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PubMed2006

Real-time imaging of nitric oxide production in living cells with 1,3,5,7-tetramethyl-2,6-dicarbethoxy-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacence by invert fluorescence microscope.

Although the importance of nitric oxide (NO) as a signalling molecule in many biological processes is becoming increasingly evident, many proposed and potential biological functions of NO still remain unclear. Bioimaging is a good technique to visualize observation of nitric oxide in biological samples. In this report, a fluorescent probe, 1,3,5,7-tetramethyl-2,6-dicarbethoxy-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacence (TMDCDABODIPY), has been first applied to real-time image NO produced in PC12 cells, Sf9 cells and human vascular endothelial cells at the presence of l-arginine with inverted fluorescence microscope. NO production in the cells is successfully captured and imaged with fine temporal and spatial resolution. The results prove that the probe combined with inverted fluorescence microscope can be developed into a sensitive and selective method for further study of NO release from cells.

Animals↗
PubMed2005

Gallium-68-DOTA-albumin as a PET blood-pool marker: experimental evaluation in vivo.

Investigations into tumor angiogenesis and antiangiogenic treatment have renewed interest in tumor perfusion. To image tumor blood-pool by PET, suitable tracers are not generally available. In this experimental study, we characterized a 68Ga-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) conjugate of rat serum albumin (68Ga-DOTA-RSA) in vivo using a generator-produced isotope. Biodistribution was determined in ACI rats after intravenous administration of 3-6 MBq of 68Ga-DOTA-RSA. Three ACI rats were imaged over 1 h by dynamic PET after intravenous administration of 15-25 MBq of 68Ga-DOTA-RSA while the blood-pool activity was recorded simultaneously in a closed extracorporeal loop (ECL) between the carotid artery and the jugular vein. Time-activity curves (TACs) were obtained from volume of interest (VOI) analysis and from the ECL data. Stability and metabolites in plasma and urine were analyzed by size exclusion HPLC (SE-HPLC) 1 h after intravenous injection of 67Ga-DOTA-RSA. Blood radioactivity decreased by 10% and 18% from 10 to 60 min p.i. by biodistribution and PET or ECL, respectively. Tissue sampling between 10 and 60 min p.i. showed slight increases in the uptake of spleen, myocardium, kidney and skeletal muscle while hepatic accretion remained unchanged. Total urinary excretion after 60 min amounted to 9% of the injected dose. HPLC demonstrated a single urinary metabolite corresponding in size to gallium-labeled DOTA. 68Ga-DOTA-RSA is a blood-pool tracer whose physical and biological half-life is well suited for PET. Our findings support clinical imaging using 68Ga-DOTA-labeled human serum albumin (HSA). The generator-produced label makes 68Ga-DOTA-labeled albumin continuously available even to centers lacking an in-house cyclotron.

Animals↗
PubMed2005

Penetration of topically applied gatifloxacin 0.3%, moxifloxacin 0.5%, and ciprofloxacin 0.3% into the aqueous humor.

PURPOSE: To investigate the aqueous penetration of 3 commercially available ophthalmic fluoroquinolones. DESIGN: Prospective, double-masked, clinical study. PARTICIPANTS: Fifty-two eyes of 52 patients. INTERVENTION: Fifty-two patients undergoing cataract surgery were given preoperative topical gatifloxacin 0.3% (Zymar), moxifloxacin 0.5% (Vigamox), or ciprofloxacin 0.3% (Ciloxan). The patients were instructed to use their antibiotic drops 4 times a day for 3 days before surgery. On the day of surgery, patients were given their assigned antibiotic every 15 minutes for 3 doses, 1 hour before their procedure. At the time of surgery, 0.1 ml of aqueous fluid was aspirated from the anterior chamber with an air cannula needle attached to a tuberculin syringe. The aspirate was immediately stored at -70 degrees C. MAIN OUTCOME MEASURE: Fluoroquinolone concentrations were determined by reverse-phase high-pressure liquid chromatography assay technique with ultraviolet detection at a wavelength of 275 nm. RESULTS: Mean aqueous concentration of gatifloxacin in 16 eyes was 0.63 microg/ml (standard deviation [SD], 0.30), moxifloxacin in 14 eyes was 1.31 microg/ml (SD, 0.46), and the mean concentration of ciprofloxacin in 22 eyes was 0.15 microg/ml (SD, 0.11). CONCLUSIONS: Both moxifloxacin (P<0.001) and gatifloxacin (P<0.005) penetrated the aqueous humor at significantly higher levels than ciprofloxacin. Moxifloxacin penetrated into the aqueous humor at significantly higher levels than gatifloxacin (P<0.05). The anterior chamber levels of moxifloxacin and gatifloxacin may be due to the difference in antibiotic concentration.

Aged↗
PubMed2005

Aqueous penetration and biological activity of moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% solution in cataract surgery patients.

PURPOSE: To measure the achievable perioperative aqueous concentration of the commercially available topically administered fourth generation fluoroquinolones, moxifloxacin 0.5% ophthalmic solution, and gatifloxacin 0.3% ophthalmic solution, and to correlate this concentration with the agents' biological efficacy in the aqueous humor of patients undergoing routine cataract surgery. DESIGN: Prospective, randomized, parallel, double-masked, clinical trial. PARTICIPANTS: Fifty patients undergoing cataract extraction. METHODS: Patients (n = 25) were given perioperative topical moxifloxacin 0.5% or topical gatifloxacin 0.3% (n = 25). One drop of antibiotic was administered every 10 minutes for 4 doses beginning 1 hour prior to surgery. Aqueous humor was sampled via paracentesis and antibiotic concentrations were determined using validated high performance liquid chromatography (HPLC) procedures. Dilution analyses were performed to determine the biological efficacy of the agents in the aqueous against Staphylococcus epidermidis, the most common cause of postcataract endophthalmitis. MAIN OUTCOME MEASURES: Aqueous humor antibiotic concentrations were measured using HPLC and microdilution bioassay techniques. Biological activity was measured as minimal inhibitory dilution and minimal bactericidal dilution. RESULTS: Aqueous humor concentrations for moxifloxacin via HPLC analysis were 1.80 (+/-1.21) microg/ml, whereas those for gatifloxacin were 0.48 (+/-0.34) microg/ml. This 3.8-fold difference in aqueous humor antibiotic concentrations was statistically significant (P = 0.00003). Similarly, the biological dilution analysis of the aqueous humor samples showed that moxifloxacin attained an estimated activity of 2.1 microg/ml, whereas the gatifloxacin activity was approximately 0.4 mug/ml, which represented a 4.9-fold difference. CONCLUSIONS: This study demonstrated that after topically administered perioperative antibiotics with cataract surgery, moxifloxacin 0.5% ophthalmic solution achieved a statistically significantly higher concentration in aqueous humor compared with gatifloxacin (P = 0.00003). Results from the broth dilution analysis showed that moxifloxacin 0.5% was biologically more active against S. epidermidis than gatifloxacin 0.3% in aqueous humor after topical application. There were no adverse events reported, and incision wounds healed quickly and as expected.

Administration, Topical↗
PubMed2006

Fourth-generation fluoroquinolone penetration into the aqueous humor in humans.

PURPOSE: To compare the penetration and levels of the fourth-generation fluoroquinolones moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% solution in the aqueous humor (AH) in humans after topical application with published levels of other available fluoroquinolones under similar dosing conditions. DESIGN: Prospective, randomized, double-masked clinical trial. PARTICIPANTS: Forty-six patients undergoing cataract extraction. METHODS: Patients scheduled for routine phacoemulsification and intraocular lens implantation were provided either moxifloxacin 0.5% ophthalmic solution (n = 22) or gatifloxacin 0.3% ophthalmic solution (n = 24) to use 4 times daily the day before surgery plus 1 drop 1 hour before the surgical entry into the anterior chamber on the day of surgery. This regimen simulated a realistic postoperative dosing schedule. Aqueous humor samples were obtained and analyzed by high-pressure liquid chromatography. Aqueous humor fluoroquinolone concentrations were calculated by peak comparison with a known concentration peak for ciprofloxacin that was used as an internal standard. These values were compared with published concentrations of other available fluoroquinolones under similar dosing conditions. RESULTS: The mean age of the moxifloxacin 0.5% group was 67.8+/-9.7 years, whereas that of the gatifloxacin 0.3% group was 69.9+/-8.7 years. The moxifloxacin AH concentration was 1.86+/-1.06 microg/ml, and that of gatifloxacin was 0.94+/-0.72 microg/ml. This 2-fold difference was statistically significant (P = 0.001). CONCLUSIONS: Aqueous humor antibiotic concentrations achieved at the time of cataract surgery after topical application can serve as an effective surrogate for what can be achieved with typical postoperative topical dosing (e.g., 4 times daily). Both fourth-generation fluoroquinolones achieved a greater AH concentration after 4 times daily dosing relative to prior-generation fluoroquinolones. Moxifloxacin 0.5% ophthalmic solution achieved a 2-fold higher aqueous humor concentration than gatifloxacin 0.3% ophthalmic solution. The superior penetration of moxifloxacin into the AH may be attributed partially to its high degree of lipophilicity, greater solubility at neutral pH, and higher concentration in the commercial formulation. The enhanced penetration of moxifloxacin 0.5% ophthalmic solution may provide better protection against ocular infections.

Administration, Topical↗
PubMed2006

Endophthalmitis after uncomplicated cataract surgery with the use of fourth-generation fluoroquinolones: a retrospective observational case series.

OBJECTIVE: To estimate the rate of acute postoperative endophthalmitis after uncomplicated cataract surgery in patients treated before and after surgery with 1 of 2 different fourth-generation fluoroquinolone ophthalmic drops for surgical prophylaxis. DESIGN: Retrospective, multicenter, observational case series. PARTICIPANTS: Included in this study were 20,013 patients from 9 cataract surgery centers in 7 states in the United States. METHODS: Patients who had undergone uncomplicated phacoemulsification who received preoperative and postoperative topical fourth-generation fluoroquinolones for surgical prophylaxis between March 2003 and July 2005 were included in the study. The files of patients in whom acute endophthalmitis developed were reviewed and analyzed. MAIN OUTCOME MEASURES: Number and rate of endophthalmitis cases after uncomplicated cataract surgery. RESULTS: During the study period, the participating surgeons performed 20,013 uncomplicated surgeries. Of these, 16,209 patients (81%) received topical gatifloxacin and 3804 patients (19%) were treated with topical moxifloxacin as antiinfective prophylaxis. A total of 14 patients experienced endophthalmitis. The overall rate of endophthalmitis was 0.07%. There were 9 endophthalmitis patients in the gatifloxacin group and 5 endophthalmitis patients in the moxifloxacin group. The rate of endophthalmitis in the gatifloxacin group was 0.06% and the rate in the moxifloxacin group was 0.1%. The difference in the rate of endophthalmitis between the 2 groups was not statistically significant. In 10 of the patients, vitreous culture results were positive. Coagulase-negative staphylococci, followed by streptococci, species were the most commonly isolated organisms in the culture-positive patients. CONCLUSIONS: The overall rate of endophthalmitis after uncomplicated cataract surgery in patients treated with topical fourth-generation fluoroquinolones as antiinfective prophylaxis was 0.07%. This rate was within the range of previously reported rates of endophthalmitis in the literature. The difference in the observed rate of postoperative endophthalmitis in patients treated with moxifloxacin versus gatifloxacin was not statistically significant.

Adult↗
PubMed2004

Efficacy and safety of oral telithromycin once daily for 5 days versus moxifloxacin once daily for 10 days in the treatment of acute bacterial rhinosinusitis.

OBJECTIVE: To compare the clinical and bacteriologic efficacy and safety of short-duration treatment with telithromycin given for 5 days with moxifloxacin given for 10 days in adults with acute bacterial rhinosinusitis (ABRS). STUDY DESIGN: In this prospective, double-blind, parallel-group, randomized, multicenter study, adult patients (N = 349) with ABRS were randomized to oral telithromycin (800 mg once daily for 5 days) or to oral moxifloxacin (400 mg once daily for 10 days) and followed for 31 to 36 days. Clinical outcome was determined by the investigator at the posttherapy/test of cure (TOC) visit. Bacteriologic outcome was determined by comparing cultures taken at the pretreatment visit with cultures obtained at the posttherapy/TOC visit. The primary objective was to demonstrate equivalence of clinical cure rates in the per-protocol population between treatment groups at the posttherapy/TOC visit. RESULTS: Clinical success at TOC (primary endpoint) was achieved in 87.4% of patients in the telithromycin group compared with 86.9% for moxifloxacin (per-protocol patients; 0.5% difference between treatment groups; 95% confidence interval [CI], -8.1, 9.2; P = 0.8930). The bacteriologic success rates were 94.1% and 93.9%, respectively (0.2% difference between treatment groups; 95% CI, -14.2, 14.5; P = 0.9734). Overall treatment-emergent adverse events for both drugs (mostly gastrointestinal) were mild to moderate in intensity. CONCLUSION AND SIGNIFICANCE: The clinical and bacteriologic efficacy of telithromycin 800 mg once daily for 5 days was equivalent to that of moxifloxacin 400 mg once daily for 10 days, establishing telithromycin as an important treatment option for ABRS.

Acute Disease↗
PubMed2005

Variables associated with recovery from acute exacerbations of chronic bronchitis and chronic obstructive pulmonary disease.

OBJECTIVE: To identify risk factors for late recovery and failure after ambulatory treatment of exacerbations of chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD). METHODS: Observational, non-randomised study of risk factors carried out in 2001 and 2002 in Primary Care practices. Patients aged 40 or older diagnosed with an exacerbation of CB or COPD of probable bacterial etiology were included in the study and followed up for 10 days. Patients were treated with amoxicillin plus clavulanic acid (co-amoxiclav) 500-125 mg tds for 10 days, clarithromycin 500 mg bd for 10 days or moxifloxacin 400 mg od for 5 days. RESULTS: Two hundred and fifty-two general practitioners participated, registering 1147 valid patients. The rate of failure at day 10 was 15.1% without significant differences among the antibiotic treatments. Median time to recovery was 5 days. Factors significantly associated with late recovery (>5 days) on multivariate analysis were: use of long-term oxygen (OR=1.96; 95%CI=1.35-2.85); use of short-acting beta-2 agonists (OR=1.51; 1.17-1.92). The use of moxifloxacin had a "protective" effect against late recovery compared to co-amoxiclav (OR=0.34; 0.26-0.45) and clarithromycin (OR=0.41; 0.31-2.85). Factors associated with therapeutic failure were: previous hospitalisation (OR=1.61; 1.08-2.42); and 2 or more exacerbations the previous year (OR=1.51; 1.04-2.17); criteria of CB had a protective effect against failure (OR=0.53; 0.35-0.79). CONCLUSIONS: There are readily identifiable risk factors for ambulatory treatment failure of exacerbations of CB and COPD. In addition, long-term oxygen therapy and short-acting beta-2 agonists are associated with late recovery, and the use of moxifloxacin compared with co-amoxiclav and clarithromycin is associated with faster recovery of symptoms.

Acute Disease↗
PubMed2006

Long-term moxifloxacin in complicated tuberculosis patients with adverse reactions or resistance to first line drugs.

STUDY OBJECTIVES: To test safety and tolerability of long-term moxifloxacin in resistant tuberculosis (TB) patients and patients with intolerance to first line anti-TB drugs. DESIGN: Clinical evaluation of adverse events (AEs) during prolonged moxifloxacin treatment. SETTING: TB Unit of the Regional TB Reference Center, Villa Marelli Institute, Niguarda Ca'Granda Hospital, Milan, Italy PATIENTS AND INTERVENTIONS: Patients treated with moxifloxacin, 400 mg orally once daily for TB in the Villa Marelli Institute from January 2001 to December 2003 were enrolled. RESULTS: Thirty-eight patients were treated with moxifloxacin at the Villa Marelli Institute in the study period, for multidrug resistant (MDR) TB (14, 36.8%), for intolerance to first line anti-TB drugs (9, 23.7%), for combined resistance and intolerance to first line anti-TB drugs (12, 31.6%), other reasons (3, 7.9%). The mean duration of moxifloxacin treatment was 6.3 +/- 5.2 months. Twelve (31.6%) patients reported at least an AE due to moxifloxacin, mostly gastrointestinal (8, 21.0%), general (5, 13.2%) and central nervous system (3, 7.9%) AEs. In 4 (10.5%) patients the drug was withdrawn for major AEs; no irreversible or fatal events were recorded. Most of the patients (31, 81.6%) reported a treatment success, even if the success rate was lower in MDR TB patients (8/14, 51.7%). CONCLUSIONS: Despite the fact that a large proportion of patients experienced at least an AE due to moxifloxacin, the drug resulted safe in the long-term administration for complicated TB cases.

Adult↗
PubMed2006

Moxifloxacin versus levofloxacin against acute exacerbations of chronic bronchitis: the Latin American Cohort.

We compared the efficacy and safety of moxifloxacin and levofloxacin for the treatment of patients with acute exacerbations of chronic bronchitis (AECB) using a prospective, randomized, double blind, parallel-group clinical trial design. A total of 563 patients with AECB were enrolled (437 efficacy-valid) at 34 centers in Mexico, Argentina, Brazil, Colombia, and Peru. Patients were randomized to oral therapy with either moxifloxacin 400 mg once daily for 5 days or levofloxacin 500 mg once daily for 7 days. Clinical success was achieved in 201 out of 221 (91.0%) patients in the moxifloxacin group, and in 203 out of 216 (94.0%) in the levofloxacin group, indicating that moxifloxacin is equivalently effective to levofloxacin. Bacteriologic eradication or presumed eradication was also similar in the two treatment groups: 92.8% in the moxifloxacin group and 93.8% in the levofloxacin group. Nausea was the most common drug-related adverse event in each treatment group. The rate of discontinuation because of adverse events was very low (2%). In conclusion, a 5-day course of moxifloxacin is clinically and bacteriologically equivalent to a 7-day course of levofloxacin in the treatment of patients with AECB. The short treatment duration with moxifloxacin may have compliance advantages over other currently used therapies in the 'real-life' clinical setting.

Anti-Bacterial Agents↗
PubMed2006

Eradication of H. influenzae in AECB: A pooled analysis of moxifloxacin phase III trials compared with macrolide agents.

Haemophilus influenzae is the most common bacterial pathogen associated with acute exacerbations of chronic bronchitis (AECB). This study determined the rate of bacterial eradication of H. influenzae during AECB treated with either macrolides or moxifloxacin. Adult AECB patients with H. influenzae were included in a pooled analysis of four double-blind, multicentre, randomised trials. Patients received either moxifloxacin (400 mg qd for 5-10 days) or macrolides (azithromycin 500 mg/250 mg qd for 5 days or clarithromycin 500 mg bid for 5-10 days). Bacterial eradication and clinical success were recorded at the test-of-cure visit (7-37 days post-therapy). Of 2555 patients in the intent-to-treat population, 910 were microbiologically valid and 292 (32%) had H. influenzae cultured at baseline. Bacterial eradication of H. influenzae was significantly higher with moxifloxacin vs. macrolide-treated patients (93.0% [133/143] vs. 73.2% [109/149], respectively, P = 0.001). Moxifloxacin also demonstrated higher eradication rates compared with azithromycin (96.8% vs. 84.6%, P = 0.019) and clarithromycin (90.1% vs. 64.2%, P = 0.001) analysed separately. Clinical success was 89.5% (128/143) for moxifloxacin vs. 85.2% (127/149) for the macrolide group (P = 0.278); similar results were found when moxifloxacin was compared individually with each macrolide. For patients with AECB due to H. influenzae, moxifloxacin provided superior bacterial eradication rates than macrolide therapy.

Acute Disease↗
PubMed2004

Spectroscopic studies of complexes of iodine with the bases 1-aza-15-crown-5 and 3,6,9,14-tetrathiabicyclo[9.2.1]tetradeca-11,13-diene.

The interactions of iodine with each of the electron donors 1-aza-15-crown-5 (AC) and 3,6,9,14-tetrathiabicyclo[9.2.1]tetradeca-11,13-diene (TTBCTD) in CHCl3 have been described in terms of 1:1 and 1:2, base: I2 complexes, respectively, forming the complexes of the type [(AC)2I]+.I3- and [(TTBCTD)(I2)2]. The [(AC)2I]+.I3- shows the characteristic absorptions of I3- ion at 265 and 365 nm while the charge-transfer transition of [(TTBCTD)(I2)2] occurs at 320 nm. The formation of the two complexes was further confirmed by far infrared measurements. The values of the complex formation constant, K, and the absorpativity, in CHCl3 are calculated for the complex [(AC)2I]+.I3-.

Aza Compounds↗
PubMed2004

Electronic, infrared and Raman spectral studies on the molecular complex of N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane with iodine.

The molecular complexation reaction between iodine and the interesting mixed oxygen-nitrogen cyclic base N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DBTODAOD) has been studied spectrophotometrically in CH2Cl2, CHCl3, and CCl4. The results of photometric titrations and elemental analysis show that the DBTODAOD base:iodine ratio is 1:4 forming the heptaiodide complex [(DBTODAOD)I]+.I7-. The heptaiodide ion (I7-) is described as I3-(2I2) confirmed by the observation of its characteristic strong absorptions around 365 and 295 nm. In addition, the far infrared spectrum of the solid complex shows the three vibrations of I3- unit at 142, 104, and 62 cm(-1) assigned to nuas(I-I), nus(I-I) and delta(I-3), respectively, while the Raman spectrum shows the corresponding bands at 147 and 108 cm(-1) beside two other bands at 181 and 214 cm(-1) related to the vibration of the I2 unit and the first overtone of nus(I-I) of I3-, respectively. The structure of the formed heptaiodide complex was further supported by thermal gravimetric analysis measurements. Group theoretical analysis indicate that the triiodide unit (I3-) in I7- may be non-linear with C2v symmetry.

Aza Compounds↗
PubMed2005

Design, synthesis and characterization of a novel fluorescent probe for nitric oxide based on difluoroboradiaza-s-indacene fluorophore.

Nitric oxide (NO) is a gaseous, free radical, which plays a role as an intracellular second messenger and a diffusible intercellular messenger. To obtain evidence for NO function in vivo, 1,3,5,7-tetramethyl-8-(4'-aminophenyl-N-(2''-amino)-phenzyl)-difluoroboradiaza-s-indacene (TMAPABODIPY) was designed and synthesized as a fluorescent probe for nitric oxide, which features high photostability and no pH dependency over a wide pH range. The fluorescence of TMAPABODIPY itself is very strong. When TMAPABODIPY traps NO in the presence of dioxygen, the weak fluorescent triazole form is obtained, which offers the advantages of specificity, and sensitivity for direct detection of NO. The relationship was obtained between the quenching fluorescence intensity and NO concentration in the range 0.02-4.0 micromol l(-1). The detection limit is 5 nmol l(-1) (S/N = 3). The proposed method has been used to monitor the release of NO from S-nitrosocysteine, a NO-releasing agent.

Aza Compounds↗
PubMed2005

Spectroscopic studies on Co(II), Ni(II) and Cu(II) complexes with a new macrocyclic ligand: 2,9-dipropyl-3,10-dimethyl-1,4,8,11-tetraaza-5,7:12,14-dibenzocyclotetradeca-1,3,8,10-tetraene.

Cobalt(II), nickel(II) and copper(II) complexes containing a tetradentate macrocyclic nitrogen donor ligand i.e. 2,9-dipropyl-3,10-dimethyl-1,4,8,11-tetraaza-5,7:12,14-dibenzocyclotetradeca-1,3,8,10-tetraene have been synthesized and characterized by elemental analysis, molar conductance, magnetic moments, mass, (1)H NMR, IR, electronic and EPR spectral studies. All the complexes are of high spin type and possess four-coordinated tetrahedral, five-coordinated square pyramidal and six-coordinated octahedral/tetragonal geometry. The ligand and its metal complexes were also screened against the growth of some bacteria and plant pathogenic fungi in vitro.

Anti-Bacterial Agents↗
PubMed2005

Spectroscopic approach in characterization of chromium(III), manganese(II), iron(III) and copper(II) complexes with a nitrogen donor tetradentate, 14-membered azamacrocyclic ligand.

The complexes of Cr(III), Mn(II), Fe(III) and Cu(II) were synthesized with the macrocyclic ligand i.e. 2,3,9,10-tetraketo-1,4,8,11-tetraazacyclotetradecane. The ligand was prepared by the [2 + 2] condensation reaction of diethyloxalate and 1,3-diamino propane. These complexes were found to have the general composition M(L)X3 and M'(L)X2 [where M = Mn(II) and Cu(II), M' = Cr(III) and Fe(III), L = ligand (N4) and X = Cl-, NO3-, 1/2SO4(2-) and [CH3COO-]. The ligand and its transition metal complexes were characterized by the elemental analyses, molar conductance, magnetic susceptibility, mass, IR, electronic, and EPR spectral studies. On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Cr(III), Mn(II) and Fe(III) and a tetragonal geometry for Cu(II) complexes.

Aza Compounds↗
PubMed2005

Spectroscopic studies on [(DD18C6H2)(HPA)2](PA)2 and [(DD18C6H2)(DDQ)2](DDQH)2 formed in the reaction of N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane with HPA and DDQ.

The interaction of the mixed oxygen-nitrogen cyclic base, N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DD18C6) with pi-acceptors such as picric acid (HPA) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) has been studied spectrophotometrically in chloroform at 25 degrees C. The results obtained indicate the formation of 1:4 charge-transfer complexes with the general formula (DD18C6)(acceptor)4. The electronic and infrared spectra of charge-transfer complexes along with the (1)H NMR spectra were recorded and discussed. Based on the data obtained, the complexes were formulated as [(DD18C6H2)(HPA)2](PA)2 and [(DD18C6H2)(DDQ)2](DDQH)2. A general mechanism explaining the formation of the DDQ complex has been suggested.

Aza Compounds↗
PubMed2005

Vibrational spectroscopic characterization of fluoroquinolones.

Quinolones are important gyrase inhibitors. Even though they are used as active agents in many antibiotics, the detailed mechanism of action on a molecular level is so far not known. It is of greatest interest to shed light on this drug-target interaction to provide useful information in the fight against growing resistances and obtain new insights for the development of new powerful drugs. To reach this goal, on a first step it is essential to understand the structural characteristics of the drugs and the effects that are caused by the environment in detail. In this work we report on Raman spectroscopical investigations of a variety of gyrase inhibitors (nalidixic acid, oxolinic acid, cinoxacin, flumequine, norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, enoxacin, sarafloxacin and moxifloxacin) by means of micro-Raman spectroscopy excited with various excitation wavelengths, both in the off-resonance region (532, 633, 830 and 1064 nm) and in the resonance region (resonance Raman spectroscopy at 244, 257 and 275 nm). Furthermore DFT calculations were performed to assign the vibrational modes, as well as for an identification of intramolecular hydrogen bonding motifs. The effect of small changes in the drug environment was studied by adding successively small amounts of water until physiological low concentrations of the drugs in aqueous solution were obtained. At these low concentrations resonance Raman spectroscopy proved to be a useful and sensitive technique. Supplementary information was obtained from IR and UV/vis spectroscopy.

Aza Compounds↗