Anti_ Pyretic, mechanism, structure ,importance

1. Antipyretic Analysis
M. Gomathy
Assistant Professor
Department of Chemistry
Sri Sarada Niketan College Of Science for Women.
Karur.

2. Introduction
 Antipyretics are drugs that reduce fever by acting on the
hypothalamus.
 Common examples include Paracetamol, Aspirin, Ibuprofen, and
Metamizole.

3. Definition of Antipyretics
 Derived from Greek: 'anti' (against) + 'pyretos' (fever).
 They lower elevated body temperature without affecting normal
temperature.
 Mostly belong to NSAIDs (Non-steroidal anti-inflammatory
drugs).

4. Mechanism of Action
 • Fever caused by prostaglandin E2 acting on hypothalamus.
 • Antipyretics inhibit COX enzyme decrease prostaglandin
→
synthesis.
 • Restores normal temperature via vasodilation and sweating.

5. Common Antipyretic Drugs
 Drug | Chemical Class | Mechanism | Example Brand
 -----------------------------------------------
 Paracetamol | p-Aminophenol derivative | COX inhibitor |
Crocin
 Aspirin | Salicylate | COX inhibition | Disprin
 Ibuprofen | Propionic acid derivative | COX inhibitor | Brufen

6. Structure of Common Antipyretics
 • Paracetamol – C8H9NO2
 • Aspirin – C9H8O4
 • Ibuprofen – C13H18O2
 (Include structural diagrams in visual version)

7. Analytical Importance
 • Ensures purity and potency of formulations.
 • Verifies correct dosage and safety.
 • Applied to tablets, syrups, and capsules.

8. Analytical Methods Used
 1. Spectrophotometric Method – UV-visible absorption at 243 nm.
 2. Titrimetric Method – Iodometric or redox titration.
 3. Chromatographic Techniques – HPLC, TLC.
 4. FT-IR Spectroscopy – Identifies functional groups.

9. Spectrophotometric Estimation of Paracetamol
 • Principle: Beer–Lambert’s Law
 • max = 243 nm (UV region)
λ
 Procedure:
 1. Dissolve sample in ethanol/water.
 2. Measure absorbance.
 3. Compare with standard curve.

10. Titrimetric Analysis Example
 • Iodometric titration of Paracetamol:
 Paracetamol oxidized by iodine in acidic medium.
 Endpoint: Starch indicator blue color disappears.
→
 Used for quantitative estimation in tablets.

11. Chromatographic Analysis
 • HPLC conditions:
 Column: C18
 Mobile phase: Methanol:Water (60:40)
 Detector: UV (243 nm)
 Retention time: ~3.5 min for Paracetamol.

12. Quality Control Parameters
 • Assay of active ingredient
 • Dissolution rate
 • Uniformity of content
 • pH, moisture content, impurities.

13. Applications of Antipyretic Analysis
 • Drug formulation and stability testing
 • Bioavailability studies
 • Detection of counterfeit drugs
 • Pharmacokinetic and toxicity studies.

14. Safety and Toxicity
 • Overdose causes liver damage (Paracetamol toxicity).
 • Safe dose: 500–1000 mg every 6 hours (max 4 g/day).
 • Analytical control prevents adverse effects.

15. Summary & References
 Summary:
 • Antipyretics inhibit prostaglandin synthesis to reduce fever.
 • Analytical methods (UV, HPLC, titration) ensure quality.
 References:
 • Beckett & Stenlake – Practical Pharmaceutical Chemistry
 • Indian Pharmacopoeia
 • WHO Guidelines on Drug Quality Control.