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A densitometry method based on steady-state and time-resolved fluorescence assessments for thioridazine and its photoproducts applied on HPTLC plates has been developed. The excitation source was a picosecond diode laser emitting at 375 nm. This method was used for the analysis of the photoproducts resulted from thioridazine irradiation with 266 nm nanosecond-pulsed laser. The validation of the developed method was performed for thioridazine in terms of linearity, precision, limits of detection and quantification. Furthermore, analysis of the photoproducts of irradiated thioridazine was performed by steady-state and time-resolved fluorescence. The fluorescence spectra and fluorescence lifetime of each photoproduct were obtained and the horizontal chromatograms of fluorescence maxima were generated.

Fluorescence and lasing emission that are produced separately in time during excitation laser pulse for an mm-sized Rhodamine 6G dye-water droplet are reported. The droplet acts as a quasi-spherical closed optical resonator and due to multiple internal reflections, the resonant amplified emission is delayed with respect to fluorescence emission. Measurements of the temporal evolution of the droplet&rsquo, s emission were performed by varying the signal acquisition gate width and gate delay with respect to the pumping pulse. The droplet emission spectra are structured in two bands which appear one after the other in time: first, the fluorescence emission band which follows pumping laser pulse time shape and then a second band, the lasing band, placed at shorter wavelengths and formed in time after the peak of the pumping laser pulse intensity, on the pulse tail. The lasing threshold pumping intensity is much lower than those for typical dye lasers.

High-resolution spectrum analysis of the lasing emission of mm3-sized pendant droplets that contain aqueous solutions of the Rhodamine 6G (Rh6G) dye is reported. Pumping was performed with a 532 nm pulsed laser beam. The lasing emission demonstrates a complex spectral structure that contains mode-cluster peaks spaced 2 nm apart and a ripple structure formed by periodic resonances, which are superimposed on the peak closest to the maximum of the dye gain curve. The periodic resonances are associated with the light-scattering resonances on a large sphere when light absorption in the sphere occurs.

This research was focused on the effects of DMSO-water ratio on the photophysics of the sensitizer Zn phthalocyanine (ZnPc) and on the photogenerated singlet oxygen. To reach this objective optical absorption, flash photolysis and time-resolved phosphorescence were used. Potential dye accumulation at the surface of the sample was studied by surface-tension measurements and at the chosen concentration no such effects were found. It was established that the sharp drop of dye absorbance at ∼40% water content is produced by dye dimerization, probably induced by a re-clustering of molecules in the solvent composition. When water runs over 0–80% range the dye triplet lifetime follows a sigmoid evolution with an inceptive plateau at 120 μs and a sharp decrease in the 25–35% water range. Complementary experiments in neat DMSO established that while the ground dye molecules strongly quench the dye triplet states they do not significantly quench singlet oxygen. Experiments also showed that previous reported behavior of the lifetime of photosensitized singlet oxygen, exhibiting a prominent peak in the range 20–40% of water content is a common feature for both water soluble and insoluble solvates. The work outlines the hypothesis of a DMSO first solvation shell around the solvated dye molecules for a water content less than 25% and of a molecular re-organisation of the solvent taking place beyond this point, which induces important variations of photophysical quantities.

This study presents results about UV laser beam interaction with Vancomycin (VCM) solutions in ultrapure water performed on bulk samples (5 mL). Photoproducts and molecular fragments resulting from the parent VCM and generated by exposure to 266 nm are evidenced by UV–vis absorption and FTIR spectroscopy and liquid chromatography electro spray ionization time-of-flight mass spectrometry (LC/ESI-TOF-MS) measurements. A novel method is reported to characterize surface active compounds produced in VCM solutions during exposure to UV laser radiation, by measuring in real time the dynamic interfacial tension of the irradiated solutions in emerging, constant volume bubble configuration. This shows that amphiphilic photoproducts are generated after the interaction of VCM molecules with laser beam that migrate at the interface air bubble/VCM solution. They accumulate at the interface leading at transition surface effects. In the paper four such amphiphilic photoproducts were identified and their chemical structures were proposed.

Phenothiazine drugs - chlorpromazine (CPZ), promazine (PZ) and promethazine (PMZ) - were exposed to 266 nm (fourth harmonic of the Nd:YAG pulsed laser radiation) in order to be modified at molecular level and to produce an enhancement of their antibacterial activity. The irradiated samples were analysed by several methods: pH and surface tension measurements, UV-vis-NIR absorption spectroscopy, laser induced fluorescence and thin layer chromatography. The purpose of these investigations was to study and describe the modified properties of the medicines to further investigate their specific interactions with materials such as cotton, polyester and Parafilm M as a model smooth surface. The textile materials may be impregnated with phenothiazines drug solutions exposed to laser radiation in order to be used in treatments applied on the surface of the organism. Some of the phenothiazines solutions exposed prolonged time intervals to laser radiation have much better activity against several bacteria. Therefore, in the paper, it is reported the wetting behaviour of CPZ, PZ and PMZ solutions, irradiated for time intervals between 1 and 240 min, on the surfaces of the three textures in order to draw a conclusion about their wettability as a function of time. (C) 2014 Elsevier B.V. All rights reserved.

Studies on the emission spectra of microdroplets containing Rh6G solutions in water doped with TiO2 nanoparticles are reported. The excitation is made by the second harmonic of a pulsed Nd:YAG laser at 532 nm, pulse duration at half maximum 6 ns and energy varied between 6 and 10 mJ. The laser induced emission spectra are analyzed function of TiO2 concentration and pumping laser energy. Comparison between fluorescence dispersed spectra emitted by pendant droplets containing TiO2 nanoparticles with respect to Rh6G water solutions droplets pumped in the same conditions is made. The surface tension measurements of the samples show that with variation of dye and nanoparticles concentrations, surface phenomena take place and influence the behavior of the droplet fluorescence. (C) 2016 Elsevier B.V. All rights reserved.

This paper presents data about photophysics of two novel thio-hydantoins that exhibit promising pharmaceutical properties in multidrug resistance control. Time stability studies are necessary to establish the proper use of these compounds in different applications. As for their administration as drugs, it is imperative to know their shelf life, as well as storage conditions. At the same time, laser induced modified properties of the two new compounds are valuable to further investigate their specific interactions with other materials, including biological targets. The two new thio-hydantoins under generic names SZ-2 and SZ-7 were prepared as solutions in dimethyl sulfoxide at different concentrations, as well as in deionised water. For the stability assay they were kept in various light/temperature conditions up to 60 days. The stability was estimates based on UV–vis absorption measurements. The samples in bulk shape were exposed different time intervals to laser radiation emitted at 266 nm as the fourth harmonic of a Nd:YAG laser. The resonant interaction of the studied compounds with laser beams was analysed through spectroscopic methods UV–vis and FTIR absorption, as well as laser induced fluorescence spectroscopy. As for stability assay, only solutions kept in dark at 4 °C have preserved the absorption characteristics, considering the cumulated measuring errors, less than one week. The vibrational changes that occur in their FTIR and modified fluorescence spectra upon laser beam exposure are also discussed. A result of the experimental analysis is that modifications are induced in molecular structures of the investigated compounds by resonant interaction with laser radiation. This fact evidences that the molecules are photoreactive and their characteristics might be shaped through controlled laser radiation exposure using appropriate protocols. This conclusion opens many opportunities both in the biomedical field, but also in other industrial activities involving the use of hydantoins.

Results for the interaction of a 532 nm pulsed laser beam with individual pendant rhodamine 6G dye droplets of a large-size parameter, x≈7300, are reported. By varying dye concentration and pumping energy, typical fluorescence bands detected in such cases are obtained, along with a narrow, instantly, or gradually blueshifted band assigned to the lasing effect at the droplet surface. The maximum blueshift value of the lasing peak wavelength is associated with the maximum of the dye fluorescence gain curve when self-absorption effects are not present. Lasing peak position is not further influenced by pumping energy or droplet diameter decrease after lasing reaches the gain curve peak wavelength.

Phenothiazine derivatives are non-antibiotics with antimicrobial, fungistatic and fungicidal effects. We exposed to a high energy UV laser beam phenothiazines solutions in water at 20mg/mL concentration to increase antibacterial activity of resulting mixtures. Compared to previous results obtained on bacteria, more research is needed about UV laser irradiated phenothiazines applications on cancer cell cultures to evidence possible anticancerous properties. Evaluation of the safety of the newly obtained photoproducts in view of use on humans is also needed. Due to expensive animal testing in toxicology and pressure from general public and governments to develop alternatives to in vivo testing, in vitro cell-based models are attractive for preliminary testing of new materials. Cytotoxicity screening reported here shows that laser irradiated (4h exposure time length) chlorpromazine and promazine are more efficient against some cell cultures. Interaction of laser irradiated phenothiazines with fabrics show that promethazine and chlorpromazine have improved wetting properties. Correlation of these two groups of properties shows that chlorpromazine appears to be more recommended for applications on tissues using fabrics as transport vectors. The reported results concern stability study of phenothiazines water solutions to know the time limits within which they are stable and may be used. Keywords: Culture cells; Fabrics; Hemolysis; In vitro cytotoxicity; Laser; Phenothiazines.

This paper deals with the rapid molecular changes induced by laser radiation on two novel hydantoin derivatives, generically named SZ-2 and SZ-7, having promising pharmaceutical properties as Szymanska et al. in 2002 and Subtelna et al. in 2010 have reported. Hydantoins solutions with concentration of 10−3 M in dimethyl sulfoxide were exposed both in droplets and bulk samples to coherent radiation emitted at 266 nm as the fourth harmonic of a Nd:YAG laser during different time intervals. The influence of exposure to laser radiation was highlighted by laser induced fluorescence. Also, dynamic wetting (in terms of surface tension and contact angle) measurements were performed in order to find information valuable for further development and modification of hydantoins. All these studies intend to provide physical data in order to better understand the behavior and the activity of this kind of potential drugs on biological targets. Experimental results prove that the investigated molecules are photoreactive. Changes produced in a pendant microdroplet are orders of magnitude faster than in the case of bulk exposure. The surface tension values of unirradiated/irradiated hydantoin derivatives solutions in dimethyl sulfoxide are stable along the time interval of measurements, indicating that the molecules are evenly distributed in drop solution and they are not adsorbed at air–liquid interface. However, a very low gradient of dynamic surface tension values of the unirradiated samples, and the irradiated ones is registered for the SZ-2 compound. This suggests the modification of the cohesive strength of the molecules inside the droplets exposed to laser radiation. The contact angles equilibrium values of droplets on hydrophobic surface show no remarkable differences for unirradiated/irradiated imidazolidines samples, though the small increase of the contact angle for irradiated SZ-7 confers it a more hydrophobic property.

The study reports an investigation of the photoproducts obtained by exposure of chlorpromazine hydrochloride in ultrapure water (concentration 2 mg/mL) to a 266-nm laser beam obtained by fourth harmonic generation from a Nd:YAG laser (6-ns full time width at half maximum, 10-Hz pulse repetition rate). The photoproducts were analyzed by steady-state UV-Vis absorption, laser-induced fluorescence, Fourier transform infrared spectroscopy, and liquid chromatography-tandem time-of-flight mass spectroscopy. Two figures showing pathways that take place during irradiation for obtaining the final products are shown. The quantum yield of singlet oxygen generation by chlorpromazine (CPZ) was determined relative to standard Zn-phthalocyanine in dimethyl sulfoxide. To outline the role of fluorescence in photoproducts formation rates, fluorescence quantum yield of CPZ during exposure to 355-nm radiation (third harmonic of the fundamental beam of Nd:YAG laser) was investigated relative to standard Coumarin 1 in ethanol. The CPZ solutions exposed 60 and 240 min to 266-nm laser beam, respectively, were tested against Staphylococcus aureus ATCC 25923 strain. For 25 μL of CPZ samples irradiated 240 min, a higher diameter of inhibition has obtained against the tested strain than for the 60-min exposed ones.

Chlorpromazine (CPZ) was exposed to a 266 nm laser beam for different periods of time ranging from minutes to 24 h. At intervals, the products from irradiation were evaluated by thin-layer chromatography (TLC) and evaluated for their activity against mycobacteria of human interest (Mycobacterium tuberculosis, M. avium, M. intracellulare and their corresponding reference strains or clinical isolates). With the exception of the M. avium 47/07 clinical strain, the products produced from the irradiation of CPZ for 4 h had greater activity against M. intracellulare ATCC, M. avium ATCC, H37Rv and the Multidrug-resistant tuberculosis (MDR-TB) strains as opposed to that produced by the unirradiated control. The level of products from the 4-h exposure of CPZ remained the same throughout the next 20 h of irradiation. Of significant note is that the irradiation products of CPZ had lower in vitro cytotoxicity against human cells, suggesting that this approach may be useful for the development of compounds more bioactive than the parental species.

International audience; Photophysical properties of phthalocyanines are important in photodynamic therapy, where these compounds are proposed as photosensitizing agents. We report here some significant solvent effects on the photophysical properties of Zn phthalocyanine (ZnPc) observed in binary solvent mixture dimethyl sulfoxide/water at several ratios of cosolvents. The absorbance of ZnPc at the maximum of Q band has a sharp drop in intensity for a water mass percent in the solvent mixture larger than 40%. The same characteristic shows also the quantum yield of fluorescence. A particular result is the increase of singlet oxygen lifetime for water percentage raise up to 20% in the solvent mixture. The effects are discussed in connection with the particular solvent microenvironment, involving DMSO/water clusters formation and the strong interaction between the solute and the solvent.

Phenothiazine exposed to white light or UV radiation undergoes a variety of reactions that result in the degradation of the parental compound and the formation of new species. Chlorpromazine exposed to the 266 nm laser beam of given energy levels yielded s pecies derived from it, whose number increased with the exposure duration. At distinct time intervals the irradiation products were evaluated by spectrophotometry between 200 -1500 nm, T hin L ayer C hromatography, and for antimicrobial act ivity of Chlorpromaz ine against different test organisms such as Staphylococcus aureus . Keywords: Ch lorpromazine, CPZ, Promazine, PZ, TLC , absorption spectroscopy, photo -degradation . 1. INTRODUCTION Ph enothiazine s are labeled as pharmaceutical s since 1950s and their derivatives are powerful antihistamines used as neuroleptics [1] . Chlorpromazine (CPZ) , a phenothiazine derivative, is used for its sedative and antipsychotic properties for over 40 years [2]. A significant number of drugs used curre ntly in medicine have their bas es in the chemical manipulation of phenothiazine s [3]. Creating new derivatives t hrough a chemical pathway is limited by the existing organic chemistry and it is also time consuming . N ew derivatives of current drugs with a be tter activity against bacteria which acquired multidrug resistan ce (MDR) at treatments with antibiotics may be obtained by exposure of the existing medicines to UV light. E xperiments dating from 1963 to 1667 [4 , 5] were made using an incoherent UV source , but the exposure time of the medicines was too long and time consuming : C PZ was expose d up to 5 -7 days to the UV lamp. A s a consequence, a better solution seems to be the use of a coherent source of light, such as a laser. The difference between using an UV instead of an incoherent UV light source is that a laser has a specific wavelength that may be as narrow as 10

IntroductionPhenothiazines when exposed to white light or to UV radiation undergo a variety of reactions that result in degradation of parental compound and formation of new species. This process is slow and may be sped up with exposure to high energy light such as that produced by a laser.MethodsVarying concentrations of Chlorpromazine Hydrochloride (CPZ) (2-20 mg/mL in distilled water) were exposed to 266 nm laser beam (time intervals: 1-24 hrs). At distinct intervals the irradiation products were evaluated by spectrophotometry between 200-1500 nm, Thin Layer Chromatography, High Pressure Liquid Chromatography (HPLC)-Diode Array Detection, HPLC tandem mass spectrometry, and for activity against the CPZ sensitive test organism Staphylococcus aureus ATCC 25923.ResultsCPZ exposure to 266 nm laser beam of given energy levels yielded species, whose number increased with duration of exposure. Although the major species produced were Promazine (PZ), hydroxypromazine or PZ sulfoxide, and CPZ sulfoxide, over 200 compounds were generated with exposure of 20 mg/mL of CPZ for 24 hrs. Evaluation of the irradiation products indicated that the bioactivity against the test organism increased despite the total disappearance of CPZ, that is due, most probably, to one or more new species that remain yet unidentified.ConclusionsExposure of CPZ to a high energy (6.5 mJ) 266 nm laser beam yields rapidly a large number of new and stable species. For biological grade phenothiazines (in other words knowing the impurities in the samples: solvent and solute) this process may be reproducible because one can control within reasonably low experimental errors: the concentration of the parent compound, the laser beam wavelength and average energy, as well as the duration of the exposure time. Because the process is "clean" and rapid, it may offer advantages over the pyrogenically based methods for the production of derivatives.

Varying concentrations of Chlorpromazine Hydrochloride (CPZ) were exposed to a 266 nm laser beam for varying periods of time ranging from 4 to 24 hrs and the products of irradiation were evaluated for activity against a panel of bacteria that consisted of representatives of Gram-positives and Gram-negatives that expressed different degrees of efflux pump activity, and compared to the parental unexposed compound with prolonged irradiation, whereas the antibacterial activity of the product against Staphylococcus aureus and Escherichia coli strains was many folds greater, no activity against their efflux pumps was noted. The activity of the products of irradiation against Salmonella enterica serovar Enteritidis was slight. However, the products of prolonged irradiation of CPZ produced increasingly significant concentration dependent inhibition of efflux by the Salmonella strains.

One of the alternatives to the existing medicines and treatment procedures in fighting multi drug resistance (MDR) is strengthening the effects of medicines by modifying their molecular structures through exposure to laser radiation. A method associated with this, is the generation of micro-droplets which contain medicines solutions; the droplets are utilized/produced as vectors to transport the medicines to targets. In our studies we try to combine these two methods in order to obtain a new technique to deliver the efficient medicines to targets that can be applied for a relative large number of chemicals. For this purpose we have developed an experimental set-up containing a liquid droplets generator, a tunable laser source used to irradiate droplets, a subunit to measure the laser induced fluorescence (LIF) signals and a real time recording system for droplet image analysis. Measurements on different probes, like ultrapure water, commercial grade medicines, newly developed medicines and laser dyes were performed.. All these measurements were performed on waterbased solutions. We present in this paper the laser induced fluorescence measurements results on medicine solutions (in bulk or in a micro-droplet form) that exhibit important modifications after the exposure at laser radiation. It was evidenced that the exposures to laser beams/coherent optical radiation of some medicines solutions in ultrapure water may produce molecular modifications in solutions. These slight modifications of the molecules made them more efficient against bacteria strains.

In this paper, laser beam resonant interaction with pendant microdroplets that are seeded with a laser dye (Rhodamine 6G (Rh6G)) water solution or oily Vitamin A emulsion with Rhodamine 6G solution in water is investigated through fluorescence spectra analysis. The excitation is made with the second harmonic generated beam emitted by a pulsed Nd:YAG laser system at 532 nm. The pendant microdroplets containing emulsion exhibit an enhanced fluorescence signal. This effect can be explained as being due to the scattering of light by the sub-micrometric drops of oily Vitamin A in emulsion and by the spherical geometry of the pendant droplet. The droplet acts as an optical resonator amplifying the fluorescence signal with the possibility of producing lasing effect. Here, we also investigate how Rhodamine 6G concentration, pumping laser beam energies and number of pumping laser pulses influence the fluorescence behavior. The results can be useful in optical imaging, since they can lead to the use of smaller quantities of fluorescent dyes to obtain results with the same quality.

Whereas exposure of combinations of a phenothiazine and bacterium to incoherent UV increases the activity of the phenothiazine, exposure of the phenothiazine alone does not yield an increase of its activity. Because the laser beam energy is greater than that produced by the incoherent UV sources, exposure of phenothiazines to specific lasers may yield molecules with altered activities over that of the unexposed parent. Chlorpromazine, thioridazine and promethazine active against bacteria were exposed to two distinct lasers for varying periods of time. Absorption and fluorescence spectra were conducted prior to and post-exposure and the products of laser exposure evaluated for activity against a Staphylococcus aureus ATCC strain via a disk susceptibility assay. Exposure to lasers alters the absorption/fluorescence spectra of the phenothiazines; reduces the activity of thioridazine against the test bacterium; produces a highly active chlorpromazine compound against the test organism. Exposure of phenothiazines to lasers alters their structure that results in altered activity against a bacterium. This is the first report that lasers can alter the physico-chemico characteristics to the extent that altered bioactivity results. Exposure to lasers is expected to yield compounds that are difficult to make via chemical manipulation methods. A survey of selected patents of interest, even co-lateral for the subject of this article is shortly made.