Absorption, Distribution and Excretion
Following oral administration, only a portion of pyrithione is absorbed. Less than 1% of zinc pyrithione is absorbed through the skin. In rats, rabbits, and monkeys, the absorption rate of radiolabeled zinc pyrithione in the bloodstream reaches 80-90% after oral or intraperitoneal injection. In rats, the primary route of excretion after oral administration is urine, with the major metabolite being S-glucuronide of 2-mercaptopyridine-N-oxide and the minor metabolite being 2-mercaptopyridine-N-oxide. Most zinc is excreted in feces after oral administration. After transdermal administration, the recovery rate from the administration site flushing fluid in pigs exceeds 90%. The urinary excretion rate in animals with intact skin is 3%. Metabolites/Metabolites In rabbits, rats, monkeys, and dogs, zinc pyrithione is bioconverted to 2-pyridinethiol 1-oxide S-glucuronide and 2-pyridinethiol S-glucuronide after oral administration.

[1]. Zinc pyrithione inhibits yeast growth through copper influx and inactivation of iron-sulfur proteins. Antimicrob Agents Chemother. 2011 Dec;55(12):5753-60.

[2]. In vitro studies with 1-hydroxy-2(1H) pyridinethione. Proc Soc Exp Biol Med. 1953 Jan;82(1):122-4.

Pyrithione is a pyridinethione, namely pyridine-2(1H)-thione, in which the hydrogen atom bonded to the nitrogen atom is replaced by a hydroxyl group. It is a zinc ion carrier; its zinc salt can be used as an antifungal and antimicrobial agent. It has the function of an ion carrier. It is a pyridinethione and a monohydroxypyridine. It is a tautomer of pyridine-2-thiol N-oxide. Zinc pyrithione, or zinc pyrithione, is a coordination compound formed by the chelation of zinc ions with pyrithione ligands through oxygen and sulfur centers. In the crystalline state, it exists as a centrosymmetric dimer. Due to its dynamic antibacterial and antifungal properties, zinc pyrithione can be used to treat dandruff and seborrheic dermatitis. Dandruff is a common scalp condition affecting more than 40% of the adult population worldwide, and its pathogens may be fungi such as Malassezia globosa and Malassezia restricta. Zinc pyrithione is a common active ingredient in over-the-counter anti-dandruff topical products such as shampoos. Its mechanism of action involves increasing intracellular copper levels and disrupting iron-sulfur clusters in proteins essential for fungal metabolism and growth. Due to its low solubility, zinc pyrithione released from topical formulations can deposit relatively effectively and remain on the target skin surface. Other uses of zinc pyrithione include as an additive in antifouling coatings and algaecides. Although approved for use by the U.S. Food and Drug Administration (FDA) as early as the early 1960s, the safety and efficacy of zinc pyrithione have been established over decades. Pyrithione has not shown any significant estrogenic activity according to in vivo and in vitro studies. Pyrithione has been found in Sargassum (Marsypopetalum modestum), and relevant data exist. Pyrithione is an antibacterial and antimicrobial derivative of aspergillus acid. Although its exact mechanism of action is not fully elucidated, pyrithione appears to interfere with membrane transport, ultimately leading to a loss of metabolic control. See also: Zinc pyrithione (active ingredient); Sodium pyrithione (salt form). Indications For the treatment of dandruff and seborrheic dermatitis. Mechanism of Action Zinc pyrithione inhibits fungal growth and is associated with increased copper uptake and elevated intracellular copper levels, manifested as decreased CTR1-lacZ expression and slightly increased CUP1-lacZ expression in infected microorganisms. Upon dissociation of the zinc pyrithione coordination complex, the pyrithione ligand forms a CuPT complex with available extracellular copper in the target organism. Pyrithione acts as an ion carrier, interacting nonspecifically with the plasma membrane to transport copper into the cell and promoting copper transmembrane transport. Copper may be transported to mitochondria. Copper inactivates iron-sulfur cluster (Fe-S) proteins through a mechanism similar to copper-induced bacterial growth inhibition. Reduced Fe-S protein activity leads to inhibition of fungal metabolism and growth. Studies have shown that zinc pyrithione can slightly increase zinc levels.

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Pharmacodynamics
Zinc pyrithione has broad-spectrum antibacterial activity, including against fungi, Gram-positive bacteria, and Gram-negative bacteria. Zinc pyrithione is effective against Malassezia and all other fungi, especially Malassezia species on the scalp. For patients with dandruff, zinc pyrithione treatment can reduce the number of fungi on the scalp, thereby reducing the content of free fatty acids, and thus reducing dandruff and itching.

C5H5NOS

127.1643

127.009

1121-30-8

15922-78-8 (hydrochloride salt)

1570

Light yellow to yellow solid powder

1.43g/cm3

253.8ºC at 760mmHg

107.3ºC

0.00275mmHg at 25°C

1.732

1.454

1

2

0

8

162

0

YBBJKCMMCRQZMA-UHFFFAOYSA-N

InChI=1S/C5H5NOS/c7-6-4-2-1-3-5(6)8/h1-4,7H

1-hydroxypyridine-2-thione

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product is not stable in solution, please use freshly prepared working solution for optimal results.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~125 mg/mL (~983.01 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (16.36 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (16.36 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (16.36 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)