Antimicrobial activity of a series of thiosemicarbazones and their Zn(II) and Pd(II) complexes.

Thirty-four thiosemicarbazones and S-alkyl thiosemicarbazones, and some of their Zn(II) and Pd(II) complexes were obtained and purified to investigate antimicrobial activity. MIC values of the compounds were determined by the disc diffusion method against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Staphylococcus aureus, S. epidermidis, and Candida albicans. The thiosemicarbazones show antibacterial and antifungal effects in free ligand and metal-complex form. Picolinaldehyde-S-methyl- and -S-benzylthiosemicarbazones did not affect the tested microorganisms but their Zn(II) complexes showed selective activity. The antimicrobial activity is relatively high in Me2SO, but the antimicrobial potential is changed in a certain range with Me2SO, HCONMe2, EtOH and CHCl3.

Antimicrobial activity of 1,2-bis-[2-(5-R)-1H-benzimidazolyl]- 1,2-ethanediols, 1,4-bis-[2-(5-R)-1H-benzimidazolyl]- 1,2,3,4-butanetetraols and their FeIII, CuII, and AgI complexes.

1,2-Bis-[2-(5-H/Me/Cl/NO2)-1H-benzimidazolyl]-1,2-ethanediols (L1-L4), 1,4-Bis-[2-(5-H/Me/Cl)-1H-benzimidazolyl]-1,2,3,4-butanetetraols (L5-L7) and their complexes with FeCl3, CuCl2, and AgNO3 were synthesized; antibacterial activity of the compounds was determined toward Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Proteus mirabilis, and antifungal activity against Candida albicans. The AgI complexes have considerable activity toward the microorganisms. Some AgI complexes show higher activity toward S. epidermidis than AgNO3 and cefuroxime. Cu(L3)Cl2 and Fe(L3)Cl3 show an antifungal effect on C. albicans but L3 itself has no activity.

Antimicrobial activity of ZnII, CdII, and HgII complexes of 1,2-bis-[2-(5-R)-1H-benzimidazolyl]-1,2-ethanediols and 1,4-bis-[2-(5-R)-1H-benzimidazolyl]-1,2,3,4-butanetetraols.

1,2-Bis-[2-(5-H/Me/Cl/NO2)-1H-benzimidazolyl]-1,2-ethanediols (L1-L4), 1,4-bis-[2-(5-H/Me/Cl)-1H-benzimidazolyl]-1,2,3,4-butanetetraols (L5-L7) and their complexes with ZnCl2, CdCl2 and HgCl2 were synthesized and antibacterial activity of the compounds was tested toward Staphylococcus aureus, S. epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Proteus mirabilis and antifungal activity against Candida albicans. HgII complexes have a considerably higher antimicrobial activity against all microorganisms. Some HgII complexes show higher antifungal activity than clotrimazole toward C. albicans. Zn2(L3)Cl4, Zn2(L4)Cl4, and Cd(L3)Cl2 were moderately effective against S. aureus and S. epidermidis; Cd(L4)Cl2 exhibited a weak activity only against S. epidermidis.

Antimicrobial activity of some 2- and 3-pyridinyl-1H-benzimidazoles and their FeIII, CuII, ZnII, and AgI complexes.

2-(2-Pyridinyl)- (LI), 2-(6-methyl-2-pyridinyl)- (LII), 2-(6-methyl-2-pyridinyl)-5-methyl-(LIII), 2-(3-pyridinyl)- (LIV), 2-(3-pyridinyl)-5-methyl-1H-benzimidazoles (LV) and their complexes with Fe(NO3)3, Cu(NO3)2, Zn(NO3)2, and AgNO3 were synthesized and antibacterial activity of the compounds was tested toward Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Proteus mirabilis and antifungal activity against Candida albicans. The methyl groups of LIII increase the antimicrobial activity. The AgI complexes have considerable activity toward the microorganisms. Some ZnII complexes show an antimicrobial effect against S. aureus and S. flexneri, although the ligands themselves have no effect. CuII complexes have a considerable antibacterial effect to S. aureus and S. epidermidis.

Antimicrobial activity of FeIII, CuII, AgI, ZnII and HgII complexes of 2-(2-hydroxy-5-bromo/nitro-phenyl)-1H- and 2-(2-hydroxyphenyl)-5-methyl/chloro/nitro-1H-benzimidazoles.

Antimicrobial activity of 2-(2-hydroxyphenyl)-5-R5-1H-benzimidazoles, 2-(2-hydroxy-5-R5'-phenyl)-1H-benzimidazoles and their FeIII, CuII, AgI, ZnII and HgII nitrate complexes was tested toward Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, and Proteus mirabilis. Antifungal activity was tested against Candida albicans. Benzimidazole benzene ring substituents increase the antimicrobial activity, phenol ring substituents decrease it. The ligands show an antibacterial effect against only S. aureus whereas AgI and HgII complexes of the ligands have a higher activity with respect to the other complexes to all the bacteria. On the other hand, FeIII complexes show a considerable activity against S. aureus and S. epidermidis.

In vivo studies on nasal preparations of ciprofloxacin hydrochloride.

Gel formulations of ciprofloxacin hydrochloride (CPH) were prepared with bioadhesive polymers such as hydroxypropyl methylcellulose (HPMC), hydroxyethyl cellulose (HEC) and methylcellulose (MC). They were administered into the nasal cavity of rabbits. A nasal aqueous suspension of CPH with glycerol was also applied. In addition, the effect of Tween 80 as penetration enhancer was examined. The agar plate diffusion technique was applied for the assay of CPH. The results were compared with oral and intravenous administrations. The bioavailability of the CPH gel formulation prepared with HPMC was almost identical to that of the oral route. Other nasal formulations with HEC and MC had bioavailabilities lower than oral preparations. The relative bioavailabilities for the formulation containing HEC and MC were 48.7 and 45.54%, respectively. To increase the bioavailabilities, 1% (w/w) of Tween 80 was added. The bioavailability of these gel formulations increased to 63.54 and 55.72%, respectively. Experiments carried out on rabbits showed that the nasal administration of CPH bioadhesive gel formulation containing HPMC may be an alternative to the oral route.