Paracetamol

CAS NO.: 103-90-2 EINECS: 203-157-5

Molecular Formula: C₈H₉NO₂ Molecular Weight: 151.16

Molecular Structure:

Property:

The melting point of paracetamol is 168-172 ºC ,the water solubility of paracetamol 14 g/L (20 ºC). Paracetamol (INN) or acetaminophen is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer). Paracetamol is commonly used for the relief of headaches, other minor aches and pains, and is a major ingredient in numerous cold and flu remedies. In combination with opioid analgesics, paracetamol can also be used in the management of more severe pain such as post surgical pain and providing palliative care in advanced cancer patients. The onset of analgesia is approximately 11 minutes after oral administration of paracetamol, and its half-life is 1–4 hours.

While generally safe for use at recommended doses (1,000 mg per single dose and up to 4,000 mg per day for adults, up to 2,000 mg per day if drinking alcohol),acute overdoses of paracetamol can cause potentially fatal liver damage and, in rare individuals, a normal dose can do the same; the risk is heightened by alcohol consumption. Paracetamol toxicity is the foremost cause of acute liver failure in the Western world, and accounts for most drug overdoses in the United States, the United Kingdom, Australia and New Zealand.

Paracetamol is the active metabolite of phenacetin, once popular as an analgesic and antipyretic in its own right, but unlike phenacetin and its combinations, paracetamol is not considered to be carcinogenic at therapeutic doses.

Specifications：

Item	Index
Characteristics	White,crystalline powder.Sparingly soluble in water,freely soluble in alcohol,very slightly soluble in methylene chloride.
Identification	A:Melthing point 168-172 ºC C:IR absorption Complies
Related Substance	Impurity J(chloroacetanilide) not more than 10 ppm Impurity K(4-aminophenol) not more than 50 ppm Impurity F(4-nitrophenol) not more than 0.05% Any other impurity not more than 0.05% Total of other impurity not more than 0.1%

Sulphated Ash	Not more than 0.1%
Heavy Metals	Not more than 20ppm
Loss On Dry	Not more than 0.5%
Assay	99.0%-101.0%(dried substance)

Usage:

Medical uses Fever

Paracetamol is approved for reducing fever in people of all ages. The World Health Organization (WHO) recommends that paracetamol only be used to treat fever in children if their temperature is greater than 38.5 °C (101.3 °F). The efficacy of paracetamol by itself in children with fevers has been questioned with it being less effective than ibuprofen.

Pain

Paracetamol is used for the relief of and pains associated with many parts of the body. Paracetamol has analgesic properties comparable to those of aspirin, while its anti-inflammatory effects are weaker. Paracetamol is better tolerated than aspirin in patients in whom excessive gastric acid secretion or prolongation of bleeding time may be a concern. Available without a prescription, paracetamol has in recent years increasingly become a common household drug.

Paracetamol can relieve pain in mild arthritis but has no effect on the underlying inflammation, redness, and swelling of the joint. Paracetamol is as effective as the nonsteroidal anti-inflammatory drug ibuprofen in relieving the pain of osteoarthritis of the knee.

Paracetamol has relatively little anti-inflammatory activity, unlike other common analgesics such as the NSAIDs aspirin and ibuprofen.

Regarding comparative efficacy, studies show conflicting results when compared to NSAIDs. A randomized controlled trial of chronic pain from osteoarthritis in adults found similar benefit from paracetamol and ibuprofen.

The efficacy of paracetamol when used in a combination form with weak opioids (such as codeine) has been questioned by recent data studies; the small amount of data available have made reaching a conclusion hard. Combination drugs of paracetamol and strong opioids like morphine have been shown to reduce the amount of opioid used and improve analgesic effect.

A randomized controlled trial of acute musculoskeletal pain in children found that the standard over-the-counter dose of ibuprofen gives greater relief of pain than the standard dose of paracetamol.

Package and Storage:

Keep in shaded, cool 25kg bag and air places. The shelf time is 4 years.

Key Words:

4-Acetamidophenol ,p-Hydroxyacetanilide; Acetaminophen; Paracetamol; N-Acetyl-4-aminophenol; APAP