Pyrithione Research Articles

Insights into the hydrophobic coating with integrated high-efficiency anti-corrosion, anti-biofouling and self-healing properties based on anti-bacterial nano LDH materials

In this work, a series of hydrophobic coatings based on the anti-bacterial nano-hydrotalcite (LDH) materials were successfully prepared in this work. Results indicate that the introduction of Ag and sodium pyrithione (SPT) can effectively increase the anti-bacterial performance of NiAlZn LDH. The designed Ag/NiAlZn LDH and Ag/NiAlZn LDH-SPT coatings not only possess high anti-corrosion performance but can effectively inhibit the adhesion of Pseudomonas aeruginosa and Chlorella vulgaris. The anti-biofouling efficiencies of Ag/NiAlZn LDH-SPT coating against P. aeruginosa and C. vulgaris are 98.5% and 98.2%. Ag/NiAlZn LDH-SPT coating possesses integrated high-efficiency anti-corrosion, anti-biofouling and self-healing properties and good mechanical performance.

Facing diseases caused by trypanosomatid parasites: rational design of multifunctional oxidovanadium(IV) complexes with bioactive ligands

Searching for new prospective drugs against Chagas disease (American trypanosomiasis) and Leishmaniasis, a series of five heteroleptic vanadium compounds, [VIVO(L-H)(mpo)], where L are 8-hydroxyquinoline derivatives and mpo is 2-mercaptopyridine N-oxide, are synthesized and characterized. Comprehensive characterizations are conducted in solid state and in solution. The compounds are evaluated on epimastigotes and trypomastigotes of Trypanosoma cruzi and in promastigotes of Leishmania infantum, alongside on VERO cells, as a mammalian cell model. The compounds exhibit activity against both forms of T. cruzi and promastigotes of L. infantum, with the trypomastigote infective stage of T. cruzi displaying the highest sensitivity. The most selective vanadium compound [VIVO(L2-H)(mpo)], with L2 = 5-chloro-7-iodo-8-hydroxyquinoline, globally shows adequate selectivity towards the parasite and was selected to carry out further in-depth biological studies. [VIVO(L2-H)(mpo)] significantly impacted the infection potential of cell-derived trypomastigotes and hindered the replication of the T. cruzi amastigote form. Low total vanadium uptake by T. cruzi parasites and preferential accumulation in the soluble proteins fraction, with negligible localization in the DNA fraction, are determined. A trypanocide effect is observed across various concentrations of the compound. The generation of oxidative stress and the induction of mitochondria-dependent apoptosis are proposed as the main mechanisms of the parasite’s death by the VIVO compounds. Both theoretical predictions and experimental data support the hypothesis that inhibiting the parasite-specific enzyme NADH-fumarate reductase activity plays a crucial role in the trypanocidal action of these complexes. Globally, [VIVO(L-H)(mpo)] complexes could be considered interesting anti-T. cruzi agents that deserve further research.

Green synthesis of sodium pyrithione salt-activated biomass-derived carbon for aqueous zinc-ion capacitors

An alternative green and sustainable route is proposed to prepare doped activated carbons with large surface areas, rich dopants, and porous structures via co-pyrolysis of lignin or hemi-lignin in the presence of sodium pyrithione.

Synthesis, Characterization, and Applications of Rare-Earth-Based Complexes with Antibacterial and Antialgal Properties.

The pursuit of environmentally friendly and highly effective antifouling materials for marine applications is of paramount importance. In this study, we successfully synthesized novel rare earth-based complexes by coordinating cerium (Ce III), samarium (Sm III), and europium (Eu III) with pyrithione (1-hydroxy-2-pyridinethione; PT). Extensive characterizations were performed, including single-crystal X-ray analysis, which revealed the intriguing binuclear structure of these complexes. This structural motif comprises two rare-earth ions intricately double-bridged by two oxygen atoms from the PT ligand, resulting in a distinctive and intriguing geometry. Furthermore, the central rare earth ion is surrounded by three sulfur atoms and two additional oxygen atoms, forming a unique distorted bicapped trigonal prismatic configuration. Compared with conventional antifouling biocides such as sodium pyrithione (NaPT), copper pyrithione (CuPT), and zinc pyrithione (ZnPT), these newly synthesized rare-earth complexes exhibited a remarkable boost in their in vitro antibacterial efficacy against both Gram-positive and Gram-negative bacteria. Additionally, these complexes demonstrated significant potential as antialgal agents, displaying impressive activity against marine planktonic organisms. These findings underscore the promising application prospects of these rare-earth complexes in the field of marine antifouling.

How do biocidals affect the non-target marine organisms: the short-term effects of antifouling agent sodium pyrithione on Mediterranean mussels (Mytilus galloprovincialis, Lamark 1819).

The metallic pyrithiones are used as antifouling paints for marine vehicles against fouling organisms. However, they are dissolved in marine water and have negative impacts on marine non-target organisms. This study evaluated the adverse effects of sodium pyrithione (NaPT) on Mytilus galloprovincialis using total hemocyte counts (THCs), oxidative stress and antioxidant parameters, and histopathological observations. Mussels were exposed to 0.1 and 1 μg/L NaPT for 96 h. The THC values of the NaPT-exposed mussels significantly decreased (p < 0.05). Lipid peroxidation and advanced oxidative protein products of digestive gland and gill tissues were decreased but only the digestive gland tissues of 0.1 μg/L NaPT values were significantly decreased compared to control groups (p < 0.05). Histological alterations were observed in the gill and the digestive gland tissues revealing malformations and hyperplasia of gill lamella; degenerations and loss of tubules of digestive gland after exposure to NaPT for 96 h. As a result, biocidal sodium pyrithione has adverse effects on the mussels even in short-term exposures and low concentrations.

Determination of acute toxicity of sodium pyrithione and its exposure effects on antioxidant enzymes activity, immune status, and histopathological changes in common carp

ABSTRACT This study determined the LC50-24 h value of sodium pyrithione (NaPT) on Cyprinus carpio at 102.7643 µg/L. Then, 60 healthy fish were randomly allocated into 6 exposure groups, each receiving varying levels of NaPT for different durations (control goup = 0% µg/L NaPT for 24 and 96 h; NaPT-10 = 10% of the LC50-24 h dose of NaPT for 24 and 96 h; NaPT-20 = 20% of the LC50-24 h dose of NaPT for 24 and 96 h). As a result, the increase in malondialdehyde (MDA) levels and the decrease in catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities in the gill and liver tissue in both duration and dose groups were found to be statistically significant. In addition, NaPT increased serum tumour necrosis factor (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6) levels in both dose groups for both durations. The results revealed that NaPT exposure caused shortening of gill tissue lamellae and vacuolisation (separation) of the secondary lamellar epithelium. Likewise, NaPT exposure was responsible for vacuolisation and hepatocellular degeneration in liver tissue in hepatocytes. In conclusion, the toxicity study, antioxidant enzyme activities, cytokine immune response, and histopathological results indicate that NaPT has a toxic effect on the carp.

Antimicrobial Zeolitic Imidazolate Frameworks with Dual Mechanisms of Action.

The horizontal transfer of drug-resistant genes and the formation of biofilm barriers have threatened the therapeutic efficacy of conventional antibiotic drugs. Development of non-antibiotic agents with high delivery efficiency through bacterial biofilms is urgently required. A pyrithione (PT)-loading zeolitic imidazolate framework (ZIF-8@PT) is synthesized to destroy biofilms and improve the sensitivity of bacteria to PT. ZIF-8@PT can target and destroy the biofilm as well as the cell membrane, promoting the intracellular delivery of PT and possibly its interaction with SmpB, a protein that could regulate the drug resistance of bacteria. ZIF-8@PT effectively suppresses abdominal infections induced by multiresistant Aeromonas veronii C4 in rodent models without systemic toxicity. ZIF-8@PT promises wide applications in treating infections caused by multidrug-resistant bacteria through a dual mechanism of action.

Acute Effects of Sodium Pyrithione (Sodium Omadine) on Rat Liver and Kidney Tissues

Bu araştırmada intraperitonal yolla uygulanan sodyum pirition (35 ve 70 mg kg-1, ip) ve serum fizyolojik (salin) (%0.09 NaCl 0.5 ml kg-1, ip)uygulanmasının sıçanlar üzerine 24 ve 96 saatlik sürelerde böbrek ve karaciğer dokuları üzerine histolojik etkileri araştırılmıştır. Araştırma sonucunda, kontrol grubu ile karşılaştırıldığında intraperitonal yolla uygulanan sodyum piritionun doz ve süre artışına bağlı histopatolojik değişimlere neden olan sitotoksik etkisinin olabileceği kanısına varılmıştır.

Enhancement of anticorrosion and antibiofouling performance of self-healing epoxy coating using nano-hydrotalcite materials and bifunctional biocide sodium pyrithione

The industry has an urgent demand for anticorrosion and antibiofouling integrated coating in the marine environment due to the huge economic loss caused by corrosion and biofouling. In this work, a self-healing epoxy coating was prepared based on nano-hydrotalcite (LDH) materials and bifunctional biocide sodium pyrithione (SPT) aiming to provide some foundations for the anticorrosion and antibiofouling areas. Surface analysis, salt spray tests, and electrochemical measurements were used to character the prepared nanomaterials or measure the anticorrosion and antibiofouling performance of prepared coatings. Results indicate that the prepared CuAl-LDH-SPT coating not only had a high corrosion resistance but effectively inhibited the adhesion of Pseudomonas aeruginosa and Spirulina. The impedance values of CuAl-LDH-SPT coating increases by two orders of magnitude compared with the pure epoxy resin coating after 60 days of testing in 3.5 wt% NaCl solution. The prepared CuAl-LDH-SPT coating has a self-healing property due to the presence of SPT.

Anticorrosion and antibiofouling performance of in-situ prepared layered double hydroxide coating modified by sodium pyrithione on aluminum alloy 7075

The anticorrosion and antibiofouling of marine engineering equipments have strong demands, especially for antibiofouling. In this work, an in-situ growth layered double hydroxide (LDH) coating on aluminum alloys (AA) 7075 was prepared and then modified by sodium pyrithione (SPT) to increase the anticorrosion and antibiofouling performance. Results indicated that CoAl-LDHs and CoAl-LDHs-SPT coatings had been successfully prepared according to TEM, XRD, XPS, Raman spectra, and SEM analysis results. The (0 1 2) plane of LDHs with a interplanar spacing of 0.26 nm was recognized from TEM images. The content of SPT in CoAl-LDHs-SPT is 38.79 wt.%. Electrochemical impedance spectroscopy (EIS) and polarization curvies demonstrate that the corrosion resistance of AA 7075 was largely improved in the presence of CoAl-LDHs and CoAl-LDHs-SPT coatings while the anticorrosion performance of CoAl-LDHs-SPT coating was better. The corrosion resistance of Co-Al LDHs-SPT coating increased by about two orders of magnitude compared with the bare AA 7075. The surface analysis results show that only a few Pseudomonas aeruginosa and Spirulina cells attached to the CoAl-LDHs coating surface, and no biofouling cells were observed for the CoAl-LDHs-SPT coating. Co-Al LDHs-SPT coating possessed the best anticorrosion and antibiofouling properties due to the presence of SPT compared with the CoAl-LDHs coating.

Comparative toxicity study of waterborne two booster biocides (CuPT and ZnPT) on embryonic flounder (Paralichthys olivaceus)

A new generation of booster biocides that include metal pyrithiones (PTs) such as copper pyrithione (CuPT) and zinc pyrithione (ZnPT) are being used as tributyltin alternatives. In the marine environment, ZnPT can easily transchelate Cu to form CuPT, and the environmental fate and persistence of these two metal pyrithiones are closely related. Although some data on the toxicity of biocides on marine fish are available, little is known about their toxicity and toxic pathway. We thus compared the toxic effects of CuPT and ZnPT on embryonic olive flounder (Paralichthys olivaceus) by investigating their adverse effects based on developmental morphogenesis and transcriptional variation. In our study, the toxic potency of CuPT was greater with respect to developmental malformation and mortality than ZnPT. Consistent with the developmental effects, the expression of genes related to tail fin malformation (including plod2, furin, and wnt3a) was higher in embryonic flounder exposed to CuPT than in those exposed to ZnPT. Genes related to muscle and nervous system development exhibited significant changes on differential gene expression profiles using RNA sequencing (cutoff value P < 0.05). Gene ontology analysis of embryos exposed to CuPT revealed affected cellular respiration and kidney development, whereas genes associated with cell development, nervous system development and heart development showed significant variation in embryonic flounder exposed to ZnPT. Overall, our study clarifies the common and unique developmental toxic effects of CuPT and ZnPT through transcriptomic analyses in embryonic flounder.

A Physiological-Based Pharmacokinetic Model For The Broad Spectrum Antimicrobial Zinc Pyrithione: II. Dermal Absorption And Dosimetry In The Rat

ABSTRACT The broad spectrum antimicrobial/antifungal zinc pyrithione (ZnPT) is used in products ranging from antifouling paint to antidandruff shampoo. The hazard profile of ZnPT was established based upon comprehensive toxicological testing, and products containing this biocide have been safely used for years. The purpose of this study was to create a dermal physiologically based pharmacokinetic (PBPK) model for ZnPT in the rat for improving dose–response analysis of ZnPT-induced toxicity where reversible hindlimb weakness was the endpoint used as the basis for ZnPT risk assessments. Previously, we developed a PBPK model which simulated the kinetics of pyrithione (PT) and its major metabolites 2-(methylsulfonyl)pyridine and S-glucuronide conjugates in blood and tissues of rats following oral ZnPT administration. The dermal model was optimized utilizing in vitro dermal penetration investigations conducted with rat skin and with historical data from a dermal repeat dose study using rats. The model replicated the observed temporal patterns and elimination kinetics of [14C]PT equivalents in blood and urine during and following repeated dermal dosing and replicated the observed dose-dependencies of absorption, blood [14C]PT equivalents and plasma PT concentrations. The model provided internal dosimetry predictions for a benchmark dose analysis of hindlimb weakness in rats that combined dermal, gavage and dietary studies into a single internal dose–response model with area-under-the-curve (AUC) for plasma PT, the toxic moiety in the rat, as the internal dose metric. This PBPK model has predictive validity for calculating internal doses of PT and/or [14C]PT equivalents from different routes of exposure in the rat.

Targeting Copper Homeostasis Improves Functioning of vps13Δ Yeast Mutant Cells, a Model of VPS13-Related Diseases.

Ion homeostasis is crucial for organism functioning, and its alterations may cause diseases. For example, copper insufficiency and overload are associated with Menkes and Wilson’s diseases, respectively, and iron imbalance is observed in Parkinson’s and Alzheimer’s diseases. To better understand human diseases, Saccharomyces cerevisiae yeast are used as a model organism. In our studies, we used the vps13Δ yeast strain as a model of rare neurological diseases caused by mutations in VPS13A–D genes. In this work, we show that overexpression of genes encoding copper transporters, CTR1, CTR3, and CCC2, or the addition of copper salt to the medium, improved functioning of the vps13Δ mutant. We show that their mechanism of action, at least partially, depends on increasing iron content in the cells by the copper-dependent iron uptake system. Finally, we present that treatment with copper ionophores, disulfiram, elesclomol, and sodium pyrithione, also resulted in alleviation of the defects observed in vps13Δ cells. Our study points at copper and iron homeostasis as a potential therapeutic target for further investigation in higher eukaryotic models of VPS13-related diseases.

Evaluation of the antimicrobial activity of pyrithione-based ionic liquids

The development of new disinfection strategies has become increasingly important over the past decades. One substance that is already used as a potent antimicrobial is pyrithione (2-mercaptopyridine N-oxide), a derivate of naturally occurring aspergillic acid. Even though pyrithione has already proved successful as an antimicrobial, it has some major disadvantages. These include ineffectiveness against viruses and bacteriostatic activity as opposed to bactericidal. A promising approach to address these disadvantages is to incorporate pyrithione into ionic liquids (ILs), to strengthen or physically modify its effects that could portend new applications. This study therefore investigated the antimicrobial properties of pyrithione-based ILs by applying a tripartite test system, including enzyme inhibition tests, virucidal activity determination against three model viruses and activity against eleven clinically relevant bacteria and two yeasts. Results confirm that pyrithione remains an effective antimicrobial even in IL form. A typical “sidechain effect” was demonstrated at the enzymatic level and it was possible to prepare ILs with antiviral properties against all three model viruses. Furthermore, at the bacterial level, this study revealed additional characteristics after incorporating pyrithione into an IL: improved diffusion of pyrithione through agar, a bactericidal effect, especially against gram-negative bacteria and a high susceptibility against clinically relevant yeast Candida tropicalis. These observations demonstrate benefits of pyrithione-IL combinations. Efficacy of pyrithione-based ILs against viruses, bacteria and yeast is particularly worthy of future investigation.

Selective precipitation study for the separation of iron and titanium from ilmenite

Ilmenite is major source of titanium dioxide production and contains high concentration of iron. It is crucial to selectively remove iron impurities during the titanium production process. The present study investigated the acid and flux fusion digestion techniques for complete dissolution of ilmenite and subsequent separation of iron and titanium by precipitation process. Analytical results indicated that the Na2HPO4/NaH2PO4·H2O, Na2B4O7 and LiBO2 flux fusion procedures were the most effective for complete dissolution of ilmenite mineral. The separation of Fe(II) and Ti(IV) from the phosphate fused solution by selective precipitation was studied using phenanthroline (phen), sodium tetraphenylborate (NaTPB) and 2-mercaptopyridine N-oxide sodium salt (NaPT) as precipitants. The combination of phen and NaTPB showed poor selectivity for the precipitation of either Ti(IV) or Fe(II) and both metals collectively precipitated under the investigated experimental conditions. Negligible selectivity was observed when only sodium tetraphenylborate was used. The selective separation of Fe(II) and Ti(IV) from fused solution using NaPT as precipitant was extremely successful with 100(1)% Fe(II) recovered in the precipitate (no titanium observed in precipitate) while 99.6(1)% Ti(IV) remained in the filtrate (no iron observed in the filtrate).

Towards Identification of Essential Structural Elements of Organoruthenium(II)‐Pyrithionato Complexes for Anticancer Activity

An organoruthenium(II) complex with pyrithione (2-mercaptopyridine N-oxide) 1 a has previously been identified by our group as a compound with promising anticancer potential without cytotoxicity towards non-cancerous cells. To expand the rather limited research on compounds of this type, an array of novel chlorido and 1,3,5-triaza-7-phosphaadamantane (pta) organoruthenium(II) complexes with methyl-substituted pyrithiones has been prepared. After thorough investigation of the aqueous stability of these complexes, their modes of action have been elucidated at the cellular level. Minor structural alterations in the ruthenium-pyrithionato compounds resulted in fine-tuning of their cytotoxicities. The best performing compounds, 1 b and 2 b, with a chlorido or pta ligand bound to ruthenium, respectively, and a methyl group at the 3-position of the pyrithione scaffold, have been further investigated. Both compounds trigger early apoptosis, induce the generation of reactive oxygen species and G1 arrest in A549 cancer cells, and show no strong interaction with DNA. However, only 1 b also inhibits thioredoxin reductase. Wound healing assays and mitochondrial function evaluation have revealed differences between these two compounds at the cellular level.

Solvent extraction and separation of palladium from platinum group elements: Synthesis and characterization of 2-mercaptopyridine N-oxide-palladium (II) complex

Platinum group elements (PGEs) are known for their similar chemical properties, which complicates their isolation and separation from mineral ores and recycled products such as autocatalysts. Therefore, this study investigated the separation of PGEs (except Os) in a synthetic autocatalyst mixture using 2-mercaptopyridine N-oxide sodium salt (NaPT) as an extractant. Solvent extraction was performed with an aqueous mixture containing Pt, Pd, Rh, Ir and Ru and NaPT in the presence of toluene, which produced a pink organic layer. An ICP analysis indicated a complete absence of Pd in the orange aqueous layer. The extractions were repeated with different [HCl] and [PT−] and the analytical results confirmed the complete extraction of Pd from the mixture. The formation of a Pd(PT)2 complex in the pink product was confirmed with IR, 1H and 13C NMR. Pd(OAc)2 reacted with NaPT in DMF to form pink crystals, which were suitable for crystallography. The pink crystals were also characterized with IR, 1H and 13C and found to be identical to the product isolated after solvent extraction. The crystal structure indicated the isolation of the square planar Pd(PT)2·DMF complex, which crystalized in the monoclinic P21/n space group with four molecules per unit cell. The two PT− ligands in the complex bonded with the sulfur atoms (and also the oxygen atoms) cis with respect to each other, with the S–Pd–S and O–Pd–O bond angles at 96.27(5) and 91.08(14)° respectively. The two Pd–S bonds distances were 2.2443(13) and 2.2416(15) Å. The selective and complete isolation of Pd from a mixture of PGE using NaPT can be extremely useful in the recovery of Pd from autoctalaysts and other mixed PGE waste materials.

Effect of Combined Exposure to EDTA and Zinc Pyrithione on Pyrithione Absorption in Rats

Zinc pyrithione (ZnPT) is a coordination complex of zinc and has been used widely as an anti-dandruff agent in shampoos. Many shampoos contain both ZnPT and EDTA, a chelating agent speculated to increase ZnPT absorption, thereby raising concerns about neurotoxicity. Here, we investigated the effect of EDTA on ZnPT absorption by direct comparison of ZnPT and pyrithione (PT) concentrations in shampoo formulations, and by pharmacokinetic analysis of ZnPT, PT, and 2-methanesulfonylpyridine (MSP), the main ZnPT metabolite, in rat plasma or urine following exposure to shampoo containing ZnPT alone or a combination of ZnPT and EDTA. Approximately 17.3% of ZnPT was converted to PT by the addition of EDTA in the shampoo formulation. Plasma ZnPT and PT concentrations were not measured up to 24 hr after treatment with shampoo containing 1% ZnPT or 1% ZnPT + 2% EDTA in all rats. However, PT amount in 24-hr urine sample, MSP concentration in plasma, and MSP amount in 24-hr urine sample were approximately 4-, 2.6-, and 2.7-fold higher, respectively, in the 1% ZnPT + 2% EDTA shampoo group than in the 1% ZnPT shampoo group. As confirmed by the formulation analysis and in vivo pharmacokinetic analysis, the exposure of ZnPT could be increased by the absorption of PT due to partial dissociation of ZnPT into PT.

Oxidation of 2-mercaptopyridine N-oxide upon iodine agent: structural and FT-IR studies on charge-assisted hydrogen bonds CAHB(+) and I\u2026I halogen interactions in 2,2\u2032-dithiobis(pyridine N-oxide) ionic cocrystal

2-Mercaptopyridine N-oxide (I) undergoes spontaneous dimerization to the disulfide form due to reaction with iodine acting as an oxidizing reagent. As a result, a di-N-oxide disulfide derivative of pyridine is obtained. During the process of crystallization, one of N-oxide groups undergoes protonation and a cation form of disulfide moiety cocrystallizes with I3− counterion forming a salt structure. Therefore, in the crystalline state, the 2,2′-dithiobis(pyridine N-oxide) molecule exists in a not observed previously form of monocation. Interestingly, the protonated N-oxide group does not form hydrogen-bonded salt bridges (of the CAHB(±) type with I3− anions) but prefers to be involved in intermolecular interactions with the unprotonated N-oxide group of the adjacent molecule This results in formation of intermolecular CAHB(+) hydrogen bridges finally linking molecules into infinite chains. The crystal structure is also stabilized by other various noncovalent interactions, including iodine...iodine and sulfur...iodine contacts.

Study of the composition of 140 shampoos: similarities and differences depending on the sales channel used.

Shampoo is a hair care product designed to clean the skin and hair of the scalp. Among the ingredients that go into the making of a shampoo are detergents, conditioners, thickeners, sequestering agents, pH adjusters, preservatives, and active ingredients such as anti-dandruff agents. The purpose of this study was to identify the composition of 140 shampoos available in pharmacies, in stores of a mass-market chain, or from mail-order retailers. Forty-one shampoos were advertised as "gentle", 12 as specially formulated for infants, 35 as anti-dandruff, and 52 without any particular claim. We analysed the cleansing base, preservatives, and anti-dandruff agents when relevant and identified the allergens regardless of whether or not they are listed under Regulation (EC) No. 1223/2009 as one of the 26 regulated substances. We discovered that unlike shampoos sold in stores of a mass-market chain and those available from mail-order retailers, those sold in pharmacies expose users to some of the 26 substances listed under Regulation (EC) No. 1223/2009. We also determined that baby shampoos sold in pharmacies are allergen-free. Regarding anti-dandruff formulations, the largest variety of active ingredients was found in shampoos sold in pharmacies. Overall, the most common active ingredients were olamines, zinc pyrithione, azoles, selenium disulphide, and plant extracts. Shampoos sold in pharmacies appear to contain fewer allergens listed under Regulation (EC) No. 1223/2009 compared to those sold elsewhere.