Bioassay of Histamine

• Bioassay of Histamine: Commonly performed using isolated guinea pig ileum to measure contraction response.
• Bioassay of Histamine: Helps determine potency and concentration of histamine in pharmaceutical preparations.

Principle

• Histamine causes contraction of smooth muscle, notably the guinea pig ileum, and also has vasodilatory and other effects.
• The classic bioassay measures the contraction of the isolated guinea pig ileum.

Method

1. Guinea Pig Ileum Assay

• Procedure:
  1. Isolate a segment of guinea pig ileum, mount it in an organ bath.
  2. Add graded doses of standard histamine and measure the contraction. Wash out between doses.
  3. Similarly, test the unknown sample in graded doses.
• Potency Determination: Plot dose-response curves (e.g.,

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