Acetaminophen CAS#103-90-2
Analgesic & Antipyretic Effects ： Effective pain relief and fever reduction.
Selective COX Inhibition ： Modulates COX-2 more than COX-1 at high doses.
Metabolic Versatility ： Generates reactive metabolites with diverse effects.
Animal Model Efficacy ：Demonstrated therapeutic properties in vivo.
Acetaminophen (CAS# 103-90-2)
Acetaminophen is an analgesic and antipyretic agent. Unlike nonsteroidal anti-inflammatory drugs (NSAIDs) that broadly inhibit both COX-1 and COX-2, early research indicated its weak activity against these isoforms. However, ex vivo studies in human blood show it inhibits COX-2 by 83% and COX-1 by 56% at high doses (1,000 mg), with IC50 values of 25.8 μM and 113.7 μM, respectively. Acetaminophen undergoes enzymatic and non-enzymatic conversion to reactive metabolites, some of which contribute to adverse effects like liver injury. At toxic levels, its metabolite N-acetyl-4-benzoquinone imine (NAPQI) depletes liver glutathione, causing NAPQI accumulation and hepatocyte necrosis. In mice, acetaminophen (250 mg/kg) reduces glutathione levels and glutathione peroxidase activity while inducing ferroptotic cell death in hepatocytes—an effect reversible by ferrostatin-1. Despite these mechanisms, it demonstrates analgesic and antipyretic efficacy in animal models
Acetaminophen Chemical Properties
Melting point | 168-172 °C(lit.) |
Boiling point | 273.17°C (rough estimate) |
density | 1,293 g/cm3 |
vapor pressure | 0.008Pa at 25℃ |
refractive index | 1.5810 (rough estimate) |
Fp | 11 °C |
storage temp. | Inert atmosphere,Room Temperature |
solubility | ethanol: soluble0.5M, clear, colorless |
form | Crystals or Crystalline Powder |
pka | 9.86±0.13(Predicted) |
color | White |
Odor | odorless |
PH | 5.5-6.5 (H2O, 20℃)(saturated solution) |
PH Range | 5.5 - 6.5 (H?O, 20 °C) (saturated solution) |
explosive limit | 15%(V) |
Water Solubility | 14 g/L (20 ºC) |
Merck | 14,47 |
BRN | 2208089 |
BCS Class | 3,4 |
Cosmetics Ingredients Functions | SKIN CONDITIONING |
InChIKey | RZVAJINKPMORJF-UHFFFAOYSA-N |
LogP | 1.098 at 25℃ |
CAS DataBase Reference | 103-90-2(CAS DataBase Reference) |
IARC | 3 (Vol. 50, 73) 1999 |
NIST Chemistry Reference | Acetaminophen(103-90-2) |
EPA Substance Registry System | Acetaminophen (103-90-2) |
Safety Information
Hazard Codes | Xn,T,F |
Risk Statements | 22-36/37/38-52/53-36/38-40-39/23/24/25-23/24/25-11 |
Safety Statements | 26-36-61-37/39-22-45-36/37-16-7 |
RIDADR | UN 3077 9/PG III |
WGK Germany | 1 |
RTECS | AE4200000 |
Autoignition Temperature | 540 °C |
TSCA | Yes |
HazardClass | 9 |
PackingGroup | III |
HS Code | 29242930 |
Hazardous Substances Data | 103-90-2(Hazardous Substances Data) |
Toxicity | LD50 in mice (mg/kg): 338 orally (Starmer), 500 i.p. (Dahlin, Nelson) |
Product Application of Acetaminophen CAS#103-90-2
Acetaminophen (Paracetamol, CAS# 103-90-2) is an antipyretic and analgesic agent. It is the most common non-anti-inflammatory analgesic-antipyretic drug, lacking anti-inflammatory and anti-rheumatic actions. Its antipyretic effect is comparable to aspirin, but its analgesic effect is relatively weaker. It is considered the best-in-class among acetanilide derivatives and is particularly suitable for patients who cannot tolerate carboxylic acid-based drugs. It is used to treat conditions such as the common cold and toothache. Beyond its pharmaceutical use, acetaminophen also serves as an intermediate in organic synthesis, a stabilizer for hydrogen peroxide, and a component in photographic chemicals.
Dosage:
1. Oral (Tablets/Capsules): Adults: 300–600 mg per dose, 3–4 times daily as needed. The total daily dose should not exceed 2 grams. Antipyretic use should generally not exceed 3 days, and analgesic use should not exceed 10 days. Children: 10–15 mg/kg every 4–6 hours. For children under 12 years old, administration should not exceed 5 times per day, with a maximum course of 5 days. Long-term use is not recommended.
2. Dispersible Tablets: The tablets should be dispersed in warm water before administration. The common pediatric dosage is 10–15 mg/kg every 4–6 hours. For children under 12, do not exceed 5 doses per day, with a maximum course of 5 days. Dosage should be reduced for children under 3 years of age.
