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 are to be found in lung, pleura, diaphragm, pericardium, and gastric wall ... .
...Transmission electron microscopy and energy dispersive X-ray spectroscopy /was used to analyze/ the total fibrous and nonfibrous mineral content of the lungs of a series of 14 male smokers with lung cancer but with no history of occupational dust exposure, and of a series of 14 control men matched by age, smoking history and general occupational class. The average concentration of mineral fibers and nonfiberous particles were 3.8 and 2.0 times higher in the group with cancer. Kaolinite, talc, mica, feldspars and crystalline silica comprised the majority of fibrous and nonfibrous particles in both groups.
Mice that received a sterile sc injection of talc were studied by measuring the incorporation of radioactive leucine and glucosamine into liver and plasma protein and the talc gramuloma at various intervals between 2 and 528 hours after injection. Incorporation into plasma proteins indicated a biphasic response with a marked increased incorporation into the perchloric acid insoluble fraction at 21 hours, a return to normal values at 45 hours, and a similar marked increase into the perchloric acid soluble fraction at 45 hours with a gradual return toward normal values. The response was dependent upon the amount of talc injected.
Using radioactive tracer techniques in rats, mice, guinea pigs, and hamsters, no intestinal absorption or translocation of ingested talc to the liver and kidneys was detected.
For more Absorption, Distribution and Excretion (Complete) data for TALC (7 total), 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 was 7-10 days, and the alveolar clearance was basically complete 4 months after exposure.

Interactions
Equal amount of talc mixed with benzo(a)pyrene administered to Syrian Golden hamsters produced papillomas, squamous cell carcinomas and undifferentiated tumors of larynx, trachea and lungs.
Chronic irritation reaction, fibrosis and granuloma formation were observed histologically after a single application of talc and zinc oxide on the wounded skin of rats.
Subcutaneous inflammation induced by magnesium silicate (talc) leads to the suppression of bone elongation, osteoblast insufficiency, and subsequent bone loss in rats. Since bone and immunological changes in talc granulomatosis are similar to those observed in zinc deficiency, the kinetics of zinc tissue distribution and the afects of zinc supplementation on the development of bone loss in rats with talc induced inflammation /were investigated/. Decrease in serum zinc concentration was observed between 5 and 15 hr in rats with talc granulomatosis. It was paralleled by the accumulation of zinc in the liver and rapid disappearance of osteoblasts from the trabecular bone surfaces. However, talc injected rats supplemented parenterally and orally with zinc sulfate exhibited a decrease in osteoblast trabecular surface comparable to that of unsupplemented rats bearing granulomas despite normalized serum zinc concentrations. Zinc supplementation slightly increased osteoblast trabecular surface in all supplemented groups, but this effect was not significant. It was concluded that zinc is the earliest indicator of the acute phase response in rats with talc granulomatosis. Although zinc appears to be important for the normal function of bone cells, there is no causative relationship between acute zinc deficiency and decreased osteoblast number and activity in rats with talc granulomatosis.
Single 20 mg ip injections of talc plus 2 mg of particulate prednisolone acetate in saline into mice induced significant numbers of multinucleated giant cells within 48 hours. Neither compound alone induced this response. The multinucleated cells arose by cell fusion, and the resultant polykarions exhibited severe chromosomal abnormalities. Prednisone in combination with talc also elicited the formation of multinucleated giant cells. Polykarions were not observed when talc was injected in combination with cortexone acetate, cortisone, or testosterone isobutyrate.

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

Talc is an odorless white to grayish-white very fine crystalline powder (unctuous). Readily adheres to the skin. Nonflammable, noncombustible, and nontoxic.
Finely powdered native hydrous magnesium silicate. It is used as a dusting powder, either alone or with starch or boric acid, for medicinal and toilet preparations. It is also an excipient and filler for pills, tablets, and for dusting tablet molds. (From Merck Index, 11th ed)

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Therapeutic Uses
Talc intrapleural aerosol is indicated to prevent recurrence of malignant pleural effusions in symptomatic patients. It is administered during thoracoscopy or open thoracotomy.
...Talc insufflation, either as a poudrage or by using slurry, is recognized as an effective treatment /for spontaneous pneumothorax/.

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Drug Warnings
...The case of a 78 yr-old man /is presented,/ who was treated with talc pleurodesis for recurrent pleural effusion and subsequently developed a massive hemothorax, a rare complication.
/The case of/ ...a young woman with a large, calcified anterior mediastinal mass discovered 18 months following a left talc pleurodesis /is reported/.

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.)