Trimethoprim API CAS 738-70-5 | ≥98% Antibacterial Synergist Manufacturer China

Key Selling Points

✓ Diaminopyrimidine Antibacterial - Selective Bacterial DHFR Inhibitor

✓ Gold-Standard Sulfonamide Synergist - Sequential Folate Blockade (Bactericidal)

✓ Co-Trimoxazole Partner - SMX:TMP 5:1, WHO Essential Medicine

✓ Broad Gram-Positive & Gram-Negative Spectrum - E. coli, Pasteurella, Streptococcus, Staph

✓ Excellent Oral Absorption & Tissue Distribution - Prostate, Respiratory, UTI

✓ Human & Veterinary API - UTI, Respiratory, Prostatitis, PJP Prophylaxis

What Is Trimethoprim Powder?

Trimethoprim Powder (TMP) is a synthetic diaminopyrimidine antibacterial, chemically 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine. It is best known as the diaminopyrimidine component of co-trimoxazole - the fixed 5:1 combination with sulfamethoxazole (SMX), listed on the WHO Model List of Essential Medicines - and is also paired with sulfadiazine (co-trimazine) and sulfadoxine (co-trimoxine).

It is used alone for uncomplicated UTI and prostatitis, and in combination with SMX for respiratory infections, traveler's diarrhea, and the prophylaxis/treatment of Pneumocystis jirovecii pneumonia (PJP), toxoplasmosis and nocardiosis. In veterinary practice it is formulated with sulfonamides for respiratory, GI and urinary infections in cattle, sheep, pigs, poultry, dogs and cats caused by susceptible organisms. Alone bacteriostatic; its value lies in selective inhibition of bacterial DHFR (~50,000-fold affinity over mammalian DHFR). Well absorbed orally, good tissue distribution (including prostate), half-life ~8–12 hours. High/prolonged doses may cause folate deficiency (manageable with folinic acid); most serious co-trimoxazole adverse effects are sulfonamide-related.

How Does Trimethoprim Powder Work?

Trimethoprim Powder selectively and reversibly inhibits bacterial dihydrofolate reductase (DHFR), blocking conversion of dihydrofolic acid (DHF) to tetrahydrofolic acid (THF) - the active folate coenzyme for purine, thymidine and amino acid synthesis. Because Trimethoprim Powder binds bacterial DHFR far more tightly than mammalian DHFR, it depletes THF selectively in microorganisms, arresting DNA replication. Alone bacteriostatic.

Its defining feature is synergy with sulfonamides: sulfonamides inhibit DHPS at the preceding folate step, while TMP blocks DHFR at the next - a sequential blockade that converts bacteriostasis to bactericidal activity, broadens spectrum and slows resistance. Optimal tissue ratio ~1:20 (TMP:sulfonamide), achieved with a 1:5 oral fixed dose. Active against Gram-positive (Staphylococcus, Streptococcus, Listeria) and Gram-negative (E. coli, Klebsiella, Proteus, Salmonella, Pasteurella) organisms, plus P. jirovecii and T. gondii with SMX. Renal excretion; dose adjustment in significant renal impairment.

What Are the Applications of Trimethoprim Powder?

Urinary Tract Infections: Uncomplicated UTI caused by susceptible E. coli and other Gram-negative uropathogens (used alone or as co-trimoxazole).
Respiratory Tract Infections: Acute exacerbations of chronic bronchitis, sinusitis and pneumonia, typically as co-trimoxazole or potentiated sulfonamide combinations.
Pneumocystis jirovecii Pneumonia (PJP): Prophylaxis and treatment in immunocompromised patients - the gold-standard indication for co-trimoxazole.
Veterinary Infections: Formulated with sulfonamides for bovine respiratory disease (Pasteurella, Mannheimia), swine pleuropneumonia (Actinobacillus, Streptococcus suis), poultry colibacillosis and pasteurellosis, and canine/feline UTI, skin and respiratory infections.
Gastrointestinal Infections: Traveler's diarrhea (ETEC), shigellosis and other susceptible bacterial enteritides.

What Is the Difference Between Trimethoprim and Sulfamethoxazole?

Feature	Trimethoprim	Sulfamethoxazole
CAS	738-70-5	723-46-6
Class	Diaminopyrimidine	Sulfonamide
Target Enzyme	DHFR (dihydrofolate reductase)	DHPS (dihydropteroate synthase)
Pathway Step	DHF → THF	PABA → DHF
Alone	Bacteriostatic	Bacteriostatic
Combined	Sequential blockade → bactericidal	Sequential blockade → bactericidal
Half-Life	8–12 hours	10–12 hours
Selective Toxicity	High (bacterial DHFR)	High (bacteria synthesize folate)
Primary Adverse Effect	Folate deficiency (high dose)	Hypersensitivity/SJS, crystalluria

How Does Trimethoprim Compare With Other Diaminopyrimidines?

Feature	Trimethoprim	Ormetoprim	Diaveridine	Pyrimethamine
CAS	738-70-5	6981-18-6	5355-16-8	58-14-0
Primary Use	Human + veterinary broad	Veterinary (poultry)	Veterinary (poultry coccidia)	Human (toxoplasma, malaria)
Typical Partner	Sulfamethoxazole	Sulfadimethoxine	Sulfadimidine	Sulfadiazine
Bacterial DHFR Selectivity	High	High	Moderate	Lower (antiprotozoal)
Half-Life	8–12 hr	~6 hr	Short	~4 days (long)
PJP Activity	Yes (with SMX)	No	No	Yes (with SD)
Veterinary Use	All species	Poultry	Poultry/coccidia	Dog/cat toxoplasma

How Is Trimethoprim Powder Manufactured?

Trimethoprim Powder is manufactured through chemical synthesis involving condensation of 3,4,5-trimethoxybenzaldehyde with a guanidine/pyrimidine intermediate, followed by reduction and purification.

Raw Material QC → 3,4,5-Trimethoxybenzaldehyde Preparation → Condensation with 2,4-Diaminopyrimidine Intermediate → Reduction / Cyclization → Crude Trimethoprim → Purification (Recrystallization from Ethanol/Water) → Drying → Milling → Final QC → Packaging

HDM BIO controls key condensation, reduction and crystallization parameters to maintain consistent purity and batch quality.

Quality Specifications

Test Item	Standard	Typical Result
Appearance	White to off-white powder	Consistent
Assay (HPLC)	≥98.0%	99.0%
Identity (IR)	Conforms to reference standard	Confirmed
Melting Point	199–203°C	201°C
Loss on Drying	≤0.5%	0.2%
Residue on Ignition	≤0.1%	Compliant
Heavy Metals	≤10 ppm	Compliant
Arsenic	≤2 ppm	Compliant
Related Substances	Within specification	Pass
Residual Solvents	Within specification	Pass

What Quality Control Tests Are Performed for Trimethoprim Powder?

Each batch undergoes multi-step quality control before release to verify identity, purity and physical properties.

Raw Material QC → In-Process Control → HPLC Assay → IR Identity Verification → Melting Point Determination → Related Substances (HPLC) → Loss on Drying → Heavy Metals → Arsenic → Residue on Ignition → Residual Solvents → Final Batch Release

Key evaluations include identification via infrared (IR) spectroscopy, HPLC active content assay, melting point determination, related substances analysis, loss on drying, heavy metal and arsenic limits, residue on ignition and residual solvent testing. Every commercial batch is supported by a batch-specific COA and relevant analytical documentation for incoming QC and supplier qualification.

What Factors Affect Trimethoprim Powder Bulk Price?

Trimethoprim Powder bulk pricing is driven by several key factors:

Synthesis Costs: Multi-step chemical synthesis including trimethoxybenzaldehyde condensation and pyrimidine cyclization directly influences manufacturing expenses.
Purity & Grade: Higher purity (≥99%) and pharmaceutical-grade (USP/EP) batches command premiums over standard grade.
Regulatory Compliance & Certification: GMP-standard API batches with DMF/CEP and consistent COA demand a higher price.
Order Volume: Large-scale pharmaceutical contracts receive steeper per-kilogram discounts than small-batch orders.
Logistics & Geography: Cool storage / light-protected packaging requirements and customs compliance add to the landed cost.

Contact HDM BIO for a current quotation and volume-based pricing.

Why Choose HDM BIO as Your Trimethoprim Powder Supplier?

High-purity (≥98% / typical 99%) diaminopyrimidine DHFR inhibitor with proven sulfonamide synergy
Gold-standard co-trimoxazole partner - 5:1 SMX:TMP, WHO Essential Medicine
Broad-spectrum activity with excellent oral absorption and tissue distribution (including prostate)
GMP-aligned production, ISO & HACCP certified quality system
Full batch traceability and complete documentation (COA, MSDS, HPLC)
Flexible supply: kilogram samples to ton-level bulk orders
Global export to 70+ countries with full customs support

Bulk Packaging, Shipping & Storage

Packaging: Foil bags for samples and moisture-proof fiber drums for bulk orders.
Custom Packaging: OEM labeling available.
Shipping Documents: COA, MSDS/SDS, commercial invoice, packing list and customs documentation available according to order requirements.
Storage: Store tightly sealed in a cool, dry, light-protected environment. Shelf life: 24 months.
Handling: For veterinary raw material use only; not for direct clinical administration.

Frequently Asked Questions About Trimethoprim Powder

Q1: What is Trimethoprim Powder?

A: A synthetic diaminopyrimidine antibacterial (TMP) that selectively inhibits bacterial dihydrofolate reductase (DHFR), best known as the partner of sulfamethoxazole in co-trimoxazole.

Q2: What is the CAS number?

A: 738-70-5.

Q3: How does trimethoprim work?

A: It reversibly inhibits bacterial DHFR, blocking conversion of DHF to THF. With sulfonamides (which inhibit DHPS at the preceding step), it creates a sequential folate pathway blockade with bactericidal synergy.

Q4: What is co-trimoxazole?

A: The fixed combination of trimethoprim and sulfamethoxazole in a 1:5 ratio (e.g., 80 mg/400 mg or 160 mg/800 mg), which is bactericidal and listed as a WHO Essential Medicine.

Q5: What is trimethoprim used for?

A: Urinary tract infections, prostatitis, respiratory infections, traveler's diarrhea, and - as co-trimoxazole - PJP prophylaxis/treatment, toxoplasmosis and nocardiosis. In veterinary: potentiated sulfonamide formulations for respiratory/GI/UTI in livestock and pets.

Q6: What documents are provided with each batch?

A: Batch-specific COA, HPLC report, IR identity records, melting point data, MSDS/SDS and relevant export documentation.

Q7: What purity do you supply?

A: Standard ≥98% HPLC; typical batch result 99%. USP/EP-grade available on request.

Q8: Where can I buy it from China?

A: HDM BIO supplies bulk Trimethoprim Powder with batch COA and global export support.

Q9: How much does Trimethoprim Powder cost?

A: Bulk pricing depends on synthesis costs, purity/grade, regulatory compliance, order volume and logistics. Contact HDM BIO for a current quotation.

Q10: Are there any safety concerns?

A: Trimethoprim is generally well tolerated, but high or prolonged doses may cause folate deficiency (megaloblastic anemia, leukopenia, thrombocytopenia), manageable with folinic acid. Most serious adverse effects in co-trimoxazole are attributable to the sulfonamide component. Dose adjustment required in renal impairment. Not for direct clinical administration.