Monographs of Topical Drugs that Have Caused Contact Allergy/Allergic Contact Dermatitis
Anton C. de Groot in Monographs in Contact Allergy, 2021
A 56-year-old woman with chronic eczema on the dorsum of the right foot associated with venous insufficiency developed eczematous lesions on sun-exposed areas (face, neck, nape, forearms, dorsum of the hands) progressing within 2 months to erythroderma, exacerbated on sun-exposed areas. She did not take any oral drugs. The patient was a farmer and handled the insecticide deltamethrin. Photopatch tests showed photocontact allergy to chlorpromazine with UVA at D2 and D3, but were negative to deltamethrin. The patient was informed by her chemist about the various topical drugs containing a phenothiazine and recognized the pharmaceutical gel containing 0.75% isothipendyl that she applied on her foot to reduce the pruritus. Next, a photopatch test with the gel was strongly positive (D1 ++, D2 +++) but was negative in the unirradiated patch test. After stopping use of the gel, the lesions disappeared within 1 month with symptomatic treatment and with strict external photoprotection (2).
Rationale and technique of malaria control
David A Warrell, Herbert M Gilles in Essential Malariology, 2017
Deltamethrin, which has a fairly high mammalian toxicity (moderately hazardous; LD50 135 mg/kg), was used at a dosage of 0.05 g/m2 in a field trial in Africa and was safe and effective as a residual spray for at least 2 months. Permethrin, a safer pyrethroid (moderately hazardous; LD50 500 mg/kg), when employed at a dosage of 0.5 g/m2 was fairly effective as a residual spray for about 3 months. The latest synthetic pyrethroid, discovered in the early 1980s and developed as an insecticide for agricultural and public health applications, is lambda-cyhalothrin. The formulations available for residual spraying are 2.5 per cent and 5 per cent emulsifiable concentrate and 10 per cent wettable powder. Application rates are typically in the range of 10–25 mg/m2 or, for prolonged action (6 months), 25–30 mg/m2 are suggested. It is classed as a ‘moderately hazardous’ insecticide, with an LD50 of 56 mg/kg.
Carboxylesterase Inhibitors: Relevance for Pharmaceutical Applications
Peter Grunwald in Pharmaceutical Biocatalysis, 2019
Besides the above-mentioned compounds, other compounds, including fatty acids, sterols, pyrethroids, and therapeutic drugs, also displayed strong inhibitory effects against carboxylesterase (Xu et al., 2016; Lei et al., 2017; Wang et al., 2017). Crow et al. found that most naturally occurring fatty acids strongly inhibited the hydrolytic activities of recombinant CES1, with the IC50 values at micromolar range Crow et al. (2010). Unsaturated fatty acids displayed potent inhibitory effects on CES1 than saturated ones, while they also display high specificity towards CES1 over CES2. 27-Hydroxycholesterol (27-HC), an oxidized form of cholesterol, also showed promising inhibitory activity against recombinant CES1 (IC50 46 nM) and high selectivity over CES2. 27-HC functioned as noncompetitive inhibitor against CES1, with the very low Ki value (10 nM) (Crow et al., 2010). Bakuchiol, a natural phenolic compound isolated from Fructus Psoraleae (Bu-gu-zhi in Chinese), strongly inhibited CES2 (Li et al., 2015). Pyrethroids are a class of organic compounds similar to the natural pyrethrins produced by the flowers of pyrethrums (Chrysanthemum cinerariaefolium). Pyrethroids are popular household insecticides for their relatively low toxicity to mammals in contrast to organophosphorus insecticides. Recently, Ge et al. found that six commonly used pyrethroids including deltamethrin showed moderate inhibitory effects against both CES1 and CES2 (Table 9.9) (Lei et al., 2017). Deltamethrin strongly inhibited CES1-mediated DME hydrolysis in HLM, with the IC50 value of 2.39 μM. Deltamethrin was a competitive inhibitor against CES1-mediated BMBT hydrolysis, but it functioned as a noncompetitive inhibitor against CES1-mediated DME or DMCB hydrolysis in HLM. Further investigations on inhibition kinetic analyses and docking simulations suggested that CES1 had at least two ligand-binding sites, and deltamethrin (DMT) could bind with the same ligand binding site as BMBT. Physostigmine, a natural alkaloid, was a highly specific CES2 inhibitor with the Ki value of 0.358 μM (Umehara et al., 2016). Physostigmine potently inhibited the hydrolysis of irinotecan but did not affect the hydrolysis of clopidogrel in human liver S9. By the catalytic asymmetric [3+2] cyclization of novel 4-isothiocyanato pyrazolones and isatin-derived ketimines, Wang and Zou et al. systhsized a wide range of intriguing dispirotriheterocyclic products in high yield with excellent diastereoselectivity and enantioselectivity (Bao et al., 2018). In addition, a chiral sulfoxide derivative (tert-butyl (3R,4′R)-1-benzyl-2′-((S)-methylsulfinyl)-2,5″-dioxo-1″-phenyl-3″-(p-tolyl)-1″,5″-dihydro-1′H-dispiro[indoline-3,5′-imidazole-4′, 4″-pyrazole]-1′-carboxylate) of this dispirocyclic product was identified to be a promising CES1 inhibitor. The IC50 of this chiral sulfoxide derivative was 0.39 μM, which activity was 20-fold stronger than its enantiomer.
Effect of deltamethrin and fluoride co-exposure on the brain antioxidant status and cholinesterase activity in Wistar rats
Published in Drug and Chemical Toxicology, 2018
Adil Mehraj Khan, Rajinder Raina, Nitin Dubey, Pawan Kumar Verma
Deltamethrin, a type II pyrethroid, is extensively used as an ectoparasiticide on animals and as an insecticide in agriculture and public health programs. Pyrethroid exposure has been reported to generate reactive oxygen species and the consequent oxidative stress in various tissues (Dubey et al.2012, 2013, Dar et al.2015, Fetoui et al.2015). Fluoride (F−) is an essential trace element within recommended levels. World Health Organization recommends a guideline maximum F− value of 1.5 mg/L as a level of minimal fluorosis (Dubey et al.2013). In the endemic fluorosis areas of Central Asia and India, water may contain F− levels up to 20 mg/L (Merian et al.2004). F− can cross cell membranes and affect various soft tissues leading to impairment of tissue functions (Kant et al.2010). Oxidative stress has been speculated to play an important role in the toxic effects of F− (Zabulyte et al.2007, Khan et al.2013a).
Mechanism of deltamethrin induced thymic and splenic toxicity in mice and its protection by piperine and curcumin: in vivo study
Published in Drug and Chemical Toxicology, 2018
Anoop Kumar, Dinakar Sasmal, Neelima Sharma
Deltamethrin is a potent toxicant; thus, there is the need for studies pertaining to the identification of safe and active plant derived compounds for its attenuation which is important for the health of general populations. In the literature, various reports have indicated the cytoprotective activities of piperine and curcumin. The oral administration of piperine (100 mg/kg body wt.) decreased in the extent of lipid peroxidation and increased in the activities of enzymatic antioxidant [(superoxide dismutase, catalase and glutathione peroxidase and non-enzymatic antioxidants (reduced GSH, vitamin E and vitamin C))] levels in Swiss albino mice (Selvendiran et al., 2003). Regarding curcumin, Sankar et al (2010) demonstrated that concurrent curcumin treatment has a beneficial role in mitigating immunotoxicological effects of cypermethrin in rats. The results of current investigation have also shown that piperine and curcumin (2.5 mg/kg) exhibit significant reduction of ROS and restoring GSH depletion, which demonstrate its antioxidant property. Cytotoxicity study results show that piperine and curcumin as such, are non-cytotoxic to immune organs.
Multiple insecticide resistance in Anopheles culicifacies s.l. (Diptera: Culicidae) in east-central India
Published in Pathogens and Global Health, 2019
Sudhansu Sekhar Sahu, Sonia Thankachy, Smrutidhara Dash, Subramanian Swaminathan, Gunasekaran Kasinathan, Jambulingam Purushothaman
There are a few earlier reports available regarding the resistance status of An. culicifacies s.l. to commonly used insecticides in the current study area. A study conducted during 1995 in Koraput district showed that An. culicifacies s.l. was resistant to DDT but susceptible to malathion and deltamethrin [23]. Subsequent studies carried out during 2004 in eight southern districts of Odisha State reported that An. culicifacies s.l. was resistant to DDT in all the eight districts, to malathion in four districts and was under ‘verification required’ category to deltamethrin in three districts [24]. A study conducted in these 10 districts during 2010–2011 showed a similar resistance status in An. culicifacies s.l. to DDT and malathion [3]. On exposure to deltamethrin, this species was found susceptible in two districts and was under ‘verification required’ category in the other eight districts [3]. However, the deltamethrin resistance recorded in the current study showed that it took nearly 16 years for An. culicifacies s.l. to develop wide-spread resistance at a low frequency after extensive use of this insecticide since 2001 both in public health and in agricultural sectors in east-central India [12]. Though An. culicifacies s.l. was reported to be resistant to all the three insecticides in the current study, the resistance was lesser to SPs than DDT and malathion.