Angiotensin-converting enzyme inhibitors for ovarian cancer? - a new adjuvant option or a silent trap.

Background: Ovarian cancer is a huge therapeutic and financial problem for which approved treatments have already achieved their limit of efficiency. A cost-effective strategy to extend therapeutic options in this malignancy is drug repurposing aimed at overcoming chemoresistance. Here, angiotensin-converting enzyme inhibitors (ACE-I) are worth considering. Materials and methods: We searched literature for publications supporting the idea of adjuvant application of ACE-Is in ovarian malignancy. Then, we searched The Cancer Genome Atlas databases for relevant alternations of gene expression patterns. We also performed in silico structure-activity relationship evaluation for predicting ACE-Is' cytotoxicity against ovarian cancer cell lines. Finally, we reviewed the potential obstacles in ACE-Is repurposing process. Results: The alternation of angiotensin receptor expression in ovarian cancer translates into poorer patient survival. This confirms the participation of the renin-angiotensin system in ovarian carcinogenesis. In observational studies, ACE-Is were shown synergize with both, platinum-based chemotherapy as well as with antiangiogenic therapy. Consistently, our in silico simulation showed that ACE-Is are probably cytotoxic against ovarian cancer cells. However, the publications on their chemopreventive properties were inconclusive. In addition, some reports correlated ACE-Is use with increased general cancer incidence. We hypothesized that this effect could be associated with mutagenic nitrosamine formation in ACE-Is' pharmaceutical formulations, as was the case with angiotensin receptor blockers (ARBs) and other well-established pharmaceuticals. Conclusions: Available data warrant further research into repositioning ACE-Is to ovarian cancer as chemosensitizers. Prior to this, however, a special research program is needed to detect possible genotoxic contaminants of ACE-Is.

In silico and in vitro screening for carcinogenic potential of angiotensin-converting enzyme inhibitors and their degradation impurities.

According to some clinical observations, the use of angiotensin-converting enzyme inhibitors (ACEI) may be associated with an increased risk of cancer. The aim of the present study was to screen for the potential carcinogenicity, mutagenicity and genotoxicity of these drugs using in silico methodology. Delapril, enalapril, imidapril, lisinopril, moexipril, perindopril, ramipril, trandolapril, spirapril were thereby analyzed. In parallel, the corresponding degradation impurities, the diketopiperazine (DKP) derivatives, were also investigated. (Q)SAR computer software (VEGA-GUI and Lazar), available in the public domain, was employed. The obtained predictions suggested that none of the compounds tested (from the group of ACE-Is and DKPs) was mutagenic. Moreover, none of the ACE-Is was carcinogenic. The reliability of these predictions was high to moderate. In contrast, in the DKP group, ramipril-DKP and trandolapril-DKP were found to be potentially carcinogenic, but the reliability of this prediction was low. As for the genotoxicity screening, all compounds tested (ACE-I and DKP) were predicted to be active and genotoxic, with moexipril, ramipril, spirapril, and all DKP derivatives within the highest risk group. They were prioritized for experimental verification studies to confirm or exclude their toxic activity. On the other hand, the lowest risk of carcinogenicity was assigned to imidapril and its DKP. Then, a follow-up in vitro micronucleus assay for ramipril was performed. It showed that this drug was genotoxic via aneugenic activity, but only at concentrations exceeding real-life levels. At concentrations found in human blood after standard dose, ramipril was not genotoxic in vitro. Therefore, ramipril was considered safe for human use with a standard dosing regimen. The other compounds of concern (spirapril, moexipril and all DKP derivatives) should be subjected to analogous in vitro studies. We also concluded that the adopted in silico software was applicable for ACE-I toxicity prediction.

Photocatalytic degradation of sulfamethoxazole using TiO2-based materials - Perspectives for the development of a sustainable water treatment technology.

Heterogeneous photocatalysis using titanium dioxide-based materials is considered a promising and innovative solution to the water pollution problem. However, due to the limitations concerning the use of the developed materials and the applied photodegradation conditions, the research on photoremediation using TiO2 often stays behind the lab door. The challenge is to convert the basic research into a successful innovation, leading to the implementation of this process into wastewater treatment. For this purpose, the most active materials and optimal photodegradation conditions must be chosen. This article collects and compares the studies on photocatalytic degradation of an emerging pollutant - sulfamethoxazole, an antibacterial drug - and attempts to find the best approaches to be successfully applied on an industrial scale. Various types of TiO2-based photocatalysts are compared, including different nanoforms, doped or polymer-based composites, composites with graphene, activated carbon, dyes or natural compounds, as well as possible supporting materials for TiO2. The paper covers the impact of the irradiation source (natural sunlight, LED, mercury or xenon lamps) and water matrix on the photodegradation process, considering the ecological and economic sustainability of the process. Emphasis is put on the stability, ease of separation and reuse of the photocatalyst, power and safety of the irradiation source, identification of photodegradation intermediates and toxicity assays. The main approaches are critically discussed, main challenges and perspectives for an effective photocatalytic water treatment technology are pointed out.

Impact of ramipril nitroso-metabolites on cancer incidence - in silico and in vitro safety evaluation.

Background: Angiotensin-converting enzyme inhibitors (ACE-I) and their pharmacologically related sartans have been associated with an increased cancer incidence in several clinical observations. In 2018, sartans were revealed as being significantly contaminated with nitrosamines. Nitrosamines are potent human mutagens that can be formed ex vivo and, more concerningly, also in vivo from nitrosatable drug precursors. Their formation in sartans may justify the reported cancer risk and, by analogy, this may also apply to ACE-Is. Materials and methods: We investigated a commonly used ACE-I, ramipril (RAM). We checked its susceptibility to in vivo interaction with nitrite, potentially resulting in the generation of mutagenic N-nitrosamines. To that end, in silico simulation of mutagenicity of RAM nitroso-derivatives was performed using VEGA-GUI software. Then, the Nitrosation Assay Procedure was conducted which served as a model of endogenous reaction. The resulting post-nitrosation mixtures were subjected to a bacterial reverse mutation test employing Salmonella typhimurium strains TA98 and TA100 with and without metabolic activation. Results: Our results showed that studied samples did not induce point mutations in the test bacteria, regardless of the catalytic cytochrome activity. Conclusion: We concluded that RAM endogenous nitrosation is not the reason for increased cancer incidence. However, other ACE-Is must be verified in a similar manner.

Nanocomposites of Titanium Dioxide and Peripherally Substituted Phthalocyanines for the Photocatalytic Degradation of Sulfamethoxazole.

Phthalocyanines (Pcs) are often used in photosensitization of titanium(IV) oxide, a commonly employed photocatalyst, as such an approach holds the promise of obtaining highly stable and efficient visible light-harvesting materials. Herein, we report on the preparation, characterization and photoactivity of a series of composites based on TiO2 and peripherally modified metallophthalocyanines: either tetrasulfonated or 4,4',4'',4'''-tetraazaphthalocyanines, with either copper(II), nickel(II) or zinc(II) as the central metal ion. Physicochemical characterization was performed using UV-Vis diffuse reflectance spectroscopy, hydrodynamic particle-size analysis, surface-area analysis using N2 adsorption-desorption measurements and thermogravimetry combined with differential scanning calorimetry. The band-gap energy values were lower for the composites with peripherally modified phthalocyanines than for the commercial TiO2 P25 or the unsubstituted zinc(II) phthalocyanine-grafted TiO2. TG-DSC results confirmed that the chemical deposition, used for the preparation of Pc/TiO2 composites, is a simple and efficient method for TiO2 surface modification, as all the Pc load was successfully grafted on TiO2. The photocatalytic potential of the Pc/TiO2 materials was assessed in the photocatalytic removal of sulfamethoxazole-a commonly used antibacterial drug of emerging ecological concern. To compare the activity of the materials in different conditions, photodegradation tests were conducted both in water and in an organic medium.

Solid-State Stability Profiling of Ramipril to Optimize Its Quality Efficiency and Safety.

High global expenditure on out-of-label-date drugs, along with safety concerns associated with the accumulation of degradation impurities, justify the need for stability profiling. In this article, a comprehensive study on the solid-state stability of ramipril (RAM) was performed via isothermal methods under stress conditions. A validated stability-indicating HPLC protocol was used. The effects of various factors on the rate of RAM degradation were investigated, including: temperature, relative air humidity (RH), excipients (talc, starch, methylcellulose and hydroxypropyl methylcellulose), mode of tablet storage, and immediate packaging. The degradation impurities were also identified by HPLC-MS. It was found that RAM was unstable, and temperature accelerated its degradation. RAM was also vulnerable to RH changes, suggesting that it must be protected from moisture. The reaction followed first-order kinetics. The studied excipients stabilized RAM as a pure substance. The tableting process deteriorated its stability, explaining the need for appropriate immediate packaging. RAM in the form of tablets must be stored in blisters, and it cannot be crushed into two halves. The degradation impurities were ramiprilat and the diketopiperazine derivative.

Lignin-Based Spherical Structures and Their Use for Improvement of Cilazapril Stability in Solid State.

Biopolymer-based spherical particles exhibit unique properties including narrow sizes and many functional groups on their surfaces. Therefore, they show great potential for application in many scientific and industrial processes. The main aim of this study was to prepare lignin-based spherical particles with the use of a cationic surfactant, hexadecyl(trimethyl)ammonium bromide (CTAB). In the first step, different preparation procedures were tested with varying parameters, including biopolymer and surfactant ratios, lignin filtration, and experimental time. The morphological and dispersion characteristics of the materials were determined to select the best samples with the most promising properties, which could then be tested for their acute toxicity. It was observed that almost all materials were characterized by spherical shapes in micro- and nanosizes. The sample with the best physicochemical properties was used for further analysis and then tested for medical applications: the improvement of the stability of a drug molecule, cilazapril (CIL). The formulated material (CIL@LC-2a 1:1 wt./wt.) exhibited outstanding properties and significantly improved the stability of cilazapril as tested in conditions of increased temperature and humidity. Lignin spherical particles may be employed as a promising material for shielding other active compounds from decomposition.

Titanium Dioxide Nanoparticles in Food and Personal Care Products-What Do We Know about Their Safety?

Titanium dioxide (TiO2) is a material of diverse applications commonly used as a food additive or cosmetic ingredient. Its prevalence in products of everyday use, especially in nanosize, raises concerns about safety. Current findings on the safety of titanium dioxide nanoparticles (TiO2 NPs) used as a food additive or a sunscreen compound are reviewed and systematized in this publication. Although some studies state that TiO2 NPs are not harmful to humans through ingestion or via dermal exposure, there is a considerable number of data that demonstrated their toxic effects in animal models. The final agreement on the safety of this nanomaterial has not yet been reached among researchers. There is also a lack of official, standardized guidelines for thorough characterization of TiO2 NPs in food and cosmetic products, provided by international authorities. Recent advances in the application of 'green-synthesized' TiO2 NPs, as well as comparative studies of the properties of 'biogenic' and 'traditional' nanoparticles, are presented. To conclude, perspectives and directions for further studies on the toxicity of TiO2 NPs are proposed.

Titanium Dioxide Nanoparticles: Prospects and Applications in Medicine.

Metallic and metal oxide nanoparticles (NPs), including titanium dioxide NPs, among polymeric NPs, liposomes, micelles, quantum dots, dendrimers, or fullerenes, are becoming more and more important due to their potential use in novel medical therapies. Titanium dioxide (titanium(IV) oxide, titania, TiO2) is an inorganic compound that owes its recent rise in scientific interest to photoactivity. After the illumination in aqueous media with UV light, TiO2 produces an array of reactive oxygen species (ROS). The capability to produce ROS and thus induce cell death has found application in the photodynamic therapy (PDT) for the treatment of a wide range of maladies, from psoriasis to cancer. Titanium dioxide NPs were studied as photosensitizing agents in the treatment of malignant tumors as well as in photodynamic inactivation of antibiotic-resistant bacteria. Both TiO2 NPs themselves, as well as their composites and combinations with other molecules or biomolecules, can be successfully used as photosensitizers in PDT. Moreover, various organic compounds can be grafted on TiO2 nanoparticles, leading to hybrid materials. These nanostructures can reveal increased light absorption, allowing their further use in targeted therapy in medicine. In order to improve efficient anticancer and antimicrobial therapies, many approaches utilizing titanium dioxide were tested. Results of selected studies presenting the scope of potential uses are discussed in this review.

Does Polyvinylpyrrolidone Improve the Chemical Stability of Cilazapril in Solid State?

In this study a solid dispersion and a physical mixture of cilazapril (CIL) with a biopolymer - polyvinylpyrrolidone (PVP) as a carrier were prepared so as to investigate the effect of PVP on the stability of CIL. CIL is unstable in solid state and decomposes rapidly under humid conditions. It requires stabilization to ensure safety of its use. The studied CIL/PVP formulations were prepared by milling and evaporation technique. Their identity was confirmed by FT-IR method. The stability of CIL in the CIL/PVP formulations was assessed by forced ageing test under isothermic conditions using RP-HPLC. The influence of temperature (experimental conditions: RH 76.4% and T = 70, 75, 80, 85, and 90 oC) and the effect of relative humidity (experimental conditions: RH 25.0%, 50.9%, 60.9%, 66.5%, 76.4%, T = 90 °C) on the rate of CIL degradation were examined. It was established that the process of CIL decay in the studied forms followed first-order kinetics with the formation of one degradation product - cilazaprilat. The degradation rate constant of this reaction was lower than that for pure CIL. The energy of activation of the CIL degradation in the presence of PVP was higher than that of pure CIL. Furthermore, CIL incorporated into PVP exhibited lower sensitivity to moisture. Based on these data PVP was considered as a potential stabilizing substance for CIL-containing dosage forms.

Beyond the boundaries of cardiology: Still untapped anticancer properties of the cardiovascular system-related drugs.

Cardiovascular disorders and cancer are the most common chronic diseases, frequently coexistent and interdependent. Based on their common etiology and molecular background, the hypothesis on the potential anti-cancer activity of cardiological drugs appeared, mainly in response to the necessity of increasing the efficacy of existing oncological treatment schemes. In fact, cancer is known to induce the profound malfunction of typical cardiovascular-regulating systems, including the renin-angiotensin system, sympathetic nervous system and coagulation cascade. Therefore, in this review we have analyzed the available preclinical and clinical data on the repurposing potential of the following classes of cardiology drugs: angiotensin converting-enzyme inhibitors, angiotensin receptor blockers, beta blockers, statins and heparins. All of them have been shown to attenuate cancer development: the renin-angiotensin system inhibitors primarily by reducing inflammation, angiogenesis and immunosuppression, beta blockers by repressing migration and metastasis, heparins by decreasing metastasis and statins by influencing cell growth, apoptosis, migration and angiogenesis. We also have discussed the specific mechanisms of anticancer action for each group and then suggestions on their potential clinical use have been presented. Nonetheless, the establishment of strong indications for repurposing procedure, both individually and collectively, is unfeasible at the moment due to insufficient clinical data and therefore further investigations in this context are necessary and encouraged.

Can cardiovascular drugs support cancer treatment? The rationale for drug repurposing.

Research on the concept of biological overlap between cardiovascular and oncological diseases is gaining momentum. In fact, in both conditions, the malfunction of common regulatory mechanisms, such as the renin-angiotensin system (RAS), sympathetic nervous system (SNS), coagulation cascade, sodium-potassium ATP-ases, and mevalonate pathway, occurs. Thus, targeting these mechanisms with well-known cardiology drugs, including angiotensin-converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), ß-adrenergic receptor blockers, statins, cardiac glycosides (CGs), and low-molecular-weight heparins (LMWHs), could be a novel, promising adjuvant strategy in cancer management. Thus, here we discuss the idea of repurposing cardiology drugs in oncology based on available preclinical and clinical data.

Synthesis, in vitro and in silico evaluation of novel trans-stilbene analogues as potential COX-2 inhibitors.

25 new trans-stilbene and trans-stilbazole derivatives were investigated using in vitro and in silico techniques. The selectivity and potency of the compounds were assessed using commercial ELISA test. The obtained results were incorporated into 2D QSAR assay. The most promising compound 4-nitro-3',4',5'-trihydroxy-trans-stilbene (N1) was synthetized and its potency and selectivity were confirmed. N1 was classified as preferential COX-2 inhibitor. Its ability to inhibit COX-2 in MCF-7 cell line was established and its cytotoxicity by MTT test was assessed. The compound was more cytotoxic than celecoxib within studied concentration range. Finally, the investigated trans-stilbene was docked into COX-1 and COX-2 active sites using "CDOCKER" protocol.

Thermo-, Radio- and Photostability of Perindopril Tert-butyloamine in The Solid State. Comparison to Other Angiotensin Converting Enzyme Inhibitors.

The main aim of this study was determination of thermo- radio- and photostability of perindopril tert-butyloamine (PER) therefore the efficiency and safety of the therapy could be maintained. A chromatographic method (RP-HPLC) had been validated before use to determine PER loss. The evaluation of stability properties of PER in solid state under the influence of isothermal condition, relative humidity - RH = 0% and 76.4%, exposure to 6 mln lux h and ionizing radiation generated by beam of electrons of 25-400 kGy was investigated. Studies pointed out that presence of moisture changes a kinetic model of PER degradation; lack of moisture in the air generates a first-order kinetic model of the reaction, increase humidity generates the autocatalytic model. PER proved to be resistant for ionizing radiation. It is possible to use radiation sterilization and decontamination (dose 25 kGy) with no significant loss of content. Investigation of PER photostability proved, that after exposure to 6 mln lux h physicochemical parameters are acceptable. Among all the ACE-I, PER has one of the shortest t0,5. PER should be stored in closed containers, protected from high temperature and moisture. PER is referred to be photostable and resistant for radiodegradation.

Unknown face of known drugs - what else can we expect from angiotensin converting enzyme inhibitors?

The renin-angiotensin system (RAS) is one of important systems among homeostatic mechanisms that control the function of cardiovascular, renal and adrenal systems. As RAS has a very complex nature, it has been also found as related to the control of cell migration and apoptosis. Angiotensin-converting enzyme inhibitors (ACEI) are drugs most commonly used in the modulation of RAS activity. ACEI have been extensively described as effective in the treatment of hypertension among adults, but also as drugs delaying progression in diabetic nephropathy and reducing mortality in left ventricular dysfunction and congestive heart failure. What is less obvious, ACEI are also widely used in pediatric nephrology and cardiology. Moreover, there are more and more reports showing evidence that ACEI can be beneficial in the treatment of many other diseases and the pleiotropic activity of ACEI is mainly based on their antioxidant properties. In this paper we focus on the less obvious possibilities of the clinical use of ACEI in neurological or oncological patients, discuss the role of ACE gene polymorphism and show the perspectives of potentially new applications of ACEI in contemporary pharmacotherapy.

COX-2 inhibitors: a novel strategy in the management of breast cancer.

Cyclooxygenase-2 (COX-2) inhibitors are common anti-inflammatory drugs with pleiotropic, endogenous actions that could be useful in the management of breast cancer. Here, we provide a complete understanding of the biochemistry of COX-2 and discuss the various molecular mechanisms behind its increased expression in breast cancer. We also analyze the possible mechanisms responsible for the anticancer effect of COX-2 inhibitors and provide an overview of the available preclinical and clinical data on the use of COX-2 inhibitors in breast cancer. Finally, we describe a mathematical model of the relation between the structure and biological potency of promising new COX-2 inhibitors (trans-stilbenes) using a 2D quantitative structure-activity relationship (QSAR) technique.

Determination of the Juglone Content of Juglans regia Leaves by GC/MS.

The constituents of walnut (Juglans regia L.) leaves are represented by tannins, phenolics, and naphthoquinones, the characteristic compound being juglone. The content of juglone in the methanolic extract of the leaves determined by the GC/MS method was 9.9 ± 0.2 mg/100 g; small amounts (1.3 ± 0.02 mg/100 g) were recorded in the infusion, whereas in the decoction it was not detected. As some studies indicate toxicity of juglone, only decoctions should be recommended for therapeutic use.

Chemistry and pharmacology of Angiotensin-converting enzyme inhibitors.

The renin-angiotensin system has been established as an attractive target for pharmacological intervention since the discovery of first angiotensin-converting enzyme inhibitors (ACE-Is). In fact, these drugs are primarily used in the management of cardiovascular system-related diseases and renal insufficiency. Their mechanism of action involves the adjustment of balance between vasoconstrictive, hypertrophic and salt/water-retentive angiotensin II and vasodilatory and natriuretic bradykinin by the inhibition of angiotensin II biosynthesis and bradykinin degradation. Currently there are thirteen family members approved for use in humans. They differ in structure, chemistry and pharmacokinetic and pharmacodynamic properties yet they display a similar pharmacologic and toxicologic profile. All of them are effective in the treatment of hypertension as well as in cardiac insufficiency or diabetic nephropathy. Although they are generally well-tolerated several serious side-effects including life-threatening angioedema, renal failure and persistent dry cough could occur during the administration of ACE-Is, which may require the cessation of therapy. Furthermore, to provide maximum safety and efficiency of ACE-Is-based therapy, the knowledge of the related drug interactions and chronokinetics seems to be an absolute requirement. Here we discuss the above-mentioned issues regarding the pharmaceutical and chemical properties of the commercially- used ACE-Is.

The mutagenicity analysis of imidapril hydrochloride and its degradant, diketopiperazine derivative, nitrosation mixtures by in vitro Ames test with two strains of Salmonella typhimurium.

AIM: The evaluation of mutagenic properties of imidapril hydrochloride (IMD) and its degradation impurity, diketopiperazine derivative (DKP), nitrosation mixtures was conducted in order to analyze the carcinogenic risk of IMD long-term treatment in patients. In this study an in vitro Ames test with Salmonella enterica serovar Typhimurium TA 98 and TA 100 strains was used. BACKGROUND: IMD and DKP contain nitrogen atoms, which makes them theoretically vulnerable to in vivo nitrosation with the production of N-nitroso compounds (NOC). NOC, in turn, are known animal mutagens indicating that their endogenous production from nitrosable drugs constitutes a carcinogenic hazard. MATERIALS AND METHODS: Pure IMD sample was exposed to forced degradation conditions of increased temperature and dry air in order to achieve a DKP sample. Both samples were then treated with a nitrosating agent and the obtained nitrosation mixtures were subjected to mutagenicity analysis by the Ames test with S. typhimurium TA 98 and TA 100 strains in the presence and absence of metabolic activation system (S9 mix) using a commercial Ames MPF 98/100 microplate format mutagenicity assay kit. RESULTS: None of the six concentrations of the investigated nitrosation mixtures exhibited any mutagenic potential in both S. typhimurium strains. The addition of S9 mix did not alter the non-mutagenic properties of the studied compounds. CONCLUSIONS: The nitrite treatment of both studied compounds has no impact on their mutagenic properties under the conditions of the present studies. Hence, IMD and DKP nitrosation mixtures are classified as non-mutagens in this test.

Stability of cilazapril in pediatric oral suspensions prepared from commercially available tablet dosage forms.

Abstract: Cilazapril is a drug commonly used in management of heart failure in pediatric population. On pharmaceutical market it is available only in inconvenient for pediatric use tablet dosage forms. Until now, no oral liquid formulation containing cilazapril has been evaluated. Therefore, the aim of this study was to prepare easy to made and palatable 1 mg/mL oral liquid formulation with cilazapril (with consideration of original and generic cilazapril tablet and different packages) and subsequent investigation of physicochemical stability of these suspensions. Formulations were compounded using cilazapril obtained from original or generic cilazapril marketed tablet formulations and Ora-Blend" suspending agent. Stability of prepared suspensions stored in closed amber glass or amber plastic PET bottles in the temperature of 298 K was estimated throughout 28 day shelf-life period. Chemical stability was assessed by HPLC cilazapril stability indicating method. Physical stability was evaluated by appearance, taste, smell, pH and theological assessments. Cilazapril oral suspensions at concentration of 1 mg/mL demonstrated satisfactory stability over 28 day long storage at room temperature. Cilazapril concentrations remained within acceptable limit (+/- 10%) stored in closed amber bottles made of glass or PET material. Moreover, suspensions physical properties remained unaffected. Cilazapril - Ora-Blend* pediatric oral liquid is easy to made, palatable and stable when stored at room temperature for 28 days. Stability of cilazapril oral liquid remains unchanged while using cilazapril tablets produced by different manufacturers and bottles made of amber glass or PET material.