESULTS Recoveries (%) obtained for 6MP, 8-8OH6MP, 6TX and 6TUA were 94.5-97.5, 96.6-103.3, 95.1-96.9 and 93.4-95.8, respectively, using PLS-1 and 96.7-101.3, 96.2-98.8, 95.8-103.3 and 94.3-106.1, respectively, using PCR. The NAS (Net analyte signal) concept was used to calculate multivariate analytical figures of merit such as limit of detection (LOD), selectivity and sensitivity. The limit of detections for 6MP, 8-8OH6MP, 6TX and 6TUA were calculated to be 0.734, 0.439, 0.797 and 0.482 μmol L-1, respectively, using PLS and 0.724, 0.418, 0783 and 0.535 μmol L-1, respectively, using PCR. HPLC was also applied as a validation method for simultaneous determination of these thiopurines in the synthetic solutions and human plasma. CONCLUSION Combination of spectroscopic techniques and chemometric methods (PLS and PCR) has provided a simple but powerful method for simultaneous analysis of multicomponent mixtures.

Synthesis and Cytotoxicity Evaluation of Some Novel 1-(3-Chlorophenyl)piperazin-2-one Derivatives Bearing Imidazole Bioisosteres

A series of substituted 3-chlorophenylpiperazinone derivatives were synthesised using L-778123 (an imidazole-containing FTase inhibitor) as a model by bioisosteric replacement of the imidazole ring. The final compounds were evaluated against two human cancer cell lines including A549 (lung cancer) and HT-29 (colon cancer) by MTT assay. The results showed that substitution of imidazole ring with 1-amidinourea, semicarbazide, and thiobiuret led to improvement of cytotoxic activity against both cell lines.

Synthesis of PCEC Copolymers with Controlled Molecular Weight Using Full Factorial Methodology.

PURPOSE Polycaprolactone (PCL) is a biodegradable polyester and has attracted attention as a suitable carrier for development of controlled drug delivery due to its non-toxicity and biocompatibility. It has been reported that the biodegradability of PCL can be enhanced by copolymerization with PEG. Molecular weight (Mw) and CL block lengths optimization in a series of synthesized PCEC copolymers was the main purpose of this study. METHODS The composition of copolymers was designed using full factorial methodology. Molecular weight of used PEG (4 levels) and weight ratio of epsilon-caprolactone/PEG (3 levels) were selected as independent variables. The PCEC copolymers were synthesized by ring opening polymerization. Formation of copolymers was confirmed by FT-IR spectroscopy as well as H-NMR. The Mn of PCEC copolymers was calculated from HNMR spectra. The thermal behavior of copolymers was characterized on differential scanning calorimeter. RESULTS Molecular weight of twelve synthesized copolymers was ranged from 1782 to 9264. In order to evaluate the effect of selected variables on the copolymers composition and Mw, a mathematical model for each response parameter with p-value less than 0.001were obtained. Average percent error for prediction of total Mn of copolymers and Mn of CL blocks were 13.81% and 14.88% respectively. CONCLUSION In conclusion, the proposed model is significantly valid due to obtained low percent error in Mn prediction of test sets.

Study of aldehyde oxidase-catalyzed metabolic pathway of phenanthridine using MCR-ALS method.

Evaluation of metabolic pathways is one of the challenging areas in biological and pharmaceutical sciences. Phenanthridine oxidation to phenanthridinone is used commonly to study aldehyde oxidase activity. This reaction could pass through phenanthridine N-oxide intermediate. In the present study, the application of multivariate curve resolution, optimized by alternating least squares (MCR-ALS) to investigate this metabolic pathway has been described. The results obtained from MCR-ALS analysis along with those obtained from the use of potassium ferrocyanide method indicated that phenanthridine is directly oxidized to phenanthridinone by rat liver aldehyde oxidase without passing through phenanthridine N-oxide intermediate. It was also found that the later compound is not metabolized by this enzyme.

Nafion-coated cadmium pentacyanonitrosylferrate-modified glassy carbon electrode for detection of dopamine in biological samples

Introduction: Dopamine is one of the key neurotransmitters (NTs) in nature, which plays a crucial role in the mammalian central nervous system (CNS). Its selective determination in the biological fluids is an essential need in the field of biomedicine studies. Methods: In this work, an amperometric sensor was developed using Nafion-coated cadmium pentacyanonitrosylferrate (CdPCNF) modified glassy carbon (GC) electrode (Nafion|CdPCNF|GC electrode) as an electrocatalyst to detect dopamine (DA) in human serum samples. To develop this sensor, the surface of bare GC electrode was coated with the film of CdPCNF through an electropolymerization method and then the modified electrode was coated with Nafion to minimize interferences, especially those arising from the presence of anionic compounds. The electrocatalytic behavior of the modified electrodes was studied using the cyclic voltammetry and amperometry, and then the ability of the sensor for the determination of DA in synthetic and biological samples was investigated. Results: The modified electrode was showed a significant electrocatalytic activity for the oxidation of DA at pH 7.4. The limit of detection (LOD) was 0.7 µM and also no interference effects arose from ascorbic acid (AA), uric acid (UA) or the other biological NTs was observed in the DA detection using the modified Nafion|CdPCNF|GC electrode. Conclusion: In comparison with the bare electrode, the Nafion|CdPCNF|GC electrode could determine DA in the biological samples with adequate sensitivity and selectivity. Therefore, we propose that the modified electrode is utilizable as an amperometric DA sensor for the biological sample analysis.