Chemotrim; Idotrim; Monotrim; Primosept; Primsol; Proloprim; 2,4-Diamino-5-(3,4,5-trimethoxybenzyl)
pyrimidine; Lidaprim; Methoprim; 5-((3,4,5-Trimethoxyphenyl)methyl)-2,4-pyrimidinediamine; Syraprim; Tiempe; TMP-Ratiopharm; Trimanyl; Trimethoprim; Trimexazole; Trimogal; Trimetoprima; 5-(3,4,5-trimetoxibencil)pirimidina-2,4-diamina (Spanish); 
Triméthoprime; 5-(3,4,5-triméthoxybenzyl)
pyrimidine-2,4-diamine (French); 5-(3,4,5-Trimethoxybenzyl)-2,4- DiaminoPyrimidine; 5-(3,4,5-Trimethoxybenzyl) pyrimidin-2,4-diamin (German);

























white to yellowish powder.



Trimethoprim, an antibacterial drug, is a bacterial dihydrofolate reductase inhibitor used as a prophylactic or to treat various bacterial infections particularly urinary tract infections such as Proteus mirabilis, Escherichia coli, and Klebsiella species as well as Pneumocystis carinii and traveler's diarrhea.



APPEARANCE: white to yellowish powder

ASSAY: 99.0 - 101.0%

LOSS ON DRYING: 0.5% max


PARTICLE SIZE: 80 - 100 (mesh

Packing: 25kg/drum

Storage: Keep container tightly closed. Keep container in a cool, well-ventilated area. Sensitive to light. Store in light-resistant containers.








Section 1: Chemical Product and Company Identification

Product Name: Trimethoprim

CAS#: 738-70-5

Synonym: Trimopan; Trimpex; Trimanyl;


Chemical Name: Trimethoprim

Chemical Formula: C14-H18-N4-O3

Section 2: Composition and Information on Ingredients


Name           CAS #    % by Weight

Trimethoprim    738-70-5       100

Toxicological Data on Ingredients: Trimethoprim: ORAL (LD50): Acute: >5300 mg/kg [Rat]. 2764 mg/kg [Mouse].

Section 3: Hazards Identification

Potential Acute Health Effects: Slightly hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation.

Potential Chronic Health Effects:


MUTAGENIC EFFECTS: Mutagenic for bacteria and/or yeast.



The substance may be toxic to blood, bone marrow.

Repeated or prolonged exposure to the substance can produce target organs damage.

Section 4: First Aid Measures

Eye Contact:

Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Cold water may be used. WARM water MUST be used. Get medical attention if irritation


Skin Contact: Wash with soap and water. Cover the irritated skin with an emollient. Get medical attention if irritation develops.

Serious Skin Contact: Not available.


If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention.

Serious Inhalation: Not available.


Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an

unconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention if

symptoms appear.

Serious Ingestion: Not available.

Section 5: Fire and Explosion Data

Flammability of the Product: May be combustible at high temperature.

Auto-Ignition Temperature: Not available.

Flash Points: Not available.

Flammable Limits: Not available.

Products of Combustion: These products are carbon oxides (CO, CO2), nitrogen oxides (NO, NO2...).

Fire Hazards in Presence of Various Substances:

Slightly flammable to flammable in presence of heat.

Non-flammable in presence of shocks.

Explosion Hazards in Presence of Various Substances:

Risks of explosion of the product in presence of mechanical impact: Not available.

Risks of explosion of the product in presence of static discharge: Not available.

Fire Fighting Media and Instructions:

SMALL FIRE: Use DRY chemical powder.

LARGE FIRE: Use water spray, fog or foam. Do not use water jet.

Special Remarks on Fire Hazards:

As with most organic solids, fire is possible at elevated temperatures.

When heated to decomposition it emits toxic fumes of nitrogen oxides.

Special Remarks on Explosion Hazards: Not available.

Section 6: Accidental Release Measures

Small Spill:

Use appropriate tools to put the spilled solid in a convenient waste disposal container. Finish cleaning by

spreading water on the contaminated surface and dispose of according to local and regional authority


Large Spill:

Use a shovel to put the material into a convenient waste disposal container. Finish cleaning by spreading water on the contaminated surface and allow to evacuate through the sanitary system.

Section 7: Handling and Storage


Keep away from heat. Keep away from sources of ignition. Ground all equipment containing material. Do not

ingest. Do not breathe dust. Wear suitable protective clothing. If ingested, seek medical advice immediately and show the container or the label. Keep away from incompatibles such as oxidizing agents.


Keep container tightly closed. Keep container in a cool, well-ventilated area. Sensitive to light. Store in

light-resistant containers.

Section 8: Exposure Controls/Personal Protection

Engineering Controls:

Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below

recommended exposure limits. If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit.

Personal Protection: Safety glasses. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent.


Personal Protection in Case of a Large Spill:

Splash goggles. Full suit. Dust respirator. Boots. Gloves. A self contained breathing apparatus should be used to avoid inhalation of the product. Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.

Exposure Limits: Not available.

Section 9: Physical and Chemical Properties

Physical state and appearance: Solid. (Crystalline powder.)

Odor: Odorless.

Taste: Bitter.

Molecular Weight: 290.32 g/mole

Color: White. Off-white.

pH (1% soln/water): Not available.

Boiling Point: Not available.

Melting Point: 199°C (390.2°F)

Critical Temperature: Not available.

Specific Gravity: Not available.

Vapor Pressure: Not applicable.

Vapor Density: Not available.

Volatility: Not available.

Odor Threshold: Not available.

Water/Oil Dist. Coeff.: The product is more soluble in oil; log(oil/water) = 0.9

Ionicity (in Water): Not available.

Dispersion Properties: See solubility in water, methanol.


Partially soluble in methanol.

Very slightly soluble in cold water.

Insoluble in diethyl ether.

Slightly soluble in alcohol.

Soluble in N,N-dimethylacetamide (DMCA) at 13.86; benzyl alcohol at 7.29; propylene glycol at 2.57; chloroform at 1.82; methanol at 1.21; ether at .003; benzene at .002 g/ml at 25 deg. C.

Solubility in water: 400 mg/l @ 25 deg. C.

Section 10: Stability and Reactivity Data

Stability: The product is stable.

Instability Temperature: Not available.

Conditions of Instability: Heat, incompatible materials, moisture, light

Incompatibility with various substances: Reactive with oxidizing agents.

Corrosivity: Not available.

Special Remarks on Reactivity: Sensitive to light.

Special Remarks on Corrosivity: Not available.

Polymerization: Will not occur.

Section 11: Toxicological Information

Routes of Entry: Inhalation. Ingestion.

Toxicity to Animals: Acute oral toxicity (LD50): 2764 mg/kg [Mouse].

Chronic Effects on Humans:

MUTAGENIC EFFECTS: Mutagenic for bacteria and/or yeast.

May cause damage to the following organs: blood, bone marrow.

Other Toxic Effects on Humans: Slightly hazardous in case of skin contact (irritant), of ingestion, of inhalation.

Special Remarks on Toxicity to Animals: Not available.

Special Remarks on Chronic Effects on Humans:

May affect genetic material (mutagenic).

May cause adverse reproductive effects (post implantation mortality, fetotoxicity) based on animal data.

Special Remarks on other Toxic Effects on Humans:

Acute Potential Health Effects:

Skin: May cause skin irritation.

Eyes: May cause eye irritation.

Inhalation: May cause respiratory tract irritation.

Ingestion: May cause gastrointestinal tract irritation with stomach cramps, abdominal pain, nausea, vomiting,

diarrhea. May also cause alteration in taste, anorexia, skin rash, dizziness, headache, mental depression,

confusion. It may affect the cardiovascular system (blood pressure lowering), blood (thrombocytopenia), urinary system (hematuria), musculosketal system (joints), metabolism (hyperkalemia).

Chronic Potential Health Effects:

Ingestion: Prolonged or repeated ingestion of high doses may the blood (changes in bone marrow), brain, and

metabolism (weight loss or decreased weight gain, hyperkalemia (abnormally high levels of potassium in the

blood). Possible allergic reaction if inhaled, ingested or in contact with skin.

Medical Conditions Aggravated by Exposure: Hypersensitivity to material, impaired kidney function, and

megaloblastic anemia due to folic acid deficiency.

Section 12: Ecological Information

Ecotoxicity: Not available.

BOD5 and COD: Not available.

Products of Biodegradation:

Possibly hazardous short term degradation products are not likely. However, long term degradation products may arise.

Toxicity of the Products of Biodegradation: The product itself and its products of degradation are not toxic.

Special Remarks on the Products of Biodegradation: Not available.

Section 13: Disposal Considerations

Waste Disposal:

Waste must be disposed of in accordance with federal, state and local environmental

control regulations.

Section 14: Transport Information

DOT Classification: Not a DOT controlled material (United States).

Identification: Not applicable.

Special Provisions for Transport: Not applicable.


Section 15: Other Regulatory Information

Federal and State Regulations: New Jersey: Trimethoprim

Other Regulations:

OSHA: Hazardous by definition of Hazard Communication Standard (29 CFR 1910.1200).

EINECS: This product is on the European Inventory of Existing Commercial Chemical Substances.

Other Classifications:

WHMIS (Canada): Not controlled under WHMIS (Canada).


Not available

Not applicable.

HMIS (U.S.A.):

Health Hazard: 1

Fire Hazard: 1

Reactivity: 0

Personal Protection: E

National Fire Protection Association (U.S.A.):

Health: 1

Flammability: 1

Reactivity: 0

Specific hazard:

Protective Equipment:


Lab coat.

Dust respirator. Be sure to use an

approved/certified respirator or


Safety glasses.

Section 16: Other Information

References: Not available.

Other Special Considerations: Not available.


Folic acid is essential for hematopoiesis. It is reduced to dihydrofolic acid and then tetrahydrofolic acid , the parent compound of the derivatives that act as coenzyme carriers of one-carbon groups in various metabolic reactions. In result, trimethoprim interferes the synthesis of tetrahydrofolic acid resulting the inhibition of the DNA nucleoside synthesis. It is usually used in combination with a sulfonamide drug, sulfamethoxazole for synergistic effect (in the ratio 1:5). The molecular structure of sulfonamide class antimicrobial agents is similar to p-Aminobenzoic acid (PABA) which is needed in bacteria organisms as a substrate of the enzyme dihydropteroate synthetase for the synthesis of tetrahydrofolic acid (THF).
Sulfonamides are capable of interfering with the metabolic processes in bacteria that require PABA. The combination drug interferes with sequential steps in the metabolism of certain bacteria.  But the use of sulfamethoxazole is declining due to reports of sulfamethoxazole bone marrow toxicity. The trade names of the combined product are Bactrim and Septra. The chemical designation of trimethoprim is 5-[(3, 4, 5-trimethoxyphenyl)methyl]-2, 4-pyrimidine diamine. It is a white to yellowish compound with bitter taste.  Sulfamethoxazole is 4-amino-N-(5-methyl-3-isoxazolyl) benzenesulfonamide or (N1-(5-methyl-3-Isoxazolyl) Sulfanilamide). It is an white to off-white compound, odorless, tasteless. Dapsone (4,4'-sulfonylbisbenzenamine) is a parent compound in preparing sulfonamide antibacterial agents such as acedapsone, acetosulfone, glucosulfone, sulfoxone and solapsone. Dapsone and its derivatives have bacteriostatic activity against a broad spectrum of gram-negative and gram-positive organisms. Dapsone is a primary treatment for Dermatitis herpetiformis and in the treatment of leprosy (Mycobacterium leprae infections) leads to apparent improvementas. It is used in the prophylaxis of falciparum malaria. It is a white crystalline powder; melting point 175 - 180C; insoluble in water and vegetable oils. Pentamidine is also used for the patients who are allergic to trimethoprim or sulfamethoxazole. Pentamidine is an antiprotozoal agent used as the isethionate salt to preventi and treat diverse phylum of eukaryotic microorganisms. It is a nonpyrogenic, lyophilized product. Pentamidine isethionate is a white crystalline powder; soluble in water and glycerin; insoluble in ether, acetone, and chloroform. The chemical designation is 4,4'- diamidino-diphenoxypentane di(beta-hydroxyethanesulfonate).