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Antibiotics and anti-infectives

Cephalexin

Also known as Cefalexin, Cephacillin, Ceporexin

CAS 15686-71-2Formula C16H17N3O4SMolar mass 347.40 g/molEC 239-773-6
GHS signal word: Danger. Pictograms: Harmful or irritant, Serious health hazard 121 suppliers listed Drug substance
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Cephalexin chemical structure, C16H17N3O4S, CAS 15686-71-2
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
15686-71-2
Formula
C16H17N3O4S
Appearance
Crystals
Solubility
SLIGHTLY SOL IN WATER, PRACTICALLY INSOL IN ALC, CHLOROFORM, ETHER
HS code
294190
Category
Antibiotics and anti-infectives
Illustrative photo, assorted laboratory chemical bottles and jars on a laboratory bench
Typical packagingIllustrative packaging image, not the actual product

What is Cephalexin?

Plain description, key identifiers and synonyms

Cephalexin is a semisynthetic first-generation cephalosporin antibiotic having methyl and beta-(2R)-2-amino-2-phenylacetamido groups at the 3- and 7- of the cephem skeleton, respectively. It is effective against both Gram-negative and Gram-positive organisms, and is used for treatment of infections of the skin, respiratory tract and urinary tract. It has a role as an antibacterial drug. It is a cephalosporin, a semisynthetic derivative and a beta-lactam antibiotic allergen. It is a conjugate acid of a cephalexin(1-).

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
(6R,7R)-7-[[(2R)-2-amino-2-phenylacetyl]amino]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid
CAS number
15686-71-2 CAS number cross-checkedOther or deprecated CAS: 23325-78-2
EC number
239-773-6
Molecular formula
C16H17N3O4S
UNII
5SFF1W6677
MDL number
MFCD00056877
InChIKey
ZAIPMKNFIOOWCQ-UEKVPHQBSA-N
InChI
InChI=1S/C16H17N3O4S/c1-8-7-24-15-11(14(21)19(15)12(8)16(22)23)18-13(20)10(17)9-5-3-2-4-6-9/h2-6,10-11,15H,7,17H2,1H3,(H,18,20)(H,22,23)/t10-,11-,15-/m1/s1
Canonical SMILES
CC1=C(C(=O)O)N2C(=O)C(NC(=O)C(N)c3ccccc3)C2SC1
Isomeric SMILES
CC1=C(N2[C@@H]([C@@H](C2=O)NC(=O)[C@@H](C3=CC=CC=C3)N)SC1)C(=O)O

Synonyms

  • Cefalexin
  • Cephacillin
  • Ceporexin
  • Mamalexin
  • Ceporex
  • Keflex
  • Carnosporin
  • Cefaleksin
  • Cephalexine
  • Cephalexinum
  • Ceporexine
  • Sinthecillin
  • Uphalexin
  • Alsporin
  • Cepexin
  • Durantel
  • Felexin
  • Pyassan
  • Cefalexina
  • Cefalexine
  • Cefaloto
  • Cepastar
  • Madlexin
  • Sencephalin
  • Celexin
Show all 39 synonyms
  • Cefalexinum
  • Cefaseptin
  • Lexibiotico
  • Neolexina
  • Larixin
  • Syncl
  • Cephalexin anhydrous
  • Keforal
  • Keflet
  • Novolexin
  • Biocef
  • Panixine Disperdose
  • Lilly 66873
  • Cefalexin anhydrous

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Crystalsexp.
Solubility
SLIGHTLY SOL IN WATER, PRACTICALLY INSOL IN ALC, CHLOROFORM, ETHERexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
347.40 g/molcalc.
Exact mass
347.094 Dacalc.
LogP (octanol/water)
0.44calc.
Topological polar surface area
112.7 Ųcalc.
Hydrogen bond donors
3calc.
Hydrogen bond acceptors
5calc.
Rotatable bonds
4calc.
Heavy atoms
24calc.
Rings
3calc.
Aromatic rings
1calc.
Fraction sp3 carbons
0.31calc.
Formal charge
0calc.
Stereocentres
3calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, O=C(Cc1ccccc1)NC1C(=O)N2C=CCSC12

O=C(Cc1ccccc1)NC1C(=O)N2C=CCSC12

3 rings, 19 atoms.

98 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS07: Harmful or irritant
Harmful or irritant
GHS08: Serious health hazard
Serious health hazard

Hazard statements

  • H317May cause an allergic skin reaction.
  • H334May cause allergy or asthma symptoms or breathing difficulties if inhaled.
Precautionary statements (15)
  • P233Keep container tightly closed.
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P271Use only outdoors or in a well-ventilated area.
  • P272Contaminated work clothing should not be allowed out of the workplace.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P284In case of inadequate ventilation wear respiratory protection.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P333 + P317If skin irritation or rash occurs: Get medical help.
  • P342 + P316If experiencing respiratory symptoms: Get emergency medical help immediately.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403Store in a well-ventilated place.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Cephalexin suppliers

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All 121 suppliers
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Where suppliers are based

121 suppliers in 24 countries

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Cephalexin price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Antibiotic for infections of the respiratory & genitourinary tracts & of the skin, eye, & bone, antibiotic for veterinary use.

Veterinary medication:.

Use classes: Pharmaceuticals, Animal Drugs.

Pharmacological actions

  • Anti-Bacterial Agents

Roles

  • antibacterial agent
  • antibacterial drug
  • antiinfective agent
  • antimicrobial agent
  • antimicrobial drug
  • pharmaceutical

Functional uses

  • Pharmaceutical

Pharmacology

Cephalexin anhydrous is a Cephalosporin Antibacterial.

How it is made

Acylation of 7-amino-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (prepared from cephalosporin c) with 2-phenylglycine in an appropriate dehydrating environment

7-Amino-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, which may be prepd from natural antibiotic cephalosporin c, is acylated with 2-phenylglycine in appropriate dehydrating environment.

Regulatory status

Inventories, regulations and trade controls that list this substance

Health and food

  • Active ingredient in FDA approved drug labels

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Cephalexin is traded under.

HS 2941.90Indicative HS code

Antibiotics, other

World exports in 2024
$6.39B
+2.3% vs 2023, imports $6.97B
2019 to 2024
Top exporters
  1. China39.7%
  2. United States11.3%
  3. Switzerland * partner reported10.9%
Top importers
  1. Italy15.0%
  2. India * partner reported12.0%
  3. China8.7%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Cephalexin is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Cephalexin, based on the data on this page

What is Cephalexin?

Cephalexin is a semisynthetic first-generation cephalosporin antibiotic having methyl and beta-(2R)-2-amino-2-phenylacetamido groups at the 3- and 7- of the cephem skeleton, respectively.

What is the CAS number of Cephalexin?

The CAS registry number of Cephalexin is 15686-71-2. Other or deprecated CAS numbers: 23325-78-2.

What is the molecular formula and weight of Cephalexin?

The molecular formula of Cephalexin is C16H17N3O4S and its molar mass is 347.40 g/mol.

What is Cephalexin used for?

Antibiotic for infections of the respiratory & genitourinary tracts & of the skin, eye, & bone, antibiotic for veterinary use. Veterinary medication:. Use classes: Pharmaceuticals, Animal Drugs.

Is Cephalexin hazardous?

Cephalexin carries the GHS signal word "Danger". Main hazards: may cause an allergic skin reaction, may cause allergy or asthma symptoms or breathing difficulties if inhaled. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Cephalexin?

Cephalexin is usually classified under HS code 294190 (Antibiotics, other). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Cephalexin?

CompoundList lists 121 suppliers of Cephalexin in China, India, United States, Spain and 20 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy Cephalexin in India?

27 suppliers in India list Cephalexin on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of Cephalexin?

Suppliers quote Cephalexin on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Cephalexin

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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