Sulfamethoxazole

CAS: 723-46-6

Overview

Sulfamethoxazole (CAS 723-46-6 ), commonly abbreviated as SMX, is a sulfonamide antibacterial active pharmaceutical ingredient used in the manufacture of finished antimicrobial drug products.

It is marketed under trade names including Urobak and Sinomin, and is most recognized globally as the fixed-dose combination partner with trimethoprim for various medical applications.

SMX is the primary active ingredient in co-trimoxazole formulations, where it is combined with trimethoprim in a 5:1 ratio to produce tablets, suspensions, and injectable preparations.

Pharmaceutical manufacturers source SMX as a bulk API for urinary tract infection treatments, which remains one of the highest-volume therapeutic categories globally for chemical suppliers.

Generic drug producers rely on SMX to supply finished-dose forms across regulated and emerging markets. Contract formulators also use SMX in veterinary pharmaceutical preparations for livestock.

Demand for sulfonamide-based antibacterials remains substantial in the global market. Sulfamethoxazole is supplied as a white crystalline powder in bulk quantities suited to commercial manufacturing.

It is available to USP , BP , and Ph. Eur. pharmacopoeial specifications, supporting registration requirements across major regulated markets and international territories.

Packaging is typically offered in fiber drums or double polyethylene-lined bags. Lot-specific CoA and full regulatory documentation are available upon request for all industrial orders.

Physical Properties

Melting Point	167 °C
Boiling Point	482°C
Density	1.08 g/cm³
Flash Point	>110°(230°F)
Appearance	solid
Color	White to Pale Yellow
Form	neat
Water Solubility	Soluble in ethanol or acetone. Very slightly soluble in water
Refractive Index	1.6630 (estimate)

Safety & Handling

Warning GHS07 GHS09 GHS08 Hazard Statements H315 Causes skin irritation H317 May cause an allergic skin reaction H319 Causes serious eye irritation H335 May cause respiratory irritation H341 Suspected of causing genetic defects H350 May cause cancer H400 Very toxic to aquatic life H410 Very toxic to aquatic life with long lasting effects Precautionary Statements P203 Obtain, consult and follow expert instructions for use. P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P264 Wash … thoroughly after handling. P271 Use only outdoors or in a well-ventilated area. P272 Contaminated work clothing should not be allowed out of the workplace. P273 Avoid release to the environment. P280 Wear protective gloves/protective clothing/eye protection/face protection. P318 IF exposed or concerned, get medical advice. P319 Get medical advice/attention if you feel unwell. P321 Specific treatment (see … on this label). P391 Collect spillage. P405 Store locked up. P501 Dispose of contents/container in accordance with local regulations. P264+P265 Wash … thoroughly after handling. P302+P352 IF ON SKIN: Wash with plenty of water. P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing. P332+P317 Get emergency medical help. P333+P317 Get emergency medical help. P337+P317 If eye irritation persists: Get medical advice/attention. Get emergency medical help. P362+P364 Take off contaminated clothing and wash it before reuse. P403+P233 Store in a well-ventilated place. Keep container tightly closed. P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code	29350090
Storage Class	11 - Combustible Solids
WGK (Germany)	2

Other Names

Industries

Pharmaceuticals & Healthcare