Environmental degradation of human metabolites of cyclophosphamide leads to toxic and non-biodegradable transformation products

The present study assessed the ready biodegradability of the prodrug cyclophosphamide (CPA) and its stable human metabolites in the closed bottle test (CBT). The results of the CBT showed that only the main human metabolite, carboxyphosphamide (CXP), was biodegradable to a certain extent (23 ± 2.4 % ThOD_NH3). All other metabolites showed neither biodegradation under these conditions nor were any toxic effects on the inoculum observed. Yet, HRMSⁿ results revealed partial primary elimination of all human metabolites and formation of 25 new transformation products. Abiotic degradation via S_Ni and S_N2 reactions was proposed as the main degradation pathway during the CBT. The main degradation products were assigned as 3-(2-chloroethyl)oxazolidin-2-one (COAZ), cytotoxic N-2-chloroethylaziridine (CEZ) and nor‑nitrogen mustard (NNM), an analogue of the chemical warfare agent HN2. While the acute ecotoxicity of the detected products is widely unknown, many have already been reported in medical literature to be either mutagenic, genotoxic, cytotoxic or carcinogenic and may therefore cause a greater risk than their precursors. QSAR models predicted that 16 of them are mutagenic and genotoxic, thus classifying the majority of the chemicals as potential environmental hazards. The central intermediates during the degradation process were proposed as CEZ and its corresponding aziridinium ion. However, other degradation products may occur depending on the type and strength of nucleophiles present in the matrices. Overall, the results demonstrated the importance to include human metabolites in the evaluation of the environmental fate of pharmaceuticals and their risk assessment especially when investigating prodrugs. The results underline the importance of identifying possible degradation products of metabolites, as they can be more toxic than related parent compounds and metabolites and can cause a greater risk to the environment and humans.

Anti-Tumor Effects of Queen Bee Acid (10-Hydroxy-2-Decenoic Acid) Alone and in Combination with Cyclophosphamide and Its Cellular Mechanisms against Ehrlich Solid Tumor in Mice

Queen bee acid or 10-hydroxy-2-decenoic acid (10-HDA) is one of the main and unique lipid components (fatty acids) in royal jelly. Previous studies have demonstrated that 10-HDA has various pharmacological and biological activities. The present study aims to evaluate the anti-tumor effects of 10-HDA alone and combined with cyclophosphamide (CP), as an alkylating agent which widely used for the treatment of neoplastic cancers, against the Ehrlich solid tumors (EST) in mice. Methods: A total of 72 female Swiss albino mice were divided into eight groups. EST mice were treated with 10-HDA (2.5 and 5 mg/kg) alone and combined with CP (25 mg/kg) orally once a day for 2 weeks. Tumor growth inhibition, body weight, the serum level of alpha-fetoprotein (AFP) and carcinoembryonic antigen tumor (CAE), liver and kidney enzymes, tumor lipid peroxidation (LPO) and nitric oxide (NO), antioxidant enzymes (e.g. glutathione reductase (GR), glutathione peroxidase (GPx), catalase enzyme (CAT)), tumor necrosis factor alpha level (TNF-α), and the apoptosis-regulatory genes expression were assessed in tested mice. Results: the findings exhibited that treatment of EST-suffering mice with 10-HDA at the doses of 2.5 and 5 mg/kg especially in combination with CP significantly (p < 0.001) decreased the tumor volume and inhibition rate, tumor markers (AFP and CEA), serum level of liver and kidney, LPO and NO, TNF-α level, as well as the expression level of Bcl-2 in comparison with the mice in the C2 group; while 10-HDA at the doses of 2.5 and 5 mg/kg especially in combination with CP significantly (p < 0.001) improved the level of antioxidant enzymes of GPx, CAT, and SOD and the expression level of caspase-3 and Bax genes. Conclusions: According to the results of the present investigations, 10-HDA at the doses of 2.5 and 5 mg/kg especially in combination with CP showed promising antitumor effects against EST in mice and can be recommended as a new or alternative anticancer agent against tumor; nevertheless, further investigations, particularly in clinical setting, are required to confirm these results.

Effect of the drug cyclophosphamide on the activity of porcine kidney betaine aldehyde dehydrogenase

The enzyme betaine aldehyde dehydrogenase (BADH EC 1.2.1.8) catalyzes the synthesis of glycine betaine (GB), an osmolyte and osmoprotectant. Also, it participates in several metabolic pathways in humans. All BADHs known have cysteine in the active site involved in the aldehyde binding, whereas the porcine kidney enzyme (pkBADH) also has a neighborhood cysteine, both sensitive to oxidation. The antineoplastic and immuno-suppressant pre-drug cyclophosphamide (CTX), and its bioactivation products, have two highly oxidating chlorine atoms. This work aimed to analyze the effect of CTX in the activity of porcine kidney betaine aldehyde dehydrogenase. PkBADH was incubated with varying CTX concentration (0 to 2.0 mM) at 25 °C and lost 50 % of its activity with 2.0 mM CTX. The presence of the coenzyme NAD⁺ (0.5 mM) decreased 95% the activity in 2.0 mM CTX. The substrate betaine aldehyde (0.05 and 0.4 mM, and the products NADH (0.1-0.5 mM) and GB (1 and 10 mM) did not have an effect on the enzyme inactivation by CTX. The reducing agents, dithiothreitol and β-mercaptoethanol, reverted the pkBADH inactivation, but reduced glutathione (GSH) was unable to restore the enzyme activity. Molecular docking showed that CTX could enter at the enzyme active site, where its chlorine atoms may interact with the catalytic and the neighboring cysteines. The results obtained show that CTX inactivates the pkBADH due to oxidation of the catalytic cysteine or because it oxidizes catalytic and neighborhood cysteine, forming a disulfide bridge with a concomitant decrease in the activity of the enzyme.

Oxidative degradation of cyclophosphamide using thermal plasma activation and UV/H2O2 treatment in tap water

There is a growing concern about pharmaceuticals entering the aquatic environment. Many of these compounds cannot be removed completely in sewage treatment plants. To remove these unwanted medicines from water, oxidative degradation techniques may complement the current purification steps. In this paper we studied the effect of advanced oxidation on the cytostatic drug cyclophosphamide (CP) by comparing thermal plasma activation with UV/H₂O₂ treatment. Plasma activated water (PAW) contains highly reactive oxygen and nitrogen species (RONS) as a result of electric gas discharges in air over water. CP solutions in tap water were oxidized over a period of 120 min and subsequently analyzed by LC-MS/MS to measure the compound degradation. Plasma activation was applied at 50, 100, or 150 W electric power input and UV/H₂O₂ treatment was carried out by the addition of H₂O₂ and placing an UV-C source above the test solution for immediate irradiation. The oxidative degradation of CP in PAW resulted in a complete degradation within 80 min at 150 W. CP was also completely degraded within 60 min applying UV/H₂O₂ oxidation. Both treatment techniques do induce different structural changes, demonstrating that CP is completely degraded in tap water.

Simultaneous degradation of the anticancer drugs 5-fluorouracil and cyclophosphamide using a heterogeneous photo-Fenton process based on copper-containing magnetites (Fe3-xCuxO4)

The effect of substitution of iron by copper in the magnetite lattice was investigated in terms of the catalytic activity in the heterogeneous photo-Fenton process. The physicochemical properties of the Fe_3-xCu_xO₄ nanoparticles were characterized by X-ray diffraction (XRD), X-ray fluorescence (WD-XRF), specific surface area measurements, field emission scanning electron microscopy (FEG-SEM), and X-ray photoelectron spectroscopy (XPS). Copper-modified magnetite showed higher catalytic activity for H₂O₂ conversion to HO^• (estimated using 7-hydroxycoumarin), compared to pristine magnetite (Fe₃O₄). Consequently, improved degradation of the anticancer drugs 5-fluorouracil (5-FU) and cyclophosphamide (CP) was observed, with high efficiencies achieved using Fe_2.75Cu_0.25O₄ (0.125 g L^-1) and 15 mmol L^-1 H₂O₂, at pH 6.5, which resulted in complete degradation of 7.7 μmol L^-1 5-FU and CP after 150 min. Low leaching of Cu and Fe demonstrated the stability of the catalyst in the Fenton process, with high catalytic activity (>90%) maintained after use in 4 cycles. The addition of radical scavengers such as methanol, tert-butanol and iodide ions indicated that surface-bonded hydroxyl radicals played a major role in the degradation of 5-FU and CP in the Fe_3-xCu_xO₄/H₂O₂ system. The substitution of octahedral Fe(II) sites of the magnetite lattice by Cu(II) and the partial oxidation of Cu(I) to Cu(II) and Fe(II) to Fe(III) on the catalyst surface after the Fenton reaction were confirmed by analysis of the XPS spectra.

Exposure-Toxicity Association of Cyclophosphamide and Its Metabolites in Infants and Young Children with Primary Brain Tumors: Implications for Dosing

PURPOSE

To characterize the population pharmacokinetics of cyclophosphamide, active 4-hydroxy-cyclophosphamide (4OH-CTX), and inactive carboxyethylphosphoramide mustard (CEPM), and their associations with hematologic toxicities in infants and young children with brain tumors. To use this information to provide cyclophosphamide dosing recommendations in this population.

PATIENTS AND METHODS

Patients received four cycles of a 1-hour infusion of 1.5 g/m² cyclophosphamide. Serial samples were collected to measure cyclophosphamide, 4OH-CTX, and CEPM plasma concentrations. Population pharmacokinetic modeling was performed to identify the patient characteristics influencing drug disposition. Associations between drug exposures and metrics reflecting drug-induced neutropenia, erythropenia, and thrombocytopenia were investigated. A Bayesian approach was developed to predict 4OH-CTX exposure using only cyclophosphamide and CEPM plasma concentrations.

RESULTS

Data from 171 patients (0.07-4.9 years) were adequately fitted by a two-compartment (cyclophosphamide) and one-compartment model (metabolites). Young infants (<6 months) exhibited higher mean 4OH-CTX exposure than did young children (138.4 vs. 107.2 μmol/L·h, P < 0.0001). No genotypes exhibited clinically significant influence on drug exposures. Worse toxicity metrics were significantly associated with higher 4OH-CTX exposures. Dosing simulations suggested decreased cyclophosphamide dosage to 1.2 g/m² for young infants versus 1.5 g/m² for children to attain similar 4OH-CTX exposure. Bayesian-modeled 4OH-CTX exposure predictions were precise (mean absolute prediction error 14.8% ± 4.2%) and had low bias (mean prediction error 4.9% ± 5.1%).

CONCLUSIONS

A 4OH-CTX exposure-toxicity association was established, and a decreased cyclophosphamide dosage for young infants was suggested to reduce toxicity in this population. Bayesian modeling to predict 4OH-CTX exposure may reduce clinical processing-related costs and provide insights into further exposure-response associations.

Photocatalytic degradation of cyclophosphamide and ifosfamide: Effects of wastewater matrix, transformation products and in silico toxicity prediction

Antineoplastic drugs have been identified in surface water and effluents from wastewater treatment and, once in the environment, may be harmful to aquatic organisms, as these compounds are possibly mutagenic, genotoxic, cytotoxic, carcinogenic and teratogenic. This work investigated the photodegradation of cyclophosphamide (CP) and ifosfamide (IF) using ruthenium doped titanate nanowires (Ru-TNW) in distilled water (DW) and in wastewater (WW) from secondary wastewater treatment, under UV-Vis radiation. The results indicated that Ru-TNW showed photocatalytic activity for the two cytotoxic drugs with the half-life (t_1/2) of 15.1 min for CP and 12.9 min for IF in WW. Four CP transformation products (TPs) and six IF TPs from the photodegradation process are here reported. These TPs were elucidated by high-resolution mass spectrometry. For both pollutants, the results showed different time profiles for the TPs when WW and DW were used as matrix. Overall, in the WW there was a higher production of TPs and two of them were detected only in this matrix. In other words, environmental matrices may produce different TPs. Degradation pathways were proposed and both drugs bear similarities. Additionally, in silico toxicity were performed by quantitative structure-activity relationship models. The predictions indicated that the TPs, with the exception of one IF TP, presented high mutagenic potential.

Protective effects of garlic extract against hematological alterations, immunosuppression, hepatic oxidative stress, and renal damage induced by cyclophosphamide in rats

Cyclophosphamide is an alkylating agent widely used as anticancer drug, reported to exert cytotoxic effects attributed to oxidative stress. Therefore, this study aimed to explore the protective effect of ethanolic extract of garlic (EEG) against cyclophosphamide (Cyp)-induced hematological disturbance and immunosuppressive and hepatotoxic effects. Forty male Wistar albino rats were randomized into four equal groups: the normal control one, the Cyp-treated group (50 mg/kg BW/IM, once weekly), the EEG-treated group (300 mg/kg BW, orally, daily), and the Cyp & EEG group. All rats received their relevant treatments for four consecutive weeks. This study revealed that Cyp significantly decreased erythrocyte count, hemoglobin (Hb), packed cell volume (PCV), and total leukocyte and lymphocyte counts. However, the counts of neutrophils, eosinophils, and toxic neutrophils were elevated. Additionally, hepatic malondialdehyde (MDA) and levels of liver and renal biomarkers were significantly elevated in the Cyp-treated group. Otherwise, hepatic catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD), and serum total antioxidant capacity (TAC) were significantly lower than the control rats. Furthermore, Cyp significantly reduced whole blood respiratory burst activity (NBT), serum lysozyme and bactericidal activities, interlukin-12 (IL-12), and interferon-γ. In contrast, the levels of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interlukin-1β (IL-1β) were elevated. Additionally, Cyp induced hepatic and renal histopathological alterations. Data in the present study demonstrated that EEG has immunomodulatory and antioxidant effects and has the ability to diminish the alterations induced by Cyp.

Transformation kinetics of cyclophosphamide and ifosfamide by ozone and hydroxyl radicals using continuous oxidant addition reactors

The detection of pharmaceuticals in water and wastewater has triggered human and ecological health concerns. As highly toxic compounds, chemotherapy agents (CAs), such as the cyclophosphamide (CYP) and ifosfamide (IFO) structural isomers, represent a unique threat. This research elucidated the fate of CYP and IFO during ozonation and advanced oxidation by hydroxyl radicals (HO^•). Novel semi-batch reactors were used to determine the second-order rate constants for CYP and IFO with O₃ and HO^•. These reactors provided independent control of the oxidant exposure through continuous and constant aqueous ozone and peroxone (O₃-H₂O₂) addition. The rate constants for transformation of CYP and IFO by ozone were 2.58 ± 0.40 M^-1s^-1 and 6.95 ± 0.21 M^-1s^-1, respectively, indicating that ozone alone is not suitable for treating CAs. Transformation of CYP and IFO by hydroxyl radicals was fast, with rate constants of 2.69(±0.17)×10⁹ M^-1s^-1 and 2.73(±0.16)×10⁹ M^-1s^-1, respectively. The major transformation products formed by O₃ and HO attack consisted of the 4-hydroxy-, 4-keto-, dechloroethyl-, and imino- derivatives of CYP and IFO. Low yields of the active metabolites of the CAs, namely phosphoramide mustard and isophosphoramide mustard, were detected. These findings suggest that treated water may retain the ability to alkylate DNA and confer toxicity.

3D printing and coating to fabricate a hollow bullet-shaped implant with porous surface for controlled cytoxan release

Intratumoral implants have aroused great interests for local chemotherapy of cancer, however, how to efficiently control drug release from implants is still a great challenge. Herein, we designed and prepared a new hollow bullet-shaped implant with porous surface by 3D printing, loaded chemotherapeutic agent cytoxan (CTX) with tetradecyl alcohol or lecithin as matrix and coated it with poly (lactic acid) to obtain a CTX implant, which has a highly tuned drug release property with a drug release time from 4 h to more than 1 month. The drug release from the implant can be easily controlled by changing pore sizes, kinds of matrices, and coating thickness.

A homogalacturonan from Hippophae rhamnoides L. Berries enhance immunomodulatory activity through TLR4/MyD88 pathway mediated activation of macrophages

Our previous study isolated a natural high-methoxyl homogalacturonan (HRWP-A) from Hippophae rhamnoides and showed antitumor activity in vivo. In this study, the immunomodulatory activity and mechanisms of action of HRWP-A were further investigated. Results showed that HRWP-A could recover the body condition and activated macrophage in Cyclophosphamide (CTX)-induced immunosuppressed mice. Further, we investigated the possible mechanism underlying the effects of HRWP-A on mouse peritoneal macrophages. qPCR and western blot revealed that HRWP-A upregulated the expression of TLR4 mRNA in vitro. This process was accompanied by a clear increase in MyD88 expression and p-IκB-α, but these effects were largely abrogated by pretreatment with anti-TLR4 antibodies. The effects of HRWP-A on macrophage NO, IL-1β and IL-6 production were also inhibited by anti-TLR4 antibodies and were greatly influenced by the NF-κB inhibitor PDTC. Moreover, HRWP-A failed to induce the production of NO, IL-1β and IL-6 in peritoneal macrophages prepared from C3H/HeJ mice, which have a point mutation in the Tlr4 gene, suggesting the involvement of the TLR4 molecule in HRWP-A-mediated macrophage activation. These results may have important implications for our understanding of the structure-activity relationship of immunopotentiating polysaccharides from medicinal herbs.

The effects and the toxicity increases caused by bicarbonate, chloride, and other water components during the UV/TiO2 degradation of oxazaphosphorine drugs

The influences of HCO₃^-, Cl^-, and other components on the UV/TiO₂ degradation of the antineoplastic agents ifosfamide (IFO) and cyclophosphamide (CP) were studied in this work. The results indicated that the presence of HCO₃^-, Cl^-, NO₃^-, and SO₄^2- in water bodies resulted in lower degradation efficiencies. The half-lives of IFO and CP were 1.2 and 1.1 min and increased 2.3-7.3 and 3.2-6.3 times, respectively, in the presence of the four anions (initial compound concentration = 100 μg/L, TiO₂ loading =100 mg/L, anion concentration = 1000 mg/L, and pH = 8). Although the presence of HCO₃^- in the UV/TiO₂/HCO₃^- system resulted in a lower degradation rate and less byproduct formation for IFO and CP, two newly identified byproducts, P11 (M.W. = 197) and P12 (M.W. = 101), were formed and detected, suggesting that additional pathways occurred during the reaction of •CO₃^- in the system. The results also showed that •CO₃^- likely induces a preferred ketonization pathway. Besides the inorganic anions HCO₃^-, Cl^-, NO₃^-, and SO₄^2-, the existence of dissolved organic matter in the water has a significant effect and inhibits CP degradation. Toxicity tests showed that higher toxicity occurred in the presence of HCO₃^- or Cl^- during UV/TiO₂ treatment and within 6 h of reaction time, implying that the effects of these two anions should not be ignored when photocatalytic treatment is applied to treat real wastewater.

Eltrombopag for the treatment of aplastic anemia: current perspectives

Aplastic anemia (AA) is a potential life-threatening hematopoietic stem cell (HSC) disorder resulting in cytopenia. The mainstays of treatment for AA are definitive therapy to restore HSCs and supportive measures to ameliorate cytopenia-related complications. The standard definitive therapy is HSC transplantation for young and medically fit patients with suitable donors and immunosuppressive therapy (IST) with antithymocyte globulin and cyclosporine for the remaining patients. A significant proportion of patients are refractory to IST or relapse after IST. Various strategies have been explored in these patients, including second course of antithymocyte globulin, high-dose cyclophosphamide, and alemtuzumab. Eltrombopag, a thrombopoietin mimetic, has recently emerged as an encouraging and promising agent for patients with refractory AA. It has demonstrated efficacy in restoring trilineage hematopoiesis, and this positive effect continues after discontinuation of the drug. There are ongoing clinical trials exploring the role of eltrombopag as a first-line therapy in moderate to severe AA and a combination of eltrombopag with IST in severe AA.

Effectiveness of a Closed-System Transfer Device in Reducing Surface Contamination in a New Antineoplastic Drug-Compounding Unit: A Prospective, Controlled, Parallel Study

Background

The objective of this randomized, prospective and controlled study was to investigate the ability of a closed-system transfer device (CSTD; BD-Phaseal) to reduce the occupational exposure of two isolators to 10 cytotoxic drugs and compare to standard compounding devices.

Methods and Findings

The 6-month study started with the opening of a new compounding unit. Two isolators were set up with 2 workstations each, one to compound with standard devices (needles and spikes) and the other using the Phaseal system. Drugs were alternatively compounded in each isolator. Sampling involved wiping three surfaces (gloves, window, worktop), before and after a cleaning process. Exposure to ten antineoplastic drugs (cyclophosphamide, ifosfamide, dacarbazine, 5-FU, methotrexate, gemcitabine, cytarabine, irinotecan, doxorubicine and ganciclovir) was assessed on wipes by LC-MS/MS analysis. Contamination rates were compared using a Chi² test and drug amounts by a Mann-Whitney test. Significance was defined for p<0.05. Overall contamination was lower in the “Phaseal” isolator than in the “Standard” isolator (12.24% vs. 26.39%; p < 0.0001) although it differed according to drug. Indeed, the contamination rates of gemcitabine were 49.3 and 43.4% (NS) for the Standard and Phaseal isolators, respectively, whereas for ganciclovir, they were 54.2 and 2.8% (p<0.0001). Gemcitabine amounts were 220.6 and 283.6 ng for the Standard and Phaseal isolators (NS), and ganciclovir amounts were 179.9 and 2.4 ng (p<0.0001).

Conclusion

This study confirms that using a CSTD may significantly decrease the chemical contamination of barrier isolators compared to standard devices for some drugs, although it does not eliminate contamination totally.

Ecotoxicity and genotoxicity of cyclophosphamide, ifosfamide, their metabolites/transformation products and their mixtures

Cyclophosphamide (CP) and ifosfamide (IF) are commonly used cytostatic drugs that repress cell division by interaction with DNA. The present study investigates the ecotoxicity and genotoxicity of CP, IF, their human metabolites/transformation products (TPs) carboxy-cyclophosphamide (CPCOOH), keto-cyclophosphamide (ketoCP) and N-dechloroethyl-cyclophosphamide (NdCP) as individual compounds and as mixture. The two parent compounds (CP and IF), at concentrations up to 320 mg L(-1), were non-toxic towards the alga Pseudokirchneriella subcapitata and cyanobacterium Synecococcus leopoliensis. Further ecotoxicity studies of metabolites/TPs and a mixture of parent compounds and metabolites/TPs performed in cyanobacteria S. leopoliensis, showed that only CPCOOH (EC50 = 17.1 mg L(-1)) was toxic. The measured toxicity (EC50 = 11.5 mg L(-1)) of the mixture was lower from the toxicity predicted by concentration addition model (EC50 = 21.1 mg L(-1)) indicating potentiating effects of the CPCOOH toxicity. The SOS/umuC assay with Salmonella typhimurium revealed genotoxic activity of CP, CPCOOH and the mixture in the presence of S9 metabolic activation. Only CPCOOH was genotoxic also in the absence of metabolic activation indicating that this compound is a direct acting genotoxin. This finding is of particular importance as in the environment such compounds can directly affect DNA of non-target organisms and also explains toxicity of CPCOOH against cyanobacteria S. leopoliensis. The degradation study with UV irradiation of samples containing CP and IF showed efficient degradation of both compounds and remained non-toxic towards S. leopoliensis, suggesting that no stable TPs with adverse effects were formed. To our knowledge, this is the first study describing the ecotoxicity and genotoxicity of the commonly used cytostatics CP and IF, their known metabolites/TPs and their mixture. The results indicate the importance of toxicological evaluation and monitoring of drug metabolites as they may be for certain aquatic species more hazardous than parent compounds.

The leaching behavior of cyclophosphamide and ifosfamide from soil in the presence of co-contaminant--Mixture sorption approach

Anticancer drugs (ACDs) exhibit high biological activity, they are cytotoxic, genotoxic, and are constantly released into the environment as a result of incomplete metabolism. Consequently they pose a serious threat to the environment and human health due to their carcinogenic, mutagenic and/or reproductive toxicity properties. Knowledge of their bioavailability, including their sorption to soils and their impact on the soil-groundwater pathway, is crucial for their risk assessment. Laboratory batch and column leaching tests are important tools for determining the release potential of contaminants from soil or waste material. Batch and column tests were carried out with soils differing in physicochemical properties, each spiked with cyclophosphamide (CK) or ifosfamide (IF). Moreover, due to the fact that environmental pollutants may occur as coexisting compounds in the soil the mobility evaluation for ACDs in the mixture with metoprolol (MET; β-blocker) as a co-contaminant was performed. In order to assess appropriateness, the batch and column tests were compared. The release depended on the properties of both the soil and the presence of co-contaminants. The faster release was observed for coarse-grained soil with the smallest organic matter content (MS soil: 90% decrease in concentration until liquid-to-solid ratio (L/S) of 0.3 L kg(-1) for all tests' layout) than for loamy sand (LS soil: 90% decrease in concentration until ratio L/S of 0.75 L kg(-1)). ACDs are highly mobile in soil systems. Furthermore, the decrease of mobility of ifosfamide was observed with the presence of a co-contaminant (metoprolol) in both of the soils (in MS soil a decrease of 29%; in LS soil a decrease of 26%). The mobility of cyclophosphamide does not depend on the presence of a contaminant for MS soil, but also exhibits a decrease of 21% in LS soil.

Degradation of cyclophosphamide and 5-fluorouracil by UV and simulated sunlight treatments: Assessment of the enhancement of the biodegradability and toxicity

The presence of pharmaceuticals in the environment has triggered concern among the general population and received considerable attention from the scientific community in recent years. However, only a few publications have focused on anticancer drugs, a class of pharmaceuticals that can exhibit cytotoxic, genotoxic, mutagenic, carcinogenic and teratogenic effects. The present study investigated the photodegradation, biodegradation, bacterial toxicity, mutagenicity and genotoxicity of cyclophosphamide (CP) and 5-fluorouracil (5-FU). The photodegradation experiments were performed at a neutral to slight pH range (7-7.8) using two different lamps (medium-pressure mercury lamp and a xenon lamp). The primary elimination of the parent compounds was monitored by means of liquid chromatography tandem mass spectrometry (LC-IT-MS/MS). NPOC (non-purgeable organic carbon) analyses were carried out in order to assess mineralization rates. The Closed Bottle Test (CBT) was used to assess ready biodegradability. A new method using Vibrio fischeri was adopted to evaluate toxicity. CP was not degraded by any lamp, whereas 5-FU was completely eliminated by irradiation with the mercury lamp but only partially by the Xe lamp. No mineralization was observed for the experiments performed with the Xe lamp, and a NPOC removal of only 18% was registered for 5-FU after 256 min using the UV lamp. Not one of the parent compounds was readily biodegradable in the CBT. Photo transformation products (PTPs) resulting from photolysis were neither better biodegradable nor less toxic than the parent compound 5-FU. In contrast, the results of the tests carried out with the UV lamp indicated that more biodegradable and non-toxic PTPs of 5-FU were generated. Three PTPs were formed during the photodegradation experiments and were identified. The results of the in silico QSAR predictions showed positive mutagenic and genotoxic alerts for 5-FU, whereas only one of the formed PTPs presented positive alerts for the genotoxicity endpoint.

[Examination of Measures for Preventing Exposure in Nurses Who Handle Cyclophosphamide]

Health hazards due to long-term exposure to anticancer drugs have been reported among health care professionals. In Yamagata Prefectural Central Hospital, constant use of personal protective equipment(gloves and mask with face shield)is mandatory, but there is no clear description of the protective gown. To verify the exposure status of nurses while handling cyclophosphamide and the usefulness of a protective gown as a protective measure, urinary concentration of cyclophosphamide was measured for nurses who handled cyclophosphamide. No cyclophosphamide was detected in the urine samples collected from nurses who handled cyclophosphamide while wearing protective gowns or in the samples collected from nurses who handled cyclophosphamide without protective gowns. This finding suggests that gloves and a mask with a face shield are sufficient for preventing exposure to cyclophosphamide. However, considering that only experienced nurses were included as subjects in this study, we cannot conclude that a protective gown is unnecessary, because inexperienced nurses may be exposed to cyclophosphamide. Our study's findings may be one reference to examine measures for preventing exposure in nurses.

Antioxidant potential of Phyllanthus fraternus Webster on cyclophosphamide induced changes in sperm characteristics and testicular oxidative damage in mice

Cyclophasphamide (CPA) is used to treat various types of cancer. It is a cytotoxic alkylating agent widely used in chemotherapeutic regimen. However, the clinical efficacy of CPA is marred by its side effects. In clinical applications of CPA, it becomes necessary to prevent the oxidative stress and reproductive toxicity induced thereby in normal cells. In the present study, we investigated the protective effect of aqueous extract of Phyllanthus fraternus (AEPF) on CPA (200 mg/kg body wt., i.p.) induced changes in sperm characteristics and testicular oxidative damage in male mice. The CPA treated group showed significant decrease in gonadosomatic index (GSI), epididymal sperm count, sperm motility and sperm viability compared to control group, while the CPA + AEPF treated group had significant increase with respect to these variables compared to the CPA-treated group. The elevated levels of lipid peroxidation by CPA were effectively reduced with AEPF. It also exhibited protective action against the CPA induced depletion of antioxidants like catalase and superoxide dismutase. DNA damage was measured by comet assay, biomonitoring with comet assay elicited significant increase in genotoxicity. Genotoxicity caused by CPA was counteracted by aqueous extract of Phyllanthus fraternus. Administration of the plant extract along with CPA restored the histopathological architecture of testis. Thus, the aqueous extract of P. fraternus by virtue of its antioxidant potential can be used as an effective agent to reduce CPA-induced oxidative stress in male mice.

TiO2 photocatalytic degradation and transformation of oxazaphosphorine drugs in an aqueous environment

This study investigated the TiO2 photocatalytic degradation and transformation of the oxazaphosphorines ifosfamide (IFO), cyclophosphamide (CP) and trofosfamide (TRO). Under the optimum conditions of TiO2=100mg/L, IFO=100μg/L and solution pH=5.5, IFO was completely removed within 10min (k=0.433min(-1)). The results indicated that OHfree radicals generated by valence holes in the bulk solution were the predominant species for the degradation of IFO. At higher initial concentrations of oxazaphosphorines (20mg/L), >50% of TOC remained after 6h of reaction time, indicating that parent compounds were transformed to byproducts, which exhibit higher Microtox acute toxicities; chlorinated byproducts were likely the source of toxicity. Photocatalytic degradation pathways of the three oxazaphosphorines were proposed. IFO, CP and TRO follow very similar pathways and bond-breaking processes: ketonization and breaking of the CCl bond, the PN bond and the CN bond (N-dechloroethylation). Chloride (Cl(-)) release is likely the first and primary step in the decomposition process. Several of the identified byproducts were also metabolites, which implies that photocatalytic oxidation proceeds through pathways that are similar to metabolic pathways.

Photodegradation of the antineoplastic cyclophosphamide: a comparative study of the efficiencies of UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2 processes

Anticancer drugs are harmful substances that can have carcinogenic, mutagenic, teratogenic, genotoxic, and cytotoxic effects even at low concentrations. More than 50 years after its introduction, the alkylating agent cyclophosphamide (CP) is still one of the most consumed anticancer drug worldwide. CP has been detected in water bodies in several studies and is known as being persistent in the aquatic environment. As the traditional water and wastewater treatment technologies are not able to remove CP from the water, different treatment options such as advanced oxidation processes (AOPs) are under discussion to eliminate these compounds. The present study investigated the degradation of CP by three different AOPs: UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. The light source was a Hg medium-pressure lamp. Prescreening tests were carried out and afterwards experiments based on the optimized conditions were performed. The primary elimination of the parent compounds and the detection of transformation products (TPs) were monitored with LC-UV-MS/MS analysis, whereas the degree of mineralization was monitored by measuring the dissolved organic carbon (DOC). Ecotoxicological assays were carried out with the luminescent bacteria Vibrio fischeri. CP was completely degraded in all treatments and UV/Fe(2+)/H2O2 was the fastest process, followed by UV/H2O2 and UV/TiO2. All the reactions obeyed pseudo-first order kinetics. Considering the mineralization UV/Fe(2+)/H2O2 and UV/TiO2 were the most efficient process with mineralization degrees higher than 85%, whereas UV/H2O2 achieved 72.5% of DOC removal. Five transformation products were formed during the reactions and identified. None of them showed significant toxicity against V. fischeri.

Removal of antineoplastic drugs cyclophosphamide, ifosfamide, and 5-fluorouracil and a vasodilator drug pentoxifylline from wastewaters by ozonation

We investigated the ozonation of the antineoplastic drugs cyclophosphamide (CP), ifosfamide (IF), and 5-fluorouracil (5-FU) and of the vasodilator pentoxifylline (PEN) in distilled water, in pharmaceutical wastewater, and in hospital effluent at pH 5-11. Under an alkaline pH of 11, all of the target compounds rapidly degraded through the attack of hydroxyl radicals, which resulted in their complete removal within 5 min at an ozone supply rate of 3 g O3/h. Under acidic pH conditions, such as pH 5.6, CP and IF exhibited slower removal rates; however, compounds with unsaturated C-C bonds, such as 5-FU and PEN, were still removed at rapid rates under acidic conditions. Although the parent compounds were removed within minutes, the resulting ozonation byproducts were resistant to further ozonation and possessed increased Microtox acute toxicity. In distilled water, the resulting ozonation products exhibited minimal mineralization but high acute toxicity, whereas in naturally buffered pharmaceutical and hospital effluents, the byproducts were more amenable to removal and detoxification.

Concurrent evaluation of general, immune, and genetic toxicity endpoints as part of an integrated testing strategy

Integrated testing strategies involve the assessment of multiple endpoints within a single toxicity study and represent an important approach for reducing animal use and streamlining testing. The present study evaluated the ability to combine general, immune, and genetic toxicity endpoints into a single study. Specifically, this study evaluated the impact of sheep red blood cell (SRBC) immunization, as part of the T-cell dependent antibody response (TDAR) assay, on organ weights, micronuclei (MN) formation (bone marrow and peripheral blood), and the Comet assay response in the liver of female F344/DuCrl rats treated with cyclophosphamide (CP) a known immunosuppressive chemical and genotoxicant. For the TDAR assay, treatment with CP resulted in a dose-dependent decrease in the antibody response with a suppression of greater than 95% at the high dose. Injection with SRBC had no impact on evaluated organ weights, histopathology, hematology, and clinical chemistry parameters. Analysis of MN formation in bone marrow and peripheral blood revealed a dose-dependent increase in response to CP treatment. Injection with SRBC had no impact on the level of MN in control animals and did not alter the dose response of CP. There was a slight increase in liver DNA damage in response to CP as measured by the Comet assay; however, injection with SRBCs did not alter this endpoint. Overall these data provide strong support for the concurrent assessment of general, immune, and genetic toxicology endpoints within a single study as part of an integrated testing strategy approach.

[Verification of reduction in preparation time and cost of cyclophosphamide when using the closed-system drug transfer device]

The closed-system transfer device (CSTD), which is used to prevent the exposure of medical staff to anticancer drugs, has been reported to allow safe preparation and administration of these drugs to patients. At many medical institutions, however, the use of such devices is limited to select anticancer drugs. This could be attributable to the longer preparation time compared to the conventional injection technique with a syringe and needle, as well as the fact that the anticancer drugs are too expensive to be covered by the remuneration available for medical services. Against this background, we measured the time required to prepare cyclophosphamide(CPA)and estimated the cost incurred. Our results indicated that the preparation time for either a single dose of 100 mg CPA or a combination of 100 mg CPA and 500 mg of another drug(100mg+500 mg group)was significantly longer than that for 500 mg of a single drug. On the other hand, use of a CSTD reduced the total cost (drug cost+CSTD cost)on switching to a single dose of 500 mg, resulting in a 5-year savings as follows: 3,755,217 yen for ChemoCLAVE®, 6,302,622 yen for PhaSeal®, and 2,698,451 yen for Chemosafe®. These findings suggest that the appropriate selection of drugs, including a large standard dose of CPA, allows shortened preparation time and reduced total drug cost as well as CSTD cost.

[Perspectives of use of polymer carriers of epidoxorubicin and cyclophosphamide in cancer therapy]

Cancer diseases are an important problem of the contemporary clinical medicine and pharmacology. Chemotherapy using cytostatic drugs has developed in the last 30 years. At present, it is the main method of therapy of metastatic cancers. Cytostatics have an important role in the cancer therapy. They have particular meaning in the therapy of solid and hematological tumors. However, using cytostatic drugs is limited due to their toxic effects on healthy cells. In last years, the decrease of toxicity of cytostatic drugs and the increase of their therapeutic properties are intensively investigated. In this paper, the polymer carriers of cytostatic drugs (mainly epirubicin and cyclophosphamide) and examples of their applications were described.

[Anti-tumor effects of a novel cyclophosphamide derivate 9b in vivo and in vitro]

This study is to investigate the anti-tumor activities of a novel cyclophosphamide derivate 4, 6-diphenyl cyclophosphamide (9b) in vivo and in vitro, and its possible mechanism of action. The inhibitory effects of 9b on human hepatoma cell line HepG2, human breast carcinoma cell line MCF-7 and human myeloid leukemia cell line K562 were measured by MTT assay in vitro. Cell cycle distribution and apoptotic rate were evaluated by flow cytometry. To evaluate the anti-tumor effect of 9b in vivo, mouse model bearing inoculated H22 tumor was established. The results indicated that 9b could inhibit the proliferation of HepG2, MCF-7 and K562 cells in a dose and time dependent manner. The ICo50 values of 9b were 32.34 micromol.L-1 to HepG2 cells, 87.07 micromol.L-1 to MCF-7 cells and 149.10 micromol.L-1 to K562 cells after incubation for 48 h. The results of flow cytometry indicated that after being treated for 48 h with different concentrations of 9b, the ratios of HepG2, MCF-7 cells at the Go/G1 phase and K562 cells at the G0/Gl phase and G2/M phase increased significantly compared with control group, and the apoptotic rate increased with the increase of the concentration of 9b. 9b could significantly reduce tumor weight of H22 solid tumor mouse model in vivo. To summarize, 9b showed significantly anti-tumor activity in vivo and in vitro, of which the mechanism might be associated with the change of cell cycle distribution and induction of tumor cell apoptosis.

Photocatalytic oxidation of 5-fluorouracil and cyclophosphamide via UV/TiO2 in an aqueous environment

Cytostatic drugs are a class of pharmaceuticals that are increasingly used in cancer therapies; 5-fluorouracil is one of the most commonly used cytostatic (antineoplastic) drugs in the world. This study applied photocatalytic oxidation to remove 5-fluorouracil. Degussa P25 showed a higher photocatalytic degradation efficiency for 5-fluorouracil removal than Aldrich TiO2 and ZnO. Under optimal conditions (20 mg L(-1) TiO2 at pH 5.8), 200 μg L(-1) 5-fluorouracil can be removed within 2 h (k = 0.0375 min(-1)). 5-fluorouracil was found to be decomposed by near-surface OH free radicals produced from valence holes (hvb(+)). At a relatively high concentration, 5-fluorouracil (27.6 mg L(-1)) is >99.9% removed within 4 h by 300 mg L(-1) Degussa P25, while 24 h is required to reach complete mineralization with 96.7% fluoride recovery. Cyclophosphamide is another widely used cancer drug that follows a similar decomposition pathway. Cyclophosphamide (27.6 mg L(-1)) was also >99.9% eliminated within 4 h, but dechlorination and mineralization reached only 79.9% and 55.1%, respectively, after 16 h of irradiation. Together with the results for Microtox(®), it is suggested that the oxidation products of cyclophosphamide are even more recalcitrant and toxic. For engineering practices, despite the fact that photocatalytic oxidation can rapidly remove target antineoplastic, it is also important to further evaluate the treatment efficiency of the photoproducts.

Phototransformation determines the fate of 5-fluorouracil and cyclophosphamide in natural surface waters

The use of cytotoxic substances, such as 5-fluorouracil and cyclophosphamide, is carefully controlled; however, these medications may still enter bodies of water through wastewater discharge. These substances may pose risks to stream and river life, as well as to humans via drinking water. In this study, the photochemical fate of 5-fluorouracil and cyclophosphamide was investigated in synthetic waters and four river waters and was found to be the most important attenuation process for each entity in natural surface waters. Bicarbonate alone was found to react with the excited states of 5-fluorouracil, thus enhancing direct photolysis rates. In the presence of nitrate and significant amounts of bicarbonate (close to 2 mM), 5-fluorouracil was rapidly removed (within 1 day) through indirect photolysis. In contrast, natural attenuation was of low importance for cyclophosphamide in most surface waters studied. A long, shallow river or lake with a long residence time (>7 days), very low alkalinity, and significant nitrate levels (>5 mg-N L(-1)) may be an exception. The phototransformation product of 5-fluorouracil was also identified. However, the total organic carbon experiments yielded important results: photolysis resulted in quick transformation of 5-fluorouracil but minimal mineralization. Additional studies of the toxicity of photobyproducts of 5-fluorouracil are needed to determine the true risk to human health of 5-fluorouracil contamination of surface water, given its near-total photodegradation and resultant, deceptively low detection rate in surface waters.

Fluorescent proteins as visible in vivo sensors

Fluorescent proteins have enabled a whole new technology of visible in vivo genetic sensors. Fluorescent proteins have revolutionized biology by enabling what was formerly invisible to be seen clearly. These proteins have allowed us to visualize, in real time, important aspects of cancer in living animals, including tumor cell mobility, invasion, metastasis, and angiogenesis. These multicolored proteins have allowed the color coding of cancer cells growing in vivo and enabled the distinction of host from tumor with single-cell resolution. Whole-body imaging with fluorescent proteins has been shown to be a powerful technology to noninvasively follow the dynamics of metastatic cancer. Whole-body imaging of cancer cells expressing fluorescent proteins has enabled the facile determination of efficacy of candidate antitumor and antimetastatic agents in mouse models. The use of fluorescent proteins to differentially label cancer cells in the nucleus and cytoplasm and high-powered imaging technology have enabled the visualization of the nuclear-cytoplasmic dynamics of cancer cells in vivo, including noninvasive techniques. Fluorescent proteins thus enable both macro- and microimaging technology and thereby provide the basis for the new field of in vivo cell biology.

Separate and simultaneous binding effects through a non-cooperative behavior between cyclophosphamide hydrochloride and fluoxymesterone upon interaction with human serum albumin: multi-spectroscopic and molecular modeling approaches

This study was designed to examine the interaction of two anti-breast cancer drugs, i.e., fluoxymesterone (FLU) and cyclophosphamide (CYC), with human serum albumin (HSA) using different kinds of spectroscopic, zeta potential and molecular modeling techniques under imitated physiological conditions. The RLS technique was utilized to investigate the effect of the two anticancer drugs on changes of the protein conformation, both separately and simultaneously. Our study suggested that the enhancement in RLS intensity was attributed to the formation of a new complex between the two drugs and the protein. Both drugs demonstrated a powerful ability to quench the fluorescence of HSA, and the fluorescence quenching action was much stronger when the two drugs coexisted. The quenching mechanism was suggested to be static as confirmed by time-resolved fluorescence spectroscopy results. The effect of both drugs on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy. Our results revealed that the fluorescence quenching of HSA originated from the Trp and Tyr residues, and demonstrated a conformational change of HSA with the addition of both drugs. The binding distances between HSA and the drugs were estimated by the Förster theory, and it was revealed that nonradiative energy transfer from HSA to both drugs occurred with a high probability. According to CD measurements, the influence of both drugs on the secondary structure of HSA in aqueous solutions was also investigated and illustrated that the α-helix content of HSA decreased with increasing drug concentration in both systems. Moreover, the zeta-potential experiments revealed that both drugs induced conformational changes on HSA. Docking studies were also performed and demonstrated that a reduction of the binding affinity between the drugs and HSA occurred in the presence of both drugs.

Replacement of conventional doxorubicin by pegylated liposomal doxorubicin is a safe and effective alternative in the treatment of non-Hodgkin's lymphoma patients with cardiac risk factors

Anthracyclines are a major component in the therapy of non-Hodgkin's lymphoma. However, due to their cardiac toxicity potential, curative and palliative treatment is often limited in patients with preexisting cardiac dysfunction. Liposomal doxorubicin formulations have been described to be less cardiotoxic than conventional doxorubicin. In the current study, we analyzed the efficacy and toxicity of pegylated liposomal doxorubicin (PLD) as constituent of the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen replacing conventional doxorubicin in 21 patients with impaired cardiac left ventricular ejection fraction or preexisting cardiac risk factors and established diagnosis of diffuse large B cell lymphoma (n = 15), mantle cell lymphoma (n = 3), follicular lymphoma (n = 1), and T cell lymphoma (n = 2). Overall and complete response rate were 85% and 40%, respectively. Event-free survival and overall survival after 2 years were 58%. One lethal event of acute cardiac death occurred during the first cycle in a patient with transposition of the big arteries, atrial flutter, and mitral valve regurgitation. In the remaining 20 patients, no deterioration of myocardial function was observed in echocardiography performed before and after treatment. Seven cases of grade III-IV hematological toxicity were observed as well as four episodes of neutropenic fever leading to hospitalization. No infection-related death occurred. However, 25% of patients developed a hand-foot syndrome (HFS) leading to discontinuation of treatment. Importantly, the incidence of HFS increased considerably when PLD doses of 15 mg/m(2)/week were exceeded. We conclude that replacing conventional doxorubicin with PLD in polychemotherapy regimens such as CHOP is an efficient alternative in the treatment of patients with preexisting cardiac dysfunction. However, we recommend that PLD dose should not exceed 15 mg/m(2)/week. The rationale for the use of non-pegylated liposomal doxorubicin formulations should be evaluated in further studies.

Comparison of APPI, APCI and ESI for the LC-MS/MS analysis of bezafibrate, cyclophosphamide, enalapril, methotrexate and orlistat in municipal wastewater

The applicability of three different ionization techniques: atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) was tested for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of five target pharmaceuticals (cyclophosphamide, methotrexate, bezafibrate, enalapril and orlistat) in wastewater samples. Performance was compared both by flow injection analysis (FIA) and on-column analysis in deionized water and wastewater samples. A column switching technique for the on-line extraction and analysis of water samples was used. For both FIA and on-column analysis, signal intensity and signal-to-noise (S/N) ratio of the target analytes in the three sources were studied. Limits of detection and matrix effects during the analysis of wastewater samples were also investigated. ESI generated significantly larger peak areas and higher S/N ratios than APCI and APPI in FIA and in on-column analysis. ESI was proved to be the most suitable ionization method as it enabled the detection of the five target compounds, whereas APCI and APPI ionized only four compounds.

Oxidation kinetics of cyclophosphamide and methotrexate by ozone in drinking water

This study investigates the aqueous degradation by ozone of two target cytostatic drugs, cyclophosphamide and methotrexate. A column switching technique for on-line solid phase extraction (SPE) coupled to electro-spray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was used for the simultaneous detection of the trace contaminants. The second-order kinetic rate constants for the reaction of cyclophosphamide with molecular ozone and hydroxyl radicals were determined in bench-scale experiments at pH 8.10. The molecular ozone oxidation kinetics was studied in buffered ultrapure water and compared to the oxidation kinetics in natural water from a municipal drinking water treatment plant in the province of Quebec (Canada). For cyclophosphamide, the degradation rate constant with molecular ozone in ultrapure water was low (k(O3)=3.3+/-0.2M(-1)s(-1)) and the extent of oxidation was linearly correlated to the ozone exposure. The impact of water quality matrix on oxidation efficacy was not significant during direct ozone reaction (k(O3) =2.9+/-0.3M(-1)s(-1)). The rate constant with hydroxyl radicals was higher at 2.0 x 10(9) M(-1)s(-1). Methotrexate reacted quickly with molecular ozone at dosages typically applied in drinking water treatment (k(O3)>3.6 x 10(3)M(-1)s(-1)). Overall, the results confirmed that organic compounds reactivity with ozone was dependent of their chemical structure. Ozone was very effective against methotrexate but high oxidant concentration x contact time (CT) values were required to completely remove cyclophosphamide from drinking water. Further studies should be conducted in order to identify the ozonation by-products and explore the impact of ozone on their degradation and toxicity.

Gas-fragmentation study of the novel synthetic zwitterionic drug 3-methyl-9-(2-oxa-2lambda5-2H-1,3,2-oxazaphosphorine-2-cyclohexyl)-3,6,9-triazaspiro[5,5]undecane chloride (SLXM-2) by electrospray ionization tandem mass spectrometry

The zwitterionic drug 3-methyl-9-(2-oxa-2lambda5-2H-1,3,2-oxazaphosphorine-2-cyclohexyl)-3,6,9-triazaspiro[5,5]undecane chloride (SLXM-2) is a novel synthetic compound which has shown anticancer activity and low toxicity in vivo. In this study, the various gas-phase fragmentation routes were analyzed by electrospray ionization mass spectrometry (positive ion mode) in conjunction with tandem mass spectrometry (ESI-MS(n)) for the first time. In ESI-MS the fragment ion at m/z 289 (base peak) was formed by loss of the chlorine anion from the zwitterionic precursor SLXM-2. The fragment ion at m/z 232 was formed from the ion at m/z 289 by loss of 1-methylaziridine. The detailed gas-phase collision-induced dissociation (CID) fragmentation mechanisms obtained from the various precursor ions extracted from the zwitterionic SLXM-2 drug was obtained by tandem mass spectrometry analyses.

Estimation of the cancer risk to humans resulting from the presence of cyclophosphamide and ifosfamide in surface water

BACKGROUND, AIM, AND SCOPE

Anti-tumour agents and their metabolites are largely excreted into effluent, along with other pharmaceuticals. In the past, investigations have focused on the input and analysis of pharmaceuticals in surface and ground water. The two oxazaphosphorine compounds, cyclophosphamide and ifosfamide are important cytostatic drugs used in the chemotherapy of cancer and in the treatment of autoimmune diseases. Their mechanism of action, involving metabolic activation and unspecific alkylation of nucleophilic compounds, accounts for genotoxic and carcinogenic effects described in the literature and is reason for environmental concern. The anti-tumour agents cyclophosphamide (CP) and ifosfamide (IF) were not biodegraded in biodegradation tests. They were not eliminated in municipal sewage treatment plants. Degradation by photochemically formed HO radicals may be of some relevance only in shallow, clear, and nitrate-rich water bodies but could be further exploited for elimination of these compounds by advanced oxidation processes, i.e. in a treatment of hospital waste water. Therefore, CP and IF are assumed to persist in the aquatic environment and to enter drinking water via surface water. The risk to humans from input of CP and IF into surface water is not known.

MATERIALS AND METHODS

The local and regional, i.e. nationwide predicted environmental concentration (PEC(local), PEC(regional)) of CP and IF was calculated for German surface water. Both compounds were measured in hospital effluents, and in the influent and effluent of a municipal treatment plant. Additionally, published concentrations in the effluent of sewage treatment plants and surface water were used for risk assessment. Excretion rates were taken into account. For a worst-case scenario, maximum possible ingestion of CP or IF by drinking 2 L a day of unprocessed surface water over a life span of 70 years was calculated for adults. Elimination in drinking water processing was neglected, as no data is available. This intake was compared with intake during anti-cancer treatment.

RESULTS AND DISCUSSION

Intake of CP and IF for anti-cancer treatment is typically 10 g within a few months. Under such conditions, a relative risk of 1.5 for the carcinogenic compounds CP and IF is reported in the literature. In the worst case, the maximum possible intake by drinking water is less than 10(-3) (IF) and 10(-5) (CP) of this amount, based on highest measured local concentrations. On a nationwide average, the factor is approx. 10(-6) or less.

CONCLUSIONS

The additional intake of CP and IF due to their emission into surface water and its use without further treatment as drinking water is low compared to intake within a therapy. This approach has shortcomings. It illustrates the current lack of methodology and knowledge for the specific risk assessment of carcinogenic pharmaceuticals in the aquatic environment. IF and CP are directly reacting with the DNA. Therefore, with respect to health effects a safe threshold concentration for these compounds cannot be given. The resulting risk is higher for newborns and children than for adults. Due to the lack of data the risk for newborns and children cannot be assessed fully. The data presented here show that according to present knowledge the additional risk of cancer cannot be fully excluded, especially with respect to children. Due to the shortage of data for effects of CP and IF in low doses during a whole lifespan, possible effects were assessed using data of high doses of CP and IF within short-term ingestion, i.e. therapy. This remains an unresolved issue. Anyway, the risk assessment performed here could give a rough measure of the risks on the one hand and the methodological shortcomings on the other hand which are connected to the assessment of the input of genotoxic and carcinogenic pharmaceuticals such as CP and IF into the aquatic environment. Therefore, we recommend to take measures to reduce the input of CP and IF and other carcinogenic pharmaceuticals. We hope that our manuscript further stimulates the discussion about the human risk assessment for carcinogenic pharmaceuticals in the aquatic environment.

RECOMMENDATIONS AND PERSPECTIVES

CP and IF are carcinogens. With respect to newborn and children, reduction of the emission of CP and IF into effluent and surface water is recommended at least as a precautionary measure. The collection of unused and outdated drugs is a suitable measure. Collection of patients' excreta as a measure of input reduction is not recommended. Data suitable for the assessment of the risk for newborn and children should be collected in order to perform a risk assessment for these groups. This can stimulate discussion and give new insights into risk assessment for pharmaceuticals in the environment. Our study showed that in the long term, effective risk management for the reduction of the input of CP and IF are recommendable.

Efficiency, costs and benefits of AOPs for removal of pharmaceuticals from the water cycle

Different advanced oxidation processes (AOP) were developed for the treatment of highly loaded wastewater streams. Optimisation of removal and improvement of efficiency were carried out on a laboratory, semiworks and pilot plant scale. The persistent cytostatic drug cyclophosphamide was selected as a reference substance regarding elimination and evaluation of the various oxidation processes because of its low degradability rate. The investigated processes are cost-efficient and suitable regarding the treatment of wastewater streams since they lead to efficient elimination of antibiotics and antineoplastics. A total reduction of toxicity was proven by means of the umuC-test. However, in order to reduce pharmaceuticals from the water cycle, it must be considered that the input of more than 80 % of the pharmaceuticals entering wastewater treatment systems results from private households. Therefore, advanced technologies should also be installed at wastewater treatment plants.

Pharmacodynamic and pharmacokinetic study of chronic low-dose metronomic cyclophosphamide therapy in mice

Prolonged, frequently administered low-dose metronomic chemotherapy (LDM) is being explored (pre)clinically as a promising antiangiogenic antitumor strategy. Although appealing because of a favorable side effect profile and mostly oral dosing, LDM involves new challenges different from conventional maximum tolerated dose chemotherapy. These include possible altered pharmacokinetic characteristics due to long-term drug exposure potentially resulting in acquired resistance and increased risk of unfavorable drug interactions. We therefore compared the antitumor and antivascular effects of LDM cyclophosphamide (CPA) given to mice that had been pretreated with either LDM CPA or normal saline, obtained blood 4-hydroxy-CPA (activated CPA) concentrations using either gas chromatography/mass spectrometry or liquid chromatography/tandem mass spectrometry in mice treated with LDM CPA, and measured hepatic and intratumoral activity of enzymes involved in the biotransformation of CPA and many other drugs [i.e., cytochrome P450 3A4 (CYP3A4) and aldehyde dehydrogenase]. Exposure of mice to LDM CPA for >or=8 weeks did not compromise subsequent activity of LDM CPA therapy, and biologically active 4-hydroxy-CPA levels were maintained during long-term LDM CPA administration. Whereas the effects on CYP3A4 were complex, aldehyde dehydrogenase activity was not affected. In summary, our findings suggest that acquired resistance to LDM CPA is unlikely accounted for by altered CPA biotransformation. In the absence of reliable pharmacodynamic surrogate markers, pharmacokinetic parameters might become helpful to individualize/optimize LDM CPA therapy. LDM CPA-associated changes of CYP3A4 activity point to a potential risk of unfavorable drug interactions when compounds that are metabolized by CYP3A4 are coadministered with LDM CPA.

Occurrence and fate of the cytostatic drugs cyclophosphamide and ifosfamide in wastewater and surface waters

The two oxazaphosphorine compounds cyclophosphamide and ifosfamide are important cytostatic drugs used in the chemotherapy of cancer and in the treatment of autoimmune diseases. Their mechanism of action, involving metabolic activation and unspecific alkylation of nucleophilic compounds, accounts for genotoxic effects described in the literature and is reason for environmental concern. The occurrence and fate of cyclophosphamide and ifosfamide were studied in wastewater treatment plants (WWTPs) and surface waters in Switzerland, using a highly sensitive analytical method based on solid-phase extraction and liquid chromatography tandem mass spectrometry. The compounds were detected in untreated and treated wastewater at concentrations of <0.3-11 ng/L, which corresponded well with concentrations predicted from consumption data and typical renal excretion rates. Weekly loads determined in influent and effluent wastewater were comparable and suggested a high persistence in WWTPs. Furthermore, no degradation was observed in activated sludge incubation experiments within 24 h at concentrations of approximately 100 ng/L. Processes that may be relevant for elimination in natural waterbodies were studied with a set of incubation experiments in the laboratory. After extrapolation to natural conditions in surface waters, a slow dark-chemical degradation (half-lives on the order of years) is the most important transformation process. Degradation by photochemically formed HO* radicals may be of some relevance only in shallow, clear, and nitrate-rich waterbodies but could be further exploited for elimination of these compounds by advanced oxidation processes, i.e., in a treatment of hospital wastewater. In surface waters, concentrations ranged from < or =50 to 170 pg/L and were thus several orders of magnitude lower than the levels at which acute ecotoxicological effects have been reported in the literature (mg/L range). However, due to a lack of studies on chronic effects on aquatic organisms and data on occurrence and effects of metabolites, a final risk assessment cannot be made.

Novel advances in drug delivery to brain cancer

The therapy of brain tumors has been limited by a lack of effective methods of drug delivery to the brain. Systemic administration is often associated with toxic side effects and ultimately fails to achieve therapeutic concentrations within a tumor. An attractive strategy that has gained importance in brain tumor therapy has relied on local and controlled delivery of chemotherapeutic agents by biodegradable polymers. This technique allows direct exposure of tumor cells to a therapeutic agent for a prolonged period of time and has been shown to prolong the survival of patients with malignant brain tumors. The use of polymers for local drug delivery greatly expands the spectrum of drugs available for the treatment of malignant brain tumors. This review discusses the rationale for local drug delivery, describes the development of currently available polymer-based therapeutic agents, and highlights examples of promising non-polymer based drug delivery methods for use in the treatment of malignant brain tumors.

Compatibility of palonosetron with cyclophosphamide and with ifosfamide during simulated Y-site administration

PURPOSE

The physical and chemical compatibility of palonosetron with cyclophosphamide and with ifosfamide during simulated Y-site administration was studied.

METHODS

Test samples were prepared in triplicate by mixing 7.5 mL of palonosetron hydrochloride 50 microg (of palonosetron) per milliliter with 7.5 mL of cyclophosphamide 10 mg/mL and with ifosfamide 20 mg/mL. Physical stability was assessed by turbidimetry, particle sizing, and visual inspection. Chemical stability was assessed by stability-indicating high-performance liquid chromatography. Evaluations were performed immediately and one and four hours after mixing.

RESULTS

The samples were clear and colorless when viewed in normal fluorescent room light and when viewed with a high-intensity monodirectional light. Turbidity remained unchanged, and particulate content was low and exhibited little change. Palonosetron, cyclophosphamide, and ifosfamide remained chemically stable throughout the four-hour test period.

CONCLUSION

Palonosetron hydrochloride was physically compatible with cyclophosphamide or ifosfamide during simulated Y-site administration.

Cytochrome P450 3A and 2B6 in the developing kidney: implications for ifosfamide nephrotoxicity

Repeated administration of agents (e.g., cancer chemotherapy) that can cause drug-induced nephrotoxicity may lead to acute or chronic renal damage. This will adversely affect the health and well-being of children, especially when the developing kidney is exposed to toxic agents that may lead to acute glomerular, tubular or combined toxicity. We have previously shown that the cancer chemotherapeutic ifosfamide (IF) causes serious renal damage substantially more in younger children (less than 3 years of age) than among older children. The mechanism of the age-related IF-induced renal damage is not known. Our major hypothesis is that renal CYP P450 expression and activity are responsible for IF metabolism to the nephrotoxic chloroacetaldehyde. Presently, the ontogeny of these catalytic enzymes in the kidney is sparsely known. The presence of CYP3A4, 3A5 and 2B6 was investigated in human fetal, pediatric and adult kidney as was the metabolism of IF (both R-IF and S-IF enantiomers) by renal microsomes to 2-dechloroethylifosfamide (2-DCEIF) and 3-dechloroethylifosfamide (3-DCEIF). Our analysis shows that CYP 3A4 and 3A5 are present as early as 8 weeks of gestation. IF is metabolized in the kidney to its two enantiomers. This metabolism can be inhibited with CYP 3A4/5 and 2B6 specific monoclonal inhibitory antibodies, whereby the CYP3A4/5 inhibitory antibody decreased the production of R-3-DCEIF by 51%, while the inhibitory CYP2B6 antibody decreased the production of S-2-DCEIF and S-3-DCEIF by 44 and 43%, respectively, in patient samples. Total renal CYP content is approximately six-fold lower than in the liver.

A new high-performance liquid chromatographic/electrospray ionization tandem mass spectrometric method for the simultaneous determination of cyclophosphamide, methotrexate and 5-fluorouracil as markers of surface contamination for occupational exposure monitoring

A new high-performance liquid chromatographic/electrospray ionization tandem mass spectrometric (HPLC/ESI-MS/MS) method was developed for the simultaneous quantification of 5-fluorouracil (5FU), methotrexate (MTX) and cyclophosphamide (CP) in environmental samples. These compounds, commonly used in the treatment of cancer, are recognized as genotoxic. In order to estimate the occupational exposure of hospital personnel handling these drugs, wipe samples were taken from the working surfaces and directly analyzed (with trophosphamide as internal standard) using a reversed-phase capillary column and MS/MS detection. This is the first HPLC/MS/MS method for the simultaneous determination of 5FU, MTX and CP. The present method offers high sensitivity, with detection limits of 1.1 microg l(-1) for MTX and CP and 33.3 microg l(-1) for 5FU, avoiding any sample preconcentration procedure. Rapidity, specificity, high accuracy (mean values between 92.4 and 99.9%) and precision (mean RSD values between 3.4 and 12.1%) make the method suitable for the routine determination of these three antineoplastic drugs.

Tandem mass spectrometric analysis of cyclophosphamide, ifosfamide and their metabolites

A detailed multi-stage (MSn) fragmentation study of cyclophosphamide (CP), ifosfamide (IF) and their major metabolites, using an ion-trap mass spectrometer and a Q-TOF mass spectrometer, was performed with the aid of specifically deuterium-labeled analogs. The analytes showed good responses in positive-ion electrospray mass spectrometry as [MH]+ ions. Tandem mass spectra revealed a wealth of structurally specific ions, allowing characterization of the fragmentation pathways of these analytes. The major fragmentation pathways of the protonated CP and IF are elimination of ethylene from C5 and C6 of 1,3,2-oxazaphosphorine-2-oxide via a McLafferty rearrangement, and cleavage of the P-N bond. However, their activated 4-OOH and 4-OH metabolites primarily underwent hydrogen peroxide elimination and dehydration, respectively, followed by fragmentation pathways similar to those of CP and IF. These results should prove useful in structural elucidation of future analogs of CP and IF, and/or of their metabolites.

Oxidative DNA damage induced by a hydroperoxide derivative of cyclophosphamide

Interstrand DNA cross-linking has been considered to be the primary action mechanism of cyclophosphamide (CP) and its hydroperoxide derivative, 4-hydroperoxycyclophosphamide (4-HC). To clarify the mechanism of anti-tumor effects by 4-HC, we investigated DNA damage in a human leukemia cell line, HL-60, and its H(2)O(2)-resistant clone HP100. Apoptosis DNA ladder formation was detected in HL-60 cells treated with 4-HC, whereas it was not observed in HP100 cells. 4-HC significantly increased 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation, a marker of oxidative DNA damage, in HL-60 cells. On the other hand, CP did not significantly induce 8-oxodG formation and apoptosis in HL-60 cells under the same conditions as did 4-HC. Using (32)P-labeled DNA fragments from the human p53 tumor suppressor gene, 4-HC was found to cause Cu(II)-mediated oxidative DNA damage, but CP did not. Catalase inhibited 4-HC-induced DNA damage, including 8-oxodG formation, suggesting the involvement of H(2)O(2). The generation of H(2)O(2) during 4-HC degradation was ascertained by procedures using scopoletin and potassium iodide. We conclude that, in addition to DNA cross-linking, oxidative DNA damage through H(2)O(2) generation may participate in the anti-tumor effects of 4-HC.

Stability of Cyclophosphamide and Mesna Admixtures in Polyethylene Infusion Bags

BACKGROUND

Cyclophosphamide (CYP) is used to treat cancers in combination with mesna to prevent cystitis. The use of extemporaneously prepared admixtures of these drugs must be supported by documentation of their chemical stability.

OBJECTIVE

To evaluate the chemical stability of CYP and mesna admixtures in dextrose 5% polyethylene infusion bags.

METHODS

The drugs were diluted in 100-mL dextrose 5% infusion bags to final concentrations of CYP 10.8 mg/mL with mesna 3.2 mg/mL (solution A) and CYP 1.8 mg/mL with mesna 0.54 mg/mL (solution B). Six infusion bags from each solution were stored at 4 degrees C and 6 were stored at room temperature. Triplicate HPLC determinations were performed on each bag to measure drug concentrations at 0, 1, 2, 4, 6, 12, 24, 48, and 96 hours.

RESULTS

At 96 hours, drug concentrations in all solutions stored at room temperature were found to be <80% compared with the initial concentrations. The solutions stored at 4 degrees C retained at least 90% of the initial drug concentrations at 48 hours. The pH of solutions A and B stored at room temperature decreased significantly by 4.44 and 4.31 units, respectively. The pH of the refrigerated infusion bags decreased significantly by 1.46 units for solution B.

CONCLUSIONS

Admixtures stored at 4 degrees C (pH 7.90 +/- 0.004; mean +/- SD) are stable for 48 hours. The CYP and mesna combination can be infused at room temperature over 6 hours without significant degradation of the drugs. Stabilities are dependent on pH, temperature, and/or concentration.

ABCC2-Mediated Biliary Transport of 4-Glutathionylcyclophosphamide and Its Contribution to Elimination of 4-Hydroxycyclophosphamide in Rat

Hematopoietic stem cell transplantation patients conditioned with cyclophosphamide (CY) and total body irradiation have substantially greater risk of nonrelapse mortality when plasma area under the concentration-time curve (AUC) of O-carboxyethylcyclophosphoramide mustard (CEPM) is high. The discovery was paradoxical because CEPM is a nontoxic elimination route of the protoxic CY metabolite hydroxycyclophosphamide (HCY). CY was administered to Wistar and TR- rats (a Wistar strain lacking functional ABCC2) at doses of 100 and 200 mg/kg CY, respectively. After either dose, Wistar rats excreted 4-glutathionylcyclophosphamide (GSCY) abundantly in bile; GSCY was absent from bile of TR- rats. Liver AUC(GSCY) was 2- to 2.5-fold greater in TR- than Wistar rats after 100 and 200 mg/kg CY, respectively. Liver AUC(HCY) was 24-46% greater in TR- rats than in Wistar rats after the respective CY doses. Plasma AUC(CEPM) of TR- rats was approximately twice that of Wistar rats after 100 mg/kg, but did not differ between the two strains after 200 mg/kg. Conversely, plasma AUC(HCY) was not different after 100 mg/kg CY, but was 40% greater in TR- rats after 200 mg/kg. The dose dependence of plasma AUC(CEPM) and AUC(HCY) was explained by the concentrations of HCY attained and the in vitro K(m) of aldehyde dehydrogenase and inhibition of aldehyde dehydrogense in TR- rats. We conclude that GSCY is a substrate of ABCC2, and plasma AUC(CEPM) functions as a reporter of liver exposure to HCY and toxins formed from it when HCY concentration is below the K(m) of aldehyde dehydrogenase and the activity is not compromised.

Regioselectivity of CYP2B6: homology modeling, molecular dynamics simulation, docking

Human cytochrome P450 (CYP) 2B6 activates the anticancer prodrug cyclophosphamide (CPA) by 4-hydroxylation. In contrast, the same enzyme catalyzes N-deethylation of a structural isomer, the prodrug ifosfamide (IFA), thus causing severe adverse drug effects. To model the molecular interactions leading to a switch in regioselectivity, the structure of CYP2B6 was modeled based on the structure of rabbit CYP2C5. We modeled the missing 22-residue loop in CYP2C5 between helices F and G (the F-G loop), which is not resolved in the X-ray structure, by molecular dynamics (MD) simulations using a simulated annealing protocol. The modeled conformation of the loop was validated by unconstrained MD simulations of the complete enzymes (CYP2C5 and CYP2B6) in water for 70 and 120 ps, respectively. The simulations were stable and led to a backbone r.m.s. deviation of 1.7 A between the two CYPs. The shape of the substrate binding site of CYP2B6 was further analyzed. It consists of three well-defined hydrophobic binding pockets adjacent to the catalytic heme. Size, shape and hydrophobicity of these pockets were compared to the shapes of the two structurally isomeric substrates. In their preferred orientation in the binding site, both substrates fill all three binding pockets without repulsive interactions. The distance to the heme iron is short enough for 4-hydroxylation and N-deethylation to occur for CPA and IFA, respectively. However, if the substrates are docked in the non-preferred orientation (such that 4-hydroxylation and N-deethylation would occur for IFA and CPA, respectively), one pocket is left empty, and clashes were observed between the substrates and the enzyme.

Kinetic analysis of the reactions of 4-hydroperoxycyclophosphamide and acrolein with glutathione, mesna, and WR-1065

The kinetics of the reactions of glutathione (GSH) with 4-hydroperoxycyclophosphamide (4OOH-CP) and acrolein, a metabolite of 4OOH-CP, were investigated in a cell-free medium (pH approximately 7.5) and peripheral blood mononuclear cells. The ability of the thiol drugs, sodium 2-mercaptoethane sulfonate (mesna) and S-2-(3-aminopropylamino)ethanethiol (WR-1065), to affect the reactions of cellular GSH with the alkyalting agents was also studied. The amount of unreacted thiols in the various reactions was determined by derivatization with monobromobimane, followed by separation of fluorescent-labeled thioether adducts using high-pressure liquid chromatography. The second-order rate constants (k(2)) for reactions of GSH, mesna, and WR-1065 with 4OOH-CP in solution were 38 +/- 5, 25 +/- 5, and 880 +/- 50 M(-1) s(-1), respectively. The corresponding k(2) for reactions of GSH, mesna, and WR-1065 with acrolein were 490 +/- 100, 700 +/- 150, and >2000 M(-1) s(-1), respectively. The apparent rate constants for reactions of cellular GSH with acrolein and 4OOH-CP were smaller than those obtained in solution. Assuming that the k(2) is the same inside and outside cells, we estimate the first-order rate constant (k(1)) for transfer of 4OOH-CP and acrolein across the cell membrane as approximately 0.01 and approximately 0.04 s(-1), respectively. WR-1065 was more effective than mesna in blocking depletion of cellular GSH (because it passes into the cell more quickly and has higher reaction rates with the alkylators than the latter compound). When WR-1065 and mesna were used together, the protection against cellular depletion of GSH was additive. Our results are relevant to the administration of thiol drugs with high-dose alkylating agents.

Cyclophosphamide-loaded nanospheres: analysis of the matrix structure by thermal and spectroscopic methods

This study reports on the preparation and evaluation of cyclophosphamide loaded-polyalkylcyanoacrylate nanospheres obtained by emulsion polymerization. Characterization by differential scanning calorimetry, infrared spectroscopy and X-ray diffraction can reveal state dispersion of the drug inside the nanospheres. Such information predicts the stability of the particles and the drug release behaviour. The study has indicated the prescence of a molecular dispersed system. The drug release behaviour was also studied.