An electrochemical biosensor based on DNA tetrahedron nanoprobe for sensitive and selective detection of doxorubicin.

Doxorubicin (DOX) is a clinical chemotherapeutic drug and patients usually suffer from dose-dependent cytotoxic and side effects during chemotherapy process with DOX. Therefore, developing a reliable strategy for DOX analysis in biological samples for dosage guidance during chemotherapy process is of great significance. Herein, a sensitive and selective electrochemical biosensor for DOX detection was designed based on gold nanoparticles (AuNPs) and DNA tetrahedron (TDN) nanoprobe bifunctional glassy carbon electrode that could detect DOX in human serum and cell lysate samples. AuNPs not only could enhance electron transfer efficiency and detection sensitivity, but also could improve the biocompatibility of electrode. TDN nanoprobes were employed as specific DOX bind sites that could bind abundant DOX through intercalative characteristics to contribute to sensitive and selective detection. Under the optimal conditions, the proposed TDN nanoprobes-based DOX biosensor exhibited a wide linear range that ranged from 1.0 nM to 50 µM and a low detection limit that was 0.3 nM. Moreover, the proposed DOX biosensor displayed nice selectivity, reproducibility and stability, and was successfully applied for DOX detection in human serum and cell lysate samples. These promising results maybe pave a way for DOX dosage guidance and therapeutic efficacy optimization in clinic.

Liposomal doxorubicin and free doxorubicin in vivo quantitation method developed on CE-LIF and its application in pharmacokinetic analysis.

As a novel drug delivery system, liposomes were used to improve pharmacokinetics/pharmacodynamics (PK/PD) characters, minimize toxicity, and enhance drug-target selectivity. However, heterogeneity of drug releasing process and liposome itself challenged traditional pharmaceutical analytical techniques, especially in vivo pharmacokinetic studies. In this study, a novel liposomal doxorubicin (L-DOX) pharmacokinetic analysis strategy was developed with capillary electrophoresis coupled with laser-induced fluorescence (CE-LIF) detector. The background electrolyte (BGE) system was composed of borate and sodium dodecyl sulfate (SDS), which was optimized to successfully achieve simultaneous online separation and quantitative analysis of free DOX and liposome-encapsulated DOX. The method was applied to the in vivo pharmacokinetic study of L-DOX in rats. The results showed that the concentration of total DOX (T-DOX) was gradually decreasing, while the concentration of L-DOX was relatively stable, with a concentration of 31.6 ± 4.8 µg/mL within 24 h. It was the first time to achieve liposomal drugs in vivo analysis with CE-LIF. CE-LIF was proved as potential rapidly real-time analytical methods for liposomal drugs in vivo occurrence monitoring.

Electrochemical sensing of doxorubicin hydrochloride under sodium alginate antifouling conditions using silver nanoparticles modified glassy carbon electrodes.

Doxorubicin (DOX) is a highly effective anticancer drug with a narrow therapeutic window; thus, sensitive and timely detection of DOX is crucial. Using electrodeposition of silver nanoparticles (AgNPs) and electropolymerization of alginate (Alg) layers on the surface of a glassy carbon electrode, a novel electrochemical probe was constructed (GCE). The fabricated AgNPs/poly-Alg-modified GCE probe was utilized for the quantification of DOX in unprocessed human plasma samples. For the electrodeposition of AgNPs and electropolymerization of alginate (Alg) layers on the surface of GCE, cyclic voltammetry (CV) was used in the potential ranges of -2.0 to 2.0 V and -0.6 to 0.2 V, respectively. The electrochemical activity of DOX exhibited two oxidation processes at the optimum pH value of 5.5 on the surface of the modified GCE. The DPV spectra of poly(Alg)/AgNPs modified GCE probe toward consecutive concentrations of DOX in plasma samples demonstrated wide dynamic ranges of 15 ng/mL-0.1 µg/mL and 0.1-5.0 µg/mL, with a low limit of quantification (LLOQ) of 15 ng/mL. The validation results indicated that the fabricated electrochemical probe might serve as a highly sensitive and selective assay for the quantification of DOX in patient samples. As an outstanding feature, the developed probe could detect DOX in unprocessed plasma samples and cell lysates without the requirement for pretreatment.

Study on the Use of Ozone Water as a Chemical Decontamination Agent for Antineoplastic Drugs in Clinical Settings.

The exposure of healthcare workers to antineoplastic drugs in hospitals has been recognized to be harmful. To minimize the risk of exposure, the removal of these drugs from work environments, such as compounding facilities, has been recommended. In our previous paper, the degradation and inactivation efficacy of ozone water, which is being introduced into Japanese hospitals as a chemical decontamination agent, was reported for its effects on typical antineoplastic drugs (gemcitabine, irinotecan, paclitaxel). This article aims to further investigate the efficacy of ozone water for eight antineoplastic drugs to clarify its application limitations. A small amount (medicinal ingredient: typically ca. 1.5 µmol) of formulation containing 5-fluorouracil, pemetrexed, cisplatin, oxaliplatin, cyclophosphamide, ifosfamide, doxorubicin, or docetaxel was mixed with 50 mL of ozone water (~8 mg/L), and the resulting solutions were analyzed by high-performance liquid chromatography over time to observe the degradation. Consequently, the ozonation was overall effective for the degradation of the drugs, however this varied depending on the chemical structures of the drugs and additives in their formulations. In addition, after the parent drugs were completely degraded by the ozonation, the degradation mixtures were subjected to 1H nuclear magnetic resonance spectroscopy and evaluated for mutagenicity against Salmonella typhimurium strains and cytotoxicity against human cancer cells. The degradation mixtures of cisplatin and ifosfamide were mutagenic while those of the other drugs were non-mutagenic. Further, the ozonation resulted in clear decreases of cytotoxicity for 5-fluorouracil, oxaliplatin, and doxorubicin, but increases of cytotoxicity for pemetrexed, cisplatin, cyclophosphamide, and ifosfamide. These results suggest that the ozone water should be restrictedly used according to the situation of contamination in clinical settings because the ozonation enhances toxicity depending on the drug even if degradation is achieved.

Box-Behnken assisted development and validation of high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles.

While histone deacetylase inhibitors, such as vorinostat, demonstrate a significant effect against hematological cancers, their application for solid tumor treatment is limited. However, there is strong evidence that combinatorial administration of vorinostat and genotoxic agents (e.g., doxorubicin) enhances the antitumoral action of both drugs against tumors. We developed a high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles designed to provide the parenteral administration of both drugs and increase their safety profile. We performed separation on Nucleodur C-18 Gravity column with a mixture of 10 mM potassium dihydrogen phosphate buffer pH 3.9:ACN (90:10 v/v) as mobile phase at 240 nm. The method was linear within the concentration range of 4.2-52.0 µg/ml for both drugs with limits of detection and quantification of 3.5 and 10.7 µg/ml for doxorubicin and 2.5 and 7.7 µg/ml for vorinostat, respectively. The method was precise and accurate over the concentration range of analysis. Drug loading was 5.4% for doxorubicin and 0.8% for vorinostat. Degradation of doxorubicin after irradiation was less than 5%, while the amount of vorinostat decreased at 88% under the same conditions. Thus, the validated method could be adopted for routine simultaneous analysis of doxorubicin and vorinostat in polymeric nanoparticles.

Development and application of a liquid chromatography coupled to mass spectrometry method for the simultaneous determination of 23 antineoplastic drugs at trace levels.

The goal of this study was to develop a method for the simultaneous quantification of 23 commonly used antineoplastic drugs in a hospital pharmacy, using ultra-high pressure liquid chromatography separation coupled to tandem mass spectrometry detection (UHPLC-MS/MS). The following drugs were investigated: 5-fluorouracil, cytarabine, ganciclovir, gemcitabine, dacarbazine, methotrexate, pemetrexed, busulfan, topotecan, rentitrexed, ifosfamide, cyclophosphamide, etoposide, irinotecan, doxorubicin/epirubicin, vincristine, docetaxel, paclitaxel, daunorubicin, idarubicin, vinblastine, oxaliplatin and carboplatin. The chromatographic separation was performed on a phenyl-hexyl column (2.1 ×100 mm, 1.7 µm) with a gradient elution of methanol and water containing 10 mM ammonium formate adjusted to pH 4.9. All compounds were analyzed in less than 13 min and detected with a triple quadrupole mass spectrometer operating in MRM mode. Limits of detection (LODs) and limits of quantification (LOQs) were comprised between 0.01 and 5 ng.mL-1, and between 0.5 and 5 ng.mL-1, respectively. Accuracies ranged between 117% and 83% at the LOQ, intermediate and upper LOQ concentrations, with relative standard deviations (RSD) inferior to 8%, for all the antineoplastic drugs. Finally, the UHPLC-MS/MS method was successfully applied to the analysis of surface samples to evaluate the chemical contamination by these highly toxic compounds in a chemotherapy preparation unit in a hospital pharmacy with the purpose of monitoring the exposure of health care professionals.

A novel 2-dimensional nanocomposite as a mediator for the determination of doxorubicin in biological samples.

In our study, the electrochemical properties of a novel activated nanocomposite were studied with 2-dimensional graphitic carbon nitride/sodium dodecyl sulfate/graphene nanoplatelets on the screen-printed electrodes (2D-g-C3N4/SDS/GNPs/SPE). The as-fabricated sensor exhibited excellent electrochemical performance, including wide dynamic ranges from 0.03 to 1.0 and 1.0-13.5 µM with a low limit of detection (LOD) of 10.0 nM. The fabricated 2D-g-C3N4/SDS/GNPs/SPE electrode exhibited high sensitivity, stability, good reproducibility, reusability, and repeatability towards DOX sensing. It can be utilized in real samples, including human plasma and urine, with excellent correlations and coefficients of variation below 6.0%. Therefore, this study presents potential application values in sensing DOX with efficient performance. Finally, the accuracy was attested by comparison with high-performance liquid chromatography (HPLC) as the reference method, signalizing a good agreement.

Phytochemical Composition and Protective Effect of Vernonanthura polyanthes Leaf against In Vivo Doxorubicin-Mediated Toxicity.

Vernonanthura polyanthes (Spreng.) A.J. Vega & Dematt. (syn.: Vernonia polyanthes Less) is popularly known as "assa-peixe" and its leaves are used in folk medicine mainly to treat respiratory diseases. In this study, we evaluated the cytogenotoxic and anticytogenotoxic potential of the V. polyanthes leaf aqueous extract (VpLAE) and its n-butanol fraction (n-BF) in the presence or absence of doxorubicin (DXR) (pre-, co-, and post-treatments) on a murine model for 24 h or 120 h. The micronucleus test (MN) and the comet assay were used to assess the cytogenotoxic and anticytogenotoxic potential of VpLAE and n-BF (250, 500, and 1000 mg/kg) administered via gavage to Swiss Webster mice. The chemical profiles of VpLAE and n-BF were assessed by liquid chromatography coupled to mass spectrometry, and their metabolites were putatively identified. Lastly, the possible biological activities related to the (anti) cytogenotoxicity of the compounds were predicted using the PASS online webserver. The in vivo results showed that different doses of VpLAE and n-BF did not present cytotoxic activity; however, the MN test revealed a slight mutagenic activity for the 24 h treatments. Moderate genotoxic effects were demonstrated for all treatments in the comet assay. Regarding anticytotoxicity and antimutagenicity, VpLAE and n-BF presented a high cytoprotective potential against DXR toxic effects. In the co-treatment, VpLAE reduced the DXR genotoxicity by ~27%, and n-BF did not demonstrate antigenotoxic potential. In contrast, an antigenotoxic effect was observed for both VpLAE and n-BF in the pre- and post-treatments, reducing DXR genotoxicity by ~41% and ~47%, respectively. Chemical analysis of VpLAE and n-BF showed the presence of eight phenolic compounds, including seven chlorogenic acids and a flavonoid. The PASS online tool predicted antimutagenic, anticancer, antineoplastic, chemoprotective, antioxidant, and radical scavenging activities for all constituents identified in VpLAE and n-BF. V. polyanthes leaves presented a protective effect against DXR cytogenotoxicity. In general, VpLAE and n-BF showed a greater antigenotoxic potential in the pre- and post-treatments. The metabolites putatively identified in VpLAE and n-BF exhibited antioxidant and chemoprotective potential according to computational prediction analysis. Altogether, our results highlight the potential application of V. polyanthes to protect against toxic manifestations induced by DXR.

ZIF-8 encapsulated upconversion nanoprobes to evaluate pH variations in food spoilage.

A novel nanoassembly was constructed through encapsulating upconversion nanoparticles (UCNPs) into a metal-organic framework structure (ZIF-8), in which doxorubicin (DOX) was absorbed into pores of ZIF-8. The blue emission of UCNPs was quenched by DOX through the fluorescence resonance energy transfer (FRET) strategy. When the nanoprobe was exposed to food samples with different pH values, ZIF-8 collapsed to release DOX molecules, resulting in upconversion recovery. The porous structure of ZIF-8 provides abundant space for DOX absorption, which significantly improves the detection capacities and accuracy. It is shown that the probe has a good linear relationship when pH values vary from 2.5 to 7.4, and can distinguish pH variations as low as 0.5 in real samples. This strategy has been successfully used to determine food spoilage by determination of pH variations.

Novel CdS/MOF Cathodic Photoelectrochemical (PEC) Platform for the Detection of Doxorubicin Hydrochloride and Gentamicin Sulfate.

Nanomaterial selection is critical for photoelectrochemical (PEC) sensing. In this report, a novel cathodic photoelectrochemical (PEC) strategy was proposed for the detection of doxorubicin hydrochloride (Dox) and gentamicin sulfate (CN). The photocathode was synthesized by noncovalently coupling cadmium sulfide (CdS) to the porphyrin-derived metal-organic framework (CdS@PCN-224). This type of assembly created a pleasant interface for the combination of doxorubicin hydrochloride and gentamicin sulfate, resulting in a good CdS@PCN-224 donor-acceptor system. When compared to a single optoelectronic material, its photocurrent is enhanced by unprecedented nine times. This research could pave the way for the realization of PCN-224's enormous potential in PEC sensing.

A rapid screening method to select microdialysis carriers for hydrophobic compounds.

Microdialysis is a minimally invasive sampling technique which is widely applied in many fields including clinical studies. This technique usually has limitation on sampling hydrophobic compounds as aqueous solutions are commonly used as the perfusates. The relative recovery of hydrophobic compounds is often low and irreproducible because of the non-specific binding to microdialysis membranes or catheter tubing. Carriers such as cyclodextrins have been used to improve the recovery and consistency, however the identification of an optimal carrier can only be achieved after time-consuming and costly microdialysis experiments. We therefore developed a rapid, convenient, and low-cost method to identify the optimal carriers for sampling hydrophobic compounds with the use of centrifugal ultrafiltration. Doxorubicin was used as the model compound and its relative recoveries obtained from centrifugal ultrafiltration and from microdialysis were compared. The results show that the relative recoveries are highly correlated (correlation coefficient ≥ 0.9) between centrifugal ultrafiltration and microdialysis when different types or different concentrations of cyclodextrins were used as the carriers. In addition to doxorubicin, this method was further confirmed on three other drugs with different hydrophobicity. This method may facilitate and broaden the use of microdialysis perfusion on sampling or delivering hydrophobic substances in various applications.

Deep eutectic solvent synthesis of iron vanadate-decorated sulfur-doped carbon nanofiber nanocomposite: electrochemical sensing tool for doxorubicin.

Detection of anticancer drug (doxorubicin) using an electrochemical sensor is developed based on a transition metal vanadate's related carbon composite material. With an environmentally friendly process, we have synthesized a metal oxide composite of iron vanadate nanoparticle assembled with sulfur-doped carbon nanofiber (FeV/SCNF). The FeV/SCNF composite was characterized using XRD, TEM, FESEM with elemental mapping, XPS and EDS. In contrast to other electrodes reported in the literature, a much-improved electrochemical efficiency is shown by FeV/SCNF composite modified electrodes. Amperometric technique has been employed at 0.25 V (vs. Ag/AgCl) for the sensitive detection of DOX within a wide range of 20 nM-542.5 µM and it possesses enhanced selectivity in presence of common interferents. The modified electrochemical sensors show high sensitivity of 46.041 µA µM-1 cm-2. The newly developed sensor could be used for the determination of doxorubicin in both blood serum and drug formulations with acceptable results, suggesting its feasibility for real-time applications.

Starch-based magnetic nanocomposite as an efficient absorbent for anticancer drug removal from aqueous solution.

In this study, carboxymethyl cassava starch (CMCS)-functionalized magnetic nanoparticles (CMCS@Fe3O4) were synthesized via a simple one-pot co-precipitation method using CMCS materials with varying degrees of substitution, and used for the adsorption/removal of doxorubicin hydrochloride (Dox; a clinically available anti-cancer drug) from aqueous solution. The adsorption of Dox was studied using experimental conditions with varied pH, temperature, initial Dox concentration, and CMCS@Fe3O4 dosage. The CMCS@Fe3O4 adsorbents were characterized by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometry. Each CMCS@Fe3O4 adsorbent exhibited a cubic inverse spinel iron oxide phase, small particle size, favorable magnetic properties, and good thermal stability. Batch adsorption experiments showed that the Dox adsorption efficiency reached 85.46% at a CMCS@Fe3O4 concentration of 20 mg mL-1 at 303 K in pH 7.0. The adsorption experimental results indicated that the adsorption kinetics followed a pseudo-second-order model and the Langmuir equation. Considering the environmentally nontoxic nature of Fe3O4 and starch, the CMCS@Fe3O4 material demonstrated significant potential for removing Dox from aqueous solution and in magnetic targeted drug delivery systems for synergistic tumor treatments.

Pressurized intra-peritoneal aerosol chemotherapy (PIPAC): increased intraperitoneal pressure does not affect distribution patterns but leads to deeper penetration depth of doxorubicin in a sheep model.

BACKGROUND: Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) is an innovative treatment against peritoneal carcinomatosis. Doxorubicin is a common intra-venous chemotherapy used for peritoneal carcinomatosis and for PIPAC. This study evaluated the impact of increased PIPAC intraperitoneal pressure on the distribution and cell penetration of doxorubicin in a sheep model. METHODS: Doxorubicin was aerosolized using PIPAC into the peritoneal cavity of 6 ewes (pre-alpes breed): N = 3 with 12 mmHg intraperitoneal pressure ("group 12") and N = 3 with 20 mmHg ("group 20"). Samples from peritoneum (N = 6), ovarian (N = 1), omentum (N = 1) and caecum (N = 1) were collected for each ewe. The number of doxorubicin positive cells was determined using the ratio between doxorubicine fluorescence-positive cell nuclei (DOXO+) over total number of DAPI positive cell nuclei (DAPI+). Penetration depth (µm) was defined as the distance between the luminal surface and the location of the deepest DOXO+ nuclei over the total number of cell nuclei that were stained with DAPI. Penetration depth (µm) was defined as the distance between the luminal surface and the location of the deepest DOXO+ nuclei. RESULTS: DOXO+ nuclei were identified in 87% of samples. All omental samples, directly localized in front of the nebulizer head, had 100% DOXO+ nuclei whereas very few nuclei were DOXO+ for caecum. Distribution patterns were not different between the two groups but penetration depth in ovary and caecum samples was significantly deeper in group 20. CONCLUSIONS: This study showed that applying a higher intra-peritoneal pressure during PIPAC treatment leads to a deeper penetration of doxorubicin in ovarian and caecum but does not affect distribution patterns.

Highly sensitive determination of doxorubicin hydrochloride antitumor agent via a carbon nanotube/gold nanoparticle based nanocomposite biosensor.

A glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs) decorated with gold nanoparticles has been investigated for the first time as an ultrasensitive electrochemical sensor for the determination of doxorubicin hydrochloride (DOX), an efficient antitumor agent. The developed nanocomposite has been characterized by scanning electron microscopy (SEM), besides cyclic and linear sweep voltammetry electrochemical techniques. An efficient catalytic activity for the reduction of DOX has been demonstrated, leading to a significant increase in peak current density and a remarkable decrease in reduction over-potential. Under the optimal condition, a wide linear DOX concentration range from 1×10-11 to 1×10-6 M with a very low detection limit of 6.5 pM was achieved with the modified electrode. Meanwhile, the functionalized MWCNTs/gold nanoparticles indicated an appropriate selectivity, reproducibility, and repeatability as well as long-term stability. The promising outcomes of this research approved the applicability of the developed nanocomposite sensor towards trace amounts of DOX in pharmaceutical and clinical preparations.

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.

Fast and Purification-Free Characterization of Bio-Nanoparticles in Biological Media by Electrical Asymmetrical Flow Field-Flow Fractionation Hyphenated with Multi-Angle Light Scattering and Nanoparticle Tracking Analysis Detection.

Accurate physico-chemical characterization of exosomes and liposomes in biological media is challenging due to the inherent complexity of the sample matrix. An appropriate purification step can significantly reduce matrix interferences, and thus facilitate analysis of such demanding samples. Electrical Asymmetrical Flow Field-Flow Fractionation (EAF4) provides online sample purification while simultaneously enabling access to size and Zeta potential of sample constituents in the size range of approx. 1-1000 nm. Hyphenation of EAF4 with Multi-Angle Light Scattering (MALS) and Nanoparticle Tracking Analysis (NTA) detection adds high resolution size and number concentration information turning this setup into a powerful analytical platform for the comprehensive physico-chemical characterization of such challenging samples. We here present EAF4-MALS hyphenated with NTA for the analysis of liposomes and exosomes in complex, biological media. Coupling of the two systems was realized using a flow splitter to deliver the sample at an appropriate flow speed for the NTA measurement. After a proof-of-concept study using polystyrene nanoparticles, the combined setup was successfully applied to analyze liposomes and exosomes spiked into cell culture medium and rabbit serum, respectively. Obtained results highlight the benefits of the EAF4-MALS-NTA platform to study the behavior of these promising drug delivery vesicles under in vivo like conditions.

Fluorometer for Screening of Doxorubicin in Perfusate Solution and Tissue with Solid-Phase Microextraction Chemical Biopsy Sampling.

The recent development of an in vivo solid-phase microextraction (SPME) method capable of analyzing drugs and metabolic products in biofluids and living tissues holds great promise. The standard in vivo SPME protocol based on mass spectrometry is a very powerful analytical approach, but it is not practical for on-site analysis in many cases. In this paper, we present a fluorescence-based SPME method and a prototype of a portable fluorometer that is capable of quickly quantifying concentrations of the anticancer drug, doxorubicin (DOX). The instrument uses thin coated, biocompatible SPME fibers, which we have previously presented as a chemical biopsy tool for use during in vivo lung perfusion (IVLP) procedures within a hospital setting. In this research, we test SPME fibers with C8-SCX, C18, and HLB coatings with our fluorometer. The mixed-mode C8-SCX fibers showed the best sensitivity of the three and were therefore used to examine DOX extraction from perfusate solution and a homogenized lamb lung tissue. The maximum concentration of free active sites in the C8-SCX fiber and the adsorption equilibrium constant were determined to be (9.1 ± 0.3) × 10-7 mol m-2 and 420 ± 30 m3 mol-1, respectively. Finally, the detection limits for DOX extracted from buffer, perfusate, and lung tissue were 40, 100, and 3700 µg L-1, respectively.

Single-Molecule Sensing of DNA Intercalating Drugs in Water.

The occurrence of pharmaceutical residues in surface water is raising environmental concern. To accompany the evolution of measures for natural resources protection, sensing methods enabling sensitive and rapid water quality monitoring are needed. We recently managed the parallelization of the Tethered Particle Motion (TPM), a single molecule technique, sensitive to the conformational changes of DNA. Here, we investigate the capacity of high throughput TPM (htTPM) to detect drugs that intercalate into DNA. As a proof-of-concept we analyze the htTPM signal for two DNA intercalating dyes, namely, YOYO-1 and SYTOX orange. The efficient detection of intercalating drugs is then demonstrated with doxorubicin. We further evaluate the possibility to detect carbamazepine, an antiepileptic massively prescribed and persistent in water, which had been described to interact with DNA through intercalation. Our results corroborated by other techniques show that, in fact, carbamazepine is not a DNA intercalator. The comparison of the results obtained with different aqueous buffers and solutions allows us to identify optimal conditions for the monitoring of intercalation compounds by htTPM.

Detection of doxorubicin, cisplatin and therapeutic antibodies in formalin-fixed paraffin-embedded human cancer cells.

A major limitation in the pharmacological treatment of clinically detectable primary cancers and their metastases is their limited accessibility to anti-cancer drugs (cytostatics, inhibitory antibodies, small-molecule inhibitors) critically impairing therapeutic efficacies. Investigations on the tissue distribution of such drugs are rare and have only been based on fresh frozen material or methanol-fixed cell culture cells so far. In this paper, we expand the detection of cisplatin-induced DNA adducts and anthracyclines as well as therapeutic antibodies to routinely prepared formalin-fixed, paraffin-embedded sections (FFPE). Using pre-treated cell lines prepared as FFPE samples comparable to tissues from routine analysis, we demonstrate that our method allows for the detection of chemotherapeutics (anthracyclines by autofluorescence, cisplatin by immune detection of DNA adducts) as well as therapeutic antibodies. This methodology thus allows for analyzing archival FFPE tissues, as demonstrated here for the detection of cisplatin, doxorubicin and trastuzumab in FFPE sections of tumor xenografts from drug-treated mice. Analyzing human tumor samples, this will lead to new insights into the tissue penetration of drugs.