Synthesis, characterization, microbiological evaluation, genotoxicity and synergism tests of new nano silver complexes with sulfamoxole: X-ray diffraction of [Ag2(SMX)2]·DMSO.

The synthesis and microbiological evaluation of two new Ag(I) complexes with sulfamoxole (SMX), [Ag2(SMX)2]·H2O and [Ag4(SCN)3(SMX)]·H2O are described. Both were characterized by elemental analysis, thermogravimetry, powder and single crystal X-ray diffraction, NMR, Raman and experimental and theoretical IR spectroscopies. Their antibacterial and antifungal properties were evaluated by agar and broth dilution assays, respectively. In addition, synergism tests for Pseudomonas aeruginosa were performed, and genotoxicity studies were carried out employing the Allium cepa test. Both complexes displayed good activity against Escherichia coli, Staphylococcus aureus, P. aeruginosa, and 10 fungi strains, with lower minimum inhibitory concentrations (MICs) than that of free SMX in all cases. The nanometrical crystallite particle size determined from XRPD, DLS and TEM might explain the good microbiological activity in spite of the low solubility of both complexes. The fractional inhibitory concentration (FIC) calculated from the P. aeruginosa test data indicated that the activity of the complexes is not due to synergism of the free components in the concentration ratios studied. Moreover, none of the complexes displayed cytotoxic effects on onions in the concentration range tested, and chromosome aberrations were not observed.

In vitro activity of sulfonamides and sulfones against Leishmania major promastigotes.

We examined the susceptibility of promastigotes of Leishmania major to sulfonamides and sulfones in vitro. In a completely defined medium only sulfamoxole, sulfaquinoxaline, and dapsone were inhibitory; the concentrations required for 50% inhibition of the rate of growth were 150, 600, and 600 microM, respectively. Eleven other sulfa drugs were ineffective at concentrations up to 2 mM. The growth inhibition was similar to that observed in procaryotes: the cells continued logarithmic growth for several cell doublings before inhibition was observed. Surprisingly, the addition of p-aminobenzoate or folate did not reverse the effects of the active sulfa drugs, the effects of sulfamoxole and methotrexate were additive rather than synergistic, and the addition of thymidine reversed methotrexate but not sulfa-drug inhibition. These results suggest that the mode of action of sulfa drugs on L. major is not by the classical route of inhibition of de novo folate synthesis. Promastigotes could be propagated for more than 40 passages in a completely defined medium in which the only added pterin was biopterin. The folate concentration in this medium was less than 10(-10) to 10(-11) M, as determined by a Leishmania bioassay. Although these data suggest that L. major may be capable of de novo synthesis of folate, the nonclassical mode of action of sulfa drugs, as well as other studies, favors the view that L. major is auxotrophic for folate.

In vitro studies with combinations of sulfamoxole and trimethoprim (co-trifamole).

Chequerboard studies with sulfamoxole and trimethoprim against urinary pathogens showed that the combination was never antagonistic but usually showed little or no synergistic effect. An exception was with the inherently sulphonamide-resistant Strep. faecalis in which marked synergism (F.I.C. Index less than 0.3) was shown with all strains tested. This synergism is thought to be clinically relevant. Experiments were undertaken with a new in vitro test system to establish whether the combination of sulfamoxole with trimethoprim will prevent the emergence of bacterial resistance. Using concentrations of the drugs attained in the blood during treatment, it was shown that trimethoprim monotherapy was likely to result in the emergence of trimethoprim-resistant pathogens, whereas treatment with sulfamoxole and trimethoprim resulted in the elimination of the test bacteria without the emergence of resistance. Using urinary concentrations of drugs, the "urinary' pathogen was shown to be eliminated by trimethoprim alone or in combination with sulfamoxole, without the emergence of resistant bacteria. This would not necessarily preclude the emergence of resistant bacteria in commensal sites exposed to lesser, sun-inhibitory drug concentrations.

Effects of trimethoprim and sulphonamide preparations on the pituitary-thyroid axis of rodents.

The effects on pituitary-thyroid function of the commonly prescribed anti-bacterial preparations co-trimoxazole and co-trifamole, and their component drugs, have been studied in the rat and compared to the changes caused by propylthiouracil. Co-trimoxazole and co-trifamole, in doses 20-fold in excess of a pharmacological dose administered for 10 days, produced marked changes in hormone levels consistent with blocking of hyperplastic goitre formation, were also demonstrated. Propylthiouracil produced less marked changes of thyroid hormone levels but higher levels of thyroid-stimulating hormone. Pharmacological doses of co-trimoxazole and co-trifamole and sulphamoxole, the sulphonamide component of co-trifamole, caused significant changes in thyroid hormone levels consistent with anti-thyroidal activity. In contrast, there was no evidence that trimethoprim, which is common to both preparations, or sulphamethoxazole, the sulphonamide component of co-trimoxazole, had an anti-thyroidal action, indeed, serum thyroxine levels were significantly increased at pharmacological dosage. We have concluded that the new commonly prescribed combination preparations retain the goitrogenic properties of the earlier sulphonamides.

A comparison of the antibacterial activity of sulphonamide-trimethoprim combinations.

Sensitivity patterns of 326 clinical isolates toward sulphonamide/trimethoprim combinations were tested in vitro. The relative merits of the different combinations are discussed in their pharmacological and bacteriological contexts. It is concluded that organisms sensitive to cotrimoxazole as judged by in vitro sensitivity tests performed at 37 degrees C are also sensitive to sulphamoxole/trimethoprim.

Bactericidal or bacteristatic effects of two sulphonamide plus trimethoprim preparations in human urine.

Rrine collections were made by ten volunteers taking cotrimoxazole and a sulphamoxole/trimethoprim combination on a cross-over basis. The latter was given in approximately half the dose of cotrimoxazole. Following collection of urine and its sterile filtration, the trimethoprim and sulphonamide concentrations were estimated. The urines were then inoculated with various species of Enterobacteriaceae whose minimum inhibitory concentrations had been previously determined. The viable counts in these urines were followed for 24 hours and from these the times to kill 90% of bacteria were calculated. These were very reproducible for any one experiment but showed no correlation with drug concentration, source of the urine or organism sensitivity, except for one organism which had high resistance to both sulphonamide and trimethoprim. When the organism was sensitive to at least trimethoprim a slow bactericidal effect was generally seen with either combination. We concluded that in this type of experiment the higher dosed combination showed no advantage contrary to a previous report, but in agreement with another. This brings into question the current dosage regime of cotrimoxazole when used to treat urinary tract infections in that its higher dosage over certain other sulphonamide/trimethoprim combinations appears to confer no advantage in our experiments.

Bacteriostatic and bactericidal activity of two trimethoprim-sulfonamide combinations.

Sulfamoxole (SDMO) has the same half-life of elimination from human plasma as sulfamethoxazole. Its antibacterial properties, however, are often inferior to those of co-trimoxazole. Its less pronounced antibacterial effect, especially against gram-negative pathogens, also becomes evident in the combination with trimethoprim (TM). The inhibition zones are often smaller around discs containing the same amount of the components SDMO/TM as those with co-trimoxazole and the inhibitory concentrations needed are frequently 2-4 times higher, especially against gram-negative bacteria, such as Escherichia coli and Proteus vulgaris. Accordingly, the curative doses 50% of the new combination are 2-3 times higher than those of co-trimoxazole in experimental infections with E. coli and P. vulgaris in mice. The bactericidal action in human urine, collected after a course of treatment with the combination SDMO/TM in the planned lower dosage, is not only often retarded, but also frequently incomplete in comparison with that in urine after co-trimoxazole in standard dosage. Clinically, this might lead to increased development of resistance or to an increase of recurrent infections.

[Antimicrobial action of the combined preparation sulfamoxole/trimethoprim in vitro (author's transl)]. / Antimikrobielle Wirkung der Kombination Sulfamoxol/Trimethoprim (CN 3123) in vitro

A number of different methods were used to test the in vitro antimicrobial activity of the combination of N1-(4,5-dimethyl-2-oxazolyl)-sulfanilamide (sulfamoxole) and 2,4-diamino-5-(3,4,5-trimethoxy-benzyl)-pyrimidine (trimethoprim). 1. The minimum bacteriostatic inhibitory concentratiions of the sulfamoxole/trimethoprim combination (5 + 1) (CN 3123; Nevin; Supristol) were determined for 131 gram-positive and gram-negative strains of bacteria. More than 88% of the strains tested were found to be highly sensitive to the combination (M1C 0.1-3.75 mug/ml). 2. Comparative studies with the combinations sulfamoxole/trimethoprim and sulfamethoxazole/trimethoprim revealed no relevant differences of the M1C-values. 3. The synergistic effects of sulfamoxole and trimethoprim can be demonstrated with the aid of the agar dilution and agar diffusion tests using various types of bacteria and different ratios of sulfamoxole and trimethoprim. 4. Results obtained by studies on growth kinetics also demonstrate the synergistic and potentiating effect of combining sulfamoxole with trimethoprim and bactericidal properties are achieved.

[Pharmacological investigations with the combination sulfamoxole/trimethoprim, a new broadspectrum chemotherapeutic agent (author's transl)]. / Pharmakologische Untersuchungen zur Verträglichkeit der Kombination Sulfamoxol/Trimethoprim (CN 3123), eines neuen Breitbandchemotherapeutikums

Investigations were conducted with the combination of N1-(4,5-dimethyl-2-oxazolyl)-sulfanilamide (sulfamoxole) and 2,4-diamino-5-(3,4,5-trimethoxy-benzyl)-pyrimidine (trimethoprim) (CN 3123, Nevin, Supristol) in a dose ratio of 5:1, with respect to pharmacological activity and possible side effects. The effects obtained with the combination CN 3123 were compared with those of the single substances. In a dose range comparable to that as used in clinical treatment, there were no effects on cardiovascular or respiratory functions, on functions of autonomic and central nervous system, on contractility of smooth muscles and on data of clinical chemistry such as urine and electrolyte excretion, blood sugar, blood coagulation and liver function tests. Doses which are 5 to 10 times higher than the initial dose or 10 to 20 times higher than the maintenance dose used in man caused an increase of urine and sodium excretion without influencing potassium and chloride output. There were no signs of sedation as alteration of motility or EEG patterns, but in mice and rats there was an increase in both duration and depth of anaesthesia caused by barbiturates or ether. Only in a dose range 30 to 40 times higher than the initial dose for man there were some slight alterations with respect to cardiovascular system and liver function tests. In vitro, with high concentrations of CN 3123 there was a weak, unspecific spasmolytic effect on the isolated ureter and an increase in the refractory period of the guinea pig atrium. There were no hints that the side effects seen with separate administration of high or very high doses of sulfamoxole or trimethoprim were increased or poteniated by their simultaneous administration. Slight side effects in animals were only observed with doses exceeding the tenfold of the doses for therapeutic use in men. Therefore, the therapeutic range of CN 3123 seems to be more than adequate.

[Investigations on the effect of the combination sulfamoxole/trimethoprim on fertility and fetal development in rats and rabbits (author's tranls)]. / Untersuchungen über den Einfluss der Kombination Sulfamoxol/Trimethoprim (CN 3123) auf Fertilität und Embryonalentwicklung an Ratten und Kaninchen

The chemotherapeutically active combination of N1-(4,5-dimethyl-2-oxazolyl)-sulfanilamide (sulfamoxole) and 2,4-diamino-5-(3,4,5-trimethoxy-benzyl)-pyrimidine (trimethoprim) in a dose ratio of 5:1 (CN 3123, Nevin, Supristol) was investigated, with respect to teratogenicity, effects on fertility and reproduction and influence on peri- and post-natal development. Experiments with the combination and partly with the single substances were done on Sprague-Dawly and Wistar rats and on rabbits (New Zealand White). With regard to the known effects of trimethoprim in this field--fetal malformations typical of those caused by folic acid antagonists--it was to clarify whether or not potentiation phenomena or new toxic effects occur with the combination. The results were as follows: 1. CN 3123 is teratogenically and fetotoxically active when given in very high doses to pregnant rats and rabbits during the critical phase of organogenesis (day 8-15 of pregnancy in rats, day 8-14 in rabbits). There were malformations, decrease in the number of pups and an increase in the number of absorption sites. Litter size and litter weight were reduced. The malformations observed were cleft palates, rarely cleft lips, micrognathies and shortening of limbs. Doses up to 180 mg/kg CN 3123, corresponding to more than tenfold the daily maintenance dose in man, were without any effects on all parameters observed. Toxic effects were observed in Sprague-Dawley rats at a dose level of 420 mg/kg and in Wistar rats with 600 mg/kg, corresponding to the effects seen following 100 mg/kg of trimethoprim alone. Sulfamoxole in the corresponding dose of 500 mg/kg caused no embryotoxic effects in the rat. In rabbits 600 mg/kg CN 3123 induced no malformations but increased fetal loss. Therefore it can be concluded, that the teratogenic and fetotoxic effects seen with high doses of CN 3123 are due to the amount of trimethoprim in the combination. The observed effects with the combination are quantitatively related to those seen with trimethoprim. 2. CN 3123 in high doses which are teratogenic also provoked a reduction of growth of the animals. Food consumption and weight gain were reduced in dams with 420 and 600 mg/kg CN 3123. In this dose range the pup weights and the weight gain of the offspring of dams with continued dosing during lactation were also reduced. Variation rate including retardations was increased. The depressing effect of CN 3123 in high doses on food consumption and weight gain is known from long-term toxicological studies previously described [7]. 3. CN 3123 even with high doses has no effects on the fertility of male and female rats. The number of corpora lutea and implantations and also the pregnancy rate were unaffected when either the female or the male rats used for mating had been treated. There was also no influence on mating activity of the male animals treated. 4. According to the results of the fertility study with treatment of the male rats for a period of ten weeks or more there were no signs of mutagenic effects due to CN 3123.

[Studies on the antibacterial activity of the combination sulfamoxole/trimethoprim (CN 3123) (author's transl)]. / Untersuchungen zur antibakteriellen Wirkung der Kombination Sulfamoxol/Trimethoprim (CN 3123)

After giving a survey on the situation of antibiotic resistance in the region of Northern Bavaria during 1973/74 and comparing the activity of a sulfamethoxazole (SMZ) trimethoprim (TMP) combination to other commonly used antibiotics and chemotherapeutic agents, the results of tests with the new combination of N1-(4,5-dimethyl-2-oxazolyl)-sulfanilamide) (sulfamoxole) and 2,4-diamino-5-(3,4,5-trimethoxy-benzyl)-pyrimidine (trimethoprim) at a ratio of 5:1 (CN 3123; Nevin, Supristol) are compared to those of tests with TMP/SMZ. This was done by correlating the inhibition zone diameters and, on the other hand, by referring to a great number of sensitivity evaluations in routine diagnostic tests. According to the size of the inhibition zone, CN 3123 showed a somewhat greater activity on Enterococcus (fecal streptococci), Escherichia coli, and Klebsiella aerogenes, whereas the TPM/SMZ combination had apparently a stronger antibacterial effect in vitro against Proteus mirabilis, Staphylococcus aureus, and the Achromobacter-group. Analysis of sensitivity readings from routine diagnosis demonstrated accordance of CN 3123 with TMP/SMZ in 92.6% (first series) and 94.2% (second series), respectively. These results should be considered critically in view of the manifold factors which influence sensitivity tests in the agar diffusion method.