RESUMEN
Objective: The aim of this in vitro study was to investigate the possible interactions between photon-induced photoacoustic streaming (PIPS™)-activated oxidizing agents and 2% chlorhexidine digluconate. Background data: There is no information about the safety of laser-activated oxidizing agents in combination usage with chlorhexidine gluconate. Materials and methods: Groups were designed as follows G1: 98% para-chloroaniline (PCA); G2: 2% chlorhexidine (CHX); G3: 5.25% sodium hypochlorite (NaOCl) +2% CHX; G4: 5.25% NaOCl (30 sec PIPS activated) +2% CHX; G5: 5.25% NaOCl (60 sec PIPS activated) +2% CHX; G6: 3.5% chlorine dioxide (ClO2) + 2% CHX; G7: 3.5% (ClO2) (30 sec PIPS activated) +2% CHX; G8: 3.5% (ClO2) (60 sec PIPS activated) +2% CHX. The laser-irrigation protocol was performed with an erbium:yttrium-aluminum-garnet laser with a wavelength of 2940 nm equipped with a 140 mm long endodontic fiber tip (PIPS) using 10 mJ at 15 Hz (0.15 W), per pulse operating outputs. Groups were analyzed with proton nuclear magnetic resonance spectroscopy, using PCA as an internal standard. Results: No free PCA was formed in any groups of mixtures or after PIPS activation. Conclusions: Mixing of 3.5% ClO2 and 2% CHX does not form bulky precipitates, unlike the mixture NaOCl + CHX. PIPS activation does not cause changes in reactions of oxidizing agents.
Asunto(s)
Antiinfecciosos Locales/efectos de la radiación , Clorhexidina/análogos & derivados , Terapia por Luz de Baja Intensidad , Oxidantes/efectos de la radiación , Técnicas Fotoacústicas , Irrigantes del Conducto Radicular/efectos de la radiación , Compuestos de Anilina/efectos de la radiación , Clorhexidina/efectos de la radiación , Láseres de Estado Sólido , Espectroscopía de Protones por Resonancia Magnética , Preparación del Conducto Radicular , Hipoclorito de Sodio/efectos de la radiaciónRESUMEN
AIM: Five photoactive compounds with variable elongated alkyl-substituents in a phenalen-1-one structure were examined in view of structural similarity to the antimicrobial agent benzalkonium chloride (BAC). METHODS: All phenalen-1-ones and BAC were evaluated for their antimicrobial properties against Staphylococcus aureus, methicillin-resistant S. aureus, Escherichia coli, Pseudomonas aeruginosa and for their eukaryotic toxicity against normal human epidermal keratinocyte (NHEK) cells to narrow down the BAC-like effect and the photodynamic effect depending on the chemical structure. All compounds were investigated for effective concentration ranges, where a bacterial reduction of 5 log10 is achieved, while an NHEK survival of 80% is ensured. RESULTS: Effective concentration ranges were found for four out of five photoactive compounds, but not for BAC and the compound with BAC-like alkyl chain length. CONCLUSION: Chain length size and polar area of the respective head-groups of phenalen-1-one compounds or BAC showed an influence on the incorporation inside lipid membranes and thus, head-groups may have an impact on the toxicity of antimicrobials.
Asunto(s)
Antibacterianos/farmacología , Antiinfecciosos Locales/farmacología , Bacterias/efectos de los fármacos , Compuestos de Benzalconio/farmacología , Fenalenos/farmacología , Antibacterianos/química , Antibacterianos/efectos de la radiación , Antiinfecciosos Locales/química , Antiinfecciosos Locales/efectos de la radiación , Compuestos de Benzalconio/química , Línea Celular , Membrana Celular/química , Escherichia coli/efectos de los fármacos , Humanos , Queratinocitos/efectos de los fármacos , Luz , Lípidos de la Membrana/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Fenalenos/química , Fenalenos/efectos de la radiación , Pseudomonas aeruginosa/efectos de los fármacos , Oxígeno Singlete/química , Staphylococcus aureus/efectos de los fármacosRESUMEN
Activity of singlet oxygen sensitizers for photoinactivation of bacteria and photodynamic therapy of tumor cells has been evaluated using nonpathogenic model cells, such as Escherichia coli, Saccharomyces cerevisiae, and HeLa cells. Among them, E. coli, gram-negative bacterium, has complex membrane structures in the cell wall, resulting in an impermeable barrier to antimicrobial agents. Therefore, few singlet oxygen sensitizers have photoinactivation activities toward E. coli at low concentrations. Recently polycationic porphyrins have received much attention as a new type of singlet oxygen sensitizers because they have strong binding affinities for DNA and proteins. Here, we prepared 13 types of di- and tricationic P- and Sb-porphyrin sensitizers substituted with the N-alkylpyridinium (APy) group at the axial ligand or the meso position to examine their bactericidal activity toward E. coli under visible-light irradiation. Photobactericidal activities were evaluated using half-life (T1/2 in min) of E. coli and minimum effective concentrations of the porphyrin sensitizers. Di-cationic P-porphyrins containing the Apy group at meso position exhibited bactericidal activity under dark conditions. Tricationic porphyrins showed a higher bactericidal activity than monocationic porphyrins. It was found that the bactericidal activity depended on the alkyl chain length of APy. Tricationic porphyrin with N-heptylpyridinium in two axial ligands was the most reactive for the photoinactivation of E. coli.
Asunto(s)
Escherichia coli/efectos de la radiación , Fármacos Fotosensibilizantes/química , Porfirinas/farmacología , Piridinas/farmacología , Antibacterianos/farmacología , Antiinfecciosos Locales/química , Antiinfecciosos Locales/farmacología , Antiinfecciosos Locales/efectos de la radiación , Escherichia coli/efectos de los fármacos , Luz , Fármacos Fotosensibilizantes/farmacología , Oxígeno Singlete/farmacología , Relación Estructura-ActividadRESUMEN
BACKGROUND: Oral health diseases are common in all regions of the world. Mouth rinses are widely used generally by population as a port of daily oral care regimen. In addition to antimicrobial activity, mouth rinses possess certain cytotoxic effects. Electron-beam (E-beam) radiation is a form of ionizing energy known to induce structural, physical, and chemical changes in irradiated products. In this study, the modulatory effects of E-beam in irradiated mouth rinses were evaluated for its biological activities. MATERIALS AND METHODS: The antimicrobial activities of nonirradiated and irradiated mouth rinses were evaluated for its antimicrobial and antibiofilm activities against oral pathogens, Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was evaluated by disc diffusion method and antibiofilm activity was evaluated by O'Toole method. The cytotoxicity was evaluated against human gingival fibroblast (HGF) cells by 3-(4, 5 Dimethythiazol-yl)-2,5-Diphenyl-tetrazolium bromide assay. RESULTS: Colgate Plax (CP) exhibited the antimicrobial activity against the tested pathogens, and a significant (P< 0.05) increase was observed against S. aureus at 750 Gy irradiation. Further, CP significantly (P< 0.05) suppressed S. mutans, S. aureus, and C. albicans biofilm. Listerine (LS) inhibited S. mutans and C. albicans biofilm. Whereas irradiated CP and LS significantly (P< 0.05) suppressed the biofilm formed by oral pathogens. The suppression of biofilm by irradiated mouth rinses was dose- and species-dependent. There was no significant (P > 0.05) difference in the cytotoxicity of irradiated and nonirradiated mouth rinses on HGF cells. However, an increased percentage viability of HGF cells was observed by mouth rinses irradiated at 750 Gy.xs CONCLUSION: The E-beam irradiation enhanced the antibiofilm activity of mouth rinses without modifying the cytotoxicity.
Asunto(s)
Antiinfecciosos Locales/farmacología , Antiinfecciosos Locales/efectos de la radiación , Biopelículas/efectos de los fármacos , Electrones , Fibroblastos/efectos de los fármacos , Antisépticos Bucales/farmacología , Antisépticos Bucales/efectos de la radiación , Antiinfecciosos Locales/química , Benzoatos , Candida albicans/efectos de los fármacos , Línea Celular , Combinación de Medicamentos , Enterococcus faecalis/efectos de los fármacos , Encía/citología , Humanos , Antisépticos Bucales/química , Salicilatos , Dodecil Sulfato de Sodio , Staphylococcus aureus/efectos de los fármacos , Streptococcus mutans/efectos de los fármacos , TerpenosRESUMEN
The photocatalytic degradation of chlorhexidine digluconate (CHD), a disinfectant and topical antiseptic and adsorption of CHD catalyst surface in dark condition has been studied. Moreover, the value of kinetic parameters has been measured and the effect of adsorption on photocatalysis has been investigated here. Substantial removal was observed during the photocatalysis process, whereas 40% removal was possible through the adsorption route on TiO2 surface. The parametric variation has shown that alkaline pH, ambient temperature, low initial substrate concentration, high TiO2 loading were favourable, though at a certain concentration of TiO2 loading, photocatalytic degradation efficiency was found to be maximum. The adsorption study has shown good confirmation with Langmuir isotherm and during the reaction at initial stage, it followed pseudo-first-order reaction, after that Langmuir Hinshelwood model was found to be appropriate in describing the system. The present study also confirmed that there is a significant effect of adsorption on photocatalytic degradation. The possible mechanism for adsorption and photocatalysis has been shown here and process controlling step has been identified. The influences of pH and temperature have been explained with the help of surface charge distribution of reacting particles and thermodynamic point of view respectively.
Asunto(s)
Antiinfecciosos Locales/química , Clorhexidina/análogos & derivados , Luz , Nanopartículas/química , Titanio/química , Contaminantes Químicos del Agua/química , Adsorción , Antiinfecciosos Locales/análisis , Antiinfecciosos Locales/efectos de la radiación , Catálisis , Clorhexidina/análisis , Clorhexidina/química , Clorhexidina/efectos de la radiación , Concentración de Iones de Hidrógeno , Cinética , Procesos Fotoquímicos , Temperatura , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/efectos de la radiaciónRESUMEN
The phototransformation of triclosan has been a matter of longstanding interest due to both its prevalence in the environment and the discovery of 2,8-dichlorodibenzodioxin as a photoproduct. In this study, photolysis of triclosan resulted in several primary photoproducts including the following: 2,8-dichlorodibenzodioxin (4%), 4,5'-dichloro-[1,1'-biphenyl]-2,2'-diol (10%), 5-chloro-2-(4-chlorophenoxy)phenol (0.5%), and 2,4-dichlorophenol (7%). Trapping studies using d8-isopropanol showed deuterium incorporation in 5-chloro-2-(4-chlorophenoxy)phenol, providing strong evidence for the involvement of organic radicals in this reaction. Density functional calculations of the excited states of triclosan support the involvement of a radical intermediate in the mechanisms responsible for the dioxin, biphenyl, and phenoxyphenol photoproducts. The pathways for C-Cl bond cleavage and cyclization reactions are discussed.
Asunto(s)
Antiinfecciosos Locales/efectos de la radiación , Triclosán/efectos de la radiación , Contaminantes Químicos del Agua/efectos de la radiación , Antiinfecciosos Locales/química , Clorofenoles/química , Dioxinas/química , Fotólisis , Bifenilos Policlorados/química , Triclosán/química , Contaminantes Químicos del Agua/químicaRESUMEN
This article describes the photolytic degradation of malachite green (MG), a cationic triphenylmethane dye used worldwide as a fungicide and antiseptic in the aquaculture industry. Photolysis experiments were performed by direct exposure of a solution of MG in water to natural sunlight. The main transformation products (TPs) generated during the process were identified by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) and gas chromatography mass spectrometry (GC-MS). The 28 TPs identified with this strategy indicate that MG undergoes three main reactions, N-demethylation, hydroxylation and cleavage of the conjugated structure forming benzophenone derivatives. These processes involve hydroxyl radical attack on the phenyl ring, the N,N-dimethylamine group and the central carbon atom. The Vibrio fischeri acute toxicity test showed that the solution remains toxic after MG has completely disappeared. This toxicity could be assigned, at least in part, to the formation of 4-(dimethylamine)benzophenone, which has an EC(50,30 min) of 0.061 mg l(-1), and is considered "very toxic to aquatic organisms" by current EU legislation.
Asunto(s)
Antiinfecciosos Locales/efectos de la radiación , Colorantes/efectos de la radiación , Fungicidas Industriales/efectos de la radiación , Colorantes de Rosanilina/efectos de la radiación , Luz Solar , Contaminantes Químicos del Agua/efectos de la radiación , Aliivibrio fischeri/efectos de los fármacos , Aliivibrio fischeri/metabolismo , Antiinfecciosos Locales/toxicidad , Acuicultura , Colorantes/toxicidad , Fungicidas Industriales/toxicidad , Hidrólisis , Luminiscencia , Fotólisis , Colorantes de Rosanilina/toxicidad , Contaminantes Químicos del Agua/toxicidadRESUMEN
The photodegradation of malachite green (MG), a cationic triphenylmethane dye, is examined both under different pH values and amounts of TiO(2). After 15W UV-365nm irradiation for 4h, ca. 99.9% of MG was degraded with addition of 0.5gL(-1) TiO(2) to solutions containing 50mgL(-1) of the MG dye. The HPLC-PDA-ESI-MS technique was used to obtain a better understanding on the mechanistic details of this TiO(2)-assisted photodegradation of the MG dye with UV irradiation. Five intermediates of the process were separated, identified, and characterized for the first time. The results indicated that the N-de-methylation degradation of MG dye took place in a stepwise manner to yield mono-, di-, tri-, and tetra-N-de-methylated MG species generated during the processes. Under acidic conditions, the results indicated that the photodegradation mechanism is favorable to cleavage of the whole conjugated chromophore structure of the MG dye. Under basic conditions, the results showed that the photodegradation mechanism is favorable to a formation of a series of N-de-methylated intermediates of the MG dye.
Asunto(s)
Colorantes/química , Colorantes/efectos de la radiación , Colorantes de Rosanilina/química , Colorantes de Rosanilina/efectos de la radiación , Titanio/química , Rayos Ultravioleta , Antiinfecciosos Locales/química , Antiinfecciosos Locales/efectos de la radiación , Catálisis , Fungicidas Industriales/química , Fungicidas Industriales/efectos de la radiación , Concentración de Iones de Hidrógeno , Nanopartículas/química , Fotoquímica , Cloruro de Sodio/química , Purificación del Agua/métodosRESUMEN
In the spring of 2003, there was an outbreak of the severe respiratory syndrome (SARS) in Hong Kong. Health concerns have thus triggered an increased and predominant use of various types of household cleansing agents such as triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol). However, it has been reported recently that triclosan could be photochemically converted to toxic 2,8-dichlorodibenzo-p-dioxin (2,8-Cl(2)DD) in the environment. It is therefore necessary to develop environmentally friendly methods for the treatment of triclosan. To this end, photocatalytic degradation of triclosan in aqueous solution was conducted using TiO(2) (Degussa P25) under irradiation of UV light (lambda < 365 nm). It was found that triclosan could be degraded by this approach. Hydrogen peroxide was added to enhance the degradation process, and the optimal initial hydrogen peroxide concentration for triclosan degradation was 0.005% (w/v). Product identification indicated that triclosan oxidation occurred at its phenol moiety and yielded quinone and hydroquinone intermediates. The formation of a dichlorophenol intermediate in triclosan degradation suggested bond-breaking of the ether linkage occurred during the process. Moreover, no chlorinated dibenzo-p-dioxin congener was detected. These findings confirm that the photocatalytic degradation of triclosan is an environmentally friendly process.
Asunto(s)
Antiinfecciosos Locales/análisis , Triclosán/análisis , Rayos Ultravioleta , Contaminantes Químicos del Agua/análisis , Antiinfecciosos Locales/química , Antiinfecciosos Locales/efectos de la radiación , Catálisis , Cromatografía de Gases y Espectrometría de Masas , Peróxido de Hidrógeno/química , Oxidación-Reducción , Fotoquímica , Titanio/química , Triclosán/química , Triclosán/efectos de la radiación , Contaminantes Químicos del Agua/efectos de la radiaciónRESUMEN
There was given evidence, using the complex of morphological, morphometrical, biochemical and microbiological investigations in experiment, of the peritonitis treatment efficacy applying photochemically activated laevomecol ointment. The experiment was performed in 120 adult male white mongrel rats, following the recommendations of Vancouver's convention for biomedical investigations.
Asunto(s)
Antiinfecciosos Locales/uso terapéutico , Cloranfenicol/uso terapéutico , Drenaje/métodos , Bases Oleosas/química , Peritonitis/cirugía , Polietilenglicoles/química , Uracilo/análogos & derivados , Animales , Antiinfecciosos Locales/administración & dosificación , Antiinfecciosos Locales/efectos de la radiación , Cloranfenicol/administración & dosificación , Cloranfenicol/efectos de la radiación , Clorhexidina/administración & dosificación , Clorhexidina/análogos & derivados , Clorhexidina/uso terapéutico , Modelos Animales de Enfermedad , Combinación de Medicamentos , Laparotomía , Masculino , Peritonitis/sangre , Peritonitis/microbiología , Fotoquímica , Ratas , Uracilo/administración & dosificación , Uracilo/efectos de la radiación , Uracilo/uso terapéuticoRESUMEN
Liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOFMS) was applied for the identification of four new photodegradation products of triclosan, a major antimicrobial agent used in personal care products. Wastewater samples, spiked at 7 microg/mL with triclosan, were irradiated with natural sunlight in order to generate the photodegradation products. Aliquots of the spiked water samples were taken at different times of irradiation and compounds were isolated from the water samples by solid-phase extraction. Separation and detection of the compounds and degradation products were accomplished by LC/TOFMS, which provided highly selective information about elemental compositions. Accurate mass measurements for the four degradation products permitted postulation of proposed empirical formulae in this study. Replacement of chlorine atoms by hydroxyl groups and chlorine losses are the major degradation pathways proposed. The degradation products were formed also under environmental conditions in wastewater matrices, thus suggesting their presence in real wastewater treatment processes.
Asunto(s)
Cromatografía Liquida/métodos , Espectrometría de Masas/métodos , Triclosán/química , Triclosán/efectos de la radiación , Antiinfecciosos Locales/química , Antiinfecciosos Locales/efectos de la radiación , Concentración de Iones de Hidrógeno , Estructura Molecular , Peso Molecular , Fotoquímica , Triclosán/metabolismo , Eliminación de Residuos LíquidosRESUMEN
Aqueous solutions (pH = 8) of both 3,3'-dimethyl and 4,4'-dimethyl substituted analogues of the photoallergen fentichlor (bis(2-hydroxy-5-chlorophenyl)sulphide) produced stable semiquinone radicals when irradiated with u.v. light (greater than 310 nm). These radicals have been characterised using electron spin resonance techniques: the results confirm the assignment of hyperfine coupling constants for the parent fentichlor radical. The binding of fentichlor to HSA was found to be partly oxygen dependent demonstrating a role for semiquinone type radicals in the binding mechanism. The stoichiometry and specificity of the binding of the dimethyl analogues to soluble proteins were found to be similar to that of fentichlor itself.