红粉

English text reference: Chinese Pharmacopoeia (2020 Edition)

Overview

Red Mercuric Oxide is the red oxide of mercury (HgO).

Description

Red, orange-red, crystalline powder or scales; scales smooth and slightly lustrous on one side,rough on the other side. Powder, orange. Hard in texture, brittle; colour deepens on exposure to light. Odour, slight.

Identification

To 0.5 g of the powder add 10 ml of water, mix well, and add dropwise with stirring a sufficient quantity of hydrochloric acid until the solution shows the identification reaction for mercuric salts <0301>.

Examination

Submercurous compounds

To 0.5 g of the powder add 25 ml of dilute hydrochloric acid, dissolve, and allow the solution to show a slight turbidity.

Chlorides

To 0.5 g of the powder add a sufficient quantity of water and 3 ml of nitric acid, dissolve, dilute with water to about 40 ml, and carry out the test for chlorides <0801>. The turbidity produced, when compared with that produced by 3 ml of the standard sodium chloride solution, does not exceed that produced by the latter (0.006%).

Assay

Weigh accurately about 0.2 g of the powder, dissolve in 25 ml of dilute nitric acid, dilute with water to 80 ml, add 2 ml of ammonium iron(III) sulfate TS as an indicator, and titrate with 0.1 mol/L ammonium thiocyanate VS. Each ml of 0.1 mol/L ammonium thiocyanate VS is equivalent to 10.83 mg of mercuric oxide (HgO).

The content of mercuric oxide (HgO) in the drug is not less than 99.0%.

Property

Hot; highly toxic.

Flavor

Pungent.

Meridian tropism

Enters the Lung and Spleen meridians.

Actions

To detoxify, eliminate pus, remove necrotic tissue, and promote tissue regeneration.

Indications

Used for carbuncles, furuncles, syphilitic chancres, all types of malignant sores, dark purple or black flesh, non-healing necrotic tissue, fistulas, atonic ulcers with copious discharge, and long-standing non-healing sores.

Dosage

For external use.

Administration

use an appropriate amount of finely powdered drug alone or in combination with other medicinal ingredients to make a powder or prepare a medicated thread.

Precautions

This drug is toxic and should only be used externally. It should not be taken orally, and prolonged external use is also not recommended. It is contraindicated for pregnant women.

Storage

Store in a dry place, protected from light, and in a tightly sealed container.