Description
Trimethoprim Lactate — Antibacterial DHFR Inhibitor (Research Grade)
Trimethoprim Lactate is the lactate salt form of trimethoprim, a potent small molecule inhibitor of bacterial dihydrofolate reductase (DHFR). This compound is frequently used in microbiology, antibiotic development, and molecular biology assays to suppress bacterial growth, select for plasmid maintenance, or study folate metabolism.
Key Specifications & Identity
| Property |
Value / Description |
| Synonyms / Alternate Names |
Trimethoprim lactate salt; Lactic Trimethoprim; 2-hydroxypropanoate salt of trimethoprim
|
| CAS Number |
23256-42-0
|
| Molecular Formula |
C₁₇H₂₄N₄O₆
|
|
Molecular Weight
|
~380.4 g/mol
|
| PubChem Chemical ID: |
3084396 |
| Appearance / Form |
White to off-white crystalline powder
|
| Solubility |
Water soluble — ~20 mg/mL in water
|
| Melting Point |
~170–172 °C
|
| Storage / Handling |
Store in dark, cool conditions (2–8 °C), protected from moisture and light |
Mechanism of Action & Biological Function
-
Trimethoprim lactate acts by inhibiting bacterial dihydrofolate reductase (DHFR), preventing the reduction of dihydrofolate to tetrahydrofolate (THF). This interrupts de novo folate biosynthesis, impeding thymidine and nucleotide synthesis and thereby suppressing bacterial DNA replication.
-
Because bacterial DHFR is much more sensitive to trimethoprim than human DHFR, this selectivity enables antibacterial activity with lower host toxicity.
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Trimethoprim is primarily bacteriostatic alone; however, when combined with sulfonamides (which block an upstream folate pathway enzyme), the two act synergistically to produce a bactericidal effect in many cases.
Suggested Applications & Usage Notes
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Selective media / plasmid maintenance: Use trimethoprim lactate in bacterial culture media to maintain plasmids or select for resistant clones.
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MIC / susceptibility assays: Employ as a standard antibiotic in minimum inhibitory concentration (MIC) testing or resistance profiling against Gram‐positive and Gram‐negative strains.
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Folate metabolism / DHFR studies: Use in enzymology or metabolic flux experiments probing folate pathways, rescue experiments (e.g. with exogenous thymidine), or DHFR inhibition kinetics.
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Combination / synergy assays: Combine with sulfonamides or other antifolates to explore synergy, resistance, or drug interactions.
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Plant / cell culture antimicrobial: In plant tissue culture, trimethoprim lactate may be used (sometimes with other antibiotics) to suppress bacterial contamination without strong phytotoxicity.
Practical Tips
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Always dissolve and dilute fresh stock just prior to use to maintain potency.
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Validate working concentration via pilot tests: typical bacterial selection ranges are often in the low µg/mL scale (varies by organism).
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Include proper negative controls and, where possible, rescue controls (e.g. exogenous thymidine) to confirm specificity.
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Because it is light sensitive and may degrade, protect stock solutions from light and store in airtight containers.
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Be aware of cross-resistance or baseline resistance in some strains (i.e. verify susceptibility beforehand).
Safety & Disclaimer
This product is for research use only, not for diagnostic or therapeutic use.
Handle according to standard laboratory safety protocols: wear gloves, eye protection, lab coat, and work in a well-ventilated area. Avoid inhalation, ingestion, or direct contact with skin or eyes.
Dispose of waste and unused material in accordance with institutional and environmental safety guidelines.
PubChem Chemical ID: 3084396
