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CAS 100-51-6 Antimicrobial Preservative / Local Anesthetic Antimicrobial Preservative / Local Anesthetic

Benzyl Alcohol (for injection)

IUPAC: Phenylmethanol View on PubChem
CAS NUMBER
100-51-6
MOL. FORMULA
C7H8O
MOL. WEIGHT
108.14 g/mol
Scientific Overview

Benzyl alcohol's antimicrobial action arises from disruption of microbial cell membranes, giving it effective bacteriostatic activity at concentrations of 0.9-2% v/v in multi-dose parenteral vials. It also has mild local anesthetic properties, contributing to reduced injection-site pain, though its use in neonates is restricted due to 'gasping syndrome' toxicity risk at high cumulative doses.

Benzyl Alcohol is an aromatic alcohol used as a bacteriostatic preservative in multi-dose injectable formulations and as a mild local anesthetic component, valued for its broad antimicrobial activity at low use concentrations.

Full Technical Data
Chemical Name Benzyl Alcohol (Phenylmethanol)
CAS Number 100-51-6
IUPAC Name Phenylmethanol
Molecular Formula C7H8O
Molecular Weight 108.14 g/mol g/mol
Boiling Point 205.3°C
Density 1.044 g/cm³
Refractive Index 1.538-1.541
Flash Point >100°C
Reaction Scheme
Toluene
NA
NA
Benzyl Alcohol
NA
Commercial Applications

Multi-Dose Injectable Preservative

Provides bacteriostatic protection in multi-use parenteral vials at 0.9-2% v/v concentration.

Local Anesthetic Component

Contributes mild local anesthetic/pain-reducing effect at the injection site in IM formulations.

Bacteriostatic Water for Injection

Key active ingredient of Bacteriostatic Water (0.9% w/v) used as a multi-dose diluent.

Cosmetic & Topical Preservative

Used as a preservative and fragrance-fixative component in topical pharmaceutical and cosmetic formulations.

Market Therapeutic Focus
ANTIMICROBIAL PRESERVATIVE / LOCAL ANESTHETIC PHARMACEUTICAL MANUFACTURING INJECTABLE & PARENTERAL FORMULATION PRESERVATIVE SYSTEMS SPECIALTY EXCIPIENTS CRO/CDMO
Scientific Literature

Benzyl Alcohol and Fatal Toxicity in Newborns: A Question Redux

Authors: Hiller, J.L. et al.

Pediatrics

Handbook of Pharmaceutical Excipients: Benzyl Alcohol Monograph

Authors: Rowe, R.C. et al.

Pharmaceutical Press

Formulation of Multi-Dose Injectable Products: Preservative Selection

Authors: Meyer, B.K. et al.

J. Pharm. Sci. Technol.

Peer Queries & FAQs
Why is Benzyl Alcohol restricted in neonatal use?
High cumulative doses have been linked to 'gasping syndrome,' a potentially fatal toxicity in premature infants, so benzyl-alcohol-preserved products are generally avoided in neonatal care.
What concentration is used as a preservative?
Typically 0.9-2% v/v, with 1% v/v being the most common concentration in multi-dose parenteral formulations.
Does Benzyl Alcohol reduce injection pain?
Yes, it has mild local anesthetic properties that can reduce discomfort at the injection site.
What is the recommended storage condition?
Store in a tightly sealed container protected from light and oxidizing agents, which can accelerate degradation to benzaldehyde and benzoic acid.

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