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Cutaneous Photosensitization
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
Another method has been developed for investigating the phototoxic potential of NSAIDs in humans.45 The method involves patients taking the appropriate drug orally for at least 1 week at the time of phototesting. The light source consists of a 900 W xenon arc lamp optically coupled to a single grating monochromator. Light is transmitted from the exit slit of the monochromator through a liquid-filled light guide to permit irradiation of a limited area of skin (0.5 cm diameter) in a controlled manner. Alternatively, banks of four to six fluorescent lamps may be used to irradiate relatively large areas of skin. Protective goggles should be worn by both patient and investigator to shield the eyes from short-wave UV light. The back of each patient is used as the phototesting site because of the high sensitivity and more uniform response to UV radiation than most other locations. Subjects are irradiated with a 20 nm bandwidth centered around 320 nm. Each individual is given a series of radiation doses ranging from 0.5 to 4 J/cm2 in a geometric fashion equivalent to doubling alternate exposures. Test sites are examined following exposure and the minimum radiation dose inducing the immediate reactions of urticarial wheals, erythema, and flaring is recorded. Subjective sensations of itching and burning also are noted.
Measuring and Quantifying Ultraviolet Radiation Exposures
Published in Francis N. Marzulli, Howard I. Maibach, Dermatotoxicology Methods: The Laboratory Worker’s Vade Mecum, 2019
Broad-band, polychromatic sources deliver much more irradiance than narrow-band sources. With a monochromator or narrow-band filters, one can achieve nearly monochromatic (one-wavelength) sources of light or UVR by sacrificing the total power available. By the Bunsen-Roscoe law, the same exposure dose would require a much longer time to deliver. Nevertheless, to determine an action spectrum for a given photobiological effect, one is forced to take this approach. If the action spectrum is known, or if one wishes simply to simulate sunlight with a solar simulator, one can achieve a threshold exposure dose in a far shorter time with broadband sources. The continuous light sources used most frequently are: Tungsten lamps and tungsten-halogen lampsHigh-pressure gas discharge lamps, such as deuterium lampsArc lamps, such as xenon or mercury-xenon high-pressure lampsLow-pressure discharge lamps, generally used for “line” sources
Solar Urticaria
Published in Henry W. Lim, Nicholas A. Soter, Clinical Photomedicine, 2018
For the determination of the action spectrum in solar urticaria, the following artificial light sources are useful, easily available, and inexpensive: a slide projector lamp for a visible light source, a fluorescent black light for a UVA source, and a fluorescent sunlamp for a UVB source. However, it should be kept in mind that the black light and sunlamp also emit a small amount of UVB and UVA, respectively. When necessary, various colored glass filters are used in combination with these light sources to eliminate shorter wavelengths. A monochromator, which can emit selected narrow bands of wavelengths, is useful for more detailed and sophisticated studies.
Formulation and performance evaluation of emulgel platform for combined skin delivery of curcumin and propolis
Published in Pharmaceutical Development and Technology, 2023
Rafaela Said dos Santos, Jéssica Bassi da Silva, Camila Felix Vecchi, Katieli da Silva Souza Campanholi, Hélen Cassia Rosseto, Mariana Carla de Oliveira, Francielle Pelegrin Garcia, Rodolfo Bento Balbinot, Lidiane Vizioli de Castro Hoshino, Tânia Ueda Nakamura, Celso Vataru Nakamura, Mauro Luciano Baesso, Wilker Caetano, Marcos Luciano Bruschi
The porcine skin sample received an emulgel sample (50 μg) homogeneously distributed over a 1-cm2 surface. After 30 min, the sample was analyzed by PAS using equipment composed of 1000 W Xenon arc lamp (Oriel, model 68820) as a light source (nominal power of 800 W). The light can be diffracted by passing through the 3.16 mm input and output slits of the monochromator (Oriel, model 77250). Afterwards, it can be modulated at 13 Hz using a mechanical chopper (Stanford Research Systems, model SR 540) to focus on the sample. Band-pass filters were utilized to eliminate the higher-order diffraction. The treated skin sample was placed inside the photoacoustic cell and a transparent quartz window (diameter of 8 mm and thickness of 2 mm) was utilized to seal it. The periodic sample heating generates pressure changes resulting in the photoacoustic signal that can be captured by a capacitive microphone (Brüel and Klaer model 2669). In addition, a lock-in amplifier by EG&G Instruments, model 5110, was utilized. The thermal diffusion length was used for calculating the depth of tissue that contributed to the photoacoustic signal (Baesso et al. 1994; Ames et al. 2017) according to Equation 3: s is the thermal diffusion length, D is the sample thermal diffusivity (4.1 × 10−4 cm2/s), and πf is the light modulation frequency (13 Hz). Consequently, μs was 32 μm for the skin, which ensures that readings are taken close to the surfaces on which the light is incident, being the sample mean thickness always around 1080 μm.
Formulation, biopharmaceutical evaluation and in-vitro screening of polyherbal phytosomes for breast cancer therapy
Published in Drug Development and Industrial Pharmacy, 2022
Lalitha K. Govindaram, Mohammed Al Bratty, Hassan A. Alhazmi, Ruckmani Kandasamy, Neelaveni Thangavel, Angum M. Ibrahim, Gover Antoniraj Mariya, Ponnuchamy Kumar
In this method, 100 nL/s of continual loading rate and 18.8 mm of band separation for the sample were maintained. The scanning was carried out at a 6.00 × 0.45 mm slit dimension and 10 mm/s speed. The monochromator was maintained at 20 nm bandwidth. The scanning of each track was performed in triplicates with baseline correction. The mobile phase of toluene, ethyl acetate, and formic acid (4.5:3.5:0.2% v/v/v) was utilized for the analysis, after 20 min of the conditioning, the chamber saturation time was maintained at room temperature (25 ± 2 °C) at a relative humidity of 55 ± 5%. The average time taken for the development was 15 min. The densitometric assessment of the plates was achieved at λmax 420 nm for curcumin, 336 nm for apigenin and 223 nm for withaferin A using a deuterium light source with Camag TLC scanner-3 furnished with win CATS software.
Application of salt engineering to reduce/mask bitter taste of clindamycin
Published in Drug Development and Industrial Pharmacy, 2019
Sogra F. Barakh Ali, Sathish Dharani, Hamideh Afrooz, Mansoor A. Khan, Eman M. Mohamed, Kanchan Kohli, Ziyaur Rahman
Modular Nicolet™ iS™ 50 system (Thermo Fisher Scientific, Austin, TX) was used for collecting FTIR, NIR, and Raman spectra of CLN-HCl, CYA and the salts. FTIR spectra was collected in absorbance mode and wavelength range of 400–4000 cm−1 with a data resolution of 8 cm−1 for 100 scans. For NIR measurement, the instrument has built-in scanning grating monochromator attached with a diffuse reflectance rapid content analyzer. Samples were placed on the sample window and centered with an iris. After conducting the diagnostic tests and reflectance standardization, NIR spectra ranging from 4000 to 10000 cm−1 in 2 nm increments with a data resolution of 8 cm−1 for 100 scans were collected. The instrument was equipped with IN-Ga-As detector with CaF2 beam splitter. Raman spectra collection parameters were 400–3250 cm−1 Raman shift, 500 scans with an optical velocity of 0.316 kHz and 0.5 W laser source using 50 mm aperture. Spectra were collected using OMNIC software version 9.0 (Thermo Fisher Scientific, Austin, TX).