Trimethoprim lactate (NSC-106568 lactate) is an antibiotic that inhibits bacterial dihydrofolate reductase (DHFR). Trimethoprim lactate has demonstrated antimicrobial activity, with excellent inhibition of Gramnegative bacteria. Trimethoprim lactate is used alone for the Trimethoprim lactate is used alone or in combination with other antibiotics to treat a variety of eye, lung, and gastrointestinal infections.

Trimethoprim lactate interferes with folate metabolism by inhibiting dihydrofolate reductase (DHFR) activity, thereby preventing the reduction of dihydrofolate to tetrahydrofolate (THF). In E. coli cells, Trimethoprim lactate causes protein aggregation and induces major heat shock proteins (Hsps), suggesting that its presence leads to protein misfolding.Trimethoprim lactate induces the expression of the heat shock proteins DnaK, DnaJ, GroEL, ClpB, and IbpA/B, of which IbpA/B was most significantly induced and co-aggregated with insoluble proteins. [1]

In an intraperitoneal infection assay in mice, the CD50 values of Trimethoprim lactate against Haemophilus influenzae, Streptococcus pneumoniae, Escherichia coli, and Neisseria meningitidis were 150 mg/kg, 335 mg/kg, 27.5 mg/kg, and 8.4 mg/kg, respectively. When conjugated with thiomaltose (TM-TMP), Trimethoprim lactate maintains stability in complete serum, with a half-life of approximately one hour, and shows an MIC of about 1 μM against E. coli [2].