Determination of unbound cefmetazole in rat blood by on-line microdialysis and microbore liquid chromatography: a pharmacokinetic study

A specific and sensitive microbore liquid chromatographic method for the determination of unbound cefmetazole in rat blood was developed. A microdialysis probe was inserted into the jugular vein/right atrium of a Sprague-Dawley rat. Cefmetazole (10 mg/kg, i.v.) was then administered via the femoral vein. Dialysates were automatically injected into a liquid chromatographic system via an on-line injector. Isocratic elution of cefmetazole was achieved by LC-UV within 10 min. Intra- and inter-assay accuracy and precision of the assay were < or = 10%. The detection limit of cefmetazole was 20 ng/ml. Pharmacokinetic analysis of results indicated that unbound cefmetazole levels in rats best fit a biexponential decay model.

Distribution of free and liposomal cefoxitin in plasma and peritoneal fluid in a porcine intra-abdominal sepsis model

The plasma and peritoneal fluid pharmacokinetic parameters obtained after the intravenous administration of free and liposomal cefoxitin were studied in a porcine model of intraabdominal sepsis. No prior assumptions were made to predict the number of compartments pertaining to drug clearance from the administration of either cefoxitin formulation. The experimental data obtained were applied to fit mathematical models of multiexponential drug clearance and the pharmacokinetic data were found to best fit a two-compartment open model. Liposomal encapsulation significantly altered the plasma drug distribution pattern resulting in changes in the magnitude of a number of pharmacokinetic parameters examined. The mean post-distributive half-life of liposomal cefoxitin was substantially longer than that of free cefoxitin by at least 3 times. The peritoneal cavity appeared to provide a reservoir for the initial distributive phase of rapid drug clearance from the plasma compartment followed by a less-rapid post-distributive phase. The cumulative drug level, as determined by the area under the concentration curve (AUC) as a function of time, in the plasma of animals treated with liposomal cefoxitin was about 3-4 fold as high as that of animals treated with free cefoxitin. The differences in pharmacokinetic parameters appeared to account for the improved therapeutic efficacy of liposomal cefoxitin in this animal model.

False-positive eluate reactivity due to the low-ionic wash solution used with commercial acid-elution kits

BACKGROUND

During the use of commercial red cell (RBC) acid-elution kits for adsorption and elution (adsorption/elution) studies with anti-D, unexpected reactive eluates (anti-D) were obtained from D- RBCs. Such results were not obtained with a parallel xylene method or, historically, with heat and ether methods.

STUDY DESIGN AND METHODS

Single-donor and commercial polyclonal anti-D samples were incubated with D+ and D- RBCs. Acid eluates were prepared by the manufacturers' directions. Variations in the wash step of the eluate preparation included the use of commercial kit wash solution versus phosphate-buffered saline versus solutions of various ionic strengths.

RESULTS

Anti-D was eluted from 20 of 22 samples of D- RBCs after incubation with commercial polyclonal anti-D (titer 512) and from 2 of 3 samples of D- RBCs incubated with single-donor anti-D (titer 256). With a low-titer (16) single-donor anti-D, 0 of 4 eluates from D- RBCs reacted. When phosphate-buffered saline was substituted for the commercial wash solution, 0 of 11 D- RBC eluates reacted, as compared with 9 of 11 D- RBCs that yielded positive 1+(-)2+ eluates with the commercial wash solution. If the recommended initial phosphate-buffered saline wash was omitted before the use of the commercial wash solution, the eluate reactivity was stronger (2+(-)3+). When low-ionic-strength (< 0.03 M) saline was substituted, anti-D was eluted from D- RBCs. All last washes were nonreactive. Antiglobulin tests on all adsorbing D- were negative.

CONCLUSION

Commercial wash solutions used for acid elution are at low ionic strength and commonly yield superior eluates, but in the presence of high-titer antibodies, false-positive eluates can result. It is our belief that the low-ionic-strength wash solution caused aggregation of IgG and nonspecific attachment of IgG on RBCs. Aggregates will contain IgG serum antibodies in proportion to the titer of the antibody. It is this nonspecifically bound antibody that is eluted from antigen-negative RBCs.

Treatment of osteomyelitis with antibiotic-soaked porous glass ceramic

We have developed a new drug delivery system using porous apatite-wollastonite glass ceramic (A-W GC) to treat osteomyelitis. A-W GC (porosity, 70% and 20% to 30%), or porous hydroxyapatite (HA) blocks (porosity 35% to 48%) used as controls, were soaked in mixtures of two antibiotics, isepamicin sulphate (ISP) and cefmetazole (CMZ) under high vacuum. We evaluated the release concentrations of the antibiotics from the blocks. The bactericidal concentration of ISP from A-W GC was maintained for more than 42 days, but that from HA decreased to below the detection limit after 28 days. The concentrations of CMZ from both materials were lower than those of ISP. An in vivo study using rabbit femora showed that an osseous concentration of ISP was maintained at eight weeks after implantation. Osteoconduction of the A-W GC block was good. Four patients with infected hip arthroplasties and one with osteomyelitis of the tibia have been treated with the new delivery system with excellent results.

The enhancing mechanism of capric acid (C10) from a suppository on rectal drug absorption through a paracellular pathway

Capric acid (C10) enhanced the absorption of cefoxitin sodium in a concentration-dependent manner following the rectal administration as a suppository in rats. The optimal concentration of C10 was 13%. C10 administered as a suppository also reduced rectal membrane resistance (Rm), showing that the above enhancing effect was induced by widening the paracellular pathway. Both the enhancing effect on the absorption and the reducing effect on Rm were inhibited by W7, an inhibitor of myosin light chain kinase. These results supported that, as shown in the in vitro Caco-2 cell system, the C10 effect on the paracellular pathway is due to activating the contraction of Ca(2+)-calmodulin-dependent actin filament.

[Clinical study on transfer into lung tissue of cefminox]

Nineteen patients who underwent pulmonary resection due to lung diseases were administered with 2 g of cefminox (CMNX) by intravenous drip infusion just before surgery. CMNX levels in the serum and lung tissue were determined and pharmacokinetic parameters were derived. The obtained results are summarized as follows: 1. Pharmacokinetic parameter (K1/K2) derived from serum and lung tissue concentrations using deconvolution method was 0.46. 2. CMNX was useful for prophylaxis of postoperative infections with lung resection.

Cefminox: correlation between in-vitro susceptibility and pharmacokinetics and serum bactericidal activity in healthy volunteers

Plasma concentration of cefminox and serum bactericidal activity against four ATCC strains (Escherichia coli 25992, Klebsiella pneumoniae 13833, Serratia marcescens 8100 and Bacteroides fragilis 25285), were determined over a 24 h period after administration of cefminox 1 and 2 g to six healthy volunteers in a randomized, cross-over, single blind study. The increase observed in the area under the bactericidal curve (AUBC) with the 2 g dose was at least 3.5 times that seen with the 1 g dose for all four test strains and was larger than predicted by the corresponding increase (1.84 times) in the area under the serum concentration versus time curve (AUC); a correlation (r = 0.88, P = 0.0001) between the cefminox concentration and the serum bactericidal titres was, however, observed with all four strains tested. The MBC6h showed a better association with the serum bactericidal titre (P < 0.01) than did the MIC or MBC.

[A clinical study of transfer of cefminox and piperacillin into pulmonary tissue]

Serum concentrations of cefminox (CMNX) and piperacillin (PIPC) and their transfer into pulmonary tissue during surgery were serially studied following 1-hour intravenous instillation of 1 g of CMNX or PIPC immediately before thoracotomy, and the following results were obtained. Maximum serum concentrations of CMNX and PIPC were observed 1 hour after the commencement of administration, and their levels gradually decreased thereafter. The mean peak level of CMNX was 72.21 micrograms/ml, and T 1/2 was 1.62 hours. The mean peak level of PIPC was 43.26 micrograms/ml, and T 1/2 was 1.54 hours. In the pulmonary tissue, mean concentrations of CMNX in the normal pulmonary (alveolar) tissue were 28.80, 26.50 and 17.80 micrograms/g at 2.5, 3 and 4 hours, respectively, after the commencement of administration, and the corresponding levels for bronchiolar tissue were 19.6, 18.40 and 20.53 micrograms/g, respectively. The mean concentrations of PIPC in the normal pulmonary (alveolar) tissue were 18.97, 7.34 and 5.0 micrograms/g at 2, 3 and 4 hours, respectively, after the commencement of administration, and the corresponding levels for bronchiolar tissue were 7.2, 9.20 and less than 0.2 micrograms/g, respectively. PIPC also showed favorable transfer into the hilar lymph node tissue and obstructive pneumonitic lesions. The transfer of both drugs into pulmonary tissue suggests that both drugs are useful for the treatment of respiratory infectious diseases and the prevention of postoperative infections.

An application of microdialysis to drug tissue distribution study: in vivo evidence for free-ligand hypothesis and tissue binding of beta-lactam antibiotics in interstitial fluids

To prove the free-ligand hypothesis for extravascular equilibration and tissue binding mechanism of beta-lactam antibiotics, the microdialysis technique has been employed for the lung, the muscle and the liver in rats. Cefminox, a cephem antibiotic, and SY5555, a new penem antibiotic, were used in the present study. During the constant infusion of each antibiotic with simultaneous infusion of antipyrine, the microdialysis studies were performed and the dialysate concentrations were determined. The dialysate concentration was extrapolated to the in vivo unbound concentration in tissue interstitial fluids (Cisf,u) according to the extrapolation method which was derived from the clearance concept. This extrapolation method incorporates the effective dialysis coefficient of a reference compound, antipyrine, which is used to correct the difference between in vivo and in vitro permeabilities of microdialysis fiber. The values of Cisf,u values for cefminox and SY5555 in the lung, muscle and liver were close to the unbound concentrations in the venous plasma leaving these organs. Furthermore, good coincidences were obtained between the unbound concentrations of SY5555 in lung and muscle interstitial fluids estimated from the total concentrations in homogenized tissues and those extrapolated by the microdialysis studies. Consequently, the present microdialysis studies provided the in vivo evidence that 1) the free-ligand hypothesis for extravascular equilibration of beta-lactam antibiotics is true, and that 2) beta-lactam antibiotics are restricted in the interstitial space in a noneliminating organ and bind only with albumin existing in this space.

Cefminox sodium penetration into prostatic tissue with and without inflammation

The concentrations of cefminox sodium (CMNX) in serum and prostatic tissue were determined in 36 cases of prostatic hyperplasia with and without inflammation. Mean ratios of CMNX in tissue over concentration in serum were 0.11 +/- 0.07 for patients with inflammation and 0.09 +/- 0.06 for those without inflammation. There was no significant difference between the two groups. These data suggest that CMNX penetration into prostatic tissue is not influenced by the presence of inflammation.

Evaluation of cephalosporins/cephamycins with antianaerobic activity by integrating microbiologic and pharmacokinetic properties

When evaluating antimicrobial agents, in vitro microbiologic activity and pharmacokinetics are important factors, but these data are usually not assessed simultaneously. The purpose of the study was to compare cefoxitin, cefotetan, ceftizoxime, cefotaxime (CT), desacetylcefotaxime (DACT), and CT/DACT (1:1 ratio) by integrating their microbiologic activity against clinical isolates of Bacteroides fragilis with their pharmacokinetic properties. Minimal inhibitory concentrations (MIC) were determined by the agar dilution method. Steady-state serum concentration--time profiles were simulated for 2-gm doses in a 70-kg patient using ADAPT software and pharmacokinetic data from published studies. Serum protein binding (%) of each agent was also obtained from published studies and used to calculate the unbound serum concentration--time profiles. As estimates of pharmacodynamic activity, time below the MIC (T less than MIC) and percentage of the dosing interval below the MIC (% INT less than MIC) were calculated for individual isolates using total and unbound serum concentrations. Data analysis included MIC50, MIC90, range, breakpoint susceptibility, and analysis of variance for T less than MIC and % INT less than MIC (Scheffé post-hoc test, P less than 0.05). The MIC90 of cefotetan was at least a twofold dilution lower than the other agents. However, using unbound (pharmacologically active) serum concentrations, T less than MIC and % INT less than MIC for ceftizoxime (at a simulated eight-hour dosing interval) were significantly smaller than with the other antibiotic regimens. Integration of in vitro and pharmacokinetic data may provide additional information to assist in the evaluation of antimicrobials. For B fragilis from our institution, the pharmacodynamic profile of unbound ceftizoxime is superior to the other antianaerobic cephalosporins/cephamycins tested.

Role of new cephamycins in the management of obstetric and gynecologic infections

The results of in vitro and in vivo studies of cefmetazole, a second-generation cephamycin, were reviewed. Cefmetazole's spectrum of activity includes clinical coverage of many Enterobacteriaceae, staphylococci, streptococci, Haemophilus species, pathogenic Neisseria organisms, Moraxella (Branhamella) catarrhalis and anaerobic bacteria. Cefmetazole is generally two to eight times more potent than cefoxitin against organisms within their spectra and is most active against staphylococci (minimal inhibitory concentration90 = 2.0 micrograms/mL). Methicillin-resistant Staphylococcus aureus strains are more susceptible to cefmetazole, alone or in combination with fosfomycin, than to any other cephamycins, and cefmetazole is remarkably resistant to the beta-lactamases produced by aerobic and anaerobic bacteria. The incidence of adverse drug reactions is low (8.8% in the United States, 2.2% in Japan), and the drug has been demonstrated to have cost-containment potential.

[Investigation on clinical efficacy and passage into ascites of cefminox in diffuse peritonitis associated with infantile acute appendicitis]

Cefminox (CMNX), one of newly developed cephamycin antibiotics, was administered to 7 cases of diffuse peritonitis associated with infantile acute appendicitis to determine its concentrations in the blood, the appendiceal tissue and the purulent ascites and simultaneously to investigate its clinical efficacy. CMNX was intravenously injected at a dose of 20 mg/kg (at a maximum amount of 1.0 g/body) before operation and intravenously by bolus injection or by drip infusion twice daily after operation for 3 to 11 days in a total dose of 2.36 to 14.06 g. Fourteen strains of bacteria were isolated from the purulent ascites: Escherichia coli was isolated from 6 cases but superinfections in 5 cases. MICs of CMNX against these isolated organisms were at or lower than 3.13 micrograms/ml for 12 out of 14 strains. CMNX penetrated into the appendiceal tissue and the purulent ascites very well. The concentrations in the pus reached higher than those in the tissue in about 1 hour after administration and were found to reach as high as 9.63 micrograms/ml in 5 hours after administration. Its clinical efficacies were excellent in 4 cases, good in 2 cases and poor in 1 case. No subjective or objective adverse reactions were observed nor any abnormalities were found in laboratory examinations.

[Study on the concentration of cefminox sodium in serum and prostatic tissue]

The concentration of cefminox sodium (CMNX) in serum and prostatic tissue was determined in 25 patients with benign prostatic hypertrophy. One gram of CMNX was intravenously administered prior to transurethral prostatectomy. Blood and prostatic tissue were obtained 1 hour after the administration of CMNX. The concentration of CMNX was 69.17 +/- 17.47 micrograms/ml (mean +/- SD) in serum and 5.33 +/- 2.33 micrograms/g (mean +/- SD) in the prostatic tissue. The ratio of the prostatic tissue concentration/serum concentration was 8.18 +/- 4.45% (mean +/- SD). There was no correlation between serum and prostatic tissue level of CMNX.

Paradoxical activity of beta-lactam antibiotics against Proteus vulgaris in experimental infection in mice

In previous papers (Y. Ikeda and T. Nishino, Antimicrob. Agents Chemother. 32:1073-1077, 1988; Y. Ikeda, T. Nishino, and T. Tanino, Antimicrob. Agents Chemother. 31:865-869, 1987), we reported that many of the 7-aminothiazolyl cephalosporins, such as cefmenoxime, showed paradoxically reduced activity against Proteus vulgaris at higher concentrations, whereas these paradoxical effects were not observed for other types of cephalosporins, such as cefbuperazone and cefoperazone. In this study, we compare the therapeutic effect of cefmenoxime with that of cefbuperazone and explore the in vivo paradoxical effect of cefmenoxime by using an experimental infection model in mice. In an intraperitoneal infection with P. vulgaris 11, the survival rate with cefmenoxime was increased to 43% at 3.13 mg/kg but was lower at higher doses. On the other hand, cefbuperazone did not show such a paradoxical therapeutic effect. In mice infected with P. vulgaris 11, cefmenoxime levels in both serum and peritoneal washings were rapidly reduced and beta-lactamase activities in the peritoneal cavity were increased at higher cefmenoxime doses. These findings suggested that high levels of cefmenoxime at the infection site induced increased production of beta-lactamase, which then rapidly inactivated the antibiotic. We conclude that the paradoxical therapeutic effect of cefmenoxime against P. vulgaris occurs by the same mechanisms as the in vitro effect and that the high beta-lactamase inducibility and low beta-lactamase stability may account for the paradoxical therapeutic effect of cefmenoxime against P. vulgaris.

[Pharmacokinetics and antimicrobial effect of cefminox in serum and ascitic fluid for experimental purulent peritonitis in mice]

An appropriate choice of antibiotics plays an important role in the treatment of purulent peritonitis. We examined the pharmacokinetics and antimicrobial effect of cefminox (CMNX) on experimental purulent peritonitis made by intraperitoneal injection of E. coli and/or B. fragilis in mice from elimination of bacteria in peripheral blood and ascitic fluid. 1) E. coli in blood and ascitic fluid decreased within one or two hrs after intravenous injection of CMNX or latamoxef (LMOX) in a dose of 25 or 100 mg/kg. The bacteria-elimination effect of CMNX was superior to that of LMOX. 2) Comparing with the effect of LMOX, B. fragilis in ascitic fluid acceleratively decreased in shorter period by the intravenous administration of CMNX. This indicated that peritoneal transfer of CMNX was better than that of LMOX. 3) Clearance of E. coli and B. fragilis from blood was accomplished by single dose (25 mg/kg) intravenous administration of CMNX, whereas it was not by the same dose of LMOX, resulting in LD50 of CMNX and LMOX were 5.0 and 39.3 mg/kg, respectively. Thus, we should select some antibiotics which shows good clearance of the causative organisms from blood and ascitic fluid as well as antimicrobial effect as a therapeutics for acute purulent peritonitis caused by E. coli and/or B. fragilis.

Experimental studies on the pharmacokinetics and therapeutic effect of cefbuperazone in biliary infection

A study was carried out using an experimental biliary infection model to investigate the pharmacokinetic characteristics and therapeutic effect of cefbuperazone in the rabbit. Thirty rabbits were divided into three equal groups; a control group of normal animals, a group of infected animals receiving no cefbuperazone, and a group of infected animals receiving 50 mg cefbuperazone/kg intramuscularly. The experimental infection was made by direct inoculation of a suspension of E. coli into the common bile duct after ligation. The results showed that extremely high levels of cefbuperazone were achieved in bile and tissues of the biliary tract and were higher than those in the blood. Moreover, the levels were maintained at effective concentrations even after 6 hours. Viable bacterial cells from bile and the gall-bladder were barely detectable 24 and 48 hours after infection in the cefbuperazone-treated group, whilst counts remained high in the other infected group. White blood cell counts were increased at 24 hours after infection but were significantly lower in the cefbuperazone-treated group. Histological examination revealed marked inflammatory changes in the gall-bladder and bile duct of infected, untreated animals but few, mild changes only were seen in cefbuperazone-treated animals. Similarly, total bilirubin and liver enzymes were markedly increased in infected animals, but transaminases and alkaline phosphatase were significantly lower in the treated compared to the untreated group. The findings indicate, therefore, that cefbuperazone can be a useful antibiotic in biliary infection.

[Excretion of antibiotics into bile and urine in patients with external cholecystostomy done in order to treat obstructive jaundice]

Biliary and urinary concentrations and recoveries of 3 different antibiotics (piperacillin (PIPC), cefbuperazone (CBPZ) and cefoperazone (CPZ], after intravenous bolus injection were studied using the crossover method with external cholecystostomies done in order to treat obstructive jaundice due to complete obstruction of the lower biliary tract; the concentrations of antibiotics in bile and urine were determined by means of a high performance liquid chromatography method. Drug concentrations and recoveries in the bile after intravenous injection of these antibiotics were at levels in the order of CPZ greater than CBPZ greater than PIPC. Since our patients were inflicted with various malignancies which made them impaired in terms of biliary excretion of antibiotics, the concentrations of those drugs in the bile were lower than those previously reported by several investigators. However, CBPZ and CPZ showed sufficient levels of excretion into the bile and their amounts were high enough when compared to the value of MIC 80% reported recently against Escherichia coli and Klebsiella pneumoniae, which are known to be main pathogens of biliary system infections. The excretion of CPZ into the bile was invariably found to be 2 times or more as high as the other 2 drugs tested. Concentrations and recoveries of the 3 antibiotics excreted into urine were similar to the cefotaxime excretion, of which into urine had been reported to be excellent. Thus, CBPZ and CPZ appeared to be effective against biliary system infections, even with blockage of antibiotics excretion into the bile.

Comparative pharmacokinetics of cefotetan and cefoxitin in patients undergoing hysterectomies and colorectal operations

Forty patients undergoing hysterectomy and 16 patients undergoing colorectal surgery were given intravenous 2 g doses of cefotetan (20 in the hysterectomy group and 8 in the colorectal group) or cefoxitin (20 in the hysterectomy and 8 in the colorectal group) before surgery. Serum samples were obtained simultaneously with tissue samples. Concentrations of each drug in serum and tissue were measured by high-pressure liquid chromatography. In both experiments, the composite drug concentration profile as a function of time in serum was consistent with that observed in nonsurgical patients; that is, a half-life of approximately 3.5 hours and 0.8 hours for cefotetan and cefoxitin, respectively. This also was true of tissue kinetics, in that tissue profiles appeared parallel to, but somewhat lower than, serum. At 20 minutes after administration, the peak myometrium concentration was 158 micrograms/g for cefotetan, and the corresponding serum concentration was 298 micrograms/ml. For cefoxitin, the corresponding values were 66 micrograms/g and 101 micrograms/ml. At 47 minutes, the cefotetan tissue and serum concentrations were 29 micrograms/g and 235 micrograms/ml respectively, and the corresponding values for cefoxitin were 15 micrograms/g and 43 micrograms/ml. Similar relationships were observed with these drugs in colorectal tissue. Although both antibiotics provide good concentrations during the early phase of surgery, cefotetan's concentrations persisted longer, which may be relevant in the prevention of infection in prolonged surgical procedures.

[Study of the prostatic tissue cefbuperazone (CBPZ) level]

The concentration of Cefbuperazone (CBPZ) was determined in the prostatic tissue and serum of 23 patients with benign prostatic hypertrophy. One or 2 of CBPZ was injected intravenously prior to transurethral prostatectomy. The mean CBPZ level in prostatic tissue and tissue/serum ratio at 1 hour was 17.4 +/- 7.2 micrograms/g (28.9 +/- 9.1%) in 10 patients administered 1 g of CBPZ, and 34.7 +/- 1C.2 micrograms/g (35.7 +/- 13.2%) in 13 patients administered 2 g of CBPZ. Serum and prostatic tissue CBPZ levels responded satisfactorily to the dose of CBPZ. Weights of resected prostatic tissue were not correlated to the tissue CBPZ level. Judging from the inhibitory concentration of CBPZ (minimum inhibitory concentration 80), the prostatic tissue CBPZ level was sufficient against pathogenic bacteria, particularly E. coli, K. pneumoiae and P. mirabilis for a relatively long time. For this reason CBPZ is a very useful drug for treatment of bacterial prostatitis and postoperative infection of prostate.

[Clinical study on transfer into lung tissue and postoperative prophylactic effect of new cephamycin antibiotics, particularly cefotetan and cefbuperazone]

The following findings were obtained in our clinical study on the transfer of cefotetan (CTT) and cefbuperazone (CBPZ), new antibiotics of cephamycin series, into the lung tissue and on their postoperative prophylactic effect. 1. The mean serum concentration 30 minutes after the start of an intravenous drip infusion of 1 g of CTT over a period of 30 minutes was 99.4 micrograms/ml, and it decreased gradually thereafter with the half-life of 2.45 hours. After an intravenous drip infusion of 1 g of CTT over a period of 1 hour, the mean peak concentration of 104.1 micrograms/ml appeared 1 hour after the start of the infusion, and mean concentrations at 2, 4 and 6 hours after the infusion were 63.4, 34.3 and 27.0 micrograms/ml, respectively, with the half-life of 2.35 hours during phase beta. 2. Following 30 minutes of an intravenous drip infusion of CTT, the tissue CTT level in normal lung tissues was Tmax 1.82 hours and Cmax 19.8 micrograms/g. After 1 hour of an intravenous drip infusion the mean concentration in the tissues was at the peak of 39.7 micrograms/g in 2 hours after the start of an administration, while mean levels at 3, 4 and 6 hours after an administration were 32.2, 22.2 and 8.76 micrograms/g, respectively, with Tmax of 1.82 hours and Cmax of 30.5 micrograms/g. 3. Following an intravenous drip infusion of 1 g of CBPZ over a period of 1 hour, the mean serum drug concentration 1 hour after the start of infusion was at its peak, 83.3 micrograms/ml, while mean values at 2, 4 and 6 hours after the start of an administration were, respectively, 40.4, 19.8 and 9.62 micrograms/ml, with the beta-phase half-life of 2.03 hours. 4. By 1 hour after the start of intravenous drip infusion of CBPZ, the mean tissue level in normal lung tissues was at the peak of 31.6 micrograms/g, while mean levels at 3, 4 and 8 hours after an administration were 16.2, 11.0 and 4.56 micrograms/g, respectively, with Tmax of 1.67 hours and Cmax of 21.9 micrograms/g. 5. Infused CBPZ was transferred into bronchiole tissues. Drug concentrations in these tissues at 3 and 5 hours after the start of the infusion were 7.87 and 4.85 micrograms/g, respectively, with their ratios to the peak serum level were 9.4 and 5.8%, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

[A study of transfer of cefbuperazone into postoperative exudates in patients with cancer mastectomy or thyroidectomy]

Cefbuperazone (CBPZ) at a dose of 2 g was administered postoperatively by intravenous drip infusion to 9 patients subjected to radical mastectomy and 10 others subjected to thyroidectomy then levels of CBPZ in postoperative exudates were measured and its prophylactic effect on postoperative infections was determined. 1. Serum CBPZ levels in the patients after cancer mastectomy and thyroidectomy on postoperative day 1 were similar to those in healthy adults. 2. Levels of CBPZ in the postoperative exudates in patients subjected to cancer mastectomy reached a mean peak value of 66.3 micrograms/ml (range: 26.0-99.6 micrograms/ml) in 0-3 hours after administration, and the mean CBPZ level at 6 hours after administration was 33.3 micrograms/ml (range: 19.1-54.1 micrograms/ml). 3. As compared to the cases of cancer mastectomy, levels of CBPZ in postoperative exudates in patients subjected to thyroidectomy varied considerably from a patient to another: a mean peak level of 76.4 micrograms/ml (range: 31.3-128 micrograms/ml) appeared in 0 to 6 hours after administration. 4. There was no correlation between CBPZ levels in the exudate and hemoglobin levels or hematocrit values. 5. Likely because of the CBPZ administration at 4 g/day for 2 to 6 days postoperatively to 19 patients, postoperative infection was absent and no side effect attributable to this drug occurred in any of the patients. Because levels of CBPZ in postoperative exudates in patients subjected to cancer mastectomy or thyroidectomy were greater than MICs for principal Gram-positive and Gram-negative bacteria, it is likely that this drug is a useful agent for prophylaxis against postoperative infections in patients undergoing cancer mastectomy or thyroidectomy.

[Laboratory and clinical studies on cefotetan in respiratory tract infections]

Seventy five patients with respiratory infections, including 40 cases of acute pneumonia, 33 cases of secondary infection after chronic pulmonary diseases and 2 cases of pulmonary abscess, were treated with cefotetan (CTT, Yamatetan) by drip infusion in order to evaluate its clinical efficacy. The overall rate of effectiveness was 83.8%. CTT was examined comparatively with other beta-lactam antibiotics for antibacterial activity on clinically isolated strains of 3 major respiratory pathogens including Haemophilus influenzae, Branhamella catarrhalis and Streptococcus pneumoniae. Minimum inhibitory concentrations (MIC's) of CTT on H. influenzae were less than 3.13 micrograms/ml regardless of the production of beta-lactamase by these organisms. As to B. catarrhalis, CTT also exerted an antibacterial activity enough to control the proliferation of all the strains at a level of 1.56 micrograms/ml. Against S. pneumoniae, on the other hand, CTT exhibited the lowest activity of all the drugs tested but still showed MIC's of 3.13 micrograms/ml or less. Drip infusion of CTT at a dose of 2 g brought about an average maximum blood concentration of 342 +/- 25.7 micrograms/ml and an average half-life in blood of 2.48 +/- 0.41 hours Maximum sputum concentration of the drug, however, was variable among the cases tested, ranging from 0.40 to 1.80 micrograms/ml. Side effects of the drug were observed in 5 cases or 6.7%. Four of them had some allergic symptoms; i.e., pyrexia and eruption. One patient was especially diagnosed as possible drug-induced interstitial pneumonia during the treatment with the drug. The diagnosis was confirmed by transbronchial lung biopsy and lymphocyte blastogenesis by CTT in vitro. As to abnormal laboratory findings, blood transaminases were elevated during drug administration in 13 cases or 17.3%, but were reduced back to the normal level after the withdrawal of the drug.

Pharmacokinetics and tissue kinetics of 1 gm cefotetan prophylaxis in abdominal or vaginal hysterectomy

Plasma and tissue levels of cefotetan after a single-gram intravenous preoperative dose were measured. Levels were high in some tissues (parametrium, fascia) but quite low in others (subcutaneous fat). The implications as to the prophylactic effectiveness of this drug are addressed.

[Changes in concentration of cefotetan in blood and lung tissue after intravenous administration]

Cefotetan (CTT), a newly-developed cephamycin antibiotic, has been used widely for the treatment of various infectious diseases because of its excellent antibacterial potency and dynamic transport in vivo. Although the drug transfer to almost every organ, tissue, and body fluid has been studied, only a few reports are available regarding the transfer to lung tissue. In the present study, 1 g of CTT was intravenously injected in a single dose to each of 22 patients subjected to pulmonary resection. Subsequently, its concentrations in blood and lung tissue were measured in sequence. The degree of transfer of the drug to the lung tissue was calculated to evaluate the pharmacodynamics of CTT in vivo. The following results were obtained in this analysis. 1. The T1/2(beta) of the concentration in blood was 4.18 hours, and AUC0-infinity was 478.7 micrograms.hr/ml. 2. Cmax in the lung tissue was 31.5 micrograms/g, and Tmax was 0.83 hour, and tissue concentrations decreased in parallel to blood concentrations. CTT was transferred to the lung tissue to achieve high concentrations following an intravenous administration. Since high concentrations are maintained for a long period of time, this antibiotic is expected to exert an excellent effect in the prevention and the treatment of respiratory infections.

Cefotetan: comparative and noncomparative studies in obstetric and gynecologic infections

Cefotetan is a recently introduced cephamycin antibiotic for parenteral administration, with a broad spectrum of antibacterial activity. Its elimination half-life of three hours or more allows a twice-daily dosage schedule. A noncomparative trial of cefotetan yielded a satisfactory clinical response in the treatment of all of ten patients with pelvic infection. Subsequently, we did a prospective, randomized comparative study of 53 patients with pelvic infections treated with either cefotetan (2 gm IV every 12 hours) or cefoxitin (2 gm IV every six to eight hours). Both drugs showed similar clinical efficacy and antimicrobial activity (100% [n = 36] with cefotetan and 94% [n = 17] with cefoxitin, the difference not statistically significant). A mean of 21.3 gm of cefotetan was required, as compared with 34.4 gm of cefoxitin, a statistically significant difference (P less than .001). Use of cefotetan is therefore more cost effective.

[Pharmacokinetics of cefmetazole during and after surgical operations]

Cefmetazole (CMZ), with its relatively broad antibacterial spectrum, good stability to beta-lactamases and a high degree of safety, has established a place in the antibacterial therapy. In this study the pharmacokinetics of CMZ during and after surgical operations were investigated. CMZ in a dose of 2 g was administered intravenously to 15 cases operated upon for ailments of abdominal organs (10 cases of cholecystolithiasis and 5 cases of early or resectable gastric cancer). The serum samples were taken during and on the 2nd or the 3rd day after operation. Concentrations of CMZ in serum were measured by bioassay with Micrococcus luteus ATCC 9341 and by a high performance liquid chromatography (HPLC) method. CMZ concentrations during the operation was at higher level than on the 2nd or the 3rd day after the operation. In cholecystolithiasis, the half-life time (T 1/2) was 2.11 hours during operation and 1.42 hours after the operation. In cases of gastric cancer, T 1/2 was 1.31 hours during operation and 2.21 hours after the operation. In cholecystolithiasis, area under the curves (AUCs) were 469.39 micrograms.hr/ml during operation and 294.44 micrograms.hr/ml after the operation. In cancer cases, AUC's were 339.83 micrograms.hr/ml during and 329.75 micrograms.hr/ml after operation. Any postoperative infections and adverse reactions were not observed in these cases. Therefore, CMZ would be very effective and available for its prophylactic role.

Pharmacokinetics of cefotetan in elderly subjects after intramuscular administration

The pharmacokinetics of cefotetan were studied in 10 healthy male subjects 65-75 years of age with normal liver function and a creatinine clearance of greater than 80 ml/min after single 2 g intramuscular doses. The mean plasma level at 0.5 h was 52.50 +/- 9.16 micrograms/ml. Peak concentrations were 91.78 +/- 12.02 micrograms/ml at 3 h, declining to 10.33 +/- 2.18 micrograms/ml at 18 h, 4.0 +/- 1.12 micrograms/ml at 24 h after the start injection. The percentage of the dose recovered in urine (0 to 24 h) was 60.3%. Cefotetan plasma clearance showed a statistically significant correlation (r = 0.956, p less than 0.001) with measured creatinine clearance and the positive intercept ordinate confirmed a nonrenal clearance of the drug (biliary excretion). The normal age-related changes in cefotetan kinetics were relatively small and dosage adjustment was not necessary for normal elderly subjects requiring cefotetan.

Biliary penetration of cefbuperazone in the presence and absence of obstructive jaundice

In thirteen patients with normal liver function, the mean concentrations of cefbuperazone in hepatic bile, gall bladder bile and gallbladder tissue 30 min after injection were 1134.8 +/- 36.8 (mean +/- S.E.M.) mg/l, 6.6 +/- 3.0 mg/l and 26.1 +/- 7.6 mg/l, respectively. In patients with obstructive jaundice, cefbuperazone concentrations in bile were 99 +/- 29.2 mg/l (mean +/- S.E.M.) 1 h post-dose and decreased to 13.9 +/- 5.1 mg/l 6 h post-dose. In both groups of patients biliary concentrations of cefbuperazone were higher than the MICs of most organisms causing biliary infection.

[A study of prostatic tissue levels of cefbuperazone]

The concentration of Cefbuperazone (CBPZ) were determined by bioassay in the serum and prostatic tissue of 36 patients with benign prostatic hypertrophy, who underwent transurethral resection. One gram of CBPZ was injected intravenously prior to surgery. Pharmacokinetic analysis was performed using the two or three compartment model theory. The maximum serum level of CBPZ was 82.2 micrograms/ml at 30 min after the start of CBPZ administration and biological half-life was 97.3 min. CBPZ concentration in prostatic tissue reached a maximum level of 26.3 micrograms/g at 50 min following CBPZ administration. The prostatic tissue level was 28-40% of the serum level. These results suggested that intravenous administration of CBPZ would be extremely effective against pathogenic bacteria, particularly Enterobacter, E. coli, Klebsiella, Serratia, Proteus and Bacteroides, judging from its prostatic concentration.