Clinical pharmacokinetics of cefotetan

Pharmacokinetics of cefmetazole in plasma, peritoneal fluid, peritoneum, and subcutaneous adipose tissue of patients scheduled for lower gastrointestinal surgery: Dosing considerations based on site-specific pharmacodynamic target attainment

INTRODUCTION

Cefmetazole (CMZ) has gained interest as a carbapenem-sparing alternative to the epidemic of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E). In this study, we investigated the pharmacokinetics (PK) of CMZ in plasma, peritoneal fluid, peritoneum, and subcutaneous adipose tissue to assess the dosing regimen needed to achieve pharmacodynamic (PD) goals at the target site.

METHODS

Patients scheduled for elective lower gastrointestinal surgery were intravenously administered CMZ. Plasma, peritoneal fluid, peritoneum, and subcutaneous adipose tissue samples were collected after CMZ infusion and during the surgery, and CMZ concentrations were measured. The non-compartmental and compartmental PK parameters were estimated and used to evaluate site-specific PD target attainment.

RESULTS

A total of 38 plasma, 27 peritoneal fluid, 36 peritoneum, and 38 subcutaneous adipose tissue samples were collected from 10 patients. The non-compartmental PK analysis revealed the ratios of the mean area under the drug concentration-time curve (AUC_0-3.5 h) of peritoneal fluid-to-plasma, peritoneum-to-plasma, and subcutaneous adipose tissue-to-plasma were 0.60, 0.36, and 0.11, respectively. The site-specific PD target attainment analyses based on the breakpoints for ESBL-E per the Japanese surgical site infection (SSI) surveillance (MIC₉₀ = 8 mg/L) revealed that 2 g CMZ every 3.5 h achieved desired bactericidal effect at all sites and 2 g CMZ every 6 h achieved PD goals at peritoneum and peritoneal fluid.

CONCLUSION

These findings clarify the PK of CMZ in abdominal tissues and could help decide optimal dosing regimens to treat intra-abdominal infection and prophylaxis of SSI.

Pharmacokinetics and Tolerability of Single and Multiple Intravenous Doses of Cefotetan Disodium in Healthy Chinese Volunteers

Background

Cefotetan is highly stable to penicillinase and cephalosporin produced by gram-negative bacteria, and it has strong antimicrobial activity against most gram-negative bacteria, some anaerobic bacteria and streptococcus. The objective of this study was to evaluate the pharmacokinetic profile and tolerability of single and multiple intravenous doses of cefotetan disodium in healthy Chinese volunteers.

Methods

In this single-center, open-label, dose-escalating study, subjects were randomized to receive a single dose of cefotetan disodium 0.5, 1.0, or 2.0 g administered as a 1 h intravenous infusion. After completion of the single-dose phase, subjects continued into the multiple-dose phase, in which they received 1.0 g cefotetan disodium BID for 7 consecutive days. Plasma samples were assayed by a validated high-performance liquid chromatography-tandem mass spectrometry method. Pharmacokinetic parameters were calculated and analyzed statistically. Tolerability was assessed based on physical examinations, vital signs, laboratory tests, and subject interviews.

Results

After intravenous administration of single doses of 0.5, 1.0, and 2.0 g cefotetan disodium, the pharmacokinetics of cefotetan were as follows: C_max was 69.49±12.10 µg·mL^-1, 132.03±22.56 µg·mL^-1 and 237.75±42.12 µg·mL^-1, respectively; AUC_last was 278.29±51.13 µg·mL^-1·h, 543.25±92.44 µg·mL^-1·h and 1003.8±172.39 µg·mL^-1·h, respectively; AUC_∞ was 284.42±50.76 µg·mL^-1·h, 551.38±95.83 µg·mL^-1·h and 1020.18±181.19 µg·mL^-1·h, respectively; t_1/2 was 4.21±0.83 h, 4.39±0.53 h and 4.27±0.74 h, respectively; CL was 1.81±0.33 L·h^-1, 1.86±0.32 L·h^-1 and 2.02±0.38 L·h^-1, respectively; V_d was 10.80±1.89L, 11.78±2.20L and 12.25±1.99L, respectively. In the multiple-dose study, the pharmacokinetics of cefotetan were as follows: C_max,ss was 147.58±22.71 µg·mL^-1; C_min,ss was 12.92±3.70 µg·mL^-1; C_avg was 45.10±7.78 µg·mL^-1; AUC_τ,ss was 541.15±93.36 µg·mL^-1·h; AUC_∞ was 612.06±114.23 µg·mL^-1·h; t_1/2 was 4.30±0.63 h; CL was 1.90±0.35L·h^-1; V_d was 8.91±1.57L; DF was 300.92±33.28%; Accumulation Index was 1.17±0.05. No serious adverse events were reported. Adverse events were generally mild.

Conclusion

Cefotetan disodium showed favorable tolerability in this study. The C_max and AUCs of cefotetan disodium demonstrated dose-dependent pharmacokinetic characteristics after single dose over a dose range (0.5-2.0 g) in healthy subjects, whereas the t_1/2 was independent of dose. Except for V_d, there was no difference in other pharmacokinetic parameters between multiple and single administration.

Pharmacokinetic differences between the epimers of cefotetan disodium after single intravenous injection in healthy Chinese volunteers

The pharmacokinetic behaviors of the epimers of cefotetan disodium (R-CTT, S-CTT) after a single intravenous injection dose in healthy Chinese volunteers were explored in this study. In an open-label, randomized, three-way, cross-over study, 12 volunteers (6 females and 6 males) received a cross-over fashion doses of 0.5, 1.0, and 2.0 g of cefotetan disodium, separated by washout periods of 7 days. The plasma concentrations of both epimers were measured by validated high-performance liquid chromatography assays. Pharmacokinetic parameters of R-CTT, S-CTT, and total-CTT (R + S mixture) were calculated using a noncompartmental analysis. Generally, the R and S epimers showed different pharmacokinetic behaviors. Following 0.5, 1.0, and 2.0 g doses of cefotetan disodium, values of the total area under the plasma concentration-time curve (AUC(0-∞)) were 124.23 ± 19.54, 231.34 ± 39.34, and 459.09 ± 80.65 for R-CTT; 100.95 ± 14.19, 193.80 ± 30.42, and 372.66 ± 67.32 for S-CTT, respectively. Total body clearance values were 4.13, 4.43, and 4.46 L/h for R-CTT and 5.05, 5.28, and 5.50 L/h for S-CTT, respectively. Mean plasma elimination half-life (t (1/2)) values of R-CTT were 4.16, 4.13, and 4.01 h for 0.5, 1.0, and 2.0 g doses, respectively, and those of S-CTT were 3.15, 3.25, and 3.21 h. There were significant differences in t (1/2) between the two epimers (P < 0.05). The t (1/2) of R-CTT was 28% longer than that of S-CTT, which indicated that the elimination of the S-CTT was greater than that of the R-CTT. All treatments were well tolerated.

Pharmacokinetic and pharmacodynamic issues in the treatment of bacterial infectious diseases

This review outlines some of the many factors a clinician must consider when selecting an antimicrobial dosing regimen for the treatment of infection. Integration of the principles of antimicrobial pharmacology and the pharmacokinetic parameters of an individual patient provides the most comprehensive assessment of the interactions between pathogen, host, and antibiotic. For each class of agent, appreciation of the different approaches to maximize microbial killing will allow for optimal clinical efficacy and reduction in risk of development of resistance while avoiding excessive exposure and minimizing risk of toxicity. Disease states with special considerations for antimicrobial use are reviewed, as are situations in which pathophysiologic changes may alter the pharmacokinetic handling of antimicrobial agents.

Multiple pharmacokinetic parameter prediction for a series of cephalosporins

The goal of quantitative structure-pharmacokinetic relationship analyses is to develop useful models that can predict one or more pharmacokinetic properties of a particular compound. In the present study, a multiple-output artificial neural network model was constructed to predict human half-life, renal and total body clearance, fraction excreted in urine, volume of distribution, and fraction bound to plasma proteins for a series of cephalosporins. Descriptors generated solely from drug structure were used as inputs for the model, and the six pharmacokinetic parameters were simultaneously predicted as outputs. The final 10 descriptor model contained sufficient information for successful predictions using both internal and external test compounds. Descriptors were found to contribute to individual pharmacokinetic parameters to differing extents, such that descriptor importance was independent of the relationships between pharmacokinetic parameters. This technique provides the advantage of simultaneous prediction of multiple parameters using information obtained by nonexperimental means, with the potential for use during the early stages of drug development.

Pharmacokinetics of drugs used in critically ill adults

Critically ill patients exhibit a range of organ dysfunctions and often require treatment with a variety of drugs including sedatives, analgesics, neuromuscular blockers, antimicrobials, inotropes and gastric acid suppressants. Understanding how organ dysfunction can alter the pharmacokinetics of drugs is a vital aspect of therapy in this patient group. Many drugs will need to be given intravenously because of gastrointestinal failure. For those occasions on which the oral route is possible, bioavailability may be altered by hypomotility, changes in gastrointestinal pH and enteral feeding. Hepatic and renal dysfunction are the primary determinants of drug clearance, and hence of steady-state drug concentrations, and of efficacy and toxicity in the individual patient. Oxidative metabolism is the main clearance mechanism for many drugs and there is increasing recognition of the importance of decreased activity of the hepatic cytochrome P450 system in critically ill patients. Renal failure is equally important with both filtration and secretion clearance mechanisms being required for the removal of parent drugs and their active metabolites. Changes in the steady-state volume of distribution are often secondary to renal failure and may lower the effective drug concentrations in the body. Failure of the central nervous system, muscle, the endothelial system and endocrine system may also affect the pharmacokinetics of specific drugs. Time-dependency of alterations in pharmacokinetic parameters is well documented for some drugs. Understanding the underlying pathophysiology in the critically ill and applying pharmacokinetic principles in selection of drug and dose regimen is, therefore, crucial to optimising the pharmacodynamic response and outcome.