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Trimethoprim stands as a trusted synthetic antimicrobial compound, often used to treat bacterial infections in both clinical and veterinary settings. Its significance stretches from prescription medicine for urinary tract infections to essential status on the WHO Model List of Essential Medicines. The molecule falls under the chemical class of diaminopyrimidines, structured to halt the growth of specific bacteria by interfering with their folic acid synthesis pathways.
Trimethoprim features the chemical formula C14H18N4O3, defined by a characteristic pyrimidine ring. Examining its molecular design, TMP displays a core 2,4-diaminopyrimidine connected through a methoxybenzyl group. This blueprint delivers the selective inhibition of bacterial dihydrofolate reductase, making it valuable in combination with other antimicrobials such as sulfamethoxazole. Its molecular weight clocks in at 290.32 g/mol, and its structure suits research as well as practical pharmaceutical applications.
At room temperature, pure TMP appears as an off-white to pale yellow crystalline powder, known for a perception of transparency when closely inspected under light. Its physical state remains solid under standard conditions. Tiny, flat flakes can often be seen under magnification, sometimes taking on a fine powder form suitable for blending into tablet or capsule formulations. Its measured density hovers around 1.36 g/cm³, contributing to its stability in both dry storage and handled processing. TMP only slightly dissolves in water, although it shows increased solubility in dimethyl sulfoxide or ethanol, giving chemists options for solution preparation.
Pharmaceutical-grade TMP arrives with tight purity specifications: the standard assay exceeds 99% by high-performance liquid chromatography (HPLC) methods. As raw material, industry packs TMP in fiber drums lined with double-layer polyethylene bags, usually in 25-kilogram units to protect from moisture, sunlight, and airborne contaminants. Some laboratories receive TMP in smaller amounts—down to gram or milligram scales—mainly for research or diagnostic use. Whether as powder, compressed flakes, or crystals, the appearance signals proper production and adherence to quality controls highlighted by pharmacopoeias in the United States, Europe, and China. Specific surface area, residual solvent content, and pH of the solution inform downstream manufacturing choices.
International shipments and documentation use HS Code 29335995 for TMP and its similar chemical substances. Customs authorities and importers rely on this code when moving raw materials across borders. Product safety information also follows the United Nations Globally Harmonized System (GHS) on chemical labeling, listing TMP as a category with potential risk for skin or eye irritation should raw powder contact unprotected tissue.
In raw material form, TMP does not meet the same hazard level as many industrial chemicals, but improper handling can still pose harm. Dusting during transfer or mixing may cause respiratory irritation; contact with exposed skin or eyes brings about mild discomfort in some cases. Safe handling practices—wearing gloves, eye protection, respiratory masks when airborne powders present—create a practical barrier against unwanted exposure. Accidental inhalation or ingestion, while unlikely to trigger immediate severe consequences, must be treated with precaution, especially among sensitive individuals or anyone with pre-existing respiratory challenges.
Within pharmaceutical industries, TMP serves as a critical raw material for various formulations. Hospitals count on finished tablets and suspensions, while diagnostic labs make use of TMP-containing growth media. Veterinary medicine adds value to livestock management, ensuring farmers can address bacterial infections in cattle, poultry, and companion animals. R&D professionals depend on TMP as a test compound when screening new antibiotics, tying its quality directly to the integrity of experimental results. Even a minor impurity or inconsistency in density or assay can ripple through downstream use, so producers keep rigid control throughout the supply chain.
Trimethoprim in storage rarely reacts with common packaging, but it does display light sensitivity and absorbs moisture from air over time, which means manufacturers and handlers keep it sealed, dry, and shielded from sunlight. In controlled laboratory environments, TMP remains stable for years if left undisturbed in amber vials or moisture-barrier bags. Finished product stocks, often stored in medical-grade environments, wait behind rigid access control to meet pharmaceutical traceability and stewardship policies.
