Related Experiment Videos
Biodistribution of mild analgesics
British Journal of Clinical Pharmacology
|October 1, 1980
Summary
Acidic mild analgesics concentrate in inflamed tissues and organs, causing therapeutic effects and side effects. Non-acidic analgesics distribute widely, correlating with fewer side effects and no anti-inflammatory action.
Area of Science:
- Pharmacology
- Toxicology
- Drug Metabolism
Background:
- Mild analgesics are commonly used for pain relief.
- Understanding drug biodistribution is crucial for predicting efficacy and toxicity.
- Inflammation can alter drug distribution patterns.
Purpose of the Study:
- To investigate the biodistribution of acidic and non-acidic mild analgesics in an inflamed rat model.
- To correlate drug distribution with therapeutic effects and side effects.
Main Methods:
- Macro-autoradiography using [3H]- or [14C]-labeled drugs.
- Carrageenan-induced inflammation model in rats.
- Assessment of drug and metabolite distribution in various tissues.
Main Results:
- Acidic analgesics (aspirin, indomethacin, phenylbutazone) accumulated in inflamed tissues, stomach, liver, blood, bone marrow, and kidneys at anti-inflammatory doses.
- Non-acidic analgesics (antipyrine, aminopyrine, paracetamol) showed even distribution throughout the body at analgesic doses, excluding the GI lumen and liver.
- Distribution patterns correlated with observed therapeutic actions and side effects.
Conclusions:
- Biodistribution of mild analgesics is dependent on their chemical properties (acidic vs. non-acidic).
- Acidic analgesics target tissues where they exert effects and side effects.
- Non-acidic analgesics' widespread distribution explains their lack of acute side effects and anti-inflammatory action at therapeutic doses.