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Immunologically mediated skin disorders
Published in Ronald Marks, Richard Motley, Common Skin Diseases, 2019
In this group of drug-induced conditions, the rash is confined to the light-exposed areas and is wavelength dependent, i.e. it only reacts to particular wavelengths in the solar ultraviolet spectrum. The rash itself is red and papular or plaque-like (Fig. 7.25). Some drugs seem able to provoke a phototoxic eruption, which is seen in many patients to whom the drug is given and is dose dependent, and others cause a photoallergic rash in which a photoallergen has formed and which only affects a few individuals. Tetracyclines and sulfonamides may cause a phototoxic response. The phenothiazines may cause either a phototoxic or a photoallergic reaction.
Acute Effects of Ultraviolet Radiation on the Skin
Published in Henry W. Lim, Nicholas A. Soter, Clinical Photomedicine, 2018
The relative effectiveness of different wavelengths in the induction of erythema is expressed as an erythema action spectrum. For minimal erythema, the most erythemogenic wavelengths are in the 250–290 nm range of the ultraviolet spectrum, with a decrease in effectiveness as the wavelength increases.
Quality Control
Published in Joseph Chamberlain, The Analysis of Drugs in Biological Fluids, 2018
The first step in ensuring the quality of an analytical method is to establish that any standards — either for calibration or for quality control — are correctly made up. It is particularly useful to run an ultraviolet spectrum of stock solutions of drugs. This guards against a weighing or diluting error in the first stages of standard preparation. For quality control purposes, these validated stock solutions are added to suitable large pools of plasma or urine to prepare pools of at least three different concentrations to cover the expected range of measured concentrations.
Protective effect of aminoguanidine against lipopolysaccharide-induced hepatotoxicity and liver dysfunction in rat
Published in Drug and Chemical Toxicology, 2021
Farimah Beheshti, Mahmoud Hosseini, Mehdi Taheri Sarvtin, Ali Kamali, Akbar Anaeigoudari
To evaluate the activity of SOD, we used the Madesh and Balasubramanian method (Madesh and Balasubramanian 1998). This method is a colorimetric assay which involves production of superoxide by pyrogallol autoxidation and the inhibition of superoxide-dependent reduction of the tetrazolium dye MTT [3–(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyl tetrazolium bromide] to its fromazan. In this method, the SOD activity was assessed at 570 nm. One unit of SOD was described an amount of enzyme that needed to suppress %50 rate of MTT reduction (Anaeigoudari et al. 2016b). To measure the activity of CAT, we used the Aebi’s method. Hydrogen peroxide (H2O2) as substrate of CAT was added into the experimental environment. The breakdown of H2O2 into water and oxygen by CAT shows itself on the ultraviolet spectrum as a reduction in the absorbance. This decrease in the absorbance is attributed to the CAT activity (Turkkan et al. 2016).
Nanocrystal: a novel approach to overcome skin barriers for improved topical drug delivery
Published in Expert Opinion on Drug Delivery, 2018
Viral Patel, Om Prakash Sharma, Tejal Mehta
There are various natural plant pigments, for example flavonoids, with antiradical and antioxidant properties. However, their bioavailability is limited due to their poor water solubility. Hatahet et al. [148] have developed the nanocrystals of quercetin. They observed that quercetin nanocrystals showed a 7.6-fold increase in dissolution velocity. In vitro DDPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay confirmed the retention of antioxidant property of quercetin in the nanocrystal form. The developed nanocrystals were safer and did not show cellular toxicity at a concentration of 50 µg/ml which was confirmed by the hydrogen peroxide assay performed on VERO cell lines. Similarly, lutein is also a very well-known carotenoid having antioxidant and free radical scavenging property. Lutein is able to filter blue light of ultraviolet spectrum, thus preventing photon-induced oxidative damage in the eye. Like other carotenoids, lutein is a lipophilic molecule having poorly solubility in water. In order to improve the solubility of lutein, lutein nanocrystals using high-pressure homogenization method were formulated. A 26.3-fold increase in the solubility of lutein nanocrystals was observed as compared with coarse powder form. Further, the nanosuspension was lyophilized and was formulated into topical cream and gel for the cosmetic application [113].
UV-Photokeratitis Associated with Germicidal Lamps Purchased during the COVID-19 Pandemic
Published in Ocular Immunology and Inflammation, 2021
Jesse D. Sengillo, Anne L. Kunkler, Charles Medert, Benjamin Fowler, Marissa Shoji, Nathan Pirakitikulr, Nimesh Patel, Nicolas A. Yannuzzi, Angela J. Verkade, Darlene Miller, David H Sliney, Jean-Marie Parel, Guillermo Amescua
The recent global outbreak of coronavirus disease 2019 (COVID-19), caused by the emergence of the novel human coronavirus SARS-CoV-2, has resulted in significant morbidity and mortality worldwide.1 In order to prevent the spread of disease, individuals and local businesses are seeking novel sanitation strategies against the virus. One such method of sterilization includes the use of consumer-grade UV lamps.2 Germicidal light is radiant energy used to inactivate microbes such as bacteria, mold, fungi, and viruses. Wavelengths on the shorter end of the ultraviolet spectrum are known to be effective for disinfection, specifically UV-C (100–280 nm), while larger wavelengths require more energy and duration of exposure.3,4