Clinical pharmacology of mezlocillin

Development and Validation of a UPLC-MS/MS Method for Ultra-Trace Level Determination of Acyl Chloride Potential Genotoxic Impurity in Mezlocillin

3-Chlorocarbonyl-1-methanesulfonyl-2-imidazolidinone (CMI) is a critical intermediate used in the synthesis of mezlocillin drug substance and also a potential genotoxic impurity with acyl chloride moiety. The content of CMI in mezlocillin should be <0.16 ppm to avoid the carcinogenicity and mutagenicity threats to patients. Therefore, a workable determination of CMI was critically crucial for ensuring the safety of mezlocillin drug products. However, the conventional HPLC method is insufficient for detection limits at ppm or lower levels. Besides, the high activity of acyl chloride also raises a challenge to the direct measurement of CMI. Thus, we explored a simple esterification approach, which converts CMI into methyl 3-(methylonyl)-2-oxoimidazolidine-1-carboxylate completely by optimizing the reaction temperature and time. Furthermore, the selected reaction monitoring model of triple quadrupole mass spectrometer optimized by the Box-Behnken design significantly enhanced the sensitivity of ultra-trace level determination. The limit of detection and limit of quantification of the method were reached 0.014 and 0.02 ppm, respectively, in the following validation study. A sensitive and specific ultra-performance liquid chromatography tandem mass spectrometry method for ultra-trace level determination of acyl chloride potential genotoxic impurity in mezlocillin drug substance has been successfully established in this study, which will provide a practical quality control tool of mezlocillin.

Sodium nitrite-promoted aerobic oxidative coupling of aryl methyl ketones with ammonium under metal-free conditions: a facile access to polysubstitution imidazoles

A sodium nitrite-promoted aerobic oxidative synthesis of polysubstitution imidazoles from aryl methyl ketones under metal-free conditions has been developed.

Prophylactic mezlocillin for transurethral prostatectomy

In a randomised clinical trial of 100 consecutive patients treated by transurethral prostatectomy, half were given prophylactic intravenous mezlocillin. Blood cultures were obtained, the urine examined and the post-operative progress of each patient was carefully followed. The results were analysed and a high incidence of bacteraemia and septicaemia was found. Single-dose prophylactic mezlocillin was highly effective in preventing this complication. The presentation of septicaemia in mild and severe form is described and the aetiology discussed. Probable risk factors are identified and prophylactic and therapeutic measures described.

Microbiology, pharmacology, and clinical use of mezlocillin sodium

The acylureido penicillin mezlocillin is active against gram-positive, gram-negative, and anaerobic bacteria. It easily penetrates the outer membrane of gram-negative bacteria, and it has a strong affinity for penicillin binding protein 3. Its stability to beta-lactamases is weak. Mezlocillin is synergistic when given in combination with aminoglycoside antibiotics. In pharmacokinetic studies mezlocillin conforms to a two compartment open model; its pharmacokinetic properties are dose-dependent. The half-life of the drug is about 1 hour after intravenous injection and 1.5 hours after intramuscular injection. Protein binding ranges from 16 to 42%, and 55% of a dose is excreted in the urine. Biliary excretion ranges from 0.5 to 25%. Clinical trial cure rates were as follows: bacteremia (78%), respiratory tract (62%), urinary tract (81%), gynecological (86%), bone and joint (55%), intraabdominal (67%) and skin and soft tissue (59%). The frequency of adverse reactions was 7.7%. Interstitial nephritis, CNS toxicity, and bleeding have not been reported.

[In vitro effect of acylureido penicillins and mezlocillin on anaerobic sporeless gram-negative rods of genus Bacteroides]

313 anaerobic gram-negative rods of the Bacteroides genus isolated from 295 clinical specimens were tested for their sensitivity to azlocillin and mezlocillin using the dilution method with agar plates. 25 mg/l of azlocillin inhibited 80.2% of the strains and the same concentration of mezlocillin inhibited 86.9%. The somewhat higher in vitro activity of mezlocillin is also seen by the lower mean minimal inhibitory concentration, which is approx. 23.6 mg/l for mezlocillin and 27.6 mg/l for azlocillin. The highest resistance for both drugs were found with B. distasonis (14 strains), followed by B. thetaiotaomicron (63 strains), B. fragilis (161 strains) and B. uniformis (7 strains). The good sensitivity of strains belonging to the B. melaninogenicus group corresponds to the well-known sensitivity of these micro-organisms to penicillins. On the basis of a "break point" of 25 mg/l, a decrease in the proportion of sensitive strains was found between 1974 and 1979. 50 mg/l, a concentration which can be maintained over a longer period of time if applied in a suitable manner, will inhibit 97.4% (azlocillin) and 98.4% (mezlocillin) of the strains. Thus in our opinion azlocillin and especially mezlocillin are suitable drugs for the initial therapy of pyogenous infections in which intestinal Bacteroidaceae are of pathogenic significance.

Carbenicillin and ticarcillin

Carbenicillin and ticarcillin are penicillins which were initially developed as agents to treat serious Pseudomonas infections in the seriously ill hospitalized patient. These drugs have made a major contribution to improved survival in the neutropenic patients with Pseudomonas infection, the burn patient and to the care of the patient with cystic fibrosis. Areas of use for the compounds have enlarged to include aspiration pneumonitis in hospitalized patients, intra-abdominal and pelvic sepsis, and infections due to Proteus and Enterobacter species. Careful attention to the pharmacology of the agents is necessary to achieve clinical and bacteriologic success and to avoid the toxic side-effects such as bleeding and hypokalemia associated with the use of these agents. A decade of use has shown that the agents have remained effective agents in institutions in which their use has not been abused. It is too early to clearly position azlocillin, mezlocillin, and piperacillin. In the next few years the role of these potent compounds will be established. As noted in this review, these three agents have been used with success to treat all of the aforementioned infections. With these drugs it is also essential that the physician closely correlate in vitro data and the human pharmacology of the drugs if he or she wishes to achieve the most effective response from the agents.

Comparative activity of N-formimidoyl thienamycin with third generation cephalosporins and ureido penicillins against multiple resistant Serratia marcescens

Twenty multiple resistant clinical isolates were tested with N-formimidoyl thienamycin, moxalactam, cefotaxime, cefoperazone, and the three ureidopenicillins: azlocillin, mezlocillin, and piperacillin. A concentration of less than 0.97 microgram/ml inhibited 100% of organisms for N-f-thienamycin and cefotaxime, 90% for moxalactam, and 60% for cefoperazone. An increase in inoculum from 10(3) to 10(6) cells reduced activity fourfold for 95% of isolates with cefoperazone, 70% with N-formimidoyl thienamycin, 65% for cefotaxime, but only 15% for moxalactam. For ureidopenicillins, 85% of strains tested had MIC's less than or equal to 15.6 micrograms/ml. An inoculum effect was observed in only 35-50%. At 10(3), the cidal concentration was the same or twofold greater than the inhibitory level for N-f-thienamycin and cephalosporins in 70% of strains tested and 65% for penicillins. With 10(6), the 70% value remained for N-f-thienamycin but was reduced to 45% for cefotaxime and 25% for moxalactam; 85% demonstrated greater than eightfold differences with cefoperazone. Single step high-level resistance was observed to moxalactam (20%). Carbenicillin resistant strains were cross-resistant to the ureidopenicillins. N-f-thienamycin and cefotaxime appeared comparable, although important differences between morphological alteration and metabolism may influence their therapeutic effectiveness.

Mezlocillin: tentative interpretive standards for disk diffusion susceptibility testing

The susceptibility of 447 clinical bacterial isolates to mezlocillin and carbenicillin was tested by standardized agar disk diffusion and reference broth micro-dilution methods. Tentative interpretive criteria for disk susceptibility testing by using 75 micrograms mezlocillin disks are proposed: susceptible, greater than or equal to 16 mm; indeterminate, 13 to 15 mm; and resistant, less than or equal to 12 mm. These would be applicable to both Pseudomonas species and the Enterobacteriaceae, but not to Staphylococcus aureus. For S. aureus, the breakpoints for susceptible, greater than or equal to 29 mm, and resistant, less than or equal to 28 mm, hold for mezlocillin as well as for the other penicillinase-susceptible penicillins.

Potential of mezlocillin as empiric single-agent therapy in febrile granulocytopenic cancer patients

Mezlocillin was used as an initial empiric antibiotic therapy for febrile (> 101 degrees F, ca. 38.33 degrees C) granulocytopenic (< 1,000/microliter) cancer patients. Patients known to be colonized with an organism resistant to 100 micrograms of mezlocillin per mol were excluded. The initial 25 cases (23 patients) received intravenous mezlocillin, 260 mg per kg per day in six divided doses; the mean 1-h-postinfusion serum level was 69 micrograms/ml. Because of the low serum level, the next 25 cases (22 patients) received 450 mg/kg per day, also in six divided doses, resulting in a mean 1-h-postinfusion serum level of 161 micrograms/ml. Both dosage regimens provided similar efficacy. Combined results show that 11 of 21 microbiologically documented infections and 7 of 13 clinically documented infections improved. Instances of bacteremia (number of cases in parentheses) were caused by Pseudomonas aeruginosa (two), Staphylococcus epidermidis (two), Clostridia perfringens (one), and Bacillus species (one); only one case improved. A rise in granulocyte count to > 500/microliters, a serum bactericidal activity of greater than or equal to 1:8 against the infecting pathogen, or both were indicators of a good therapeutic response. Despite exclusion of patients known to be previously colonized with mezlocillin-resistant organisms, 7 of 23 pathogens required a minimal concentration of greater than or equal to 100 micrograms of mezlocillin per ml for inhibition. In addition, surveillance cultures from 18 cases showed resistant organisms colonizing the gingiva, rectum, or both. Side effects of mezlocillin were minimal and included pseudoproteinuria, asymptomatic transient rise in bilirubin, and easily reversible kypokalemia. Mezlocillin, a new semisynthetic penicillin with little toxicity, was found to be inadequate as a single-agent empiric antibiotic therapy for febrile, granulocytopenic cancer patients.

Mezlocillin for treatment of infections in cancer patients

Mezlocillin, at a dose of 3 g intravenously over a 2-h period every 4 h, was used for the treatment of 92 episodes of documented infections in 75 myelosuppressed cancer patients. The response rate in 59 evaluable bacterial infections was 46%. Eight of 23 patients with septicemia (35%) responded. The response rates for Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli, the three most common gram-negative infections, were 42, 64, and 70%, respectively. Mezlocillin was well tolerated; the only toxicity attributable to this antibiotic was a skin rash in one patient. The formation of a false-positive urine protein reaction by mezlocillin was noted. This study demonstrated that mezlocillin administered as a single agent was effective against some infections in myelosuppressed cancer patients. The response rate for Klebsiella sp. infections was especially encouraging. However, because it had limited or little activity against many infections, especially those caused by P. aeruginosa and Staphylococcus aureus, the general use of mezlocillin as a single agent for treatment of infections in immunocompromised cancer patients cannot be recommended.

Agar disk diffusion susceptibility characteristics of azlocillin, carbenicillin, mezlocillin, piperacillin, and ticarcillin

The agar disk diffusion susceptibility of Enterobacteriaceae to mezlocillin and piperacillin was correlated with agar minimal inhibitory concentrations and compared with the susceptibility to carbenicillin. The agar disk susceptibility of Pseudomonas aeruginosa to azlocillin, mezlocillin, and piperacillin was correlated with agar minimal inhibitory concentrations and compared with the susceptibility to carbenicillin and ticarcillin. Criteria are offered for the zones of inhibition to provide information about resistant and susceptible isolates that correlate with known serum levels.

Mezlocillin pharmacokinetics in patients with normal and impaired renal functions

The pharmacokinetics of intravenous bolus doses of 1.0 g of mezlocillin were studied in 13 persons with normal and reduced renal functions. In renal failure a moderate increase was observed for the terminal serum half-life(t1/2 beta). This changed from a mean of 1.1 h at a glomerular filtration rate of 100 ml/min to 1.6 h at 10 ml/min. The difference was not statistically significant. The excretion of unchanged drug in urine during 24 h was reduced from a mean of 59.4% (range, 52 to 77) in subjects with glomerular filtration rate above 50 ml/min to 10% (range, 7.9 to 12.1) in two patients with glomerular filtration rate of 10 to 20 ml/min. The volume of distribution during the beta-phase, Vd,b, was 14% of the body weight. Much of the antibiotic was metabolized, and this proportion increased upon reduction in renal function.