Ibuprofen 2D chemical structure (propionic-acid NSAID), C13H18O2

Ibuprofen Chemical Structure

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1. Identification

Summary
Ibuprofen is a widely used nonsteroidal anti-inflammatory drug (NSAID) indicated for relief of mild–moderate pain, fever, and inflammatory conditions; available OTC in many regions and by prescription for higher strengths/formulations.

Brand Names
Advil, Motrin, Nurofen, Brufen (regional variants and numerous generics)

Name
Ibuprofen

Background
A propionic-acid NSAID introduced in the late 1960s/1970s; supplied as a racemic mixture. Oral tablets/capsules, suspensions, topical products, and IV (certain jurisdictions) are available.

Modality
Small molecule

Groups
Approved; OTC/Rx (region-dependent)

Structure

Ibuprofen skeletal formula. Formula C₁₃H₁₈O₂; CAS 15687-27-1; UNII WK2XYI10QM.
Ibuprofen 2D chemical structure (propionic-acid NSAID), C13H18O2

Weight
~206.28 g/mol

Chemical Formula
C₁₃H₁₈O₂

Synonyms
Isobutylphenylpropionic acid; (RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid

External IDs
CAS: 15687-27-1; PubChem CID: 3672; UNII: WK2XYI10QM; KEGG: D00126; ChEMBL: 521; ChEBI: 5855

2. Pharmacology

Indication
Short-term management of pain (e.g., headache, dental, musculoskeletal, dysmenorrhoea), fever, and inflammatory conditions (e.g., osteoarthritis/RA symptoms). Certain formulations are used in hospitals; some IV/lysine forms are approved for specific uses per local labeling.

Associated Conditions
Fever, primary dysmenorrhoea, musculoskeletal/soft-tissue pain, postoperative pain, migraine, osteoarthritis flares.

Associated Therapies
Used within multimodal analgesia with acetaminophen/paracetamol or adjuvants; various fixed-dose combinations exist regionally.

Contraindications & Blackbox Warnings
Class boxed warnings for NSAIDs: ↑ risk of serious cardiovascular thrombotic events (MI, stroke) and GI bleeding/ulceration/perforation; contraindicated for peri-operative pain in CABG setting. Avoid with history of NSAID/aspirin hypersensitivity, active GI bleeding, and in certain renal risks per label.

Pharmacodynamics
Reversible, non-selective inhibition of COX-1/COX-2, reducing prostaglandin synthesis → analgesic, antipyretic, anti-inflammatory effects.

Mechanism of action
Competitive COX blockade decreases prostaglandins and thromboxane formation; antipyresis via central action; analgesia via peripheral/central prostaglandin reduction.

Absorption
Rapid after oral dosing; food may delay tₘₐₓ and reduce Cmax, but total exposure typically similar for IR products; taking with food improves GI tolerability.

Volume of distribution
Relatively low (on the order of ~0.1–0.2 L/kg), consistent with strong protein binding and limited tissue partitioning.

Protein binding
High—~98–99% at therapeutic concentrations.

Metabolism
Hepatic, mainly CYP2C9 to hydroxylated and carboxylated metabolites; conjugation (glucuronides) follows.

Route of elimination
Predominantly renal, largely as metabolites (a small fraction unchanged).

Half-life
Typically ~2–4 hours (formulation/individual factors may vary).

Clearance
Primarily renal for metabolites; apparent oral clearance is influenced by protein binding, hepatic biotransformation, and renal function.

Adverse Effects
Common: dyspepsia, heartburn, nausea, abdominal pain, dizziness, rash. Serious: GI bleeding/ulcer, CV thrombotic events, renal events, anaphylaxis/bronchospasm in aspirin-sensitive individuals, severe cutaneous reactions (rare).

Toxicity
Overdose may cause GI symptoms, CNS depression, metabolic acidosis, renal compromise; management is supportive with attention to airway/hemodynamics and complications.

Pathways
COX-1/COX-2 inhibition; downstream reduction of PGE₂/PGI₂/TXA₂; renal prostaglandin modulation relevant to fluid/electrolyte balance and renal blood flow.

Pharmacogenomic Effects/ADRs
CYP2C9 polymorphisms can affect metabolism/exposure; aspirin-exacerbated respiratory disease (AERD) reflects clinical susceptibility rather than a single gene determinant.

3. Interactions

Drug Interactions

  • Aspirin (low-dose): Ibuprofen may interfere with aspirin’s antiplatelet effect—timing separation is often advised in labels/agency guidance.
  • Anticoagulants/antiplatelets (e.g., warfarin): ↑ bleeding risk; monitor.
  • ACEIs/ARBs/diuretics (“triple whammy”): additive renal risk; monitor renal function.
  • Lithium / Methotrexate: potential ↑ levels/toxicity; monitor.
  • SSRIs/SNRIs, corticosteroids: additive GI bleeding risk.

Food Interactions
May be taken with food to reduce GI upset; food can delay peak absorption but usually doesn’t meaningfully reduce overall exposure for IR products. Alcohol co-use increases GI risk.

4. Categories

ATC Codes
M01AE01 (ibuprofen; anti-inflammatory and antirheumatic products, non-steroids)

Drug Categories
NSAID; Analgesic; Antipyretic; Anti-inflammatory; Small molecule

Chemical Taxonomy
Propionic-acid derivative; aromatic carboxylic acid; racemate (R/S)

Affected organisms
Humans (therapeutic use)

5. Chemical Identifiers

UNII
WK2XYI10QM

CAS number
15687-27-1

InChI Key
HEFNNWSXXWATRW-UHFFFAOYSA-N

InChI
InChI=1S/C13H18O2/c1-9(2)8-11-4-6-12(7-5-11)10(3)13(14)15/h4-7,9-10H,8H2,1-3H3,(H,14,15)

IUPAC Name
(RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid

SMILES
CC(C)Cc1ccc(cc1)C(C)C(=O)O

6. References

  1. PubChem Compound Summary: Ibuprofen (CID 3672) — formula, molecular weight, identifiers. PubChem
  2. FDA GSRS / precision.fda: UNII WK2XYI10QM (Ibuprofen) — UNII, InChIKey, formula. precision.fda.gov+1
  3. StatPearls: Ibuprofen — PK (food effect, tₘₐₓ), distribution, protein binding (~99%), clinical use overview. NCBI
  4. DailyMed (multiple ibuprofen labels) — NSAID boxed warnings (CV/GI), CABG contraindication, consumer/HC-professional labeling. DailyMed+2DailyMed+2
  5. FDA Safety Communication / Q&A: Ibuprofen with low-dose aspirin — potential antiplatelet interference and timing considerations. U.S. Food and Drug Administration+1
  6. NIST WebBook: Ibuprofen — IUPAC Standard InChI and InChIKey. NIST WebBook
  7. Sigma-Aldrich (product page) — canonical SMILES, InChI string confirmation. MilliporeSigma
  8. ATC/DDD Index: M01AE01 (ibuprofen) — ATC classification, DDD/routes. atcddd.fhi.no
  9. WHO eEML (Electronic Essential Medicines List): Ibuprofen — essential-medicine status and codes. list.essentialmeds.org
  10. StatPearls: Ibuprofen Toxicity — overdose features and management overview. NCBI

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