Absorbent cotton|MARUSAN INDUSTRY CO.,LTD.


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Absorbent cotton

Manufacturing medical absorbent cotton

医療製品(脱脂綿)Ever since its founding, Marusan Industry Co., Ltd has been committed to developing uncompromisingly high-quality absorbent cotton used in the medical field.

What is medical absorbent cotton?

The classification of medical absorbent cotton has been changed from “drugs” under The Japanese Pharmacopoeia (14th edition) to “medical device” under The Japanese Pharmacopoeia (14th edition, Supplement II).
Desi cotton (Indian cotton) which is characterized as having short and thick fibers tends to be preferred​ for making medical absorbent cotton.

Current classification of medical absorbent cotton under The Japanese Pharmacopoeia (14th edition, Supplement II)

Generic Name medical absorbent cotton (CODE:70975000)
Classification  general medical device (class-1)
Definition Medical absorbent cotton is an instrument made from cotton in the form of a pad. It is mainly used in the medical setting for the purpose of absorbing body fluids and coating the skin with liquid medication applied.

Manufacturing of medical absorbent cotton

While Marusan can provide medical adsorbent cotton in a variety of sizes according to client request, our most popular size 40mm×40mm) is manufactured under a fully automated system. For other sizes, the manufacturing process will end with final touches made manually by our skilled workers.

Purity test for medical absorbent cotton

Our absorbent cottons are required to comply with standards for the following test categories:
・Acid or alkali ・Water-soluble substances ・Dyes ・Fluorescent whitening agents ・Submersion rate ・Absorbency ・Other filaments ・Nep texture and impurities ・Total ash content
Material for testing is prepared by obtaining a certain amount (5g) of the absorbent cotton from 10 different parts of the same sample and combining them to the required amount (50g).

A) Acid or alkali Add 100ml of freshly boiled and cooled water to 10g of the absorbent cotton, and let it macerate. When 3 drops of phenolphthalein test solution is added to 25ml of the resulting liquid, there should be no detection of red color; when 1 drop of methyl orange test solution is added, there should be no detection of red color.
B) Water-soluble substances To 5 g of the absorbent cotton, 500ml of water is added, and boiled gently for 30 minutes while adding water to maintain the original volume. The resulting liquid is poured through a funnel into another vessel, the cotton is placed atop the funnel, and pressed to squeeze out the liquid with a glass rod. The cotton is washed twice with 150ml of hot water each time, pressing the cotton after each washing to combining the water from the two washings with the liquid from the first soak. Filter the combined liquids, evaporate to concentrate it, transfer to a weighing bottle, and dry at 105℃ to constant mass, at which point the amount of the residue should not be more than 14mg. Perform a blank test, and make any necessary corrections.
C) Dyes To 10g of absorbent cotton, add 100ml of ethanol (95) and let it macerate. Press, and transfer 50ml of the resulting liquid to a Nessler tube, and observe from above. The liquid may show some yellowing, but it should not develop any blue or green color.
D) Fluorescent whitening agents Irradiate the absorbent cotton with ultraviolet rays in a dark place. There should be no perceptible fluorescence on the surface.
E) Submersion rate Prepare a test basket weighing 3g, made with copper wire 0.44mm in diameter in the form of a cylinder that is 50mm in diameter and 80mm deep, with 20mm space between the wires. Place 5g of the absorbent cotton in the basket. Hold the basket on its side at 12mm above the surface of the water with a temperature between 24℃ and 26℃, and drop the basket gently into the water 200 mm deep. The basket should hit bottom in no more than 8 seconds.
F) Absorbency Leave the submerged basket at the bottom of the water in above test E for 3 minutes. Lift the basket gently from the water, keeping it horizontal, allowing it to drain for 1 minute on a No.10 wire sieve in the same horizontal position. When it is placed in a beaker and weighed, the mass of water absorbed should not be any less than 100g.
G) Other filaments Dip 1g of absorbent cotton into 0.5mol/l iodine test solution for 1 minute, and wash well with water. There should be no colored fibers found.
H) Nep texture and impurities Spread 1g of absorbent cotton evenly between two 10㎠-size colorless, transparent plates, and check for neps and adhering impurities (e.g., fragments of rinds and seeds). There should be no more than a total number of 5 fragments that are 2.5mm in diameter or larger.
I) Ash content Heat a platinum, quartz, or porcelain crucible at 500-550℃ for one hour. After cooling, perform a precision measurement of its mass. Place the absorbent cotton in the crucible and perform a precision measurement of its mass. If necessary, open or shift the lid, and heat at a low setting at first, then gradually raise the temperature to 500-550℃ and heat at this high temperature for more than 4 hours, until no carbonated substance remains. After it is cooled naturally, perform a precision measurement of its mass and calculate the ash content. Ash content must be 0.25% or less.