Epimerization of moxalactam by albumin and simulation of in vivo epimerization by a physiologically based pharmacokinetic model

We investigated the mechanism of epimerization (R to S or S to R) of moxalactam in serum of rats, dogs, and humans. The epimerization of moxalactam occurred in the serum of these animals, but not in the serum filtrate. The albumin fraction of human serum purified by gel filtration catalysed the epimerization of moxalactam at an identical rate to serum, but other fractions (i.e., lipoproteins and globulins) showed slower epimerization. alpha 1-acid glycoprotein, which was eluted in the same fraction with albumin by G-200 gel filtration, did not epimerize moxalactam. The presence of 2 mM warfarin decreased the binding of R- and S-moxalactam and decreased the epimerization of moxalactam in human serum. These results demonstrate moxalactam was epimerized on the warfarin binding site on albumin in serum. Additionally, a physiologically based pharmacokinetic model shows that the epimerization of moxalactam after administration in dogs is simulated by the epimerization in serum.

Improvement of the rectal bioavailability of latamoxef sodium by adjuvants following administration of a suppository

The absorption of an antibiotic, latamoxef sodium (LMOX), following the rectal administration of a suppository containing adjuvants was investigated. A lipophilic base (Witepsol H15) was used. The rectal absorption of LMOX following the administration of a suppository without adjuvants was very low. Diclofenac sodium (DF) was used as an absorption promoter; it enhances rectal membrane permeability. The blood level of LMOX following the addition of DF(10 mg) to the base was increased only about 1.3-fold compared with that achieved with LMOX alone (difference not significant); even with a higher dose of DF, the absorption of LMOX was not sufficient. The release rate of LMOX from the base was slow. When Tween 80, a non-ionic surfactant, was added to improve the release rate of LMOX, the rate was sufficiently increased. The rectal absorption of LMOX on the addition of both Tween 80 and DF was markedly increased compared to that achieved with LMOX alone or with DF. These results indicate that the rectal absorption of LMOX after administration by a suppository was sufficiently improved by enhancing both the release rate from the base and the membrane permeability of the rectum. Lymphatic uptake and blood levels of LMOX were also investigated after the rectal administration of the LMOX preparation containing both Tween 80 and DF; the lymphatic uptake of LMOX was significantly enhanced compared with the LMOX preparation in which only DF was used as an adjuvant. The mechanism whereby adjuvants lead to the absorption of a non-absorbable drug, and the subsequent drug transportation routes through the membrane are discussed.

Epimerization kinetics of moxalactam in frozen urine and plasma samples

The epimerization of moxalactam (LMOX) in frozen urine and plasma samples was studied during long-term storage. The R/S ratio at equilibrium [(R/S)eq] at -10 degrees C was similar in urine and in rat and human plasma ultrafiltrate but differed from that in water. The (R/S)eq values in human plasma and its ultrafiltrate differed slightly, while they were the same in rat plasma and in its ultrafiltrate. The difference for the human plasma and ultrafiltrate may result from differences in plasma protein binding between R- and S-epimers in the liquid region of the frozen plasma. The change of R/S ratio in frozen human plasma continued below the collapse temperature of LMOX aqueous solution, where the liquid region appeared still to exist as determined by NMR measurement. Consequently, the biological LMOX samples should be preserved at or below -70 degrees C to prevent changes in the R/S ratio.

Pharmacokinetics of single-dose administration of moxalactam in unweaned calves

Twenty-nine healthy 17- to 29-day-old unweaned Israeli-Friesian male calves were each given a single IV or IM injection of 10 or 20 mg of moxalactam disodium/kg of body weight. Serum concentrations were measured serially during a 12-hour period. Serum concentration vs time profiles were analyzed by use of linear least-squares regression analysis and the statistical moment theory. The elimination half-lives after IV administration were 143.7 +/- 30.2 minutes and 155.5 +/- 10.5 minutes (harmonic mean +/- SD) at dosages of 10 and 20 mg of moxalactam/kg of body weight, respectively. Corresponding mean residence time values were 153.1 +/- 26.8 minutes and 169.9 +/- 19.3 minutes (arithmetic mean +/- SD). Mean residence time values after IM administration were 200.4 +/- 17.5 minutes and 198.4 +/- 19.9 minutes at dosages of 10 and 20 mg/kg, respectively. The volumes of distribution at steady state were 0.285 +/- 0.073 L/kg and 0.313 +/- 0.020 L/kg and total body clearance values were 1.96 +/- 0.69 ml/min/kg and 1.86 +/- 0.18 ml/min/kg after administration of dosages of 10 and 20 mg/kg, respectively. Moxalactam was rapidly absorbed from the IM injection site and peak serum concentrations occurred at 1 hour. The estimated bioavailability ranged from 69.8 to 79.1%. The amount of serum protein binding was 53.4, 55.0, and 61.5% when a concentration of moxalactam was at 50, 10, and 2 micrograms/ml, respectively. The minimal inhibitory concentrations of moxalactam ranged from 0.01 to 0.2 micrograms/ml against Salmonella and Escherichia coli strains and from 0.005 to 6.25 micrograms/ml against Pasteurella multocida strains.

Ocular pharmacokinetics of latamoxef and cefaclor in rabbits. Penetration into aqueous humor

Penetrations of latamoxef (LMOX) and cefaclor (CCL) into the aqueous humor after intravenous or oral administration were investigated in rabbits. Concentrations of antibiotics in plasma and aqueous humor after administration were determined periodically by microbiological assay. LMOX disappeared from plasma in a monoexponential manner with a half-life of 43 min after intravenous administration at a dose of 50 mg/kg. The maximum concentration of LMOX in aqueous humor (6.4 micrograms/ml) was observed 1 h after administration. When CCL was administered orally at a dose of 50 mg/kg, the maximum concentration of CCL in aqueous humor was 1.00 microgram/ml 1.5 h after administration, whereas the maximum plasma concentration of 19.2 micrograms/ml was observed at 30 min. Pharmacokinetic analysis (simultaneous simulation) of plasma and aqueous humor concentration-time courses was made using the best fitted compartment model examined (modified two-compartment model). Prediction of the concentration of antibiotics in aqueous humor from the plasma concentration profile was also examined using the same compartment model in a separate experiment. The predicted concentration in aqueous humor was proved to coincide reasonably well with the measured concentration.

Moxalactam vs tobramycin-clindamycin. A randomized trial in secondary peritonitis

One hundred five patients with peritonitis were randomized to receive either tobramycin sulfate plus clindamycin phosphate or moxalactam alone before surgical intervention. Fifty-nine patients were evaluable. A mean of 3.1 (moxalactam) and 3.5 (tobramycin-clindamycin) pathogens per patient were identified. Overall success rate was 85% (tobramycin-clindamycin, 24/30; moxalactam, 26/29). When patients with appendicitis were excluded, there was an observed but not statistically significant advantage of moxalactam over tobramycin-clindamycin (85% vs 67%). There were five deaths (tobramycin-clindamycin, four; moxalactam, one). Other complications included hypoprothrombinemia (tobramycin-clindamycin, five; moxalactam, five), renal dysfunction (tobramycin-clindamycin, three; moxalactam, one), and superinfection (tobramycin-clindamycin, nine; moxalactam, six). More wound infections were noted in the group given tobramycin-clindamycin. These data suggest that moxalactam is as safe and efficacious as tobramycin plus clindamycin. The observed benefits of this agent warrant study in a larger sample to verify advantages of moxalactam over combination therapy.

Comparative serum bactericidal activity against test anaerobes in volunteers receiving imipenem, clindamycin, latamoxef and metronidazole

Ten healthy volunteers received on separate days the following regimens: imipenem 500 mg, clindamycin 600 mg, latamoxef 1 g, and metronidazole 500 mg. The antibiotics were given intravenously as an infusion over 15 min. Blood samples were obtained before and 30 min, 1 and 6 h after the start of the infusion. Serum bacteriostatic and bactericidal activities were measured against the following strains of strict anaerobes: two strains of Bacteroides fragilis, one strain each of B. vulgatus, B. thetaiotaomicron, B. oralis, Fusobacterium symbiosum, Eubacterium lentum, Clostridium perfringens, and Peptostreptococcus magnus. Sera from patients receiving clindamycin showed the highest inhibitory and bactericidal activities except against B. thetaiotaomicron and F. symbiosum. Imipenem had similar inhibitory and bactericidal activity to that shown by latamoxef. Metronidazole had a moderate activity against all strains although the activity persisted for 6 h. Latamoxef was the most active antibiotic against the test strain of C. perfringens.

Effects of various doses of latamoxef (moxalactam) on haemostasis

The effects of intravenous latamoxef therapy at two doses of 3g and 6g daily for 7 days was assessed by various haemostatic parameters. With both doses, the prothrombin time, thrombin time and activated partial thromboplastin time remained within the normal range throughout the study. However, with the 6g day-1 dose there was a marked prolongation of the bleeding time associated with defective platelet aggregation to adenosine diphosphate and low dose collagen after 7 days therapy. With the 3g day-1 dose of latamoxef, there was no prolongation of the bleeding time and only minor changes in platelet aggregation responses.

Human vitreous levels of cefamandole and moxalactam

We gave 2-g intravenous doses of either cefamandole or moxalactam to 22 patients before vitrectomy. At 1 1/2 to 2 1/2 hours after administration, cefamandole vitreous concentrations varied from 0.36 to 2.05 micrograms/ml (mean, 0.94 micrograms/ml). Individual levels above the minimum inhibitory concentration of cefamandole for 90% (MIC90) of Staphylococcus aureus were found in five of 11 patients. Levels above the MIC90 for S. epidermidis were found in only two of 11 samples. Vitreous concentrations above the MIC90 of cefamandole for common gram-negative pathogens were found in only two patients. Moxalactam concentrations in the vitreous varied from 1.1 to 4 micrograms/ml 30 minutes to six hours after administration. These levels were not above moxalactam's MIC90 for S. aureus or S. epidermidis but were many times higher than the MIC90 of moxalactam for Enterobacteriaceae excluding Pseudomonas.

A double beta-lactam combination versus an aminoglycoside-containing regimen as empiric antibiotic therapy for febrile granulocytopenic cancer patients

The double beta-lactam combination of moxalactam plus piperacillin was compared with the aminoglycoside-containing regimen of moxalactam plus amikacin in a prospective, randomized trial of empiric therapy for 302 febrile episodes in granulocytopenic cancer patients. The moxalactam/piperacillin regimen was found to be as effective as the moxalactam/amikacin regimen (70 percent overall responses); responses with moxalactam/piperacillin and moxalactam/amikacin were similar for microbiologically documented infections (24 of 37, 65 percent, versus 20 of 35, 57 percent), for the subgroup with bacteremias (19 of 32 versus 14 of 28), and for clinically documented infections (41 of 58, 71 percent, versus 40 of 48, 83 percent). Responses were similar also for bacteremia in patients with persistent, profound (less than 100/microliter) granulocytopenia. Among profoundly (less than 100/microliter) granulocytopenic patients with gram-negative bacteremia, an increase in the granulocyte count to more than 100/microliter during therapy and a peak bactericidal activity of 1:16 or more (the latter noted in seven of nine moxalactam/piperacillin trials and six of nine moxalactam/amikacin trials) correlated with a favorable clinical response in 85 percent (p less than or equal to 0.00003) and 92 percent (p less than or equal to 0.044), respectively. Although serious side effects were minimal with either regimen, the double beta-lactam combination was associated with significantly less frequent nephrotoxicity (two of 145 versus 12 of 130; p less than or equal to 0.003) and ototoxicity (none of 34 versus seven of 34; p less than or equal to 0.006). The double beta-lactam combination of moxalactam plus piperacillin was found to be as effective as moxalactam plus amikacin but to have significantly less nephro- and ototoxicity.

Pharmacokinetics of cefotaxime, moxalactam, and cefoperazone in the early puerperium

Twelve parturient women volunteered to receive 1 g of cefotaxime on the second or third day postpartum by intravenous infusion over 3 min. Blood was taken from the antecubital vein of the contralateral arm at 0.25, 0.5, 0.75, 1, 2, 4, and 6 h. The concentration of cefotaxime in serum was assayed by agar diffusion, with Sarcina lutea ATCC 9341 as the indicator strain. The same 12 women received an identical dose of antibiotic 4 months after the first dose, and blood was taken at the same time intervals as in the first study to measure antibiotic levels. An additional 24 women participated in identical studies with either moxalactam or cefoperazone. Cefoperazone afforded the highest concentration in serum of the three drugs, followed by moxalactam. These differences in the concentration in serum were seen both early postpartum and 4 months later. However, the concentration in serum of all three drugs was diminished 2 and 3 days postpartum compared with 4 months postpartum. Most pharmacokinetic parameters were also significantly altered early in the puerperium relative to those obtained 4 months later. The altered pharmacokinetic behavior of antibiotics associated with pregnancy appears to persist into the early puerperium.

Imipenem coadministered with cilastatin compared with moxalactam: integration of serum pharmacokinetics and microbiologic activity following single-dose administration to normal volunteers

We administered 1 g of imipenem along with equal amounts of cilastatin (a dehydropeptidase I inhibitor) or 2 g of moxalactam intravenously over a period of 30 min to six volunteers in a crossover manner 1 week apart. The antibiotic concentrations and pharmacokinetics for each drug were determined and integrated with the microbiologic activity by measuring the duration of time that the free drug concentrations remained above the MICs for 90% of 581 clinical isolates and by measuring serum bactericidal activities against organisms which commonly infect granulocytopenic cancer patients. Moxalactam produced serum levels at 1 h after infusion of 99.9 micrograms/ml; these levels were four times greater than the plasma levels of imipenem (22.8 micrograms/ml). The trough (5.5-h) moxalactam serum levels were 10 times greater than those of imipenem (18.5 and 1.7 micrograms/ml, respectively). Essentially all of the imipenem was unbound to protein, whereas 36 to 42% of the moxalactam was unbound. Moxalactam produced free antibiotic concentrations that were above the MIC for 90% of the strains tested for more than 6 h against all of the species tested except Staphylococcus aureus (5.3 h), Enterobacter hafnia (1.6 h), and Pseudomonas aeruginosa (0 h). The imipenem concentrations were above the MIC for 90% of the strains tested for 5.6 h or more against all of the bacteria tested except Proteus spp. and Pseudomonas aeruginosa (4.5 h). The geometric mean peak bactericidal titers from volunteers receiving imipenem were more than 1:8 against all bacteria and were significantly higher than the titers from volunteers receiving moxalactam against S. aureus (1:7.3) and Pseudomonas aeruginosa (1:4.5). These data, in addition to information obtained from animal models, indicate that imipenem is a promising new candidate for carefully controlled clinical trials as a single agent for therapy of serious infections, including empiric therapy for fever in granulocytopenic cancer patients.

Serum kinetics of intraperitoneal moxalactam

Continuous intraperitoneal administration of antibiotics has been recommended as treatment for peritonitis. The necessity of simultaneous systemic administration of antibiotics remains undefined but usually is performed. Moxalactam kinetics in serum were studied in dogs receiving 15 mg/kg intravenously; 15 mg/kg intraperitoneally; 5 mg/kg hourly with peritoneal lavage; 15 mg/kg intravenously followed by 5 mg/kg hourly intraperitoneally; 15 mg/kg intraperitoneally after 24 hours of peritonitis; and 5 mg/kg hourly by peritoneal lavage after 24 hours of peritonitis. Intraperitoneally administered moxalactam resulted in sustained serum levels compared with intravenously administered drugs. Repeated exchanges in lavage fluid resulted in progressively higher serum levels with each exchange. Peritonitis results in statistically higher levels of serum antibiotic concentration when compared with controls. Continuous intraperitoneal lavage with antibiotics would not appear to require concomitant systemic drug therapy.

A novel pharmacokinetic method for analysis of placental transfer of latamoxef in humans

A novel pharmacokinetic method was developed for analysing the behaviour of a drug in tissues. The absolute transfer ratio of a drug to a tissue was defined using the pharmacokinetic parameters obtained by this method. Composite data of latamoxef (moxalactam) concentration in maternal blood, umbilical cord blood and amniotic fluid following a 2g intravenous injection to pregnant women at delivery were analysed by this method to study the drug behaviour in pregnant women, fetuses and amniotic fluid. Latamoxef kinetics in pregnant women at full term were generally similar to that in previously reported healthy subjects. The concentration of latamoxef in umbilical cord blood peaked about 2 hours after dosing then decreased in parallel with the maternal blood concentration. The amniotic fluid concentration peaked about 7 hours after administration, then decreased slowly. The absolute transfer ratios to fetus and amniotic fluid were calculated to be about 2.5 and 0.37% respectively.

Antibiotic prophylaxis in vascular surgery: pharmacokinetic study of four commonly used cephalosporins

Plasma levels of antibiotics often do not correlate well with their tissue levels. To determine optimal antibiotic coverage for prophylactic effect in vascular surgery, we studied the tissue pharmacokinetics of four cephalosporins in dogs: cefazolin, cefoxitin, cefamandole, and moxalactam for 3 hours after a single (25 mg/kg) intravenous injection. The minimal inhibitory concentration (MIC) of these antibiotics for the three most common pathogens involved in graft infections (Staphylococcus aureus, S. albus, and Escherichia coli) and their tissue concentration (TC) in the plasma, muscle, subcutaneous tissue, and aortic wall were assayed. The data are presented as TC/MIC ratio. Cefoxitin and moxalactam failed to achieve an effective therapeutic TC/MIC ratio (greater than 10) for S. aureus and S. albus in all the tissues studied whereas cefoxitin and cefamandole were above therapeutic levels. All antibiotics achieved an effective therapeutic ratio against E. coli, but cefamandole performed better (p less than 0.05) than cefoxitin; the latter reached effective levels at 3 hours. Cefamandole attained the most effective bioactive aortic tissue levels when the three most common pathogens were considered together and should therefore be considered as an antibiotic agent of choice for prophylaxis in vascular surgery.

Correlation of predicted serum bactericidal activities and values measured in volunteers

A method was devised for predicting the serum bactericidal activity of new drugs. Six healthy volunteers received 2 g moxalactam, cefoperazone and cefotaxime, respectively, as 30-min infusions in a crossover manner at one-week intervals. The pharmacokinetics of each drug was characterized and the bactericidal activity of the serum 1 h after infusion was measured against panels of six strains of Pseudomonas aeruginosa, six strains of Escherichia coli, six strains of Staphylococcus aureus, and four strains of Klebsiella pneumoniae. The minimum bactericidal concentration of each antibiotic was determined for each organism by the standard NCCLS reference method and the method of Stratton and Reller. On the basis of these values and a serum concentration-time curve constructed from individual patient pharmacokinetic parameters, the bactericidal activity of the serum 1 h after infusion was predicted. These predictions showed a 90% agreement with measured values calculated according to the method of Stratton and Reller, whereas an agreement of 74% was obtained with the reference method. This difference was statistically significant (p less than 0.001).

[Clinical experience of latamoxef in the field of neurosurgery on the penetration into the cerebrospinal fluid in the patients with postoperative meningitis]

Latamoxef (LMOX) at a dose of 2 g was intravenously administered to 12 cases with postoperative meningitis and the concentrations in serum and cerebrospinal fluid (CSF) were examined up to 2 hours and the results obtained were as follows; The average serum and CSF concentrations of LMOX were 125.0 micrograms/ml, 4.33 micrograms/ml at 0.5 hour, 80.7 micrograms/ml, 4.64 micrograms/ml at 1 hour and 45.8 micrograms/ml, 3.82 micrograms/ml at 2 hours, respectively. The clinical responses of LMOX against postoperative meningitis were revealed excellent in 4 cases and good in 8 cases. No side effects were observed. LMOX was thought to be effective agent in the treatment of the postoperative meningitis.

Cerebrospinal fluid penetration of moxalactam in ventriculostomy patients

The cerebrospinal fluid penetration of moxalactam was simultaneously investigated in three patients with presumed bacterial meningitis. When ratios of simultaneously drawn ventriculostomy to serum moxalactam levels of 1, 2, 3, and 4 h were examined, the penetration ratios were 7.8 +/- 2.4, 11.2 +/- 1.3, 14.2 +/- 2.5, and 15.0 +/- 4.9%, respectively. These ratios were not statistically different from the penetration of moxalactam calculated by the area under the concentration-time curve technique (8.97 +/- 1.89%).

The lack of inactivation of tobramycin by cefazolin, cefamandole, and moxalactam in vitro

We examined the effects of mixing tobramycin with three cephalosporins, cefazolin, cefamandole, and moxalactam. Each cephalosporin was prepared from standard powder and diluted with human serum to concentrations of 50, 250, and 500 micrograms/ml and added to 10 micrograms/ml of tobramycin in human serum. Temperature environments of 4 degrees C (refrigeration), 24 degrees C (room temperature), and 37 degrees C (body temperature) were used and sampled at 0 hours (control), and at 8, 24, and 48 hours. The results indicated no inactivation of tobramycin by any of the cephalosporins, regardless of temperature, concentration, or contact time. These results indicate that significant inactivation of tobramycin does not occur when it is combined in vitro with moxalactam, cefamandole, or cefazolin.

Assessment of serum bactericidal activity after administration of cefoperazone, cefotaxime, ceftizoxime, and moxalactam to healthy subjects

Bactericidal activity in serum produced after administration of 1-g intravenous doses of cefoperazone, cefotaxime, ceftizoxime, and moxalactam was ascertained in six healthy subjects. The assay organisms were a strain of Staphylococcus aureus which was moderately susceptible to the drugs (MBC, 2 to 8 micrograms/ml) and an isolate of Escherichia coli which was highly susceptible (MBC, 0.08 to 0.3 microgram/ml). Drug concentrations and bactericidal titers were measured from samples taken for up to 12 h after the dose. No bactericidal activity against the S. aureus strain was found at 4 to 6 h and beyond for any of the drugs. Ranking of the in vivo bactericidal activity of the drugs was cefoperazone = cefotaxime greater than ceftizoxime = moxalactam. Against the E. coli isolate, bactericidal activity was present for 8 h for cefotaxime, and for 12 h for the other drugs. Ranking of the drugs in terms of extent and duration of in vivo bactericidal activity versus E. coli was moxalactam = ceftizoxime greater than cefoperazone greater than cefotaxime. After administration of 1-g doses of these new beta-lactams, bactericidal activity in serum was maintained for 12 h against highly susceptible bacteria. More frequent (6 to 8 h) or higher (greater than or equal to 2 g) dosing appears to be necessary to achieve prolonged serum bactericidal activity against less susceptible isolates (MBC, greater than or equal to 2 to 8 micrograms/ml).

Influence of imipenem on the serum resistance of enterobacteriaceae

Following growth in a subinhibitory concentration of imipenem and additional incubation in a 20% dilution of normal human serum (NHS) for 90 minutes, five of 12 serum-resistant strains of enterobacteriaceae showed a decrease in colony-forming units of two or more logs of growth compared with the control. Two strains (of Escherichia coli and Enterobacter aerogenes) showed this phenomenon even with incubation in 5% NHS. Treatment with imipenem did not change the serum resistance of the other seven strains (two strains each of Enterobacter cloacae, Klebsiella pneumonia, and Serratia marcescens, and one strain of Proteus morganii). The phenomenon of induced serum susceptibility is dose dependent and reversible. Other beta-lactam antibiotics either caused only a slight decrease of resistance (cefsulodin, cefoxitin, cefuroxime, cefodizime-HR221) or did not influence the serum resistance at all (cefotaxime, mecillinam). Killing of the induced serum-sensitive strains appeared to be antibody dependent.

High performance liquid chromatographic determination of moxalactam in human plasma and cerebrospinal fluid

A sensitive and reproducible method for the measurement of moxalactam in plasma and cerebrospinal fluid is described. Plasma proteins were removed by precipitation with ice-cold methanol at pH 5.6 and centrifugation. The supernatant was analysed by HPLC on a mu-Bondapack/phenyl column, with a mobile phase of acetonitrile/water/PIC Reagent A (20/80/1), and detection at 280 nm. The calibration curve was linear for plasma concentrations from 10 micrograms/ml to 60 micrograms/ml. Reproducibility was 4.7% (coefficient of variation) for within-day analysis and 13.8% for day-to-day analysis. Plasma concentrations in 9 moxalactam-treated patients with severe infections ranged from 0.9 micrograms/ml to 409 micrograms/ml. Individual pharmacokinetic parameters were calculated using a personal computer. In selected cases moxalactam concentrations were also determined in cerebrospinal fluid and tracheal aspirates.

Penetration and clearance of cefoperazone and moxalactam in pleural fluid

The penetration of cefoperazone and moxalactam into pleural fluid was studied in 11 patients after intravenous infusion of 2-g doses of these agents. Clearance of these agents from pleural fluid was studied in seven patients after instillation of 1-g doses into the pleural space. The concentrations in pleural fluid after intravenous infusion of 2-g doses reached a peak of 7 to 25 micrograms/ml for cefoperazone and 9 to 35 micrograms/ml for moxalactam at 4 to 6 h after administration. These levels exceeded reported MICs for most susceptible organisms. The elimination half-life of both agents was about two to five times longer in pleural fluid than in serum. These prolonged elimination rates of both agents might be of great advantage for killing bacteria in the pleural space.

Moxalactam and piperacillin: a study of in vitro characteristics and pharmacokinetics in cancer patients

We evaluated the microbiologic characteristics including MIC determinations, synergy plate assays and serum bactericidal activity for two regimens being examined as empiric antibiotic therapy for febrile granulocytopenic cancer patients. The regimens consisted of moxalactam (4 g.i.v. q12h) plus piperacillin (75 mg/kg i.v. q6h) or moxalactam (as above) plus amikacin (levels adjusted to one hour post-infusion levels of 25 mg/l and troughs of 6-8 mg/l). Detailed pharmacokinetics were ascertained for the beta lactams. All drugs were active against a panel of 11 strains each of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. The pharmacokinetic profile showed serum levels sufficient to provide good antimicrobial activity throughout the dosing interval. Both regimens displayed synergistic or partially synergistic activity in the main for the test organisms; moxalactam plus piperacillin produced good results against S. aureus and P. aeruginosa. In the serum bactericidal assays, the moxalactam-piperacillin combination produced significantly higher mean titers at both peak and trough when compared to the moxalactam-amikacin regimen. This may be because moxalactam acts as a beta lactamase inhibitor for both staphylococcal beta lactamase, as well as the Sabath-Abraham Id type beta lactamase carried by P. aeruginosa (among others). Moxalactam-piperacillin deserves extensive evaluation as empiric therapy for the febrile neutropenic cancer patients.

Penetration of latamoxef, cefoperazone and piperacillin into the sputum of patients with cystic fibrosis

Concentrations of latamoxef, cefoperazone and piperacillin, administered intravenously, were measured in serum and sputum of cystic fibrosis patients with recurrent pulmonary infections, chronically colonized with Pseudomonas aeruginosa. Serum pharmacokinetic data were consistent with prior reports. Peak sputum to peak serum concentrations were approximately 3% for each antimicrobial. However, the more prolonged sputum concentrations of piperacillin were reflected in greater areas under the sputum concentration-time curve and a longer duration above the MIC50 of tested P. aeruginosa strains for that drug.

Pulmonary disposition of moxalactam

Moxalactam is a new synthetic oxa-beta-lactam antibiotic with a broad spectrum of activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria. It has proven clinical efficacy in pneumonia caused by a variety of infecting organisms. Therapeutic concentrations of moxalactam are achieved in most body tissues and fluids, including pleural fluid and sputum. However, assessment of the adequacy of lung tissue levels in pneumonia requires the sampling of material at an alveolar level. We performed bronchoalveolar lavage (BAL) in 13 patients one hour after they had been given moxalactam intravenously in doses ranging from 250 mg to 2 g. Absolute alveolar drug levels ranged from less than 1 to 6 micrograms/ml, and serum levels from 8 to 50 micrograms/ml. When expressed per micromole of creatinine, there was a significant relationship (r = 0.85; p less than 0.01) between serum and alveolar moxalactam levels in those patients in whom the drug concentration could be quantified accurately in BAL fluid.

Pharmacokinetic study of moxalactam in patients undergoing gynecologic operations

Moxalactam was administered prior to operation to patients undergoing operation for a known or suspected gynecologic malignancy. Subsequent plasma and tissue levels demonstrated a prolonged duration of action and rapid concentration in pelvic organs after infusion.

The serum bactericidal activity of latamoxef (moxalactam), cefoperazone and cefotaxime

We determined the serum bactericidal activity 1 h after the end of 2 g, 30 min infusions of latamoxef, cefoperazone and cefotaxime in six volunteers against six strains each of Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa. All produced excellent serum bactericidal activity against E. coli. Latamoxef and cefotaxime were superior for K. pneumoniae. Cefoperazone produced the highest titres against Staph. aureus. None of these agents produced sufficient bactericidal activity against Ps. aeruginosa to be useful in initial single agent therapy for the septic, granulocytopenic cancer patient.

Antimicrobial activity of latamoxef (moxalactam) against both Bacteroides fragilis and Escherichia coli in an intraperitoneal abscess model

The antimicrobial activity of latamoxef (moxalactam) was examined against Bacteroides fragilis and Escherichia coli individually and in combination in an intraperitoneal tissue capsule animal model during ten days of therapy given at 40 mg/kg/day. Mean peak serum concentration was 32.8 mg/l. Mean capsular latamoxef concentrations during samplings on days three, seven and ten were 1.8 mg/l for Bact. fragilis, 0.7 mg/l for E. coli, less than 0.5 mg/l for polymicrobial infection and 3.4 mg/l in uninoculated controls. Capsular colony counts for Bact. fragilis and E. coli monomicrobial infections decreased by 2.2 and 4.0 log10 cfu respectively and 1.9 and 3.6 log10 cfu in polymicrobial infections. Latamoxef concentrations necessary to eliminate viable bacteria in both monomicrobial and polymicrobial capsules were not achieved.

Moxalactam penetration into normal heart valve, cardiac vegetations, and myocardium in relation to protein binding and physiological distribution spaces

Rabbits with catheters implanted in the left ventricle were given a single dose of moxalactam and sacrificed at various times thereafter for measurement of the concentration of this antimicrobial agent in serum, heart muscle, and various heart valves. Penetration into both extravascular sites was rapid; steady state was achieved within 5 min after the dose. Moxalactam showed essentially complete penetration into valve lesions, whereas concentrations in heart muscle were only 20% of those in serum. The physiological distribution of moxalactam in heart muscle was beyond the inulin space, but substantially lower than total body water. This myocardial distribution ratio was not predicted by the serum-free fraction or blood trapped in tissues alone, but was in good agreement with that of extracellular fluid plus blood trapped in tissues. The moxalactam distribution profile was most compatible with that of drugs which are excluded from cells but readily distributed throughout extracellular fluids. This explains its nearly complete penetration into heart valves as well as its incomplete penetration into heart muscle, since the two sites differ in their relative proportions of cells and extracellular fluid spaces.

[Fundamental and clinical studies on latamoxef in the perinatal period]

Fundamental and clinical studies on latamoxef (LMOX) in the perinatal period were carried out, and following results were obtained. Concentration of LMOX was showed high peak levels in maternal serum, umbilical serum and amniotic fluid. LMOX seemed to be a very transferable compound to human tissues. LMOX was administered to 28 cases of various perinatal infections. Clinical responses were excellent in 13 cases, good in 15 cases and poor in none. And 140 cases of prophylactic use in the field of perinatal period were evaluated in good. No side effect was seen and an abnormal laboratory finding, the increase of GPT, was observed in only 1 case. LMOX was a highly useful antibiotic in perinatal infections, the safe dose range of LMOX into the perinatal mothers was estimated to be 2 g/day, with the maximum safe dose being 4 g/day.

Latamoxef and the newborn

Thirty one preterm neonates who had clinical, radiological, or bacteriological evidence of infection and who would normally have received gentamicin and penicillin were treated with latamoxef (Moxalactam) 100 mg/kg/day. All were examined prospectively for clinical improvement and possible side effects. Biochemical and haematological values were monitored and pharmacokinetic variables determined. Thirty babies improved during treatment; latamoxef was effective in eradicating the infecting organisms in 7 of 9, including three babies infected with Lancefield group B streptococci. High serum concentrations of latamoxef were achieved after either intravenous or intramuscular administration and accumulation did not occur. Treatment had no effect on renal or hepatic function nor did it result in increased serum values of non-protein bound bilirubin. Clotting studies, where performed, were normal and no babies had bloody stools. Two disulfiram-like reactions were recorded. Latamoxef proved a safe and efficacious alternative to gentamicin with penicillin in the initial treatment of neonates with clinical evidence of infection.

Moxalactam therapy of Haemophilus influenzae type b meningitis in children

Thirty-four children with Haemophilus influenzae type b meningitis were given prospectively either moxalactam (200 mg/kg/day) or ampicillin (400 mg/kg/day) plus chloramphenicol (75 mg/kg/day). One patient in each group died. The mean duration of fever, clinical response, sequential cerebrospinal fluid findings, and incidence of neurologic sequelae were similar between groups. Moxalactam cerebrospinal fluid bioactivity was significantly greater than that of ampicillin or chloramphenicol throughout therapy. Neutropenia, liver enzyme abnormalities, and diarrhea were not significantly different. In eight of 11 patients given moxalactam (versus one of 14 controls) there was complete elimination of gram-negative aerobic flora in the stools by day 10 (P = 0.002); however, none acquired Clostridium difficile. Moxalactam in effective therapy for H. influenzae type b meningitis.

Interactions of moxalactam and tobramycin in normal volunteers and in patients with impaired renal function

In studies of the in vivo and in vitro interactions of moxalactam and tobramycin, normal volunteers and anuric patients were given one of the drugs or both drugs simultaneously, and the antibiotics were incubated separately or in combination in pooled human plasma. In both normal volunteers and patients with renal failure, the rate of elimination of tobramycin increased when the drug was given in combination with moxalactam. In patients with normal renal function, the rate of elimination of moxalactam decreased when the drug was given in combination with tobramycin; in contrast, this value did not decrease when the combination was given to anuric patients. In vitro, neither drug was affected by the presence of the other. Thus, the observed changes in elimination rates apparently are not caused by a chemical interaction that can be demonstrated in vitro. However, they are of sufficient magnitude to be of potential clinical significance.

Evaluation of latamoxef as initial therapy of bone and joint infections in childhood

The efficacy and pharmacokinetics of latamoxef were evaluated during initial therapy of bacteriologically proven bone and joint infections in children. Pharmacokinetic evaluation revealed no significant difference in latamoxef biodisposition after the first dose or at steady state. Peak serum concentrations exceeded 140 mg/l and 8-hour trough concentrations averaged 6.5 mg/l. The patients were infected with a variety of gram-positive and gram-negative pathogens. All were sensitive to readily achievable serum concentrations of latamoxef; moreover, the serum concentration remained above the MIC of the most resistant organism for at least 7 h after each dose. All patients responded favorably to initial therapy and there have been no relapses in more than 2 years of clinical follow-up.

A study of cefoxitin, moxalactam, and ceftazidime kinetics in pregnancy

In 27 women with fetuses affected by beta-thalassemia major, termination of gestation between 19 and 21 weeks was induced by amniocentesis and intrauterine instillation of prostaglandin F2 alpha. Pharmacokinetics in maternal blood and amniotic fluid were studied after at least three doses of one of the following antibiotics and before prostaglandin F2 alpha infusion: (1) cefoxitin, 2 gm, intravenously, 1/2-hour infusion, three times per day; (2) moxalactam, 2 gm, intravenously, 1/2-hour infusion, three times per day; and (3) ceftazidime, 1 gm, intramuscularly, three times per day. Successful amniotic fluid levels effective against various pathogens implicated in maternal-fetal infections appeared at least 3 hours beyond administration of the drug and ranged between 2.3 and 6.7 micrograms/ml, 1.56 and 15 micrograms/ml, and 1.5 and 5 micrograms/ml for cefoxitin, moxalactam, and ceftazidime, respectively. Beyond the third-hour after infusion a percentage ratio of amniotic fluid to simultaneous maternal serum level of almost greater than or equal to 50 was constantly observed for all studied antibiotics. Cefoxitin serum levels were about the same as those in nonpregnant women, while moxalactam and ceftazidime serum levels were 50% lower than the expected level in normal individuals.

Moxalactam for the treatment of bacterial meningitis in children

Increasing resistance to antibiotics in meningeal pathogens has stimulated a search for new antimicrobial agents for the treatment of bacterial meningitis. Moxalactam penetrates well into infected cerebrospinal fluid (CSF) and is highly active against most gram-negative bacteria. The clinical efficacy and safety of moxalactam in the treatment of childhood meningitis caused by Haemophilus influenzae (25 patients) or Neisseria meningitidis (five patients) was evaluated in a random, uncontrolled study. The penetration of the antibiotic into CSF was also evaluated in these patients and in another five children with bacterial meningitis. The clinical results were excellent, with 29 of 30 cases cured. The single adverse clinical reaction noted was the development of a wound hematoma in a postoperative patient; this problem may have been related to moxalactam therapy. The levels of moxalactam achieved in CSF greatly exceeded the minimal bactericidal concentrations for the infecting organisms. Moxalactam appears to be safe and effective as primary therapy for meningitis caused by H influenzae or N meningitidis.

A comparison of the pharmacokinetics and tissue penetration of ceftriaxone, moxalactam and cefotaxime

One gram each of moxalactam and cefotaxime and 0.5 g of ceftriaxone was administered intravenously to six volunteers. The pharmacokinetics and tissue penetration (as measured by a blister fluid model) were studied. The initial (i.e. 15 min) concentrations of the agents were 89.7 mg/l, 101 mg/l and 55 mg/l for ceftriaxone, moxalactam and cefotaxime respectively. The serum half-lives differed considerably, being 8.8, 2.8 and 1.2 h respectively. All agents penetrated the blister fluid rapidly the maximum penetration being found with ceftriaxone, namely 32.7 mg/l.

[Evaluation of latamoxef in the treatment of infections of newborn infants]

The usefulness of latamoxef (LMOX) in the treatment of newborn infants was investigated. The results that were obtained are summarized below. LMOX was injected intravenously in a dose of about 20 mg/kg, and 30 minutes later the concentration of the drug in the serum was determined. In a very low-birth-weight infant, weighing only 978 g at the time of birth, the serum concentration on the 3rd day after birth was 94 micrograms/ml, while it was found to be 100 micrograms/ml when the dosing and determination were performed on the 37th day after birth. Another premature infant weighed 1,980 g at birth, and on the 8th day of life the serum concentration was 73 micrograms/ml. The half-lives of LMOX in these 3 administrations were 4.74, 3.95 and 3.20 hours, respectively. LMOX was administered by intravenous injection to 4 patients diagnosed as having 6 diseases (2 patients each had both septicemia and a urinary tract infection; 1 patient had pneumonia; 1 patient had septicemia). Each dose ranged from about 15 to 25 mg/kg, and 3 doses were administered daily (in 1 patient, 4 doses were given over a 2-day period). The evaluation of the clinical results for each disease case showed 4 excellent cases and 2 poor cases. The 2 poor cases consisted of 1 case of pneumonia caused by S. aureus, and 1 case of a mixed urinary tract infection caused by E. coli and S. faecalis.(ABSTRACT TRUNCATED AT 250 WORDS)

Moxalactam therapy of serious infections

Twenty-four patients were treated with moxalactam for 25 serious infections. Nineteen patients were septicemic and 18 presented severe underlying diseases considered to impair the normal response to bacterial pathogens. All of the pathogens had MICs of less than 12 mg/l except one Pseudomonas aeruginosa strain with an MIC of 32 mg/l. The dosage ranged from 3 to 12 g/day; the route of administration was either i.v. or i.m. The duration of treatment was six to 26 days. Six patients had urinary tract infections (three bacteremia), four had pulmonary abscesses (two bacteremia), five had septic thrombophlebitis (five bacteremia) and ten had miscellaneous infections (nine bacteremia). Twenty-two (92%) patients responded favourably. Four patients (16.6%) developed superinfections due to organisms highly resistant to moxalactam: three Streptococcus faecalis, one Bacteroides fragilis and one Aspergillus flavus. Tolerance was good. Nine moderate adverse reactions were observed: three cases of transient eosinophilia, two of phlebitis, three hepatic enzyme alterations and one rash. Moxalactam kinetics were measured in serum from 15 patients with normal renal function after receiving 1 g i.v. over 30 min. The mean peak level after the infusion was 82.8 +/- 12.1 (SE) mg/l; the mean trough level 8 h later was 6.2 +/- 1.7 (SE) mg/l. The serum half-life was 2.6 +/- 0.6 (SE) h for the beta phase. Plasma clearance was 76.8 +/- 8.2 ml/min. Moxalactam was found to be highly effective in the therapy of life-threatening infections.

Studies on lamoxactam penetration into the aqueous humor of the human eye

Eighteen patients scheduled for surgical lens removal were assigned to six groups of three patients each. These patients received 25 mg/kg lamoxactam i. v. 30 to 180 min prior to surgery. In the course of the operation, aqueous humor was obtained and a serum sample taken to determine the antibiotic concentration. The mean peak serum level was 154.5 mg/l after 30 min; it was still 46.4 mg/l after 3 h. The lamoxactam concentrations in the aqueous humor increased slowly. Peak levels after 2 h were 4.2 mg/l. The ratio of aqueous humor level: serum level after 1 h was 4.7%, after 1.5 h 5.3% and after 2 h 6.9%. The ratio then remained constant up to the third hour. Aside from some gram-positive bacterial species and Pseudomonas species, all relevant microorganisms which cause eye infections are included in lamoxactam's spectrum of susceptibility.

Serum bactericidal activity and kinetics of azlocillin and moxalactam after single and combined administration

Ten healthy volunteers received 5 g azlocillin and 2 g moxalactam iv in single and combined administration. Serum and urine concentrations were measured with bioassay and HPLC (high pressure liquid chromatography), and serum bactericidal activity (SBA) was determined at 1 h and 6 h against 6 different clinical isolates. The combined applications of both antibiotics resulted in minor differences in serum kinetics and urine recovery in comparison to single administration. SBAs of both antibiotics against Enterobacteriaceae were between 1:4 and 1:8.4 for azlocillin and between 1:3 and 1:8 for moxalactam after 1 h. The combination of both beta-lactam antibiotics did not result in a decrease in SBA against any strain; rather all Enterobacteriaceae showed a slight increase of SBA at 1 h. It can be concluded from these results that combination therapy with azlocillin and moxalactam has no adverse influence on the pharmacokinetics or the bactericidal activity of either substance.

Penetration of moxalactam and cefazolin into atrial appendage after simultaneous intramuscular or intravenous administration

This study compared the penetration of moxalactam and cefazolin into the human atrial appendage after simultaneous administration of both drugs by two routes. Nineteen adult patients scheduled for coronary vein bypass surgery randomly received 10 mg of moxalactam and cefazolin per kg by either the intramuscular or intravenous (bolus) route on administration of anesthesia. Concentrations of cefazolin in serum were significantly greater than concentrations of moxalactam at all times for both routes of administration. There were no significant differences, however, in the concentration of these drugs in atrial appendages, although concentrations of both agents administered intravenously were significantly greater than of drugs administered intramuscularly. (19.3 +/- 10.3 and 21.0 +/- 11.0 micrograms intravenously versus 8.3 +/- 3.6 and 10.1 +/- 3.2 micrograms/g intramuscularly for moxalactam and cefazolin, respectively).