Aspects of the degradation kinetics of doxorubicin in aqueous solution

Synthesis of targeted doxorubicin-loaded gold nanorod -mesoporous manganese dioxide core-shell nanostructure for ferroptosis, chemo-photothermal therapy in vitro and in vivo

In the current study, a core-shell inorganic nanostructure comprising a gold nanorod core and -mesoporous manganese dioxide shell was synthesized. Then, the mesoporous manganese dioxide shell was loaded with doxorubicin (DOX) and then coated with pluronic F127 and pluronic F127-folic acid conjugate (1.5:1 wt ratio of pluronic F127: pluronic F127-folic acid conjugate) to prepare targeted final platform. In this design, mesoporous manganese dioxide acted as a reservoir for DOX loading, anti-hypoxia, and MRI contrast agent, while the gold nanorod core acted as a photothermal and CT scan imaging agent. DOX was encapsulated in the mesoporous manganese dioxide shell with a loading capacity and loading efficiency of 19.8 % ± 0.2 and 99.0 % ± 0.9, respectively. The in vitro release experiment showed the impact of glutathione (GSH), mildly acidic pH, and laser irradiating toward accelerated stimuli-responsive DOX release. The ·OH production of the prepared platform was verified by methylene blue (MB) decomposition reaction. Furthermore, thermal imaging exhibited the ability of the prepared platform to convert the NIR irradiation to heat. In vitro cytotoxicity tests on the folate receptor-positive 4 T1 cell line revealed the remarkable cytotoxicity of the targeted formulation compared to the nontargeted formulation (statistically significant). The MTT experiment demonstrated that exposure to laser 808 irradiation enhanced cytotoxicity of the targeted formulation (p < 0.0001). The production of ROS in 4 T1 cells following treatment with the targeted formulation was demonstrated by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. Furthermore, in vivo investigations by implementing subcutaneous 4 T1 tumorized female BABL/c mice indicated that the prepared platform was an effective system in suppressing tumor growth by combining chemotherapy with PTT (photothermal therapy). Additionally, simultanous PTT and anti-hypoxic activity of this system showed potent tumor growth suppression impact. The percent of tumor size reduction in mice treated with FA-F127-DOX@Au-MnO2 + 808 nm laser compared to the control group was 99.7 %. The results of the biodistribution investigation showed tumor accumulation and modified pharmacokinetics of the targeted system. Lastly, 6 and 24 h post-intravenous injection, CT-scan and MR imagings capability of the prepared platform was verified in preclinical stage. The prepared multipurpose system introduces great opportunity to provide multiple treatment strategy along with multimodal imaging capability in a single platform for breast cancer treatment.

Interactions of a Novel Anthracycline with Oligonucleotide DNA and Cyclodextrins in an Aqueous Environment

Berubicin, a chemotherapy medication belonging to the class of anthracyclines, is simulated in double-stranded DNA sequences and cyclodextrins in an aqueous environment via full-atom molecular dynamics simulations on the time scale of microseconds. The drug is studied in both the neutral and protonated states so as to better comprehend the role of its charge in the formed complexes. The noncovalent berubicin-DNA and berubicin-cyclodextrin complexes are investigated in detail, paying special attention to their thermodynamic description by employing the double decoupling method, the solvent balance method, the weighted solvent accessible surface model, and the linear interaction energy method. A novel approach for extracting the desolvation thermodynamics of the binding process is also presented. Both the binding and desolvation Gibbs energies are decomposed into entropic and enthalpic contributions so as to elucidate the nature of complexation and its driving forces. Selected structural and geometrical properties of all the complexes, which are all stable, are analyzed. Both cyclodextrins under consideration are widely utilized for drug delivery purposes, and a comparative investigation between their bound states with berubicin is carried out.

Supermolecule—Drug Conjugates Based on Acid-Degradable Polyrotaxanes for pH-Dependent Intracellular Release of Doxorubicin

Doxorubicin (DOX)-conjugated acid-degradable polyrotaxanes (PRXs) were designed as supramolecular drug carriers capable of releasing drugs in acidic cellular environments. Acid-degradable PRXs composed of α-cyclodextrin (α-CD) as a cyclic molecule, poly(ethylene glycol) (PEG) as a polymer axis, and N-triphenylmethyl (N-Trt) groups as an acid-labile stopper molecules were synthesized and DOX was conjugated with the threaded α-CDs in the PRXs. Because the acid-induced cleavage of N-Trt groups in PRXs leads to PRX dissociation, the DOX-modified α-CDs were released under acidic conditions (pH 5.0). The cytotoxicity of DOX-conjugated PRXs in colon-26 cells revealed significant cell death for DOX-conjugated PRXs after 48 h of treatment. Confocal laser scanning microscopy (CLSM) analysis revealed that the fluorescence signals derived from DOX-conjugated PRXs were observed in cellular nuclei after 48 h, suggesting that the DOX-modified α-CDs were released and accumulated in cellular nuclei. These results confirmed that acid-degradable PRXs can be utilized as drug carriers capable of releasing drug-modified α-CDs in acidic lysosomes and eliciting cytotoxicity. Overall, acid-degradable PRXs represent a promising supramolecular framework for the delivery and intracellular release of drug-modified α-CDs, and PRX–drug conjugates are expected to contribute to the development of pH-responsive drug carriers for cancer therapy.

Designing an "all-in-one" microextraction capsule device for the liquid chromatographic-fluorescence determination of doxorubicin and its metabolites in rat plasma

In this study, an "all-in-one" microextraction device was designed and fabricated for the extraction of doxorubicin and its two metabolites from rat plasma prior to their determination by high performance liquid chromatography coupled to fluorescence detector. A sol-gel-based sorbent was synthesized in situ and incorporated within two conjoined porous polypropylene tubes together with a cylindrical magnetic bar in order to avoid the need of an external stirring bar. Among other sorbents investigated, the moderately polar sol-gel poly(tetrahydrofuran) was found to be advantageous due to its high affinity toward the target analytes. Systematic investigation of the critical parameters affecting the adsorption and the desorption step was carried out. Due to the "built-in" filtration mechanism of the porous microextraction capsules, the isolation of the analytes was performed directly in the plasma matrix without any previous sample pretreatment (i.e., protein precipitation, centrifugation, etc.). The proposed method was validated in terms of linearity, accuracy, precision, specificity, sensitivity, and stability according to the FDA guidelines. The limits of detection ranged between 1 - 2 ng mL^-1 while the lower limits of quantitation of the analytes were calculated as 10 ng mL^-1. The accuracy (% relative error) was found within -9.7 - 15.3% under both intra- and inter-day conditions. The precision was better than 13.4% in all cases. ComplexGAPI index was employed to present the green attributes of the developed protocol from the preparation of the microextraction device to the final determination of the analytes. Finally, the applicability of the fabricated stand-alone extraction device was demonstrated in the analysis of the target analytes in rat plasma after intravenous administration of doxorubicin in order to assess its pharmacokinetic profile.

Engineered Protein-Iron Oxide Hybrid Biomaterial for MRI-traceable Drug Encapsulation

Labeled protein-based biomaterials have become a popular for various biomedical applications such as tissue-engineered, therapeutic, or diagnostic scaffolds. Labeling of protein biomaterials, including with ultrasmall super-paramagnetic iron oxide (USPIO) nanoparticles, has enabled a wide variety of imaging techniques. These USPIO-based biomaterials are widely studied in magnetic resonance imaging (MRI), thermotherapy, and magnetically-driven drug delivery which provide a method for direct and non-invasive monitoring of implants or drug delivery agents. Where most developments have been made using polymers or collagen hydrogels, shown here is the use of a rationally designed protein as the building block for a meso-scale fiber. While USPIOs have been chemically conjugated to antibodies, glycoproteins, and tissue-engineered scaffolds for targeting or improved biocompatibility and stability, these constructs have predominantly served as diagnostic agents and often involve harsh conditions for USPIO synthesis. Here, we present an engineered protein-iron oxide hybrid material comprised of an azide-functionalized coiled-coil protein with small molecule binding capacity conjugated via bioorthogonal azide-alkyne cycloaddition to an alkyne-bearing iron oxide templating peptide, CMms6, for USPIO biomineralization under mild conditions. The coiled-coil protein, dubbed Q, has been previously shown to form nanofibers and, upon small molecule binding, further assembles into mesofibers via encapsulation and aggregation. The resulting hybrid material is capable of doxorubicin encapsulation as well as sensitive T₂*-weighted MRI darkening for strong imaging capability that is uniquely derived from a coiled-coil protein.

Laccase–TEMPO as an Efficient System for Doxorubicin Removal from Wastewaters

A large number of drugs are used to treat different diseases, and thus to improve the quality of life for humans. These represent a real ecological threat, as they end up in soil or ground waters in amounts that can affect the environment. Among these drugs, doxorubicin is a highly cytotoxic compound used as anticancer medicine. Doxorubicin can be efficiently removed from wastewater or polluted water using a simple enzymatic (biocatalytic) system, employing the oxidoreductase enzyme laccase and a stable organic nitroxide-free radical, TEMPO. Results presented in this work (as percentage of removal) were obtained at pH 5 and 7, after 2, 4, 6, and 24 h, using different ratios between doxorubicin, laccase, and TEMPO. It was shown that longer time, as well as an increased amount of catalyst, led to a higher percentage of removal, up to 100%. The influence of all these parameters is also discussed. In this way it was shown that the laccase–TEMPO biocatalytic system is highly efficient in the removal of the anticancer drug doxorubicin from wastewaters.

The anticancer activity of doxorubicin-loaded levan-functionalized gold nanoparticles synthesized by laser ablation

Here, gold nanoparticles (AuNPs) were synthesized upon exposure to nano-pulsed Nd-YAG laser irradiation in de-ionized water (PLAL) and functionalized with levan polysaccharide for assessing the anticancer efficacy of doxorubicin (DOX)-conjugated levan-capped AuNPs complexes to MCF-7 breast cancer cells. According to the physicochemical test results, the increments in levan amount enhanced the colloidal stability and the drug encapsulation efficiency (DEE) significantly. For the 10L-AuNP group having the highest levan amount (10 mg/mL levan), DEE was calculated as 92.21 ± 0.56%. The lean levan, uncapped AuNPs, and 10L-AuNP were found non-cytotoxic (>80% cell viability) in the studied concentrations with 48 h MTT assays. At higher DOX loadings (25, 50, and 100 μg/mL) of 10L-AuNP, the cell viability reduced significantly compared to free DOX. Overall, these nanoparticle complexes could be proposed as potent drug delivery vehicles for cancer drugs such as DOX, as well as other drugs in the prospective studies.

Porous Au-Ag Nanoparticles from Galvanic Replacement Applied as Single-Particle SERS Probe for Quantitative Monitoring

Plasmonic nanostructures have raised the interest of biomedical applications of surface-enhanced Raman scattering (SERS). To improve the enhancement and produce sensitive SERS probes, porous Au-Ag alloy nanoparticles (NPs) are synthesized by dealloying Au-Ag alloy NP-precursors with Au or Ag core in aqueous colloidal environment through galvanic replacement reaction. The novel designed core-shell Au-Ag alloy NP-precursors facilitate controllable synthesis of porous nanostructure, and dealloying degree during the reaction has significant effect on structural and spectral properties of dealloyed porous NPs. Narrow-dispersed dealloyed NPs are obtained using NPs of Au/Ag ratio from 10/90 to 40/60 with Au and Ag core to produce solid core@porous shell and porous nanoshells, having rough surface, hollowness, and porosity around 30-60%. The clean nanostructure from colloidal synthesis exhibits a redshifted plasmon peak up to near-infrared region, and the large accessible surface induces highly localized surface plasmon resonance and generates robust SERS activity. Thus, the porous NPs produce intensely enhanced Raman signal up to 68-fold higher than 100 nm AuNP enhancement at single-particle level, and the estimated Raman enhancement around 7800, showing the potential for highly sensitive SERS probes. The single-particle SERS probes are effectively demonstrated in quantitative monitoring of anticancer drug Doxorubicin release.

A rapid and simple electrochemical detection of the free drug concentration in human serum using boron-doped diamond electrodes

Monitoring drug concentration in blood and reflecting this in the dosage are crucial for safe and effective drug treatment.

Individual and mixed effects of anticancer drugs on freshwater rotifers: A multigenerational approach

Human population growth has led to an increased release of chemical contaminants into aquatic environments. Emerging chemical contaminants (ECCs) are of increasing concern because they can affect non-target organisms in aquatic ecosystems. The application of anticancer drugs is increasing because of enhanced cancer rates and use of chemotherapy. We assessed the impacts of two widely used anticancer drugs known for their distinct modes of action, namely 5-fluorouracil (5-FU) and doxorubicin (DOX), on the freshwater rotifer Brachionus calyciflorus across generations. Rotifer mortality (24 h) and population growth (48 h) were assessed to determine initial lethal and sub-lethal effects. Exposure of rotifers to 5-FU (up to 200 mg L^-1) did not cause mortality, while DOX caused mortality at high concentrations (EC₅₀ = 15.6 mg L^-1). Effects of 5-FU on population growth rate was higher than DOX (5-FU EC₅₀ =10.49 µg L^-1, DOX EC₅₀ = 8.78 mg L^-1). The effects of the drugs in binary mixture on population growth rates were dose dependent; significant antagonistic effects were found when 5-FU was present in the mixture at high concentrations. Finally, a transgenerational assay for five generations revealed that rotifers were able to recover their population growth rate after fourth generation when exposed to 5-FU; however, population became non-viable after the second generation of exposure to DOX. At the cellular level, accumulation of reactive oxygen species and plasma membrane damage were observed at EC₁₀ and increased at EC₅₀ for both drugs. After exposure of rotifers to 5-FU across generations, there were signs of oxidative stress recovery, as shown by a decrease in ROS accumulation and plasma membrane damage. Our results showed for the first time that the adverse effects of anticancer drugs on freshwater rotifer populations are drug and dose dependent and can persist or be attenuated along generations.

Thermoresponsive Chitosan-Grafted-Poly(N-vinylcaprolactam) Microgels via Ionotropic Gelation for Oncological Applications

Microgels can be considered soft, porous and deformable particles with an internal gel structure swollen by a solvent and an average size between 100 and 1000 nm. Due to their biocompatibility, colloidal stability, their unique dynamicity and the permeability of their architecture, they are emerging as important candidates for drug delivery systems, sensing and biocatalysis. In clinical applications, the research on responsive microgels is aimed at the development of "smart" delivery systems that undergo a critical change in conformation and size in reaction to a change in environmental conditions (temperature, magnetic fields, pH, concentration gradient). Recent achievements in biodegradable polymer fabrication have resulted in new appealing strategies, including the combination of synthetic and natural-origin polymers with inorganic nanoparticles, as well as the possibility of controlling drug release remotely. In this review, we provide a literature review on the use of dual and multi-responsive chitosan-grafted-poly-(N-vinylcaprolactam) (CP) microgels in drug delivery and oncological applications.

An Electrochemical Strategy for the Simultaneous Detection of Doxorubicin and Simvastatin for Their Potential Use in the Treatment of Cancer

The aim of this study was to develop a disposable, simple, fast, and sensitive sensor for the simultaneous electrochemical detection of doxorubicin (DOX) and simvastatin (SMV), which could be used in preclinical studies for the development of new pharmaceutical formulations for drug delivery. Firstly, the electrochemical behavior of each molecule was analyzed regarding the influence of electrode material, electrolyte solution, and scan rate. After this, the proper electrode material, electrolyte solution, and scan rate for both active substances were chosen, and a linear sweep voltammetry procedure was optimized for simultaneous detection. Two chronoamperometry procedures were tested, one for the detection of DOX in the presence of SMV, and the other one for the detection of DOX and SMV together. Finally, calibration curves for DOX and SMV in the presence of each other were obtained using both electrochemical methods and the results were compared. The use of amperometry allowed for a better limit of detection (DOX: 0.1 μg/mL; SMV: 0.7 μg/mL) than the one obtained in voltammetry (1.5 μg/mL for both drugs). The limits of quantification using amperometry were 0.5 μg/mL for DOX (dynamic range: 0.5-65 μg/mL) and 2 μg/mL for SMV (dynamic range: 2-65 μg/mL), while using voltammetry 1 μg/mL was obtained for DOX (dynamic range: 1-100 μg/mL) and 5 μg/mL for SMV (dynamic range: 5-100 μg/mL). This detection strategy represents a promising tool for the analysis of new pharmaceutical formulations for targeted drug delivery containing both drugs, whose association was proven to bring benefits in the treatment of cancer.

A novel method to detect intracellular metabolite alterations in MCF-7 cells by doxorubicin induced cell death

BACKGROUND

Metabolic reprogramming within cancer cells has been recognized as a potential barrier to chemotherapy. Additionally, metabolic tumor heterogeneity is the one of factors behind discernible hallmarks such as drug resistance, relapse of the tumor and the formation of secondary tumors.

METHODS

In this paper, cell-based assays including PI/annexin V staining and immunoblot assay were performed to show the apoptotic cell death in MCF-7 cells treated with DOX. Further, MCF-7 cells were lysed in a hypotonic buffer and the whole cell lysate was purified by a novel and specifically designed metabolite (~ 100 to 1000 Da) fractionation system called vertical tube gel electrophoresis (VTGE). Further, purified intracellular metabolites were subjected to identification by LC-HRMS technique.

RESULTS

Cleaved PARP 1 in MCF-7 cells treated with DOX was observed in the present study. Concomitantly, data showed the absence of active caspase 3 in MCF-7 cells. Novel findings are to identify key intracellular metabolites assisted by VTGE system that include lipid (CDP-DG, phytosphingosine, dodecanamide), non-lipid (N-acetyl-D-glucosamine, N1-acetylspermidine and gamma-L-glutamyl-L-cysteine) and tripeptide metabolites in MCF-7 cells treated by DOX. Interestingly, we reported the first evidence of doxorubicinone, an aglycone form of DOX in MCF-7 cells that are potentially linked to the mechanism of cell death in MCF-7 cells.

CONCLUSION

This paper reported novel methods and processes that involve VTGE system based purification of hypotonically lysed novel intracellular metabolites of MCF-7 cells treated by DOX. Here, these identified intracellular metabolites corroborate to caspase 3 independent and mitochondria induced apoptotic cell death in MCF-7 cells. Finally, these findings validate a proof of concept on the applications of novel VTGE assisted purification and analysis of intracellular metabolites from various cell culture models.

Bioanalysis of doxorubicin aglycone metabolites in human plasma samples-implications for doxorubicin drug monitoring

The widespread clinical use of the cytostatic doxorubicin together with the induction of chronic cardiomyopathy necessitates the conduct of further pharmacokinetic trials. Novel analytical technologies suitable for point-of-care applications can facilitate drug level analyses but might be prone to interferences from structurally similar compounds. Besides the alcohol metabolite doxorubicinol, aglycone metabolites of doxorubicin might affect its determination in plasma. To evaluate their analytical relevance, a validated HPLC method for the quantification of doxorubicin, doxorubicinol and four aglycones was used. The degradation pattern of doxorubicin in plasma under long-term storage was analysed with respect to the formation of aglycone products. In addition, overall 50 clinical samples obtained within the EPOC-MS-001-Doxo trial were analysed. Substantial degradation of doxorubicin in plasma occurred within a storage period of one year, but this did not lead to the formation of aglycones. In clinical samples, 7-deoxydoxorubicinolone was the major aglycone detectable in 35/50 samples and a concentration range of 1.0–12.7 µg L⁻¹. If at all, the other aglycones were only determined in very low concentrations. Therefore, analytical interferences from aglycones seem to be unlikely with the exception of 7-deoxydoxorubicinolone whose concentration accounted for up to 65% of the doxorubicin concentration in the clinical samples analysed.

Impact of Medium pH on DOX Toxicity toward HeLa and A498 Cell Lines

The influence of the pH of the multicomponent cell medium on the performance of doxorubicin (DOX), an anticancer drug, was studied on the examples of cervical (HeLa) and kidney (A498) cancer cell lines. The change of pH of the cell medium to more acidic led to a decrease of DOX toxicity on both cell lines due to the change of drug permeability across the cell membrane as a result of drug protonation. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) studies and lactate dehydrogenase (LDH) release tests have shown low toxicity of the drug, especially in the case of A498 cells, which are characterized by an extremely high glycolytic metabolism. The behavior was ascribed primarily to the increased proton concentration in the peripheral blood follicle in the presence of products of the acidic glycolytic metabolism. It is not observed in the measurements performed in commercially available media since they usually have a neutral pH. In earlier reports on kidney cancer, several mechanisms were discussed, including the metabolism of DOX to its less toxic derivative, doxorubicinol, overexpression of ATP binding cassette subfamily B member 1 (ABCB1) transporters, that remove DOX from the inside of cells; however, there was no focus on the simple but very important contribution of drug protonation described in the present study. Drug pH-dependent equilibria in the cell medium should be considered since changes in the drug form may be an additional reason for multidrug resistance.

Eu-Doped Citrate-Coated Carbonated Apatite Luminescent Nanoprobes for Drug Delivery

In the field of Nanomedicine, there is an increasing demand for new inorganic nanophosphors with low cytotoxicity and efficient loading-release ability of drugs for applications in bioimaging and drug delivery. This work assesses the potentiality of matured Eu-doped citrate-coated carbonated apatite nanoparticles to be used as theranostic platforms, for bioimaging, as luminescent nanoprobes, and for drug delivery applications, using Doxorubicin as a model drug. The drug adsorption isotherm fits the Langmuir-Freundlich (LF) model, showing that the Eu:cit-cAp nanoparticles can carry a maximum of 0.29 ± 0.02 mg Doxo mg Eu:cit-cAp-1 (Qmax). The affinity constant KFL for this binding is 44 ± 2 mL mg-1, and the cooperativity coefficient r is 6 ± 1. The nanoparticle suspensions presented charge reversion from negative to positive after loading with Doxo as revealed by the ζ-potential versus pH characterization. The release of drug from the loaded nanoparticles was found to be strongly pH-dependent, being around 5 wt % at physiological pH 7.4 and 20 wt % at pH 5, in experiments lasting 24 h. Luminescence spectroscopic measurements of Doxo-loaded nanoparticles revealed the increase of luminescence with a decrease in the amount of adsorbed Doxo, due to the so-called inner filter effect. The nanoparticles free of Doxo were cytocompatible when interacted with two human cell lines derived respectively from a gastric carcinoma (GTL-16), and a hepatocarcinoma (Huh7), while Doxo-loaded nanoparticles displayed significant toxicity in a dose-dependent relationship. Therefore, the new nanoassemblies might have a dual function, as nanoprobes in bioimaging by detecting the fate of the nanoparticles in biological environments, and for monitoring the delivery of the drug in such environments, by measuring the rise of the luminescence provided by the desorption of Doxo.

Doxorubicin-loaded PLGA nanoparticles for the chemotherapy of glioblastoma: Towards the pharmaceutical development

Brain delivery of drugs by nanoparticles is a promising strategy that could open up new possibilities for the chemotherapy of brain tumors. As demonstrated in previous studies, the loading of doxorubicin in poly(lactide-co-glycolide) nanoparticles coated with poloxamer 188 (Dox-PLGA) enabled the brain delivery of this cytostatic that normally cannot penetrate across the blood-brain barrier in free form. The Dox-PLGA nanoparticles produced a very considerable anti-tumor effect against the intracranial 101.8 glioblastoma in rats, thus representing a promising candidate for the chemotherapy of brain tumors that warrants clinical evaluation. The objective of the present study, therefore, was the optimization of the Dox-PLGA formulation and the development of a pilot scale manufacturing process. Optimization of the preparation procedure involved the alteration of the technological parameters such as replacement of the particle stabilizer PVA 30-70 kDa with a presumably safer low molecular mass PVA 9-10 kDa as well as the modification of the external emulsion medium and the homogenization conditions. The optimized procedure enabled an increase of the encapsulation efficiency from 66% to >90% and reduction of the nanoparticle size from 250 nm to 110 nm thus enabling the sterilization by membrane filtration. The pilot scale process was characterized by an excellent reproducibility with very low inter-batch variations. The in vitro hematotoxicity of the nanoparticles was negligible at therapeutically relevant concentrations. The anti-tumor efficacy of the optimized formulation and the ability of the nanoparticles to penetrate into the intracranial tumor and normal brain tissue were confirmed by in vivo experiments.

Doxorubicin - chitosan - hydroxyapatite composite coatings on titanium alloy for localized cancer therapy

The doxorubicin-chitosan composite is deposited electrochemically on the Ti alloy post hydroxyapatite coated for reducing the side effects by sustaining release of drugs localized near the tumor to achieve the inhibition or apoptosis of cancer. The possibility of danger in case of exfoliation of medicine composite and HA agglomerates from the alloy surface due to the dynamic erosion of blood flow could be overcome with the additional surface modification by the electrochemical deposition way. The cathodic polarization tests coupled with electrochemical reactions were analyzed to speculate the deposition mechanism of doxorubicin, spectrophotometer (UV visible spectrometer) to measure doxorubicin loading and release, field emission scanning electron microscope (FESEM) to observe surface morphology, Fourier transform infrared (FTIR) spectroscopy for chemical bonding of composites, and X-ray diffractometry (XRD) for crystal structure. The cell culture was carried out to analyze the drug efficacy on cell viability. It is concluded that doxorubicin-chitosan composites can be successfully deposited on the uncoated and hydroxyapatite-coated titanium specimen alloy by electrochemical methods. Both have revealed the sustaining drug release for a month and the latter with high porosity can enhance the drug loading to 37.46 μg/cm², revealing this electrochemical method is a practical way to load doxorubicin cancer drug releasing locally to significantly reduce the amount of medication needed for future clinical applications.

Photo-oxidative degradation of doxorubicin with siloxane MOFs by exposure to daylight

Doxorubicin (DOX) is a chemotherapeutic agent from anthracycline class, which acts unselectively on all cells; thus, it may have genotoxic and/or mutagenic effects and cause serious environmental problems. Herein, the decomposition of a diluted solution of DOX hydrochloride for injection has been investigated under photo-oxidative conditions, in ambient light and without pH modification, using hydrogen peroxide as oxidizing agent and hydrophobic siloxane-based metal-organic frameworks (MOFs) as heterogeneous catalysts. The kinetics of the photodegradation process was followed by UV-Vis spectroscopy and by ESI-MS. According to UV-Vis data, two pseudo-first-order kinetic steps describe the process, with rate constants in the order of 10^-3-10^-2 min^-1 for the rate-determining one. ESI-MS provided more accurate information, with a rate constant of 2.6 · 10^-2 min^-1 calculated from the variation of DOX ion abundance. Complete decomposition of DOX was achieved after 120 min in the shade and after only 20 min by exposure to sunlight. The analysis of the residual waters by mass spectrometry and 1D and 2D NMR spectroscopy showed complete disappearance of DOX in all cases, excluded any anthracycline species, which are destroyed in the tested conditions, and proved formation of an un-harmful compound-glycerol, while no trace of metal was detected by XRF. Preliminary data also showed decomposition of oxytetracycline in similar conditions. By this study, we bring into attention a less-addressed pollution issue and we propose a mild and effective method for the removal of drug emerging pollutants.

pH-Dependent Adsorption Release of Doxorubicin on MamC-Biomimetic Magnetite Nanoparticles

New biomimetic magnetite nanoparticles (hereafter BMNPs) with sizes larger than most common superparamagnetic nanoparticles were produced in the presence of the recombinant MamC protein from Magnetococcus marinus MC-1 and functionalized with doxorubicin (DOXO) intended as potential drug nanocarriers. Unlike inorganic magnetite nanoparticles, in BMNPs the MamC protein controls their size and morphology, providing them with magnetic properties consistent with a large magnetic moment per particle; moreover, it provides the nanoparticles with novel surface properties. BMNPs display the isoelectric point at pH 4.4, being strongly negatively charged at physiological pH (pH 7.4). This allows both (i) their functionalization with DOXO, which is positively charged at pH 7.4, and (ii) the stability of the DOXO-surface bond and DOXO release to be pH dependent and governed by electrostatic interactions. DOXO adsorption follows a Langmuir-Freundlich model, and the coupling of DOXO to BMNPs (binary biomimetic nanoparticles) is very stable at physiological pH (maximum release of 5% of the drug adsorbed). Conversely, when pH decreases, these electrostatic interactions weaken, and at pH 5, DOXO is released up to ∼35% of the amount initially adsorbed. The DOXO-BMNPs display cytotoxicity on the GTL-16 human gastric carcinoma cell line in a dose-dependent manner, reaching about ∼70% of mortality at the maximum amount tested, while the nonloaded BMNPs are fully cytocompatible. The present data suggest that BMNPs could be useful as potential drug nanocarriers with a drug adsorption-release governed by changes in local pH values.

pH and Thermal Dual-Responsive Nanoparticles for Controlled Drug Delivery with High Loading Content

A pH and thermal dual-responsive nanocarrier with silica as the core and block copolymer composed of poly(methacrylic acid) (PMAA) and poly(N-isopropylacrylamide) (PNIPAM) as the shell was prepared by surface-initiated reversible addition-fragmentation chain-transfer (SI-RAFT) polymerization. The resulting SiO2-PMAA-b-PNIPAM particles dispersed individually in an aqueous solution at a high pH and a low temperature but reversibly agglomerated under acidic conditions or at elevated temperatures. These dual-responsive nanoparticles were used as carriers to deliver the model drug doxorubicin (DOX) with unusually high entrapment efficiency and loading content, which is due to the small size (15 nm), light weight of the cores, and high graft density (0.619 chains/nm2) achieved by SI-RAFT polymerization. The release rate was controlled by both the pH and temperature of the surrounding medium. Moreover, these particles selectively precipitated at acidic conditions with increased temperature, which may enhance their ability to accumulate at tumor sites. Cytotoxicity studies demonstrated that DOX-loaded nanoparticles are highly active against Hela cells and more effective than free DOX of an equivalent dose. A cellular uptake study revealed that SiO2-PMAA-b-PNIPAM nanoparticles could successfully deliver DOX molecules into the nuclei of Hela cells. All these features indicated that SiO2-PMAA-b-PNIPAM nanoparticles are a promising candidate for therapeutic applications.

Evaluation of boron nitride nanotubes and hexagonal boron nitrides as nanocarriers for cancer drugs

AIM

Boron nitride nanotubes (BNNTs) and hexagonal boron nitrides (hBNs) are novel nanostructures with high mechanical strengths, large surface areas and excellent biocompatibilities. Here, the potential use of BNNTs and hBNs as nanocarriers was comparatively investigated for use with cancer drugs.

MATERIALS & METHODS

Doxorubicin (Dox) and folate are used as model drugs and targeting agents, respectively.

RESULTS & DISCUSSION

The obtained results indicate that BNNTs have about a threefold higher Dox loading capacity than hBNs. It was also found that cellular uptake of folate-Dox-BNNTs was much higher when compared with Dox-BNNTs for HeLa cells, due to the presence of folate receptors on the cell surface, leading to increased cancer cell death. In summary, folate and Dox conjugated BNNTs are promising agents in nanomedicine and may have potential drug delivery applications.

Stability of Epidoxorubicin Hydrochloride in Aqueous Solutions: Experimental and Theoretical Studies

The first-order degradation kinetics of epidoxorubicin were investigated as a function of pH, temperature, and buffers concentrations. The degradation was followed by HPLC. Buffer catalysis was observed in acetate and phosphate buffers. The pH-rate profiles were obtained at 333, 343, 353, and 363 K. The pH-rate expression was kpH=k1×aH+×f1+k2×f1+k3×f2+(k4×f2+k5×f3)×aOH-, where k1, k4, and k5 are the second-order rate constants (mol−1 L s−1) for hydrogen ion activity and for hydroxyl ion activity, respectively, and k2 and k3 are the first-order constants (s−1) for spontaneous reaction under the influence of water. Epidoxorubicin demonstrates the greatest stability in the pH range 3–5. The electrostatic molecular potential orbitals HOMO-LUMO were also defined in order to determine the cause of the reactivity of particular epidoxorubicin molecule domains in solutions with various pH values.

Compatibility of epirubicin-loaded DC bead™ with different non-ionic contrast media

Purpose

The aim of this study was to determine the compatibility of epirubicin-loaded DC bead™ with different non-ionic contrast media over a period of seven days when stored light protected under refrigerated conditions.

Methods

DC bead™ (2 ml) (Biocompatibles UK Ltd) of the bead size 70–150 µm ( = DC bead M1) or bead size 100–300 µm were loaded with 75 mg epirubicin powder formulation (Farmorubicin® dissolved in 3 ml water for injection to a concentration of 25 mg/ml) or 76 mg epirubicin injection solution (Epimedac® 2 mg/ml) within 2 h or 6 h, respectively. After removal of the excess solution, the epirubicin-loaded beads were mixed in polypropylene syringes with an equal volume (∼1.5 ml) of contrast media, i.e. Accupaque™ 300 (Nycomed Inc.), Imeron® 300 (Bracco S.p.A), Ultravist® 300 (Bayer Pharma AG), Visipaque™ 320 (GE Healthcare) and agitated in a controlled manner to get a homogenous suspension. Syringes with loaded beads in contrast media were stored protected from light under refrigeration (2–8℃). Compatibility was determined by measuring epirubicin concentrations in the suspensions in triplicate on day 0, 1, and 7. A reversed phase high-performance liquid chromatography assay with ultraviolet detection was utilized to analyze the concentration and purity of epirubicin.

Results

Mixing of epirubicin-loaded beads with different non-ionic contrast media released 0.1–0.5% of epirubicin over a period of 24 h, irrespectively, of the DC bead™ size or type of contrast media. No further elution or degradation was observed after seven days when the admixtures were stored protected from light under refrigeration.

Conclusion

Compatibility of epirubicin-loaded DC bead™ with an equal volume of different contrast media in polypropylene syringes is given over a period of seven days. Due to a maximum elution of 0.1–0.5% of epirubicin from loaded DC bead™, admixtures with contrast media can be prepared in advance in centralized cytotoxic preparation units. Microbiological aspects have to be considered when determining the expiration date of the product.

The “click-on-tube” approach for the production of efficient drug carriers based on oxidized multi-walled carbon nanotubes

An efficient drug delivery system through a straightforward approach to multi-walled carbon nanotube decoration.

Nanotherapeutics With Anthracyclines: Methods of Determination and Quantification of Anthracyclines in Biological Samples

Anthracyclines, e.g. doxorubicin, pirarubicin, are widely used as cytostatic agents in the polymer nanotherapeutics designed for the highly effective antitumor therapy with reduced side effects. However, their precise dosage scheme needs to be optimized, which requires an accurate method for their quantification on the cellular level in vitro during nanocarrier development and in body fluids and tissues during testing in vivo. Various methods detecting the anthracycline content in biological samples have already been designed. Most of them are highly demanding and they differ in exactness and reproducibility. The cellular uptake and localization is predominantly observed and determined by microscopy techniques, the anthracycline content is usually quantified by chromatographic analysis using fluorescence detection. We reviewed and compared published methods concerning the detection of anthracycline nanocarriers.

Identification of four new degradation products of epirubicin through forced degradation, LC-UV, MSn and LC-MS-TOF studies

Epirubicin (EPI) was subjected to International Conference on Harmonization recommended forced degradation under the conditions of hydrolysis, oxidation, dry heat and photolysis to characterize its possible impurities and/or degradation products. The drug was found highly unstable to alkaline hydrolysis even at room temperature, unstable to acid hydrolysis at 80°C and to oxidation at room temperature. The hydrolytic and oxidative degradation products were resolved on an Agilent RP8 (150 mm × 4.6 mm; 5 µm) column with isocratic elution using mobile phase composed of ammonium formate (10 mM, pH 3.0), acetonitrile and methanol. The drug degraded to four oxidative products (O-I, O-II, O-III and O-IV) and to one acid hydrolyzed product (A-I). Purity of each peak in liquid chromatography-ultraviolet (LC-UV) chromatogram was ascertained through photodiode array (LC-PDA) analysis. The products were characterized through electrospray ionization-mass spectrometry (+ESI-MS(n)) studies on EPI and liquid chromatography-time of flight mass spectrometry (LC-MS-TOF) studies on degraded drug solutions. The products, O-I-O-IV, were characterized as 2-hydroxy-8-desacetylepirubicin-8-hydroperoxide, 4-hydroxy-8-desacetylepirubicin-8-hydroperoxide, 8-desacetylepirubicin-8-hydroperoxide and 8-desacetylepirubicin, respectively, and product A-I was characterized as deglucosaminylepirubicin. While A-I was found to be a pharmacopoeial impurity, all oxidative products were found to be new degradation impurities. The mechanisms and pathways of degradation of EPI were discussed and outlined.

Payload drug vs. nanocarrier biodegradation by myeloperoxidase- and peroxynitrite-mediated oxidations: pharmacokinetic implications

With the advancement of nanocarriers for drug delivery into biomedical practice, assessments of drug susceptibility to oxidative degradation by enzymatic mechanisms of inflammatory cells become important. Here, we investigate oxidative degradation of a carbon nanotube-based drug carrier loaded with Doxorubicin. We employed myeloperoxidase-catalysed and peroxynitrite-mediated oxidative conditions to mimic the respiratory burst of neutrophils and macrophages, respectively. In addition, we revealed that the cytostatic and cytotoxic effects of free Doxorubicin, but not nanotube-carried drug, on melanoma and lung carcinoma cell lines were abolished in the presence of tumor-activated myeloid regulatory cells that create unique myeloperoxidase- and peroxynitrite-induced oxidative conditions. Both ex vivo and in vitro studies demonstrate that the nanocarrier protects the drug against oxidative biodegradation.

Prevention of doxorubicin sorptive losses in drug delivery studies using polyethylene glycol

Polyethylene glycol enhances the accuracy of drug delivery system evaluations by preventing sorptive losses of hydrophobic drugs to plastic reaction vessels.

Polymersomes from polypeptide containing triblock Co- and terpolymers for drug delivery against pancreatic cancer: asymmetry of the external hydrophilic blocks

Well-defined amphiphilic polymers of the ABA and ABC type are synthesized, where A is poly(L-lysine hydrochloride) (PLL), B is poly(γ-benzyl-(d7) L-glutamate) (PBLG(-d7)), and C is poly(ethylene oxide) (PEO). The two polymers exhibit similar PBLG(-d7) composition, while in the ABC, the volume fraction of PEO block is higher than that of PLL. Both polymers form polymersomes in water. The polymersomes are loaded with doxorubicin or paclitaxel. It is found that in the ABC, due to asymmetry of the two hydrophilic blocks, PEO is always on the outer periphery and the dimensions of the vesicles are smaller. The release of the vesicles is temperature- and pH-dependent. In vivo toxicity tests of the empty vesicles show that they are not toxic. In vitro activity of the loaded vesicles against human pancreatic cancer cell lines reveals comparable activity to Myocet for the ABA loaded with doxorubicin, while lower activity is observed for the ABC.

Overcoming cancer multidrug resistance by codelivery of doxorubicin and verapamil with hydrogel nanoparticles

The efficacy of chemotherapy is often inhibited by multidrug resistance (MDR). A highly engineerable hydrogel nanoparticle (NP) serves as a carrier for the optimal codelivery to tumor cells of the chemodrug, doxorubicin (Dox) and the chemosensitizer, verapamil (Vera), aiming at alleviating tumor MDR. The hydrogel NPs are prepared via the copolymerization of acrylamide and 2-carboxyethyl acrylate. Dox and Vera are post-loaded into the respective NPs, with drug loading around 7.7 wt% and 8.0 wt%, respectively. The codelivery of Dox-NPs and Vera-NPs increases the intracellular accumulation of Dox, and significantly enhances the cell killing ability of Dox with respect to NCI/ADR-RES cells in vitro. These findings suggest that such codelivery nanoplatforms provide a promising route for overcoming tumor MDR.

Dendrimer-assisted formation of fluorescent nanogels for drug delivery and intracellular imaging

Although, in general, nanogels present a good biocompatibility and are able to mimic biological tissues, their unstability and uncontrollable release properties still limit their biomedical applications. In this study, a simple approach was used to develop dual-cross-linked dendrimer/alginate nanogels (AG/G5), using CaCl2 as cross-linker and amine-terminated generation 5 dendrimer (G5) as a cocrosslinker, through an emulsion method. Via their strong electrostatic interactions with anionic AG, together with cross-linker Ca(2+), G5 dendrimers can be used to mediate the formation of more compact structural nanogels with smaller size (433 ± 17 nm) than that (873 ± 116 nm) of the Ca(2+)-cross-linked AG nanogels in the absence of G5. Under physiological (pH 7.4) and acidic (pH 5.5) conditions, the sizes of Ca(2+)-cross-linked AG nanogels gradually decrease probably because of their degradation, while dual-cross-linked AG/G5 nanogels maintain a relatively more stable structure. Furthermore, the AG/G5 nanogels effectively encapsulate the anticancer drug doxorubicin (Dox) with a loading capacity 3 times higher than that of AG nanogels. The AG/G5 nanogels were able to release Dox in a sustained way, avoiding the burst release observed for AG nanogels. In vitro studies show that the AG/G5-Dox NGs were effectively taken up by CAL-72 cells (a human osteosarcoma cell line) and maintain the anticancer cytotoxicity levels of free Dox. Interestingly, G5 labeled with a fluorescent marker can be integrated into the nanogels and be used to track the nanogels inside cells by fluorescence microscopy. These findings demonstrate that AG/G5 nanogels may serve as a general platform for therapeutic delivery and/or cell imaging.

Antitumor efficacy of doxorubicin-loaded laponite/alginate hybrid hydrogels

Degradable hybrid hydrogels with improved stability are prepared by incorporating nanodisks of biocompatible laponite (LP) in alginate (AG) hydrogels using Ca(2+) as a crosslinker. The Dox-loaded hybrid hydrogels give a controlled Dox release at physiological environment in a sustained manner. Under conditions that mimic the tumor environment, both the sustainability in the Dox release (up to 17 d) and the release efficiency from LP/AG-Dox hydrogels are improved. The in situ degradation of these hybrid hydrogels gives rise to nanohybrids that might serve as vehicles for carrying Dox through the cell membrane and diminish the effect of Dox ion-trapping in the acidic extracellular environment of the tumor and/or in the endo-lysosomal cell compartments.

Bicontinuous cubic liquid crystalline nanoparticles for oral delivery of Doxorubicin: implications on bioavailability, therapeutic efficacy, and cardiotoxicity

PURPOSE

The present study explores the potential of bicontinous cubic liquid crystalline nanoparticles (LCNPs) for improving therapeutic potential of doxorubicin.

METHODS

Phytantriol based Dox-LCNPs were prepared using hydrotrope method, optimized for various formulation components, process variables and lyophilized. Structural elucidation of the reconstituted formulation was performed using HR-TEM and SAXS analysis. The developed formulation was subjected to exhaustive cell culture experiments for delivery potential (Caco-2 cells) and efficacy (MCF-7 cells). Finally, in vivo pharmacokinetics, pharmacodynamic studies in DMBA induced breast cancer model and cardiotoxicity were also evaluated.

RESULTS

The reconstituted formulation exhibited Pn3m type cubic structure, evident by SAXS and posed stability in simulated gastrointestinal fluids and at accelerated stability conditions for 6 months. Dox-LCNPs revealed significantly higher cell cytotoxicity (16.23-fold) against MCF-7 cell lines as compared to free drug owing to its preferential localization in the vicinity of nucleus. Furthermore, Caco-2 cell experiments revealed formation of reversible "virtual pathways" in the cell membrane for Dox-LCNPs and hence posed significantly higher relative oral bioavailability (17.74-fold). Subsequently, Single dose of Dox-LCNPs (per oral) led to significant reduction in % tumor burden (~42%) as compared that of ~31% observed in case of Adriamycin® (i.v.) when evaluated in DMBA induced breast cancer model. Moreover, Dox induced cardiotoxicity was also found to be significantly lower in case of Dox-LCNPs as compared to clinical formulations (Adriamycin® and Lipodox®).

CONCLUSION

Incorporation of Dox in the novel LCNPs demonstrated improved antitumor efficacy and safety profile and can be a viable option for oral chemotherapy.

Evaluation of doxorubicin-loaded 3-helix micelles as nanocarriers

Designing stable drug nanocarriers, 10-30 nm in size, would have significant impact on their transport in circulation, tumor penetration, and therapeutic efficacy. In the present study, biological properties of 3-helix micelles loaded with 8 wt % doxorubicin (DOX), ~15 nm in size, were characterized to validate their potential as a nanocarrier platform. DOX-loaded micelles exhibited high stability in terms of size and drug retention in concentrated protein environments similar to conditions after intravenous injections. DOX-loaded micelles were cytotoxic to PPC-1 and 4T1 cancer cells at levels comparable to free DOX. 3-Helix micelles can be disassembled by proteolytic degradation of peptide shell to enable drug release and clearance to minimize long-term accumulation. Local administration to normal rat striatum by convection enhanced delivery (CED) showed greater extent of drug distribution and reduced toxicity relative to free drug. Intravenous administration of DOX-loaded 3-helix micelles demonstrated improved tumor half-life and reduced toxicity to healthy tissues in comparison to free DOX. In vivo delivery of DOX-loaded 3-helix micelles through two different routes clearly indicates the potential of 3-helix micelles as safe and effective nanocarriers for cancer therapeutics.

A permeation method for detection of self-aggregation of doxorubicin in aqueous environment

For pharmaceutical scientists, it is important to know if dissolved drug molecules are present only as monomers or in the form of aggregates in a test solution or formulation. Amphiphilic or hydrophobic drugs frequently self-associate to form dimers, trimers or higher order aggregates. Doxorubicin aggregation was examined by a previously developed permeation technique to detect oligosaccharide aggregation in aqueous solutions. At very low doxorubicin concentrations dimers and trimers have been observed, but in aqueous 0.5mg/ml doxorubicin solutions aggregates containing about 40 molecules were observed. The permeation studies were supported by TEM studies. The results indicate that neutral doxorubicin molecules aggregate more readily than the protonated ones. Doxorubicin aggregation is a stepwise process resulting in formation of aggregates of variable sizes are enhanced aggregation with increasing doxorubicin concentration.

pH-responsive delivery of doxorubicin from citrate-apatite nanocrystals with tailored carbonate content

In this work, the efficiency of bioinspired citrate-functionalized nanocrystalline apatites as nanocarriers for delivery of doxorubicin (DOXO) has been assessed. The nanoparticles were synthesized by thermal decomplexing of metastable calcium/citrate/phosphate solutions both in the absence (Ap) and in the presence (cAp) of carbonate ions. The presence of citrate and carbonate ions in the solution allowed us to tailor the size, shape, carbonate content, and surface chemistry of the nanoparticles. The drug-loading efficiency of the two types of apatite was evaluated by means of the adsorption isotherms, which were found to fit a Langmuir-Freundlich behavior. A model describing the interaction between apatite surface and DOXO is proposed from adsorption isotherms and ζ-potential measurements. DOXO is adsorbed as a dimer by means of a positively charged amino group that electrostatically interacts with negatively charged surface groups of nanoparticles. The drug-release profiles were explored at pHs 7.4 and 5.0, mimicking the physiological pH in the blood circulation and the more acidic pH in the endosome-lysosome intracellular compartment, respectively. After 7 days at pH 7.4, cAp-DOXO released around 42% less drug than Ap-DOXO. However, at acidic pH, both nanoassemblies released similar amounts of DOXO. In vitro assays analyzed by confocal microscopy showed that both drug-loaded apatites were internalized within GTL-16 human carcinoma cells and could release DOXO, which accumulated in the nucleus in short times and exerted cytotoxic activity with the same efficiency. cAp are thus expected to be a more promising nanocarrier for experiments in vivo, in situations where intravenous injection of nanoparticles are required to reach the targeted tumor, after circulating in the bloodstream.