In vivo activity of epiroprim, a dihydrofolate reductase inhibitor, singly and in combination with dapsone, against Mycobacterium leprae.

The antimicrobial effects of a new dihydrofolate reductase inhibitor, epiroprim, either singly or in combination with dapsone against Mycobacterium leprae, were evaluated in vivo using a mouse footpad model. When fed to mice at concentration of 0.05% in diet, epiroprim completely inhibited the growth of both dapsone-sensitive and dapsone-resistant strains of M. leprae in the footpads of mice and the effects were bactericidal. To achieve similar effects, the concentration of dapsone in the diet had to be 0.0005 and 0.01%, respectively. When used in combination, the concentrations of the drugs in the diet could be lowered by 50-80% and still achieve bactericidal effects. The data support the earlier results on in vitro studies and suggest the use of epiroprim in the multidrug regimen in the treatment of leprosy.

In vitro activity of epiroprim, a dihydrofolate reductase inhibitor, singly and in combination with brodimoprim and dapsone, against Mycobacterium leprae.

The antimicrobial effects of a new dihydrofolate reductase inhibitor, epiroprim, alone and in combination with dapsone and brodimoprim against Mycobacterium leprae were evaluated in vitro in cell-free culture system. Two biochemical parameters were used to measure metabolic activity (and growth) of the organism. The minimal inhibitory activity of epiroprim against M. leprae was 10 mg/l and the action was bactericidal. When combined with dapsone, epiroprim exhibited a strong synergism; on the other hand, combination of epiroprim and brodimoprim provided only additive effects. The results suggest that epiroprim can be a component in multidrug therapy regimen in leprosy.

In vitro and in vivo results of brodimoprim and analogues alone and in combination against E. coli and mycobacteria.

New diaminodiphenylsulfone inhibitors of dihydropteroate synthase are described with increased inhibitory activity against mycobacteria and plasmodia, whereas their side effect of methemoglobin formation could be suppressed. The optimization of diaminobenzylpyrimidines, inhibitors of dihydrofolate reductase, led to derivatives with increased inhibitory effect against mycobacteria, especially M. leprae and plasmodia. Some of these derivatives show autosynergism. Finally the combination of brodimoprim (BDP) and dapsone (DDS) was developed for the treatment of leprosy. First clinical trials in Paraguay and Ethiopia show that combinations of BDP/DDS and BDP/DDS plus rifampicin were highly effective and may become an alternative multi-drug therapy for the treatment of leprosy. The tolerance of the regimens used was generally good.

In vitro and in vivo experiments with the new inhibitor of mycobacterium leprae brodimoprim alone and in combination with dapsone.

The antibacterial effect of brodimoprim alone and in combination with dapsone has been studied in vitro in cell-free systems and in whole mycobacterial cells as well as in vivo in mice and humans. The obtained inhibitory effects in vitro and in vivo against model mycobacterial strains and M. leprae, the pharmacokinetic properties in human and its synergistic effect with the most used drug in the chemotherapy of leprosy, dapsone, make brodimoprim a promising candidate in the therapy of leprosy.

Effect of brodimoprim on Mycobacterium leprae in vitro and in mouse foot-pads.

The new in vitro screening system reported earlier was adopted to determine anti-M. leprae activity of a dihydrofolate reductase inhibitor, brodimoprim, and the results were compared with those obtained using mouse foot-pad technique. Even though the MIC of brodimoprim against M. leprae was very high compared to other commonly used anti-leprosy drugs, in combination with dapsone it showed a remarkable synergistic activity in inhibiting the growth of M. leprae at concentrations much lower than the MICs of each of the drugs used singly. Similar effects were also demonstrated in mouse foot-pad experiments.

Bacterial growth kinetics of Escherichia coli and mycobacteria in the presence of brodimoprim and metioprim alone and in combination with sulfamerazine and dapsone (VI).

Bacterial growth kinetics and checkerboard titration experiments have been performed to determine the inhibitory power of metioprim (I) and brodimoprim (II) alone and in combination with diaminodiphenylsulfone (DDS) using Escherichia coli and mycobacteria as test organisms. The evaluated potency of the new TMP derivatives alone and in combination is compared to TMP and other derivatives. A strongly synergistic activity of I and II in combination with DDS against E. coli and various mycobacteria is observed which is also operative in case of highly DDS-resistant mycobacterial strains. The implication of these findings for the development of a combined chemotherapy with these drugs against atypical mycobacterial infections - especially leprosy - is discussed.