Pyrithione zinc

ISO 846 A (top) and ISO 846 B (bottom) tests of PVC samples containing zine pyrithione at extrusion times of 20 minutes and 60 minutes at 180 °C 

Oxime sealant with no biocide, ACTICIDE PIN 8 (8% IPBC in diisononyl phthalate carrier), 20% IPBC (in glycol ether) and 30% IPBC (in glyeol), respeetively, before and after heating to 50 C 

Technical Folpet is usually 90% pure. The main impurities are phthalimide (up to 4.0%) and sodium chloride (up to 5%). 

Pure Folpet is a white crystalline solid with a reported melting point of 177 °C. Solubility in water is only 1 ppm at room temperature. In the dry state, it is stable at room temperature, but it is hydrolysed in an aqueous solution at a rate that depends on the pH. Degradation products and hydrolysis in water can be carbon dioxide, hydrochloric acid, hydrogen sulfide, phthalamic acid, and phthalic acid. 

The Agency concluded that captan is only a potential human carcinogen at an exposure threshold significantly greater than likely dietary or non-dietary exposure. In other words, the EPA concluded that labelled uses of captan are imlikely to cause human cancers (EPA Pesticide Program Update, 12-9-04). 

---

Medicated Dandruff Shampoos. Dandmff is a scalp condition characterized by the production of excessive cellular material (18). A number of shampoos have been marketed which are designed to control and alleviate this condition, and many additives have been included in shampoo compositions to classify them as treatment products for dandmff. These additives include antimicrobial additives, eg, quaternary ammonium salts keratolytic agents, eg, saUcychc acid and sulfur heavy metals, eg, cadmium sulfide coal tar resorcinol and many others. More recent (ca 1993) systems use selenium sulfide [7488-56-4] or zinc pyrithione [13463-41 -7] as active antidandmff shampoo additives. Both of these additives are classified as dmgs, but can be found in over-the-counter products. A stronger version, incorporating the use of higher levels of selenium sulfide in a shampoo, is available but requires a prescription for purchase. 

Textile Finishing. Polyethyleneimine-A/-methylolurea derivatives improve the crease and wear resistance of cotton (429,430). The adhesion between individual wool fibers is improved by pretreatment with amines, which leads to improved shrink resistance (431). An antimicrobial finish can be appHed to cotton by using a combination of PEI and ureas to bind zinc pyrithione to the fabric (432). After wool has been provided with a flameproof finish using fluorozirconate or fluorotitanate, the wool can be neutralized with PEI (433). Conventional neutralizing agents caimot be used for this purpose since they impair the flameproof characteristics of the impregnated fabric. 

Pyridine A Oxides. Analgesic and antiinflammatory dmgs niflumic acid [4394-00-7] (68) and pranoprofen [52549-17-4] (69) are manufactured from nicotinic acid N-oxide [2398-81 -4]. The antiulcer dmg omeprazole (66) is produced from 2,3,5-trimethylpyridine N-oxide [74409-42-0]. Zinc pyrithione, the zinc salt of pyrithione (45), is a fungicide derived from 2-chloropyridine N-oxide (45). 

Zinc is used for a variety of indications. Zinc acetate (8.102) or, rarely, zinc sulfate (8.103) have been used orally to treat Wilson s disease, a recessively inherited disorder of copper metabolism, characterized by brain and liver dysfunction arising from excessive deposits of copper. Zinc pyrithione (8.104) is used in shampoos to treat seborrhea. Zinc propionate (8.105) and zinc caprylate (8.106) have been used as topical antifungal agents. 

Pyrithione zinc, 1-2% shampoo, apply once or twice weekly Denorex Daily, Head Shoulders, Sebulon, various generic Both selenium sulfide and zinc pyrithione are cytostatic agents that decrease epidermal turnover rates. Massage into wet scalp for 2-3 minutes. Rinse thoroughly and repeat application. Selenium sulfide can be irritating to the eyes and skin. 

Different copper compounds mainly replaced TBT as the active component in anti-fouling products (Dahl and Blanck 1996 Yebra et al. 2004). However, several algal species showed tolerance to copper and to achieve protection against these tolerant species, a number of so-called booster biocides, e.g. zinc pyrithione, irgarol... 

Today in Sweden, the active substances used in anti-fouling preparations for use on pleasure boats on the west coast are mainly different kinds of copper compounds alone or in combination with the herbicide irgarol. For larger boats (>12 m), antifouling paints containing the biocides zinc pyrithione and isothiazoline are also allowed for use. 

Figure 3.86 Preparation of zinc pyrithione from 2-chloropyridine.

Isolation of Processes To minimize cross-contamination and microbiological contamination, the manufacturer may develop special procedures for the isolation of processes. The level of facilities isolation depends on the types of products to be manufactured. For instance, steroids and sulfas require more isolation than over-the-counter (OTC) oral products [6], To minimize exposure of personnel to drug aerosols and loss of product, a sealed pressure vessel must be used to compound aerosol suspensions and emulsions [21], An example of cross-contamination with steroids was the controversial case of a topical drug manufactured for the treatment of skin diseases. Fligh-performance liquid chromatography/ultraviolet and mass spectrometry (FIPLC/UV, FIPLC/MS) techniques were used by the FDA for the detection of clobetasol propionate, a class 1 superpotent steroid, as an undeclared steroid in zinc pyrithione formulations. The product was forbidden and a warning was widely published [22],... 

Reepmeyer, J. C., Revelle, L. K., and Vidavsky, I. (1998), Detection of clobetasol propionate as an undeclared steroid in zinc pyrithione formulations by high-performance liquid chromatography with rapid-scanning ultraviolet spectroscopy and mass spectrometry. Journal of Chromatography A, Vol. 828, Number 1,18 December 1998, pp. 239-246(8). 

Complexes with the thio-oxamate ligands NH2(CO)CSO and NH2(CS)C02, which bind through O and S, exhibit trigonal bipyramidal geometry around the zinc. The zinc complex of the 0,S-donor ligand 2-pyridinethiolate 1-oxide, known as zinc pyrithione, is a fungicide andbacteriocide much used in hair shampoos. 

Zinc products are extensively used in shampoos and other non-medical items and severe reactions occasionally occur. In one instance a shampoo based on zinc pyrithione caused a serious relapse in a woman with stable psoriasis (SEDA-22, 251). 

Nielsen NH +, Am J Contact Dermat8(i), 170 (zinc pyrithione shampoo)... 

More common is the use of antibacterial ehemical additives, e.g., Triclosan, silver compounds and complexes, and zinc pyrithione... 

Zine is a crucial element in the formulation of many heat stabilisers used in PVC, however exeessive use ean have a negative impact on the degradation of the PVC (30). This is because zinc pyrithione typieally eontains 20% zinc. Some PVC formulations, particularly those calendered or extruded under higher sheer, are zinc sensitive as they reaet with hydrogen chloride and form zinc chloride, whieh catalyses further degradation of the PVC. The outeome is yellowing and poor PVC stability (Figure 32). 

---