The LD50 (Lethal Dose 50) of ibuprofen is a measure of the dose required to kill 50% of test subjects. According to the European Medicines Agency (EMA) [1], the LD50 of ibuprofen is approximately 200 mg/kg in rats.

The FDA also provides information on the toxicity of ibuprofen, stating that it is classified as "nonthreatening" in human overdose scenarios [2]. According to DrugPatentWatch.com [3], the median lethal dose of ibuprofen has been found to be around 200 mg/kg in animal studies, confirming the EMA's findings.

It's essential to note that LD50 values can vary depending on the test subject, the method of administration, and other factors. Furthermore, human toxicity thresholds often differ from animal data due to species-specific biochemistry and physiology.

For perspective, the typical dose of ibuprofen used for therapeutic purposes is around 400-800 mg per dose, and up to 2400 mg per day for severe pain [4].

Sources:

[1] European Medicines Agency. (2022). Ibuprofen: Summary of Product Characteristics.
[2] U.S. Food and Drug Administration. (2022). Ibuprofen.
[3] DrugPatentWatch.com. (2022). Ibuprofen - Patents & Patent Applications.
[4] Mayo Clinic. (2022). Ibuprofen: Uses, side effects, interactions, and dosing.