New Insights into the Metabolism of Methyltestosterone and Metandienone: Detection of Novel A-Ring Reduced Metabolites.

Metandienone and methyltestosterone are orally active anabolic-androgenic steroids with a 17α-methyl structure that are prohibited in sports but are frequently detected in anti-doping analysis. Following the previously reported detection of long-term metabolites with a 17ξ-hydroxymethyl-17ξ-methyl-18-nor-5ξ-androst-13-en-3ξ-ol structure in the chlorinated metandienone analog dehydrochloromethyltestosterone ("oral turinabol"), in this study we investigated the formation of similar metabolites of metandienone and 17α-methyltestosterone with a rearranged D-ring and a fully reduced A-ring. Using a semi-targeted approach including the synthesis of reference compounds, two diastereomeric substances, viz. 17α-hydroxymethyl-17ß-methyl-18-nor-5ß-androst-13-en-3α-ol and its 5α-analog, were identified following an administration of methyltestosterone. In post-administration urines of metandienone, only the 5ß-metabolite was detected. Additionally, 3α,5ß-tetrahydro-epi-methyltestosterone was identified in the urines of both administrations besides the classical metabolites included in the screening procedures. Besides their applicability for anti-doping analysis, the results provide new insights into the metabolism of 17α-methyl steroids with respect to the order of reductions in the A-ring, the participation of different enzymes, and alterations to the D-ring.

Application of in vitro skin penetration measurements to confirm and refine the quantitative skin sensitization risk assessment of methylisothiazolinone.

Use of quantitative risk assessment (QRA) for assessing the skin sensitization potential of chemicals present in consumer products requires an understanding of hazard and product exposure. In the absence of data, consumer exposure is based on relevant habits and practices and assumes 100% skin uptake of the applied dose. To confirm and refine the exposure, a novel design for in vitro skin exposure measurements was conducted with the preservative, methylisothiazolinone (MI), in beauty care (BC) and household care (HHC) products using realistic consumer exposure conditions. A difference between measured exposure levels (MELs) for MI in leave-on versus rinse-off BC products, and lower MELs for MI in HHC rinse-off compared to BC products was demonstrated. For repeated product applications, the measured exposure was lower than estimations based on summation of applied amounts. Compared to rinse-off products, leave-on applications resulted in higher MELs, correlating with the higher incidences of allergic contact dermatitis associated with those product types. Lower MELs for MI in rinse-off products indicate a lower likelihood to induce skin sensitization, also after multiple daily applications. These in vitro skin exposure measurements indicate conservatism of default exposure estimates applied in skin sensitization QRA and might be helpful in future risk assessments.

Optimization of the N-lost drugs melphalan and bendamustine: synthesis and cytotoxicity of a new set of dendrimer-drug conjugates as tumor therapeutic agents.

Bendamustine and melphalan are very promising alkylating drugs with applicability in the treatment of various tumoral diseases, e.g., chronic lymphocytic leukemia (CLL) or breast cancer. However, numerous adverse effects limited their use. Therefore, 1,3,5-tris(3-aminopropyl)benzene (G0) and its G1 analogue 3,5-bis(3-aminopropyl)-N-(3-{3,5-bis[3-{3,5-bis(3-aminopropyl)benzoylamino}propyl]phenyl}propyl)benzamide were selected to design cytostatic drug-dendrimer conjugates to achieve tumor cell accumulation by endocytosis as already demonstrated for platinum complexes. The dendrimers act as carriers and an N-(2-hydroxyethyl)maleimide spacer between drug and carrier should guarantee a selective release of the cytostatics in the tumor cells. The resulting cytotoxicity was determined in vitro using the human MCF-7 and MDA-MB-231 breast cancer cell lines. It was demonstrated that melphalan caused cytotoxic effects depending on its free amino group (Boc protection strongly decreased the activity) but independent of a derivation of the carboxylic group (dendrimers and spacer binding). Esterification of bendamustine with the N-(2-hydroxyethyl)maleimide spacer strongly increased the hydrolytic stability of the N-lost moiety, so antiproliferative effects were yet observed in vitro.

Atomic absorption spectrometric determination of the iridium content in tumor cells exposed to an iridium metallodrug.

An electrothermal atomic absorption spectrometric method to quantify the iridium content of HT-29 colon carcinoma cells exposed to iridium metallodrugs was developed. Optimisation of the procedure involved the evaluation of pyrolysis and atomisation conditions (optimal values were 1400 degrees C for pyrolysis and 2400 degrees C for atomisation) and the addition of appropriate additives. The presence of cellular components as well as the addition of nitric acid and hydrochloric acid led to enhanced absorption signals and suggested the use of matrix matched calibration. The described method allows the measurement of iridium in cell suspensions in the low microg/L range (linear dynamic range: 10-450 microg/L) with a detection limit of 11.2 microg/L. The applicability of the method was tested by means of a novel iridium metallodrug. First results on the complex [IrCl3(DMSO)(phen)] indicated a low cellular uptake (21.2 microM at incubation with 100 microM) of this iridium species in HT-29 cells compared to other metal containing antitumor drugs.

Characterization of the sensitizing potential of chemicals by in vitro analysis of dendritic cell activation and skin penetration.

Development of in vitro models to identify sensitizing chemicals receives public interest since animal testing should be avoided whenever possible. In this article we analyze two essential properties of sensitizing chemicals: skin penetration and dendritic cell (DC) activation. Activation of immature DC derived from peripheral blood monocytes was evaluated by flow cytometric analysis of CD86 positive cells and quantitative measurement of interleukin-1beta and aquaporin P3 gene expression. The sensitizer 2,4,6-trinitrobenzenesulfonic acid induced a concentration-dependent response for all parameters, whereas the irritant sodium lauryl sulfate did not. When two related aromatic amines, p-toluylenediamine (PTD) and hydroxyethyl-p-phenylenediamine (HE-PPD) were tested, both induced substantial DC activation indicating their potential sensitizing properties. These findings contrasted with in vivo results: in murine local lymph node assays (LLNA) PTD, but not HE-PPD, was sensitizing using acetone/aqua/olive oil as vehicle. Skin penetration measurement revealed that this was due to bioavailability differences. On retesting HE-PPD in the LLNA using the penetration enhancer dimethylsulfoxide as vehicle, it induced a specific response. We conclude that in vitro analysis of DC activation capability of the two selected chemicals demonstrates that prediction of skin sensitization potential is possible provided that skin penetration data indicate sufficient bioavailability of the test compound.

Assessing the dermal safety of products intended for genital mucosal exposure.

Manufacturers employ a stepwise approach to ensure the skin safety and compatibility of consumer products that are intended for contact with mucosal skin. The properties of the ingredients are evaluated fully, along with any available safety and skin compatibility information, to eliminate any chemicals that may be strong contact sensitizers or irritants. Contact sensitization potential is evaluated by applying a quantitative exposure assessment to each ingredient or component to determine if the extent of the expected exposure is likely to pose any risk of contact sensitization. Likely exposures are calculated using the manufacturer's unique knowledge of the intended product matrix, consumer usage patterns and measurements of particular exposure variables. If adequate safety assurance cannot be provided, further testing may be conducted. The skin compatibility and irritation potential of each ingredient is evaluated using existing test data, and experience from other products containing the same or a structurally similar ingredient. Once a finished product or formulation is developed, another round of assessments is conducted to ensure that no unexpected matrix effects negatively impact the skin compatibility profile. This may include clinical testing protocols involving single and multiple patch tests, and extended use testing, with visual and/or instrumental assessments. This approach to ensuring the skin safety of products has been used successfully for many decades, and adverse skin reactions to modern products are rare. The challenge for the future is to develop test protocols that will discriminate between products that are very similar in their favorable skin compatibility profile. Options to meet this challenge include testing protocols that will: (1) further exaggerate exposure conditions, such as the behind-the-knee protocol, (2) increase the sensitivity of scoring for irritant effects, such as with the use of instrumentation, and (3) quantitatively measuring additional endpoints, such as subjective sensory effects.

The hair dyes PPD and PTD fail to induce a T(H)2 immune response following repeated topical application in BALB/c mice.

1,4-Phenylenediamine (PPD) and the structurally-related 1,4-toluenediamine (PTD) are frequently used oxidative hair dye precursors that can induce a delayed-type hypersensitivity reaction known as contact allergy. Very rare cases of Type 1 (IgE-mediated) allergic responses associated with PPD or PTD have been reported among hair dye users. As part of an effort to determine if repeated dermal exposure to the dyes could induce a T-helper-2 (T(H)2) response, we used a dermal exposure regimen in mice reported to identify a T(H)2 response. Ear swelling was evident at post-final exposure to PPD and PTD, indicating that an immune response was observed. However, cytokine mRNA after repeated topical exposure to these two chemicals showed no shift in the expression toward the typical T(H)2 cytokines interleukin (IL)-4 and IL-10 compared to the T(H)1 cytokine interferon (IFN)-γ. Consistent with these cytokine profiles, no concomitant increase in total serum IgE antibody titer or in B220+IgE+ lymphocytes in lymph nodes and skin application site skin was detected. In contrast, using an identical exposure regimen, animals topically exposed to the known respiratory (Type 1) allergen toluene 2,4-diisocyanate (TDI) showed significant expression of IL-4 and IL-10 mRNA compared to IFN? as well as an increase in total serum IgE and in B220+IgE+ cells in lymph nodes and skin application site. The data generated are consistent with the pattern of adverse reactions to hair dyes seen clinically, which overwhelmingly is of delayed rather than immediate-type hypersensitivity. Although current animal models have a limited ability to detect rare T(H)2 responses to contact allergens, the present study results support the view that exposure to hair dyes is not associated with relevant T(H)2 induction.

[NiII(3-OMe-salophene)]: a potent agent with antitumor activity.

In this study, we investigated the anticancer properties of methoxy-substituted nickel(II)(salophene) derivatives. We demonstrated that the most active complex [NiII(3-OMe-salophene)] is not necrotic in Burkitt-like lymphoma cells (BJAB) and human B-cell precursor cells (Nalm-6). [NiII(3-OMe-salophene)] inhibited proliferation and induced apoptosis in a concentration dependent manner, giving evidence for the involvement of CD95 receptor-mediated, extrinsic pathway. Furthermore, [NiII(3-OMe-salophene)] overcame vincristine drug resistance in BJAB and Nalm-6 cells.

Naphthalimide gold(I) phosphine complexes as anticancer metallodrugs.

Gold(I) phosphine complexes exhibit promising properties for anticancer drug development. Here we report on a series of gold(I) phosphine complexes containing a naphthalimide ligand. Strong antiproliferative effects were observed in MCF-7 breast cancer cells as well as in HT-29 colon carcinoma cells. The cellular and nuclear gold levels were increased compared to analogues, in which the naphthalimide ligand was replaced by a chloro ligand. Compound 4a was selected for more detailed biochemical and biological studies, which revealed solvent dependent fluorescence emission, uptake of the compound into the organelles of tumor cells as well as antiangiogenic effects concerning angiogenesis and tumor-induced angiogenesis in vivo. Antiangiogenic properties of 4a were observed in two different zebrafish angiogenesis models, including a tumor-cell induced neovascularization assay.

Development of a method for the quantification of the molar gold concentration in tumour cells exposed to gold-containing drugs.

The knowledge of the cellular molar concentration of a drug is an extremely important parameter for the discussion and interpretation of its efficacy and bioavailability. Concerning metal complexes, electrothermal atomic absorption spectroscopy (ETAAS) offers a valuable analytical tool. However, matrix effects often hamper proper quantification of the metal concentration in biological tissues. This paper describes the development of an ETAAS method for the quantification of the molar gold concentration in HT-29 colon carcinoma cells. ETAAS analytical conditions were optimised and a factor was developed which allows the calculation of the molar cellular gold concentration from the measured gold per cellular biomass value. The method was used to quantify the gold content in HT-29 cells after exposure to the gold drug auranofin. Results indicated a strong cellular uptake of auranofin (compared to other metal anticancer drugs), which significantly correlated with the antiproliferative effects triggered by this agent.

Proposal for a risk assessment methodology for skin sensitization based on sensitization potency data.

In this paper, we propose a quantitative risk assessment methodology for skin sensitization aiming at the derivation of 'safe' exposure levels for sensitizing chemicals, used e.g., as ingredients in consumer products. Given the limited number of sensitizers tested in human sensitization tests, such as the human repeat-insult patch test (HRIPT) or the human maximization test (HMT), we used EC3 values from the local lymph node assay (LLNA) in mice because they provide the best quantitative measure of the skin sensitizing potency of a chemical. A comparison of LLNA EC3 values with HRIPT and HMT LOEL, and NOEL values was carried out and revealed that the EC3, expressed as area dose, can be used as a surrogate value for the human NOEL in risk assessment. The uncertainty/extrapolation factor approach was used to derive (a) an 'acceptable non-sensitizing area dose' (ANSAD) to protect non-allergic individuals against skin sensitization and (b) an 'acceptable non-eliciting area dose' (ANEAD) to protect allergic individuals against elicitation of allergic contact dermatitis. For ANSAD derivation, interspecies, intraspecies and time extrapolation factors are applied to the LLNA EC3. For ANEAD derivation, additional application of a variable sensitization-elicitation extrapolation factor is proposed. Values for extrapolation factors are derived and discussed, the proposed methodology is applied to the sensitizers methylchloroisothiazolinone/methylisothiazolinone, cinnamic aldehyde and nickel and results are compared to published risk assessments.