Impurity profiling of Cefteram pivoxil based on Fourier transform ion cyclotron resonance MS.

Profiling impurities for the active pharmaceutical ingredients (APIs) is an indispensable step in drug development process. Nowadays, high resolution mass spectrometry is the first choice for determining the chemical formula of organic impurities. However, merely base on the accurate mass to screen the formula is obviously not a flawless method. In this paper, a reliable strategy based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was presented to profile the related impurities. Firstly, Cefteram pivoxil was subjected to forced degration under hydrolytic (acidic and basic), oxidative, photolytic and thermal conditions according to ICH guidelines. Then, a highly specific and efficient HPLC-FT-ICR MS compatible method was developed and it was used to separate and characterize the process related substances and the major degradation products in Cefteram pivoxil. Next, isotopic fine structures (IFSs) of all impurities were acquired to decisively determine their elemental composition. Finally, the possible chemical structures of impurities were predicted by combining the information of accurate mass, retention time, IFSs and characteristic fragmentation ions. As a result, a total of 20 related substances including 6 process related substances and 14 degradation products were identified and characterized. To the best of our knowledge, 13 of these related substances were not reported in the previous literature. It indicates that the developed strategy is accurate and standard independent to determine the chemical formulae of organic impurities in APIs. In conclusion, the impurity profiles obtained in this study are critical to the quality control and stability study of Cefteram pivoxil. Moreover, the developed method can be used as a versatile workflow to profile the impurities in APIs in the future, especially for the unknown impurities.

Preparation of Fine Particles with Improved Solubility Using a Complex Fluidized-Bed Granulator Equipped with a Particle-Sizing Mechanism.

A new type of fluidized-bed granulator equipped with a particle-sizing mechanism was used for the preparation of fine particles that improved the solubility of a poorly water-soluble drug substance. Cefteram pivoxyl (CEF) was selected as a model drug substance, and its solution with a hydrophilic polymer, hydroxypropyl cellulose (HPC-L), was sprayed on granulation grade lactose monohydrate (Lac). Three types of treated particles were prepared under different conditions focused on the spraying air pressure and the amount of HPC-L. When the amount of HPC-L was changed, the size of the obtained particles was similar. However, particle size distribution was dependent on the amount of HPC-L. Its distribution became more homogenous with greater amounts of HPC-L, but the particle size distribution obtained by decreasing the spraying air pressure was not acceptable. By processing CEF with HPC-L using a complex fluidized-bed granulator equipped with a particle-sizing mechanism, the dissolution ratio was elevated by approximately 40% compared to that of unprocessed CEF. Moreover, in the dissolution profile of treated CEF, the initial burst was suppressed, and nearly zero order release was observed up to approximately 60% in the dissolution profile. This technique may represent a method with which to design fine particles of approximately 100 µm in size with a narrow distribution, which can improve the solubility of a drug substance with low solubility.

[Evaluation of antimicrobial prophylaxis after normal delivery].

In Japan, as a measure to prevent puerperal infection, oral antimicrobial prophylaxis has been conducted after delivery in many maternity clinics. However, there are only a few reports on the evidence supporting the validity of antimicrobial prophylaxis following normal delivery. There is concern that unnecessary antimicrobial administration may be conducted in such clinics. In the present study, the puerperal females after normal delivery were placed on different treatments. A group of females received no oral antimicrobial administration. The remaining females were given cefteram pivoxil (CFTM-PI) in the two different doses. In this manner, we evaluated usefulness of antimicrobial prophylaxis. We compared three treatment groups with respect to the incidence of infection for the period until the first week after discharge, and obtained the following results: non-antimicrobial prophylaxis group (group A), 5.83%; antimicrobial prophylaxis group (group B), 1.77%; antimicrobial prophylaxis group (group C), 0%. In group B, the puerperal females were orally given CFTM-PI in a total daily dose of 300 mg, three times daily for three days. In group C, the puerperal females were orally given CFTM-PI in a total daily dose of 300 mg, three times daily for five days. The incidence of infection was the lowest in group C which was followed by group B and group A in this order and the significant intergroup difference was recognized (p=0.004). We also compared the total counts of bacteria, aerobes and anaerobes in lochia on the fifth day during the puerperal period with those on the first day in each treatment group. The decrease in bacterial count was the largest in group C, which was followed by group B and group A in this order. Compared with the total bacterial counts obtained on the first day, those obtained on the fifth day decreased significantly (p<0.001). The results of the present study showed usefulness of antimicrobial prophylaxis after normal delivery. As one of the factors, a significant decrease in the count of bacteria in lochia seems to contribute toward producing the satisfactory outcome.

Pharmacokinetics and bioequivalence studies of cefteram pivoxil in healthy Chinese volunteers.

A simple, sensitive and specific method has been developed for the determination of cefteram in human plasma. Sample preparation was accomplished through protein precipitation with 20% trichloroacetic acid (v/v) and chromatographic separation was performed on a C18 column at 25 degrees C. The mobile phase consisted of methanol-aqueous 20 mM ammonium acetate (18:82, v/v) at flow rate of 1.0 mL/min. Wavelength was set at 235 nm. The lower limit of quantification was 0.04 microg/mL and the assay exhibited a linear range of 0.04-3.2 microg/mL (r=0.9996). The relative recoveries of cefteram from human plasma at three different concentrations were more than 90%. The method was successfully applied to investigate the bioequivalence between two kinds of cefteram pivoxil preparations (test vs reference) in 24 healthy Chinese volunteers. After a single 100 mg dose for the test and reference product, the resulting means of major pharmacokinetic parameters such as AUC(0-t), AUC(0-infinity), Cmax and Tmax of cefteram pivoxil were 4.75 +/- 1.35 vs 4.76 +/- 1.29 microg h/mL, 4.89 +/- 1.36 vs 4.91 +/- 1.29 microg h/mL, 1.65 +/- 0.45 vs 1.73 +/- 0.45 microg/mL and 1.48 +/- 0.59 vs 1.73 +/- 0.45 h, respectively, indicating that these two kinds of preparations were bioequivalent.

Pharmacokinetic and bioequivalence comparison of a single 100-mg dose of cefteram pivoxil powder suspension and tablet formulations: a randomized-sequence, open-label, two-period crossover study in healthy Chinese adult male volunteers.

BACKGROUND: Cefteram pivoxil (CFTM-PI) is an oral antibiotic available in powder suspension and tablet formulations indicated in China for the treatment of bacterial infections. Although these 2 formulations are marketed in China, published information regarding their pharmacokinetics and bioequivalence in the Chinese population is not available. OBJECTIVE: The aim of this study was to compare the pharmacokinetics and bioequivalence of the powder suspension (test) and tablet (reference) formulations of CFTM-PI 100 mg available in China. METHODS: This single-dose, randomized-sequence, open-label, 2-period crossover study was performed at the Nanjing First Hospital of Nanjing Medical University. Eligible subjects were healthy male volunteers who were randomly assigned at a 1:1 ratio to receive a single 100-mg dose of the test or reference formulation, followed by a 1-week washout period and administration of the alternate formulation. The study drugs were administered after a 12-hour overnight fast. Plasma was assayed using a high-performance liquid chromatography method. For analysis of pharmacokinetic properties, including C(max), AUC from time 0 (baseline) to 6 hours (AUC(0-6)), and AUC from baseline to infinity (AUC(0-infinity)), blood samples were obtained at intervals over the 6-hour period after study drug administration. The formulations were considered bioequivalent if the log-transformed ratios of C(max) and AUC were within the predetermined equivalence range (80%-125%) as established by the US Food and Drug Administration (FDA). Tolerability was assessed by monitoring vital signs and laboratory tests (hematology, blood biochemistry, hepatic function, and urinalysis), and by questioning subjects about adverse events (AEs). RESULTS: Twenty-four Chinese male subjects (mean [range] age,24.2 [23-32] years;weight,64.3 [58-67] kg; height, 172 [167-185] cm) enrolled; all completed the study. No period or sequence effect was observed. The 90% CIs for the log-transformed ratios of C(max), AUC(0-6;), and AUC(0-infinity) were 96.5 to 120.1, 95.7 to 110.2, and 96.2 to 110.4, respectively (all, P>0.05). Similar results were found for the data without log-transformation. No AEs occurred or were reported during the study. CONCLUSIONS: In this small study in healthy Chinese adult male volunteers, a single 100-mg dose of the powder-suspension formulation was bioequivalent to a single 100-mg dose of the tablet formulation based on the US FDA's regulatory definition (rate and extent of absorption). Both formulations were well tolerated.

Ceftezole, a cephem antibiotic, is an alpha-glucosidase inhibitor with in vivo anti-diabetic activity.

Using a high throughput-compatible assay to screen for potential alpha-glucosidase inhibitors, we found that the beta-lactam antibiotic ceftezole exhibited potent alpha-glucosidase inhibitory activity. In in vitro alpha-glucosidase assays, ceftezole was shown to be a reversible, non-competitive inhibitor of yeast alpha-glucosidase with a Ki value of 5.78 x 10(-7) M when the enzyme mixture was pretreated with ceftezole. Using an in vivo streptozotocin-induced mouse model, we confirmed that blood glucose levels decreased by 30% 20 min after ceftezole treatment (10 mg/kg/day). Expression levels of glycogen synthase kinase-3, peroxisome proliferator-activated receptor-gamma, and uncoupling protein-3 mRNA were also slightly decreased compared to controls following ceftezole treatment. Taken together, these in vivo and in vitro results suggest that ceftezole may be a clinically useful anti-diabetic compound.

In vitro synergistic effects of double combinations of beta-lactams and azithromycin against clinical isolates of Neisseria gonorrhoeae.

In Japan, Neisseria gonorrhoeae, a sexually transmitted pathogen, has recently shown significant resistance to various antimicrobial agents. In this study, a checkerboard method was utilized to investigate the in vitro activities of cefixime (CFIX), cefteram (CFTM), or amoxicillin (AMPC) in combination with azithromycin (AZM) against 25 clinical isolates of N. gonorrhoeae. Synergy, defined as a fractional inhibitory concentration (FIC) index of less than or equal to 0.50, was observed in 32% of isolates with CFIX+AZM, 12% of isolates with CFTM+AZM, and 4% of isolates with AMPC+AZM. Moreover, partial synergy, defined as an FIC index of greater than 0.50 and less than 1, was observed in 44% of isolates with CFIX+AZM, 68% of isolates with CFTM+AZM, and 52% of isolates with AMPC+AZM. In particular, as a result of the combination of CFIX and AZM, for all isolates, significant reductions were observed in the median CFIX minimum inhibitory concentration (MIC; from 0.25 to 0.008 microg/ml; P < 0.0001) and the median AZM MIC (from 0.12 to 0.03 microg/ml; P < 0.0001). However, antagonism, defined as an FIC index of greater than 1, was observed in only 4% of the isolates with both CFIX+AZM and CFTM+AZM, while it was seen in 12% of the isolates with AMPC+AZM. To our knowledge, this is the first study to demonstrate that the in vitro activity of CFIX against N. gonorrhoeae can be significantly enhanced in combination with AZM.

Enhancement of antimicrobial activities of cefteram or clavulanic acid/amoxicillin against cefixime-resistant Neisseria gonorrhoeae in the presence of clarithromycin or azithromycin.

We investigated the enhancement of the antimicrobial activities of beta-lactams against cefixime (CFIX)-resistant Neisseria gonorrhoeae in the presence of macrolides. Ten strains of CFIX-resistant N. gonorrhoeae, isolated between 2000 and 2003 from male patients with urethritis at Jikei University Affiliated Hospital and its related clinics in the Tokyo metropolitan area, were tested. The fractional inhibitory concentrations of clavulanic acid/amoxicillin (CVA/AMPC), CFIX, or cefteram (CFTM), in the presence of clarithromycin (CAM) or azithromycin (AZM), against these strains were determined. Synergism, partial synergism, or additivity was recognized between CVA/AMPC or CFTM and macrolides against nine strains. Additivity and partial synergism between CFTM and macrolides against nine and ten strains, respectively, were also recognized. On the other hand, antagonism between CFIX and macrolides was recognized. These results indicate that combination antimicrobial chemotherapy, using CFTM or CVA/AMPC with macrolides, is a possible alternative treatment for CFIX-resistant N. gonorrhoeae infections.

Hepatic natural killer and natural killer T cells markedly decreased in two cases of drug-induced fulminant hepatic failure rescued by living donor liver transplantation.

The human liver contains significant numbers of innate immune cells, such as natural killer (NK) cells and natural killer T (NKT) cells, which express both T-cell receptors and NK-cell receptors simultaneously. It has been suggested that the innate immune system plays a crucial role in the liver. In this report, the distribution of NK and NKT cells in the liver and peripheral blood of two patients with drug-induced fulminant hepatic failure (FHF) who had undergone living donor liver transplantation was examined. In both the liver and peripheral blood, the proportions of NK and NKT cells markedly decreased compared with those in healthy donors. It was also revealed that, unlike murine NKT cells, human CD56(+) T cells and CD57(+) T cells did not constitutively express CD28, which is one of the important costimulatory molecules on T cells. Additionally, the residual CD56(+) T cells and CD57(+) T cells in the patients expressed more CD28 than in controls. This result suggests that NKT cells might be more activated in FHF. Although the accumulation of further cases is required, it is suggested that both NK and NKT cells might be involved in hepatic injury in FHF.

Comparative clinical study of cefcapene pivoxil and cefteram pivoxil in chronic respiratory tract infections by a double-blind method.

In a double-blind study, the efficacy and safety of the novel cephem antibiotic cefcapene pivoxil (CFPN-PI; 450 mg/day) was compared with cefteram pivoxil (CFTM-PI; 600 mg/day) in 171 patients with chronic respiratory tract infections. There was no significant difference between the clinical efficacy of the two drugs (80.2% for CFPN-PI versus 78.9% for CFTM-PI). There was no significant difference in the rate of elimination of the causative bacteria (60.5% for CFPN-PI versus 65.9% for CFTM-PI). Side-effects were observed in 6.0% of patients treated with CFPN-PI compared with 6.4% of patients treated with CFTM-PI. There were no significant differences in incidence of abnormal laboratory findings following treatment with the two drugs (13.9% for each), and none of the side-effects was severe. We conclude that CFPN-PI (450 mg/day) was as effective and as well tolerated as CFTM-PI (600 mg/day) in the treatment of chronic respiratory tract infections.

[Antimicrobial susceptibility surveillance of Streptococcus pneumoniae and Haemophilus influenzae isolates to cefteram and other antimicrobial drugs during January 2003 to July 2004].

The antimicrobial susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolates during January 2003 to July 2004 was determined to seven various antimicrobial drugs including cefteram (CFTM). The in vitro activities of these drugs against the fresh isolates were compared. The oral cephalosporins including CFTM were potently active against penicillin susceptible S. pneumoniae. The activity of CFTM and cefditoren was the most active among four oral cephalosporins. The susceptibilities of penicillin intermediate S. pneumoniae and penicillin resistant S. pneumoniae to antimicrobial agents were decreased. The MIC of CFTM was not beyond 4 microg/mL for any isolate of S. pneumoniae. The activity of CFTM was very high to beta-lactamase-negative and ampicillin-susceptible H. influenzae isolates. These MIC against all isolates were 0.03 microg/mL or less. The MIC of CFTM was not beyond 1 microg/mL for any isolate of beta-lactamase-positive H. influenzae or beta-lactamase-negative-ampicillin resistant H. influenzae. In conclusion, CFTM exhibits a potent activity against fresh isolates of S. pneumoniae and H. influenzae, and has a potential of effectiveness in the infections.

Effects of the quantity of water and milk ingested concomitantly with AS-924, a novel ester-type cephem antibiotic, on its pharmacokinetics.

The effect of the quantity of water ingested concomitantly with drugs, on the absorption of AS-924, a novel prodrug-type cephem antibiotic, was studied in five healthy adult volunteers by a cross-over method, using cefteram-pivoxil (CTER-PI) as the control drug. In addition, the effect of milk on the absorption of AS-924 was also investigated. The absorption of CTER-PI was significantly reduced when administered together with 30 ml of water compared with its absorption when administered together with 150 ml of water, whereas no such reduction was found in the case of AS-924. Ingestion of milk did not significantly affect the absorption of AS-924. These results confirm that absorption of AS-924 after oral administration is not likely to be affected by the quantity of water taken concomitantly with the drug, nor by milk.

Effect of antacid pretreatment on the pharmacokinetics of AS-924, a novel ester-type cephem antibiotic--comparison with cefteram-pivoxil.

The effect of pretreatment with ranitidine, an antacid, on the absorption of AS-924, a novel prodrug-type cephem antibiotic derived from ceftizoxime (CTIZ), was examined in eight healthy adult male volunteers by the cross-over method, using cefteram-pivoxil (CTER-PI) as the control drug. The C(max) and area under the concentration (AUC) values and cumulative urinary excretion rate (0-24 h) of cefteram (CTER) after administration of CTER-PI decreased by 32, 38 and 37%, respectively, in the ranitidine pretreatment group whereas those of AS-924 were not affected by the antacid. The urinary levels of pivaloyl-carnitine determined to evaluate the solubility of these antibiotics in the gastrointestinal tract suggested that this was not affected by ranitidine. These results indicate that the absorption of CTER-PI was affected by pretreatment with ranitidine largely due to inactivation of this antibiotic in the gastrointestinal tract at high pH rather than to a decrease in solubility. In contrast, isomerization of AS-924 was hardly induced by the elevation of pH, thus demonstrating that AS-924 was less likely to be affected by pretreatment with antacids.

Evaluation of oral antimicrobial agent levels in tooth extraction sites.

OBJECTIVE: The purpose of this study was to evaluate various oral antimicrobial agent levels in tooth extraction sites. STUDY DESIGN: The concentration of dental alveolar blood in extraction wounds after the oral administration of talampicillin (500 mg), cefaclor (500 mg), cefteram pivoxil (200 mg), cefuroxime axetil (250 mg), cefdinir (200 mg), and ofloxacin (100 mg) was determined in 338 patients and was assessed on the basis of its antimicrobial activity against Streptococcus isolated in odontogenic infections. RESULTS: The percentage of patients whose concentrations exceeded the minimum inhibitory concentration for 90% of Streptococcus was 62.5% to 100% for talampicillin at 30 to 360 minutes, 0% to 12.5% for cefaclor at 30 to 360 minutes, 18.2% to 100% for cefteram pivoxil at 30 to 480 minutes, 50% to 100% for cefuroxime axetil at 30 to 480 minutes, 0% to 50% for cefdinir at 16 to 290 minutes, and 0% to 40% for ofloxacin at 30 to 480 minutes. CONCLUSION: These results indicate that talampicillin, cefteram pivoxil, and cefuroxime axetil have minimum inhibitory concentration levels for 90% of Streptococcus in tooth sockets.

[The frequency of Streptococcus pneumoniae strains and sensitivity surveillance for several antibiotics in Gifu Prefecture].

The frequency and the antibacterial sensitivity of Streptococcus pneumoniae strains isolated from 6 key hospitals (in 5 areas) and 1 otorhinolaryngology clinic in Gifu Prefecture from February to March, 1999, were investigated with several antibiotics. A total of 128 strains of Streptococcus pneumoniae were isolated throughout the study: 47 strains (36.7%) of penicillin-susceptible S. pneumoniae (PSSP), 51 strains (39.8%) of penicillin-intermediate S. pneumoniae (PISP), and 30 strains (23.4%) of penicillin-resistant S. pneumoniae (PRSP); the resistant bacteria being relatively prominent. In these hospitals, PSSP was isolated by 38.8% in all the key hospitals and by 30% in the otolaryngology clinic with almost no discernible difference. PISP was isolated by 63.3%, higher in the otolaryngology clinic and PRSP by 28.6%, higher in the key hospitals conversely. The MIC90s in PISP and PRSP were determined with the antibiotics. In result, only cefditoren (CDTR) showed favorable antibacterial activities with the MIC90 of 0.78 microgram/ml among penicillins or oral cephems. The MIC90s of carbapenems such as imipenem (IPM), meropenem (MEPM), and panipenem (PAPM) were less than 0.39 microgram/ml; particularly, PAPM showed the highest antibacterial activities. Among new quinolones such as tosufloxacin (TFLX), levofloxacin (LVFX), sparfloxacin (SPFX), and ciprofloxacin (CPFX), TFLX showed the highest antibacterial activities with the MIC90 of 0.39 microgram/ml. Other agents showed very low antibacterial activities as the MIC90s were 25 micrograms/ml in minocycline (MINO) and more than 100 micrograms/ml in clarithromycin (CAM) and clindamycin (CLDM).

Failure of pre-diarrheal antibiotics to prevent hemolytic uremic syndrome in serologically proven Escherichia coli O157:H7 gastrointestinal infection.

A girl had hemolytic uremic syndrome after Escherichia coli O157:H7 infection, despite pre-diarrheal administration of an antibiotic that prevented detectable intestinal colonization. This report casts doubt on the advisability of antibiotic therapy for E coli O157:H7 infections and has implications for our understanding of the mechanism of this disorder.

[In vitro antibacterial activities of cefteram and other beta-lactam agents against recent clinical isolates].

In vitro antibacterial activity of the third-generation oral cephem cefteram (CFTM)--ten years after its first use in the clinical setting--against recent clinical isolates was evaluated and compared with those of other oral cephems. A total of 851 clinical isolates belonging to 13 species used in this study were collected from five medical institutions across Japan during 1996. CFTM showed excellent antibacterial activity against methicillin-susceptible S. aureus and S. pyogenes, equivalent to those of other third-generation oral cephems, except cefixime. Of the S. pneumoniae strains, a high proportion, 34.1%, were penicillin-resistant strains (PRSP), with MIC values of 2.0 micrograms/ml or above, but the MIC50 of CFTM against PRSP was 1.0 microgram/ml. CFTM and the other third-generation oral cephems showed potent antibacterial activity against E. coli, K. pneumoniae, and P. mirabilis. A few strains of E. coli, however, were highly resistant to third-generation oral cephems; that might include extended-spectrum beta-lactamase producing strains. MIC values against P. vulgaris varied significantly, depending on whether they were determined by the broth micro-dilution method or the agar dilution method; growth was observed at high concentrations in the broth micro-dilution method, in which the skip phenomenon was demonstrated, but not in the agar dilution method. The reason for this discrepancy is unknown. Most strains of S. marcescens, C. freundii, and E. cloacae demonstrated resistance to CFTM and the other third-generation oral cephems. CFTM and the other third-generation oral cephems showed excellent antibacterial activities against M. (B.) catarrhalis, N. gonorrhoeae, and H. influenzae, including ampicillin-resistant strains.

In vitro and in vivo antibacterial activities of CS-834, a novel oral carbapenem.

CS-834 is a novel oral carbapenem antibiotic. This compound is an ester-type prodrug of the active metabolite R-95867. The antibacterial activity of R-95867 was tested against 1,323 clinical isolates of 35 species and was compared with those of oral cephems, i.e., cefteram, cefpodoxime, cefdinir, and cefditoren, and that of a parenteral carbapenem, imipenem. R-95867 exhibited a broad spectrum of activity covering both gram-positive and -negative aerobes and anaerobes. Its activity was superior to those of the other compounds tested against most of the bacterial species tested. R-95867 showed potent antibacterial activity against clinically significant pathogens: methicillin-susceptible Staphylococcus aureus including ofloxacin-resistant strains, Streptococcus pneumoniae including penicillin-resistant strains, Clostridium perfringens, Neisseria spp., Moraxella catarrhalis, most members of the family Enterobacteriaceae, and Haemophilus influenzae (MIC at which 90% of strains are inhibited, < or =0.006 to 0.78 microg/ml). R-95867 was quite stable to hydrolysis by most of the beta-lactamases tested except the metallo-beta-lactamases from Stenotrophomonas maltophilia and Bacteroides fragilis. R-95867 showed potent bactericidal activity against S. aureus and Escherichia coli. Penicillin-binding proteins 1 and 4 of S. aureus and 1Bs, 2, 3, and 4 of E. coli had high affinities for R-95867. The in vivo efficacy of CS-834 was evaluated in murine systemic infections caused by 16 strains of gram-positive and -negative pathogens. The efficacy of CS-834 was in many cases superior to those of cefteram pivoxil, cefpodoxime proxetil, cefdinir, and cefditoren pivoxil, especially against infections caused by S. aureus, penicillin-resistant S. pneumoniae, E. coli, Citrobacter freundii, and Proteus vulgaris. Among the drugs tested, CS-834 showed the highest efficacy against experimental pneumonia in mice caused by penicillin-resistant S. pneumoniae.