Naturally occurring mineral

Talc is a naturally occurring mineral, mined from the earth, composed of magnesium, silicon, oxygen, and hydrogen. Chemically, talc is a hydrous magnesium silicate with a chemical formula of Mg3Si4O10(OH)2. Talc has many uses in cosmetic products and other personal care products. For example, it may be used to absorb moisture, to prevent caking, to make facial makeup opaque, or to improve the feel of a product.

Published scientific literature going back to the 1960s has suggested a possible association between the use of powders containing talc in the genital area and the incidence of ovarian cancer. However, these studies have not conclusively demonstrated such a link, or if such a link existed, what risk factors might be involved. More research is needed to confirm if there is a link or not. In addition, questions about the potential contamination of talc with asbestos have been raised since the 1970s.

Absorption, Distribution and Excretion
Foreign body granulomas containing talc fibers can be found in the lungs, pleura, diaphragm, pericardium, and stomach wall… Transmission electron microscopy and energy-dispersive X-ray spectroscopy were used to analyze the total fibrous and non-fibrous mineral content in the lungs of 14 male smokers with lung cancer but no history of occupational dust exposure, and 14 age-, smoking history, and general occupational category-matched control men. The mean concentrations of mineral fiber and non-fibrous particles in the cancer group were 3.8 times and 2.0 times that in the control group, respectively. The main components of fibrous and non-fibrous particles in both groups were kaolinite, talc, mica, feldspar, and crystalline silica. Mice injected subcutaneously with sterile talc powder were studied, and the incorporation of radioactive leucine and glucosamine in talc granulomas was measured at different time intervals from 2 to 528 hours post-injection. The incorporation of plasma proteins exhibited a biphasic response: at 21 hours, the incorporation of perchloric acid-insoluble components increased significantly, returning to normal levels at 45 hours; similarly, at 45 hours, the incorporation of perchloric acid-soluble components also showed a significant increase, subsequently gradually returning to normal levels. The response depended on the amount of talc injected. Using radioactive tracing techniques in rats, mice, guinea pigs, and hamsters, no ingested talc was detected to be absorbed from the intestines or transported to the liver and kidneys. For more complete data on the absorption, distribution, and excretion of talc (7 types), please visit the HSDB record page.

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Biological half-life
In hamsters, ... the biological half-life of talc deposited in the alveoli is 7–10 days, and alveolar clearance is largely complete 4 months after exposure.

Interactions
Administering equal amounts of talc mixed with benzo[a]pyrene to Syrian golden hamsters induced papillomas, squamous cell carcinomas, and undifferentiated tumors in the larynx, trachea, and lungs. A single application of talc and zinc oxide to wounded skin in rats resulted in histological observation of chronic irritation, fibrosis, and granuloma formation. Subcutaneous inflammation induced by magnesium silicate (talc) led to inhibited bone elongation, osteoblast dysfunction, and subsequent bone loss in rats. Since the skeletal and immunological changes associated with talc granulomas are similar to those of zinc deficiency, the dynamics of zinc tissue distribution and the effect of zinc supplementation on the development of bone loss in talc-induced inflammatory rats were investigated. In rats with talc granulomas, serum zinc concentrations decreased within 5 to 15 hours. Simultaneously, zinc accumulation in the liver and rapid disappearance of osteoblasts on the surface of bone trabeculae were observed. However, despite the return to normal serum zinc levels, rats injected with talc and supplemented with zinc sulfate via parenteral and oral administration showed a reduction in osteoblasts on the trabecular surface comparable to those in unsupplemented granuloma rats. In all zinc-supplemented groups, the reduction in osteoblasts on the trabecular surface was slightly increased, but this effect was not significant. Therefore, it is concluded that zinc is the earliest indicator of the acute phase response in talc-granuloma rats. Although zinc appears important for normal osteocyte function, there is no causal relationship between acute zinc deficiency and decreased osteoblast number and activity in the talc-granuloma rat model. A single intraperitoneal injection of 20 mg talc and 2 mg granulated prednisolone acetate (dissolved in saline) induced the formation of numerous multinucleated giant cells within 48 hours in mice. Neither compound alone induced this response. These multinucleated cells were generated by cell fusion, and the resulting multinucleated bodies exhibited severe chromosomal abnormalities. The combined use of prednisolone and talc also induced the formation of multinucleated giant cells. When talc was injected in combination with cortisone acetate, cortisone, or testosterone isobutyrate, no multinuclei were observed.

[1]. https://www.fda.gov/cosmetics/cosmetic-ingredients/talc

Talc is an odorless, white to off-white, very fine crystalline powder (oily). It adheres easily to the skin. It is non-flammable, non-toxic, and non-toxic. It is a fine powder of naturally hydrated magnesium silicate. It can be used alone or mixed with starch or boric acid as a powder in pharmaceuticals and cosmetics. It can also be used as an excipient and filler for pills and tablets, and as a powder for tablet molds. (From Merck Index, 11th edition)

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Therapeutic Uses
Talc intrapleural aerosol is indicated for the prevention of recurrence of malignant pleural effusion in symptomatic patients. It can be used during thoracoscopic or open-chest surgery.
...Talc spraying or infusion with talc slurry is considered an effective method for treating spontaneous pneumothorax.

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Drug Warnings
...This article reports a case of a 78-year-old male patient who underwent talc pleural fixation for recurrent pleural effusion, subsequently developing massive hemothorax, a rare complication.
...This article reports a case of a young female patient who, 18 months after undergoing left talc pleurodesis, developed a large calcified mass in the anterior mediastinum.

H2O3SI

78.10

77.977

14807-96-6

16211421

White to off-white powder

2.7-2.8 g/cm3

800ºC

1

12

0

19

20.3

0

[Si](=O)=O.[Si](=O)=O.[Si](=O)=O.[Si](=O)=O.[Mg]=O.[Mg]=O.[Mg]=O.O([H])[H]

FPAFDBFIGPHWGO-UHFFFAOYSA-N

InChI=1S/3Mg.4O2Si.H2O.3O/c;;;4*1-3-2;;;;/h;;;;;;;1H2;;;

dioxosilane;oxomagnesium;hydrate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

H2O: < 0.1 mg/mL
DMSO: < 1 mg/mL

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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