MT-141 is a new cephamycin type antibiotic with a broad spectrum of antibacterial activities. The antibacterial activity of MT-141 was compared with cefotetan (CTT), latamoxef (LMOX), cefmetazole (CMZ) and cefoxitin (CFX). The results are summarized as follows.
1) MT-141 possessed a broad spectrum of in vitro antibacterial activity against gram-positive and gram-negative bacteria except P. aeruginosa. MT-141 was more effective than CMZ and CFX against gram-negative bacteria, although MT-141 was less active than CTT and LMOX. Especially in the case of B. fragilis, the activity of MT-141 was more potent than CTT and LMOX. The activity of MT-141 against gram-positive bacteria was slightly less than those of CMZ and CFX.
2) Bactericidal activity of MT-141 against E. coli and K. pneumoniae was confirmed by determining the minimum bactericidal concentration (MBC).
3) MT-141 was stable against both R-plasmid mediated and chromosome mediated β-lactamases as well as CTT, LMOX, CMZ and CFX. Moreover, MT-141 was found to possess an inhibitory activity against a number of various types of β-lactamase.
4) In vivo activity of MT-141 against experimental infections of mice with E. coli and K. pneumoniae was more active than those of other cephamycin antibiotics when compared with its in vitro efficacy.

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MT-141, a new cephamycin (7 α-methoxycephalosporin) antibiotic with a D-cysteine moiety in its 7 β-side chain, exerted a rapid lytic action on many gram-negative bacteria such as Escherichia coli. Not only logarithmically growing cells of E. coli K-12, but also cells in the early stationary phase could be lysed rapidly by this antibiotic. Similarly, the antibiotic inhibited not only the growth of E. coli cells that had been freshly spread on an agar plate, but also that of densely cultured cells that had been spread on the plate for 3 hours. Growing cells treated with this antibiotic at low concentrations showed characteristic morphological changes, in addition to normal, single bulges, before lysis of most cells. These changes were twin bulges about 180° apart in the growing zone of the cells, and multiple bulges at rather irregulary located positions on the cell surface. As MT-141 did not bind to E. coil penicillin-binding proteins more tightly than most other cephamycins, the observed novel, rapid lytic action of this antibiotic was assumed to be due in part to an unknown novel mechanism involving the 7 β-side chain structure.

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In vitro and in vivo antibacterial activities of MT-141, a new cephamycin antibiotic, were compared with those of cefmetazole, cefoxitin, cefazolin, cefmenoxime and latamoxef.
MT-141 was active against gram-negative and gram-positive bacteria showing greater activity than other cephamycins particularly against gram-negative bacteria including E. coli, K. pneumoniae, Proteus sp.(P. mirabilis, P. vulgaris, M. morganii, P. rettgeri & P. inconstans) and S. marcescens, but less active than cefmenoxime and latamoxef. Activity of MT-141 against B. fragilis was stronger than any other cephems tested.
MT-141 was as stable as other cephamycins to inactivating enzymes derived from 22 strains of 11 species.
Therapeutic efficacy of MT-141 was comparable to latamoxef being superior over cefmetazole in experimental infections on mice caused by K. pneumoniae, C. freundii and S. marcescens.

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The antibacterial activity of a newly developed cephamycin antibiotic, MT-141, was compared to that of cefmetazole (CMZ) and latamoxef (LMOX), and the following results were obtained:
1) MT-141 had a wide spectrum of antibacterial activity against gram-positive and gram-negative bacteria. The in vitro antibacterial activity (MIC) of MT-141 was slightly superior or similar to that of CMZ but was inferior to that of LMOX.
2) MT-141 had a dose-dependent potent bactericidal activity against E. coli, K.pneumoniae, P. morganii and Serratia sp., and a markedly decreased cell counts at the early stage of its addition. Inhibition of regrowth after removal of MT-141 was slightly stronger than that of CMZ.
3) When the relationship between MIC and MLC (minimal lethal concentration) was examined, it was found that 3-hour-MLC of MT-141 accorded with its MIC, and MT-141 exerted an excellent bactericidal activity within a short time.
4) When the affinity for penicillin binding proteins of E. coli was examined, it was found that MT-141 had a marked affinity for PBP 1A, 1Bs and 3.
5) The therapeutic effect was examined in mice infected with E. coli No.29, E. coli KC-14, K. pneumoniae KC-1, P. morganii 101, Serratia sp. GN 629, and S. marcescens T-55.The results revealed that MT-141 had a more excellent therapeutic effect than CMZ and LMOX.
6) When fluctuations in number of bacteria were examined in the mouse peritoneal cavity, the data supporting the ED₅₀ of each drug were obtained.

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Studies were performed on the sensitivity of clinical isolates to MT-141 and the penetration of this antibiotic to the cerebrospinal fluid (CSF) of rabbits with experimental meningitis induced by inoculation of Staphylococcus aureus.
The minimum inhibitory concentrations (MIC) of MT-141 were compared with those of cefmetazole. Against S. aureus, MT-141 was inferior to cefmetazole, but it was slightly superior against E. coli and K. pneumoniae and approximately the same against Serratia. For P. aeruginosa, the MICs of both of these antibiotics were in excess of 100μg/ml.
In the study on the penetration of MT-141 to the CSF of rabbits with experimental meningitis, the data were averaged for 4 animals.When MT-141 was administered at 100mg/kg by intravenous injecton, the peak concentration in the CSF occurred at 1 hour post-injection and was 18.1±0.43μg/ml. The maximum CSF: serum concentration ratio was 5.48%.The CSF: serum ratios of the areas-under-the-curve (AUC) at 1, 2 and 3 hours were 7.23%, 11.9% and 15.5%.
The CSF: serum half-life ratio was 4.46. These values are better than for any of the conventional cephamycin antibiotics.
On the basis of the above results, it was concluded that MT-141 is a new antibiotic that can be considered to have potential for further clinical trial in the field of pediatrics.

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Quantitative determination methods of MT-141 in biological fluids are described. Among various microbiological methods tested, a cup-plate method using Vibrio percolans ATCC 8461 as a test organism in a Nutrient agar turned out to be most suitable for determining MT-141 levels in biological fluids.
As diluents, 0.05 M phosphate buffer (pH 7.0) could be used for diluting urine samples, and Moni-trol I or Consera for serum samples. For the latter samples, the buffer could also be used if they were more than 10 fold diluted with it. The lowest detectable concentration of MT-141 by above methods was 0.25 μg/ml.
HPLC method was found to be a good alternative for determining MT-141 levels in biological fluids and the results by this method were in good agreement with those by microbiological assay method.
MT-141 was stable for more than a week at 5°C or below in human serum, urine and bile.

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MT-141 was intravenously administered to rabbits and dogs at a dose of 20 or 40mg/kg in order to compare its pharmacokinetics with that of cefmetazole (CMZ) and cefotaxime (CTX), and following results were obtained.
1) The serum level of MT-141 was higher than those of CMZ and CTX in either rabbits or dogs. In MT-141, dogs showed higher serum level than rabbits did.
2) Dogs and rabbits showed similar biological half-life of about 43 minutes in MT-141. In CMZ, however, the half-lives in dogs and rabbits were 36 minutes and 15 minutes respectively. CTX showed similar biological half-life in dogs of 34 minutes to that of MT-141.
3) Successive administration of MT-141 to dogs at a dose of 40mg/kg twice a day for 14 days did not affect its serum level and biological half-life.
4) Urinary excretion of MT-141 in rabbits and dogs after 24 hours accounted for 90% or more showing that MT-141 was mainly excreted through the kidney.
5) A small amount of bioactive urinary metabolite, N-acetyl-MT-141, which had not been found in human urine, was found in rabbits (0.32%) and dogs (3.21%).

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MT-141 was intravenously infused to rabbits at a dose of 40mg/kg in order to compare its distribution to various tissues with that of cefmetazole (CMZ), and the following results were obtained.
1) The concentration of MT-141 was highest in the kidney, followed by serum, uterus, lung, pericardiac fluid, ovarium, trachea, heart, liver, pancreas, spleen, bile, thymus, muscle, aqueous humor in decreasing order.
2) The concentration of MT-141 in all the tissues or body fluids tested were higher than those of CMZ except for bile, so better distribution of MT-141 than CMZ to the tissues was suggested.
3) Biological half-life of MT-141 or CMZ in serum was about 37 minutes or 12 minutes respectively.
4) The half-life of MT-141 in the kidney was about 50 minutes. It was apparently longer than that of CMZ in the kidney.
5) When MT-141 was infused to rabbits at a dose of 40mg/kg twice a day for 14 days, no accumulation of the drug in tissues was found.

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Renal excretion mechanism of MT-141, a novel cephamycin antibiotic, was studied in dogs and rats. The serum level and the cumulative urinary excretion of MT-141 and CBPC administered with probenecid were compared with those of MT-141 and CBPC administered without probenecid. There was no effect of probenecid on the serum level and urinary excretion of MT-141. On the other hand, in the case of CBPC, an antibiotic actively secreted in the renal tubules, the serum level of CBPC administered with probenecid was higher throughout the experiment than that of CBPC administered alone. Moreover, the renal excretion of CBPC was remarkably inhibited by the coadministration of probenecid in dogs. From the results of the clearance experiments in rats, iodopyracet, a potent active secretion inhibitor, failed to diminish the excretion ratio (ER) of MT-141.
Accordingly, MT-141 is not actively secreted in the renal tubules, and mainly excreted by the glomerular filtration of unbound drug in plasma in dogs and rats.

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In the treatment of infectious diseases, it is very important to know the MIC of the antibiotics against the pathogenic bacteria and the distribution of the drug to the infected target tissues. This study investigated the serum, various body fluids and tissue concentrations of MT-141, a new semisynthetic cephamycin, which in resistant to β-lactamase, and has a broad bactericidal spectrum anainst various bacterial species. One gram was administered intravenously before or during operations to 27 patients with infectious diseases. They were 5 cases of birialy tract infection, 15 cases of acute localized peritonitis due to appendicitis and 7 cases of other diseases. Tissue specimens and various body fluid samples were taken during the operations and from the removed organs. The MT-141 concentrations were determined by means of bioassay using Vibrio percolans ATCC 8461 as the test organism.
The MT-141 concentration in the common duct bile ranged from 6. 6 to 67. 8 μg/ml at 22 to 149 minutes after intravenous bolus injection of 1 g of MT-141. These level in the gall bladder bile ranged from 2.8 to 76.8 μg/ml, and that in the gall bladder wall showed 29. 8 to 55.5μg/g. In a case of cholecystitis, cholangitis with mechanical jaundice due to choledocholithiasis and liver dysfunction (S-GOT 85, S-GPT 105, Al-P 22. 8 and total bilirubin 13.5μg/dl), the MT-141 levels in the common duct bile were lower than in the other cases, and that were also lower than those in the gall bladder bile. The levels were at highest in the gall bladder wall. These results show that the MT-141 enters in gall bladder bile through the gall bladder wall in the cases of obstructive jaundice. In the other 3 cases, the cystic duct was obstructed, the MT-141 levels in the gall bladder bile were lower than those in gall bladder wall. These results show that MT-141 enters the gall bladder bile through the gall bladder wall in the cases of obstructive cystic ducts.
The MT-141 concentration in the infected appendix wall ranged from a trace to a range of 69.7 peg at 10 to 35 minutes after injection. In 3 cases of empyemic appendicitis, the MT-141 concentrations were 6.8, 18.7 and 46.1μg/g in the appendix wall, and 18.7, 33.6 and 74.2 μg/ml in pus from the appensix, respectively. The MT-141 concentrations in the pus were higher than that those in the appendix wall itself. The MT-141 concentration in purulent ascites ranged from 8.5 to 139.5 μg/ml at 2 to 55 minutes after administration.
The MT-141 concentrations in common duct bile, gall bladder bile, gall bladder wall, infected appendix wall, pus in the appendix, purulent ascites and other tissues were superior to the MICs of almost all of the organisms which were isolated from these cases. Therefore, MT-141 appears to be very useful drug when used for chemotherapy of acute peritonitis, biliary tract infection and other infectious diseases of surgical field.

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MT-141, a newly-developed cephamycin antibiotic, was intravenously drip-infused in a dose of one gram to patients with biliary tract diseases. Then the drug levels were determined for the bile collected from a PTC-drain, choledochal bile obtained during surgery, gall bladder bile and extirpated gall bladder wall. The results were as follows.
1. The mean durg levels in the bile and gall bladder 1 to 3 hrs after administration of MT-141were 21.2μg/ml in the common bile duct, 15.9μg/ml in the gall bladder and 15.4μg/g in the gall bladder wall. The highest level of transfer was thus to the common bile duct.
2. The transfer of MT-141 to the bile depended on the internal pressure of the bile duct, i. e., it was a mean of 25.7μg/ml in patients without obstruction of the common bile duct, but as low as 12.0μg/ml in those with obstruction. In the patients with obstruction, the levels just after receiving PTCD and 2 weeks after receiving it were 3.4μg/ml and 10μg/ml, respectively.
3. The transfer of MT-141 to the bile and gall bladder wall differed with the individual patient, and it was influenced more by the degree of inflammation of the gall bladder wall than by the presence or absence of a bile duct obstruction. In both occasions, the drug levels were very low in patients with strong inflammation. The drug levels in the gall bladder wall were, however, 20μg/g or more in 2 of the 3 patients with moderate inflammation, indicating that MT-141 should have therapeutic efficacy against cholecystitis.

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MT-141, a new parenteral cephamycin antibiotic, was administered to 21 healthy male volunteers to study its tolerance and pharmacokinetics, by intramuscular injection (0.5g), intravenous bolus injection (0.5g and 1g), 1-hour intravenous drip infusion (1g and 2g), multipule intravenous bolus injection (1g, at 12 hour intervals, 11 times) and multipule 1-hour intravenous drip infusion (2g, at 12 hour intervals, 11 times).
In the examinations on tolerance such as subjective and objective symptoms, physical examination, haematology, biochemistry, urinalysis, etc., no abnormalities attributable to MT-141 were noted.
MT-141 achieved high serum levels after intramuscular, intravenous bolus injection and intravenous drip infusion, corresponding to the increase of the administerd dose. The serum half life of MT-141 was 2.17-2.98 hours, which was comparatively long, and even at 8-9 hours after administration, 3.37-10.6 μg/ml of MT-141 was detected in serum.
MT-141 was not inactivated in the body and about 90% of the dose was excreted within 12-13 hours after administration regardless of dose levels or administration routes.
In multipule dose of MT-141 (1g i. v. bolus injection and 2g i. v. drip infusion), there was no variation in the serum level and urinary excretion level, nor tendency to accumulation.
From the above results, MT-141 was considered to be a safety drug with favorable pharmacokinetics, and from its high antibacterial activity, MT-141 was expected to be a clinically effective drug in various infection.

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The antibacterial activity of MT-141, a new cephamycin antibiotic, was tested aginst each 27 clinical isolates of 7 species, using plate dilution method with inoculum size of 10⁶cells/ml. The peak concentrations of MT-141 in MIC distributions were obtained at 6.3-12.5μg/ml forS. aureus, 0.4 for E. coli, 0.4-0.8 for K. pneumoniae, 0.8-1.6 for P. mirabilis, 0.8 for P. morganii, 6.3-25 for S. marcescens, and >100 forP. aeruginosa.
Pharmacokinetics of MT-141 were investigated in 6 healthy male volunteers. Intravenous adminisstration of the drug at a dose of 0.5g or 1g yielded that mean serum levels measured by bioassay method were 89.0μg/ml at a dose of 0.5g and 176.7μg/ml at a dose of 1g after 5 minutes, after 1 hour, 41.0 and 80.3, and after 8 hours, 3.9 and 8.5, respectively.
The β-phase biological half-life of the drug were estimated to be 2 hours approximately.
The urinary excretion rates within 8 hours were about 78% at two different doses. The pharmacokinetics of MT-141 were compared with those of latamoxef (LMOX) using the cross-over test.
The results show that the data of MT-141 were similar to those of LMOX.
Twenty eight patients with infections were treated with MT-141 at a daily dose of 2g twice a day by intravenous drip infusion. The clinical effect to the treatment were excellent in 13 cases, good in 8 cases, fair in 4 cases, and poor in 3 cases. The effectiveness rate was calculated as 75%. As to the side effect, one eosinophilia was observed.

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To evaluate the clinical efficacy of MT-141, the treatment was made with the drug in 12 patients, including 2 with acute bronchitis, 6 with pneumoniae, 1 with lung abscess, 1 with acute cystitis, 1 with chronic cystitis and 1 with acute pyelonephritis. Responses were excellent in 2 patients, good in 6, fair in 1 and poor in 3. Of the 16 patients, 4 patients showed the following abnormal laboratory findings after the treatment; decrement of erythrocyte and hemoglobin, erythrocyte and hemoglobin in each one case, and elevation of S-GPT in one case.

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Clinical investigation on MT-141, a new cephamycin, was performed and the results obtained were as follows:
Among 8 patients treated with MT-141 via drip infusion twice daily (2g) for their respiratory tract infection due to H. influenzae, B. catarrhalis or E. coli, 5 cases resulted in bacteriologically eradicated.
In two cases with H. influenzae or E. coli showed the change to P. aeruginosa or P. rnaltophilia as causative agent, respectively. The remaining case with H. influenzae and E. aerogenes showed no any change. The clinical results were effective in 5 cases (62.5%). No adverse effect clearly due to this drug was observed except two cases in which GOT, GPT and LDH elevated transiently during the administration. From the above results, it was suggested that MT-141 is useful for respiratory tract infections, particularly for the acute exacerbation of chronic pulmonary diseases.

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In vitro antimicrobial activity of MT-141, a new derivative of cephamycin, was examined by a broth dilution method with Dynatech MIC 2000 system. Also, the therapeutic efficacy of MT-141 was evaluated in patients with respiratory tract infections.
The minimum inhibitory concentrations (MICs) of MT-141 against the following 120 strains of clinical isolates were compared with those of cefmetazole (CMZ), cefotiam (CTM), cefoperazone (CPZ), and ceftizoxime (CZX) against each 20 strains of S. aureus, E. coli, K. pneumoniae, S. marcescens, E. cloacae and P. aeruginosa. Against S. aureus, MT-141 was shown to be less active than CMZ, CPZ and CZX. In contrast, MT-141 was far more active than CMZ, although less active than CZX, against E. coli and K. pneumoniae, and more active than CMZ and CTM against S. marcescens and E. cloacae. But, MT-141 was almost inactive against P. aeruginosa.
Ten patients suffering from respiratory tract infections were treated with intravenous drip infusion of MT-141 at the dose of one gram twice a day. The response to the treatment with MT-141 was good in eight patients and poor in the other two. Undesirable symptoms were not observed, but abnormal laboratory findings such as a slight elevation of GOT, a mild thrombocytopenia with mild anemia and an eosinophilia were observed during or after the administration of MT-141.

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The clinical examinations of MT-141 on respiratory tract infections such as pneumonia, acute exacerbation of chronic bronchitis, and diffuse panbronchiolitis were performed. MT-141 gave excellent or good results in all the fourteen cases, indicating the effective rate of 100%. The agent eliminated 8 out of 9 strains of clinical isolates, which were gram negative bacilli.
No side effects were observed.

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A new cephamycin antibiotic (MT-141) was administered by intravenously or intravenous drip infusion for 1-18 days at daily doses of 1-2g to 31 patients, including 24cases of respiratory tract infection (RTI), 6 cases of urinary tract infection (UTI) and 1case of bacillary dysentery.
Clinical results of MT-141 for 24 cases of RTI were excellent in 2, good in 15 and fair in 3. The effectiveness rate was 71%.The effectiveness rate of UTI was 100%. The over all effectiveness rate was 76.7%.
As for bacteriological response 4 cases of H. influenzae and E. coli, each one strain of Serratia, Shigella and S. haemolyticus were eliminated.
Skin rush were observed in 3cases. S-GOT and S-GPT were slightly elevated in 4cases. However, they returned to normal after MT-141 was discontinued.

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MT-141, a new antibiotic of the cephamycin group, was employed in the treatment of various infectious diseases, and the drug's clinical efficacy was investigated. MT-141 was administered to 4 patients with respiratory tract infections, 3 patients with urinary tract infections and 3 patients with biliary tract infections, or 10 cases in total. The results of the evaluation of the clinical efficacy of MT-141 were 3“excellent” cases, 6“good” cases and 1 “fair” case.The efficacy rate was thus 90%. Diarrhea was observed in one patient as a side effect, but no abnormal values were found in the laboratory tests.

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The antibacterial activity of MT-141 was found to be similar to that of cefotetan and cefbuperazone but slightly or markedly superior to that of cefoxitin or cefmetazole against E. coli and K. pneumoniae, while cefbuperazone and cefotetan had more excellent activity than MT-141 against S. marcescens.
Healthy adult male volunteers received intravenous injection of 1g of MT-141. The serum concentration of MT-141 was 134.0±22.3μg/ml after 5 min. and was reduced relatively slowly with a half life (±-phase) of 2.25±0.14hr. The serum concentration of MT-141 was higher and more persistent than that of cefotaxime.
The urinary recovery rate within 24hr was 88.0±6.5%, which was higher than 69.9±12.9% of cefotaxime. MT-141 was administered to 2 cases of respiratory tract infections and found to be effective in both cases.
As with side-effects, mild diarrhea was noted in 1 case, which promptly disappeared following cessation of therapy.

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We did fundamental and clinical studies on MT-141, one of new cephamycins, in the internal field. The MICs of MT-141 against clinically isolated E. coli were between 0.2 and 1.6μg/ml and the peak was between 0.4 and 0.8μg/ml. Klebsiella gave the peak MIC as between 0.4 and 0.8μg/ml. Enterobacter strains were inhibited by 50μg/ml or more and almost all strains had MICs of 100μg/ml or more. Serratia showed bimodal peaks of between 3.2 to 6.3μg/ml and 100μg/ml or more. Almost all P. aeruginosa strains were inhibited by MICs of 100μg/ml or more. Clinically, we treated 3 patients with acute pyelonephritis, chronic cystitis and acute tonsillitis. The causative orgainsms were E. coli and K. pneumoniae in the urinary tract infections, and unknown in the cases of acute tonsillitis. One gram of MT-141 was given by intravenous drip infusion twice a day. Clinical results were “excellent” in 2 and “good” in one. There were no side effects or abnormal clinical laboratory test values.

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Basic clinical research was carried out on MT-141, a newly-developed cephamycin antibiotic. The results obtained were as follows.
1. The MICs of MT-141 were determined for 25 strains of each of S. aureus, E. coli, K. pneumoniae, P. mirabilis, P. vulgaris, E. cloacae, C. freundii and S. marcescens, and 20 strains of H.influenzae. These values were then compared with the corresponding MICs determined for LMOX and CAZ. Overall, it was found that the antibacterial potency of MT-141 was slightly inferior to the activities of LMOX and CAZ. MT-141 showed an MIC range of 6.25-25 μg/ml against S. aureus, while 92% of the E. cloacae strains had MICs of 50 μg/ml and 96% of the C. freundii strains had MICs of 25μg/ml. The MIC range for the S. marcescens strains was from 6.25 to>100μg/ml.
2. MT-141 was administered to one patient with chronic cystitis for 5 consecutive days in 2 daily doses of 500mg each. During this therapy, the urine was cultured to detect changes in the bacteria present. Prior to the start of the MT-141, the urine culture had yielded E. coli and K. pneumoniae, but the bactericidal activity of the drug was seen to eliminate these bacteria quickly. S. faecalis had also been detected, and the bactericidal activity of MT-141 against this microbe took a little longer to become evident.

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T-141 showed favorable antibacterial activities against clinically isolated E. coli, Klebsiella and Proteus. It was similar to those of cefoperazone and latamoxef, and superior to those of cefazolin and cefmetazole. But the minimum inhibitory concentrations against P. aeruginosa were higher than 100μg/ml.
Serum concentrations of MT-141 were measured by high performance liquid chromatography in two patients administered 1g intravenously.
Maximum serum concentrations were 122μg/ml at 6 minutes after injection in one case and 96.6μg/ml at 10 minutes after injection in another case. Half lives in β-phase were 3.75 and 6.14 hours respectively.
MT-141 was administered to one case of acute pyelonephritis, one of thoracic empyema after operation of lung cancer and one of pneumonia at doses of 1.0g drip infusion twice a day for 9 to 24 days. In the case of thoracic empyema the right thoracic cavity was irrigated with 0.5g of this antibiotic drug a day for 18 days.
Clinical effects were excellent in the 1st and 3rd cases and good in the 2nd case. Pathogenic organisms, which were E. coli in the 1st case and S. marcescens in the 2nd case, were eradicated in two cases. Neither side effect nor abnormal laboratory finding was found in those cases.

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The susceptibilities of 100 multiply resistant S. aureus were determined by the agar dilution technique. MIC of MT-141 ranged from 12.5μ/ml to more than 100μ/ml with MIC₅₀ of 100μ/ml and MIC₈₀ of more than 100μ/ml. Clinical evaluation was performed on 3 cases with respiratory tract infection, one case with urosepsis and one with cholecystitis. Satisfactory response was observed in 2 with respiratory tract infection and in the case with cholecystitis.

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A new antibiotics, MT-141, was administered for 5-14 days at daily doses of 2.0g to 9 patients, including 2 cases of bronchopneumonia, 1 case of acute bronchitis and 6 cases of chronic urinary tract infection.
The results obtained were effective in 5 cases. The total efficacy rate was 55.6%.
Neither side effects nor abnormal laboratory findings were observed in any of these patients.

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MT-141 was administered to patients diagnosed in the Department of Internal Medicine as having respiratory tract infections. The following points summarize the method and therapeutic results of this study.
1. MT-141 was administered to a total of 14 patients, consisting of 12 cases of acute bronchopneumonia, 1 case of chronic bronchitis and 1 case of bronchiectasis.
2. The therapeutic efficacy was rated as “excellent” in 2 patients, “good” in 7 patients, “fair” in 2 patients and “poor” in 2 patients, while the results could not be evaluated in 1 patient. The “good” or greater efficacy rate was thus 69. 2%(9 out of 13 patients; excluding the 1 case which could not be evaluated).
3. Bacteriologically, the causative microbe was isolated from 5 patients. There was no change in 4 of these bacteria, while 1 was replaced by another bacterium.
4. One patient was seen to develop a fever which was considered to be caused by MT-141. Howeever, there were no abnormalities in the laboratory test results which were considered attributable to MT-141.
5. It can be concluded that MT-141 is a useful antibiotic in the treatment for respiratory tract infections.

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MT-141 is a newly developed cephamycin which has much more excellent therapeutic effect in experimentally infected animals than that expected by the level of MIC.
It is very interesting to investigate to what degree the advantage of MT-141 will be reflected in clinical use. I tried MT-141 in 18 patients who were suffering from various infectious diseases and the results obtained were as follows.
1. MT-141 was used in 10 cases from pneumonia. Its clinical effect was excellent in 5 cases, good in 3 cases and fair in 2 cases.
2. MT-141 had excellent result in a case from acute cholecystitis and a case of severe tonsillitis.
3. Clinical results could not be estimated in 6 cases in whom the administration of MT-141 was not finally indicated.
4. Maximum level in sputa of MT-141, 5.87 μg/ml, was obtained in one patient 2 hours after the DIV administration of 1g MT-141.

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A new cephem-group antibiotic, MT-141 was administered to two patients with acute exacerbation of chronic bronchitis.
The results was that one patient was judged as good, but another one was fair. No adverse effect was observed.

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MT-141 is a new parenteral cephamycin antibiotic which possesses a following chemical structure;_??_
MT-141 was parenterally administered to six patients with pneumonia, two leukemic patients with fever of unknown origin, one with periprostatic abscess and one with hypersensitivity pneumonitis. These patients received the drug for 5 to 31 days in doses of 2 to 4 g/day. Five of these patients responded well in the therapy. None of 10 patients recognized the side effect of MT-141.

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The serum and urinary concentrations of MT-141 in four healthy male volunteers who were given 1g 1 hour constant infusion were determined using bioassay and high-performance liquid chromatography (HPLC). The values from the two different methods agreed well with the regression coefficients of 0.992 in serum levels and 0.993 in urinary levels respectively. The mean peak serum concentration of MT-141 determined by bioassay at the end of infusion was 109μg/ml and existed 5.4μg/ml in serum at eight hours. Urinary concentrations of MT-141 were higher than 1, 000 μg/ml within four hours, and than 350μg/ml between 6 and 8 hours. The mean 8-hour urinary recovery rate was 89%. The mean serum half-life of β-phase was 1.83 hours.
MT-141 was administered to ten patients with various infection. In three cases of four patients with pneumonia and bronchopneumonia good effects were observed and in one was fair. In each one case with biliary tract infection and septicemia of E. coli caused by acute pyelonephritis excellent effect was observed. Clinical and bacteriological effects were good in other four patients with acute or chronic pyelonephritis. Drug eruption was observed in one case, but abnormality of laboratory data was not observed.

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A new antibiotic MT-141 has been studied in the clinic, resulting the following findings.
1. MT-141 was administered to 21 patients: 18 with respiratory tract infection, 1 with urinary tract infection, 1 with meningitis and 1 with sepsis.
2. 19 patients with normal renal function were injected intravenously with 1 to 2g of MT-141 every 12hr., 2 with renal insufficiency with 1g were injected similarly every 24hr., for 4 to 14.5 days.
3. Clinical response were excellent in 2 cases, good in 11, fair in 3, poor in 4, undetermined in 1.
4. Laboratory tests revealed leucopenia in 2 patients and thrombocytopenia in 1. However, these laboratory abnormalities disappeared immediately after the termination of MT-141 administration.
No severe side effects were observed in all cases.

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A new cephamycin antibiotic MT-141, was administered to 5 cases of respiratory tract infection by intravenous drip infusion in a daily dose of 2-4g.
The clinical efficacy was excellent in one case, good in 3 cases and poor in one case.
No adverse reaction was noticed in all cases.

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Fundamental and clinical studies were carried out on MT-141, and the following results were obtained.
1) Fundamental study: Rats were employed to investigate the transfer of MT-141 to the bronchoalveolar spaces. The bronchoalveoli were washed, and the concentration of MT-141 in the collected wash solution was determined. A comparison was made with the case of CEZ.
In the case of i. m. administration of the drugs at 100 mg/kg, both MT-141 and CEZ showed high recovery amounts at 0.5hr. The recovery of CEZ, however, was slightly superior. At 1hour after dosing, the amount of CEZ recovered decreased suddenly, becoming about 1/2 that of MT-141. At 2hr after dosing, the amount of both drugs recovered had decreased to only traces. When the administered dose was 20mg/kg, both MT-141 and CEZ could be recovered in only trace amounts.
2) Clinical study: MT-141 was administered as therapy to 7 patients diagnosed as having the following infections: 4 cases of pneumonia, and one case each of acute bronchitis, diffuse panbronchiolitis and acute urinary tract infection. These patients consisted of 6 males and one female, and they ranged in age from 38 to 73 years (mean age: 62 years). The daily dosage of MT-141 was 1g in 3 patients and 2g in 4patients, divided into a morning dose and an evening dose. The MT-141 therapy was continued for 7-15 days (mean duration: 11days), and the total dosage thus ranged from 14g to 28g (mean: 17.3g). The clinical efficacy was evaluated as “excellent” in one case, “good” in 5cases, and “poor” in one case. The “good” or greater efficacy rate was thus 85.7%.
The causative bacterium was able to be identified in 2 of the patients. In the patient with diffuse panbronchiolitis, Acinetobacter was isolated, and then this was found to be replaced by P. aeruginosa; nevertheless, the MT-141 therapy was clinically effective in this patient. In the patient with diffuse panbronchiolitis, Acinetobacter was isolated, and then this was found to be replaced by P. aeruginosa; nevertheless, the MT-141 therapy was clinically effective in this patient. E. coli was isolated from the patient with an acute urinary tract infection, and the therapy was clinically effective in this case, with the bacterium being eliminated. No particular adverse experiences or abnormal laboratory test values were recorded, with the exception of one patient showing eosinophilia.

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MT-141, a new member of cephamycin antibiotics, was applied to the treatment of the patients with respiratory tract infections.
The drug was administered intravenously, 2g/day in seven cases, 1g/day in one case, 4g/day in one case, 2-4g/day in one case, divided into two doses, for the period of nine to 21 days.
The results obtained were excellent in one case, good in six cases, slightly good in two cases and poor in one case.
Itching appeared in one case. Slightly elevated values of GOT and GPT were observed in four cases, but the value returned to normal without treatment within several days.

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MT-141, a new antibiotic of cephamycin group developed by MEIJI SEIKA Co., was examined on its antibacterial activity in vitro as well as on its clinical effectiveness.
The results obtained were as follows:
1) Antibacterial activity in vitro against bacterial strains isolated from clinical infection foci: S. aureus strains were less sensitive to MT-141, similarly to latamoxef, than to ceftizoxime and cefmetazole. The activity of MT-141 against E. coli, Klebsiella, Proteus(mirabilis, vulgaris, etc.) and Serratia strains were found to be generally weaker than ceftizoxime and latamoxef, but stronger than cefmetazole. Enterobacter strains were resistant to MT-141.
2) Clinical trials: Thirteen patients (RTI 8, UTI 4, and BTI 1) were treated with MT-141 (2g/day, d. i.). Seven out of the eight RTI cases had underlying diseases. Five of the RTI patients well responded to the therapy, and one fairly, while two* of them failed to respond (*Bronchitis by S. pneumoniae, and infected lung cancer). As to the UTI cases, two of them infected by S. faecalis could not respond to the therapy, while other two cases were cured by the drug administration. The therapy was found to be effective in the BTI patient, too.
Two cases of neutropenia and one case with elevation of GOT, GPT and Al-P were observed.

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MT-141 is an antibiotic of cephamycin type which has been developed by the Central Laboratories of Meiji Seika Kaisha Ltd. The in vitro antibacterial activity of MT-141 against clinical isolates and its clinical usefulness were evaluated.
The peak of sensitivity-distribution of S. aureus to MT-141 was at 100μg/ml, that of E. coli at 0.78 and at 100μg/ml, that of K. pneumoniae at 0.78 and at 100μg/ml, that of P. mirabilis at 0.78μg/ml, that of P. vulgalis at 0.39μg/ml, and that of P. aeruginosa at >100μg/ml respectively.
In the clinical trial, MT-141 was administered to fifteen patients i. e. one patient with infected pulmonary emphysema, six patients with pneumonia, three patients with lung abscess, one patient with infected lung cancer plus septicemia, one patient with cholecystitis, two patients with pyelonephritis and one patient with fever unknown origin. MT-141 was administered intravenouslyby drip infusion at a dose of one gram, b. i. d. for a period of 2 to 25 days.
The clinical responses were “excellent” in two, “good” in seven, “fair” in one and “poor” in three cases. Two cases were excluded from the evaluation, because they were not the indication of the treatment with MT-141.
As regards adverse reactions, one patient developed a rash. In one patient each there occurred elevation of GOT, elevation of GOT, GPT and ALP, neutropenia, and eosinophilia. Otherwise, no side effects and laboratory abnormalities related to MT-141 were observed.

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Bacteriological and clinical studies of MT-141, a new injectable cephamycin, were carried out, and the following results were obtained.
1) Sensitivities of clinically isolated strains to MT-141 were tested by the agar plate dilution method and compared with those of cefazolin (CEZ), cefmetazole (CMZ) and cefbuperazone (CBPZ). Antibacterial activity of MT-141 against S. aureus were inferior to that of CMZ but superior to CBPZ. The MICs of MT-141 against Proteus spp. were superior to those of CEZ, CMZ and CBPZ. But the MICs against E. coli, Klebsiella spp., and S. inarcescens were similar to those of CMZ and inferior to those of CBPZ. 25-50μg/ml or higher concentrations were necessary to inhibit the growth of P.aeruginosa, P.cepacia or Acinetobacter spp.
2) MT-141 was applied at a dose of 1.0-2.0g twice a day for 2-27 days to 22 patients with respiratory tract infections and efficacy was evaluated in 21 patients. Clinical response were excellent in 2, good in 14, fair in 2, poor in 3 cases and efficacy rate was 76.2%. As to the side effects, eosinophilia was observed in 2 patients, eosinophilia with decrease of the platelet count was observed in one patient, and s-GOT, s-GPT and s-Al-P were elevated in 2 patients. However they returned to normal after cessation of the therapy.

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The clinical effects of MT-141, a new cephem antibiotic, were studied in 10 patients, 5 with respiratory tract infections (RTI), 4 with urinary tract infections (UTI), and one with cholecystitis. Six patients had underlying diseases. This antibiotic was administered 1.0-2.0g a day by intravenous injection for 5-18 days.
Two cases with RTI were not evaluated. Clinical response was observed in remaining 8 cases, and was excellent in 4 cases, good in 3 cases, fair in one case. Efficacy rate was 87.5%.
No subjective side effect was observed.
Laboratory abnormalities were observed in three patients. A patient revealed moderate elevation of transaminase and two patients showed elevation of alkaliphosphatase and/or BUN. Relationships of these abnormalities in two patients with the drug therapy were not clearly determined. Leukopenia was developed in one patient during the therapy, but recovered after cessation of the therapy.

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MT-141, a new cephamycin antibiotics, was given to 4 patient with pneumonia, 1 with chronic bronchitis, 1 with lung abscess.
MT-141 was administered 2g a day by intravenous drip infusion. The duration of administration ranged from 10 to 30 days.
Excellent or good clinical response was observed in 5 cases and clinical efficacy rate was 83.3%.
No objective and subjective side effects and abnormalities of clinical laboratory findings due to the drug were observed.

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MT-141 is semisynthetic cephamycin antibiotic, which possesses D-cysteine structure in the side chain, have a lysis action and bulge formation. Laboratory and clinical studies have been performed on MT-141 in order to evaluate its usefulness in respiratory infections.
In vitro antibacterial activity of MT-141 against 168 isolates of 6 major pathogens of respiratory infection, i. e., S. aureus, S.pneumoniae, H. influenzae, K.pneumoniae, P.aeruginosa and B. cata-rrhalis, was measured comparing with other penicillins and cephems. MIC₈₀ of MT-141 against H.influenzae (27 strains) was 1.56 μg/ml, S. pneumoniae (37 strains) 1.56μg/ml, K. peumoniae (24 strains) 0.39μg/ml and B. catarrhalis (26 strains) 0.2μg/ml. Against S.aureus, MT-141 was not active like other cephamycins, and only 13 of 27 isolates were inhibited at the concentration of 100 μg/ml or less. All of P.aeruginosa (27 strains) were resistant for this drug.
MT-141 showed high bactericidal activity in early time and was stable against B.catarrhalis with β-lactamase. The therapeutic effect of MT-141 against experimental infections was much higher than that of CMZ.
Then, MT-141 was given to 25 patients with respiratory infections; pneumonia 8, lung abscess 1, chronic bronchitis 9, chronic bronchiolitis 2, bronchiectasis 2 and chronic pulmonary emphysema 3. The dosage used was 0.5 g to 1 g administered intravenously 2 times a day.
25 initial pathogens were all eradicated except P. aeruginosa in a patient with chronic pulmonary emphysema, while superinfection occurred in a patient with chronic bronchiolitis and in another patient, P.aeruginosa re-appeared during MT-141 treatment which was resistant against MT-141 (MIC:>100μg/ml). The penetration rate of MT-141 from blood into sputum was measured. The ratios of sputum peak level vs. serum peak level ranged from 0.9 to 1.9%. Clinical response of MT-141 treatment in 25 cases was excellent in 10, good in 14 and poor in 1. So, clinical cure was obtained in 24 (96%) of 25 patients. No side effect was observed, while one of the patients also developed mild eosinophilia and elevated transaminase was noted in another patient.
Considering from the above results, it is concluded that MT-141 is one of the superior antibiotics against respiratory infections.

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Laboratory and clinical studies out with the following results.
1) Antibacterial activity: The in vitro antibacterial activity of MT-141 was tested by microbroth dilution method. The minimum inhibitory concentrations (MICs) against total 372 strains consisting of 30 standard strains and 240 clinical isolates including S. aureus 30, S. faecalis 30, E. coli 30, K. aerogenes 30, E. cloacae 29, P. mirabilis 30, P. vulgaris 30, S. marcescens 30, P. aeruginosa 30, A. anitratus 30, H. influenzae 43 were compared with those of cefazolin (CEZ), cefmetazole (CMZ) and cefo-perazone (CPZ). Antibacterial activities of MT-141 against S. aureus and S. faecalis were less potent than those of CEZ, CMZ and CPZ.
On the other hand, it was strongest among antibiotics tested against E. coli, K. aerogenes, P. mirabilis, P. vulgaris and A. anitratus. CPZ was most active against H. influenzae, E. cloacae, S. marcescens, P.aeruginosa, and MT-141 followed.
2) Serum and sputum levels in chronic bronchitis: Four patients with chronic bronchitis were subjected to this study. After a dose of 1gr. of MT-141 was given to them by intravenous drip infusion for 1 hour, their levels in sera and sputa were measured by bioassay method. As the results, peak serum levels were obtained at the end of DIV showing values of 89.5 to 100.8μg/ml, and serum levels after 6 hours showed values of 12.8 to 34.9μg/ml. On the other hand, concentrations in sputa reached their peaks at 1 to 2 hours after administration in two cases with purulent sputum and theirit values were 0.38 and 0.48μg/ml. But in one case with muco-purulent sputum the value was under the limit of measurement, and in one case with bloody sputum the value was 23.0μg/ml.
3) Clinical effect and adverse reactions: Twenty three patients with respiratory infections (pneumonia 16, chronic bronchitis 4, bronchiectasis 3) were treated with 1 to 2 gr. of MT-141 daily for 5 to 34 days by intravenous drip infusion. Eighteen of 23 patients responded satisfactorily to the treatment and the efficacy rate was 78.3%(excellent 4, good 14, fair 3, poor 2). Subjective and objective symptoms, hematological and biochemical data and renal functions were checked up before and after administration of MT-141.
Five cases in total showed the following adverse reactions: slight elevations of S-GOT in 2, that of BUN in 1, transient eosinophilia in 1 and anemia in 1. These abnormal values returned to normal after discontinuation of the drug.

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This study investigated on MT-141, a new semisynthetic cephamycin, having marked resistance to β-lactamase, and a broad spectrum of antibacterial activity against various bacterial species. Included in this investigation were 7 cases of acute or subacute cholecystitis and cholangitis, 17 cases of acute localized peritonitis, 5 cases of acute diffuse peritonitis and 3 cases of infectious disease of skin and soft tissues.
MT-141 was given principally in a dose of 1g by intravenous drip infusion twice a day for 4 to 8 days. The clinical efficacy obtained was excellent in 10 cases, good in 21 cases and fair in 1 case. In no case was MT-141 found to be completely ineffective. Clinically, adverse effect was not recognized. Therefore, MT-141 appears to be very useful drug when used for chemotherapy of acute peritonitis and biliary tract infection.

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MT-141 was administered to four surgical infections including panperitonitis, aspiration pneumonia and intraabdominal abscess, and the efficacy rate was 75% (3/4).
A daily dose was 2.0g in 3 cases and 4.0g in 1 case. The maximum total dose and duration were 50.0g and 15 days, respectively.
No side effect was observed.

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Fundamental and clinical studies were carried out on MT-141. This drug proved to possess a broad antimicrobial spectrum similar to cefotetan, including antimicrobial activity against B. fragilis. But the antimicrobial activity against P. aeruginosa could not be recognized.
Its antimicrobial activity against clinical isolates of S. aureus was similar to CTT and LMOX, but was inferior to CFX and LMOX against S. epidermidis.
MT-141 was stronger active against E. coli, K. pneumoniae, and Proteus than CFX and CMZ, and was similar to CTT against B. fragilis. It had no activity against P. aeruginosa.
MT-141 was intravenously administered at a single dose of 1. 0 g to three healthy male volunteers to determine serum and urine concentrations by HPLC and bioassay. Mean peak serum level of MT-141 was 126.7 μg/ml by HPLC and 133 μg/ml by bioassay at 5 minutes after administration. At 8 hours, it was 7.1 μg/ml by HPLC and 5.9 μg/ml by bioassay. Mean peak urine level was 9433 μg/ml (HPLC) and 8733 μg/ml (bioassay) at 1 hour, and its urinary recovery rate was 73.1%(HPLC) and 60.4%(bioassay).
Pharmacokinetic studies were carried out by use of twocompartment open model method. The parameters by HPLC data demonstrated that it was 1.16 hr^-1 for K₁₂, 2.24 hr^-1 for K₂₁, 0.48 hr^-1 for K_el, 2.28 hr for T_{1/2 (β)} 10.6 liters for V_d and 295.9 hr·μg/ml for AUC. Analysis of human urine by use of TLC and bioautography showed that MT-141 was not metabolized in the body.
Following intramuscularly administration of 20 mg/kg to SD strains of rat, high levels were detected in descending order of kidney, serum, liver and lung.
The drug was administered to 17 cases with surgical infection and the clinical resposes were excellent in 2 cases, effective in 11 cases, and failure in 4 cases, with the effective rate of 76.5%.
As side effects, the elevation of both GOT and GPT were observed in 2 cases.

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MT-141, a novel antibiotic of the cephamycin group, was employed in the treatment of various infectious diseases encountered in the field of surgery, and the drug's clinical efficacy was investigated. MT-141 was administered to a total of 11 patients. In 3 cases, however, the drug was used concomitantly with other antibiotics, or it was administered with the purpose of preventing postoperative infections. Therefore, in these 3 cases, only the safety of the drug was evaluated and no efficacy evaluation was attempted. Administration of this agent was achieved by means of one-shot i. v. injection or i. v. drip infusion, in a dose of 1.0-2.0g, 1-2 times a day.
The patients who were the subjects of evaluation of the efficacy of MT-141 consisted of 6 cases of cholangitis and 2 cases of peritonitis, or 8 cases in total. The results of the evaluation of the clinical efficacy of MT-141 were 4 cases of “excellent”, 3 cases of “good” and one case of “poor”. The efficacy rate was thus 88%. No subjective or objective symptoms of side effects were observed. Mild transient fluctuations in the serum GOT and GPT were observed in the laboratory tests in 4 of the cholangitis cases and the one case of peritonitis. These fluctuations were, however, considered not to be related to the effects of MT-141; they might be a pathological symptom of the bile duct infection, or might be due to the effects of a basal disease, surgical treatment, etc. In addition to the efficacy of MT-141 as mentioned above, the drug shows potent in vivo antibacterial effects against gram-negative bacteria. Therefore, MT-141 is thought to be a useful drug in the treatment of infections encountered in the field of surgery.

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Clinical studies on MT-141 in the surgical field were performed and following results were abtained.
1) Bile excretion: On the two clinical cases with biliary disorder, 1 gm of MT-141 was administered intra-venously, and bile levels were measured every one hour. Peak bile levels of MT-141 were 26.0μg/ml and 7.4μg/ml, respectively. Therefore, bile excretion of MT-141 was not so good.
2) Clinical results: MT-141 was administered to 8 patients with surgical infections, and clinical results were excellent in 2 cases, good in 4, fair in 1 and poor in 1.
No adverse reaction could be found.

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MT-141, a new antibiotic of the cephamycin group, is said to show a more pronounced effect in vivo than in vitro. This agent is expected to provide excellent clinical efficacy in the treatment of biliary tract infections and peritonitis, which tend to progress into intractable infections. Hence, studies were conducted on MT-I41 to determine its clinical efficacy in the treatment of a total of 80 patients with abdominal disease. These patients consisted of 55 cases of infection of the abdominal cavity and 25 cases where the drug was administered for the purpose of preventing infection. In the latter cases, basic studies were also conducted on the penetration of the drug into the bile and the gallbladder tissue. The results are summarized below.
1. The concentration of MT-141 in the blood five minutes after i. v. injection of 1 g of the drug was 246. 6±22.4μg/ml (mean value for 33 cases). The concentration of the drug in the gallbladder tissue after i. v. injection of 0.5 g was 8.8±2.1μg/g (4 cases) while, when 1 g was injected i. v., the highest value was 67.7μg/g and the mean value was 23.4±2.0μg/g (34 cases).
2. The penetration of MT-141 into the bile was monitored for 6 hours in 9 patients with T-tube intubation. The peak concentration of MT-141 in the bile showed a range of 4.6-36.0μg/ml (mean 16.8±2.2μg/ml). By employing a crossover method in which LMOX and MT-141 were simultaneously administered, the recovery rates of the agents from the bile were calculated on the basis of the drugs' penetration rate into the bile per unit time. The recovery rate of MT-141 was 0.15-0.19%, which was comparable to LMOX's rate of 0.14-0.17%.
3. When 0.5-2.0g of MT-141 was administered 1-3 times daily by i. v. bolus or drip infusion, its clinical efficacy in the treatment of 33 cases of cholecystitis consisted of 4 cases of “excellent” and 24 cases of “good”, while the evaluation showed 1 “excellent” case and 10 “good” cases in the treatment of 14 cases of cholangitis. Good efficacy rates of 87.5% and 84.6%, respectively, were thus obtained. An efficacy rate of 79.2% was obtained for the treatment of all 55 cases of infection of the abdominal cavity, which included 1 ccse of bile peritonitis, 2 cases of liver abscess and 5 cases of peritonitis.
The efficacy rate in the treatment of 19 cases of single infection was 82. 4%, while it was only 45. 5% in the treatment of 11 cases of mixed infection.
4. One case of rash and 4 cases of abnormal liver function were observed as side effects.

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MT-141 is a newly-developed cephamycin antibiotic. The concentrations of this antibiotic in the serum and the bile were investigated, and the efficacy of MT-141 was also studied in clinical patients.
Following intravenous one shot injection of 1 g of MT-141 on a patient, serum concentration was 68μg/ml at 1 hour, and 22μg/ml even at 8 hours.
In the case of an iv dose of 0.5 g, as well, the serum concentration was 29μg/ml at 1 hour after administration, which was approximately half of the level following the 1 g dose.
In the case collected bile from a T-tube, the peak of bile concentration of MT-141 following administration of the 1 g dose was 21μg/ml. In the 2 cases collected bile from a PTCD-tube, the peak of bile concentration of MT-141 was low following the administration of both 1 g and 0.5 g: these values were only 7.2 and 6.8μg/ml, respectively.
MT-141 was administered to 20 patients with infections encountered in the field of surgery. The efficacy was evaluated as “excellent” in 10 patients, “good” in 8 patients and “fair” in 2 patients. The efficacy rate was thus 90%.
No side effects were noticed.
Elevation in serum LAP and Al-P value were noted in one case, but these were mild and reversible.

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MT-141, a new cephamycin, was studied in surgical field. The drug was administered 2g a day for 3-10 days by I. V. injection to 7 in-patients with surgical infection-5 patients with postoperative wound infection and 2 patients with postoperative intra-abdominal abscess.
The results were as follows:
1. The clinical effect was good in 2, fair in 2 and poor in 3 patients.
2. Bacteriologically, S. epidermidis, S. faecalis and C. freundii were eradicated. P. morganii was decreased and P. aeruginosa was persisted in wound infection. In the cases with intra-abdominal abscess, S. marcescens and P. aeruginosa were persisted.
3. No side effects and no pathological laboratory data caused to this drug was observed.

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We carried out the experimental and clinical studies on the new cephamycin, MT-141. The obtained results were as follows.
1) Antibacterial activity
MT-141 showed the excellent antibacterial activity against the clinically isolated E. coli, K. pneumoniae, P. mirabilis, and indole positive Proteus sp. but the poor against Enterobacter sp., Citrobacter sp., S. marcescens, and P. aeruginosa.
2) Clinical studies
Twenty-two patiens with chronic complicated urinary tract infection were treated 0. 5g or 1.0g of MT-141 twice a day for 5 days by intravenous injection. Eighteen cases were evaluable. Eleven patients received 1.0g daily dose. The excellent clinical response was observed in 1 case, good in 4 cases and poor in 6 cases. The efficacy rate was 45%. Of 7 cases with 2.0g daily administration, 1 case represented the excellent clinical response, 4 good and 2 poor. The efficacy rate was 71%.
No remarkable adverse reaction was observed in 22 cases.

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