Cetirizine

Cetirizine – Technical Information (Reference Only)

Chemical Information

• Synonyms:
  • Cetirizine hydrochloride
  • Zyrtec, Reactine (brand names)
  • (±)-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid hydrochloride

• Formal Name:
  (±)-2-[2-[4-(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid hydrochloride

• CAS Number:
  83881-51-0

• Molecular Formula:
  C21H25ClN2O3 · HCl

• Molecular Weight:
  388.9 g/mol (hydrochloride salt)

• Chemical Class:
  Second-generation antihistamine; H1 receptor antagonist

• Appearance:
  White to off-white crystalline powder

Structural / Spectral Information

• SMILES:
  Clc1ccc(cc1)C(c2ccc(Cl)cc2)N3CCN(CC3)CCOCC(=O)O

• InChI:
  InChI=1S/C21H25ClN2O3.HCl/...

• InChI Key:
  KYCMFZLURCCTDL-UHFFFAOYSA-L

• λmax (UV):
  ~ 229–231 nm

Solubility

• Water: Freely soluble (as hydrochloride salt)

• Methanol / Ethanol: Soluble

• DMSO: Soluble

• Chloroform / Ether: Insoluble

Formulation

• Supplied as Cetirizine hydrochloride USP/EP grade

• Purity: ≥98% (analytical/research grade)

• Common pharmaceutical strengths:
  • 5 mg tablet / chewable tablet
  • 10 mg tablet
  • 1 mg/mL oral solution
  • Syrup formulations for children

Storage & Stability

• Storage Temperature: 20–25 °C (room temperature)

• Shipping: Ambient temperature acceptable

• Stability: ≥3–5 years under proper storage

• Light/Moisture Sensitivity: Protect from prolonged exposure

Safety / Handling

• Use PPE when handling bulk powder

• Generally well tolerated; monitor for drowsiness or allergic reactions

• Store in sealed, dry containers away from children