Trimethoprim lactate is a synthetic derivative of trimethoxybenzyl-pyrimidine with bacteriostatic and antiprotozoal properties. As a pyrimidine inhibitor of bacterial dihydrofolate reductase, trimethoprim binds tightly to the bacterial enzyme, blocking the production of tetrahydrofolic acid from dihydrofolic acid, arresting folic acid synthesis. When Trimethroprim lactate is combined with sulfonamides (like sulfamethoxazole (S045))the two compounds show bactericidal effects, but are only bacteriostatic when used separately. The activity is attributed to their synergistic effect in inhibiting folic acid metabolism in bacteria. Trimethoprim lactate has a wide antibacterial spectrum and is active against most gram-positive and gram-negative aerobic bacteria, including Nocardia, Brucella, Gram-negative bacilli, and some Gram-positive bacteria like Streptococcus, Toxoplasma and some other coccidians. It is used to treat recurrent cystitis, mild acute prostatitis, urinary tract infections, asymptomatic bacteriuria during pregnancy and respiratory tract infections. TOKU-E offers two forms of trimethoprim: trimethoprim (T011) and trimethoprim lactate (T012). Trimethoprim is slightly soluble in aqueous solution (12.1 mg/mL). Trimethoprim lactate is freely soluble in aqueous solution (19.6 mg/mL).