Pharmacodynamic evaluation of biapenem in peritoneal fluid using population pharmacokinetic modelling and Monte Carlo simulation

Metabolomic Insights Into the Synergistic Effect of Biapenem in Combination With Xuebijing Injection Against Sepsis

The drug combination of biapenem (BIPM) and xuebijing injection (XBJ) is commonly applied for the treatment of sepsis in China. However, the potential synergistic mechanism is still enigmatic. There have been no studies focused on the plasma metabolome alterations in sepsis after the intervention of this combination. In this work, an untargeted metabolomics approach was performed by liquid chromatography-mass spectrometry coupled with multivariate statistical analysis to provide new insights into the synergistic effect of BIPM in combination with XBJ. We characterized the metabolic phenotype of sepsis and described metabolic footprint changes in septic rats responding to XBJ and BIPM individually and in combination, in addition to histopathological and survival evaluation. A total of 91 potential biomarkers of sepsis were identified and 32 disturbed metabolic pathways were constructed. Among these biomarkers, 36 metabolites were reversely regulated by XBJ, mainly including glycerophospholipids, sphingolipids, free fatty acids (FFAs), bile acids and acylcarnitines; 42 metabolites were regulated by BIPM, mainly including amino acids, glycerophospholipids, and acylcarnitines; 72 metabolites were regulated after XBJ-BIPM combination treatment, including most of the 91 potential biomarkers. The results showed that the interaction between XBJ and BIPM indeed exhibited a synergistic effect by affecting some key endogenous metabolites, 15 metabolites of which could not be regulated when XBJ or BIPM was used alone. Compared with Model group, 13, 22, and 27 metabolic pathways were regulated by XBJ, BIPM, and XBJ-BIPM combination, respectively. It suggested that many more endogenous metabolites and metabolic pathways were significantly regulated after combination treatment compared with XBJ or BIPM monotherapy. Metabolisms of lipids, amino acids, acylcarnitines, and bile acids were common pathways involved in the synergistic action of XBJ and BIPM. This study was the first to employ metabolomics to elucidate the synergistic effect and decipher the underlying mechanisms of BIPM in combination with XBJ against sepsis. The results provide some support for clinical application of antibiotics in combination with traditional Chinese medicines and have important implications for the treatment of sepsis in clinic.

Optimal dosing regimen of biapenem in Chinese patients with lower respiratory tract infections based on population pharmacokinetic/pharmacodynamic modelling and Monte Carlo simulation

In this study, a population pharmacokinetic (PPK) model of biapenem in Chinese patients with lower respiratory tract infections (LRTIs) was developed and optimal dosage regimens based on Monte Carlo simulation were proposed. A total of 297 plasma samples from 124 Chinese patients were assayed chromatographically in a prospective, single-centre, open-label study, and pharmacokinetic parameters were analysed using NONMEN. Creatinine clearance (CLCr) was found to be the most significant covariate affecting drug clearance. The final PPK model was: CL (L/h)=9.89+(CLCr-66.56)×0.049; Vc (L)=13; Q (L/h)=8.74; and Vp (L)=4.09. Monte Carlo simulation indicated that for a target of ≥40% T>MIC (duration that the plasma level exceeds the causative pathogen's MIC), the biapenem pharmacokinetic/pharmacodynamic (PK/PD) breakpoint was 4μg/mL for doses of 0.3g every 6h (3-h infusion) and 1.2g (24-h continuous infusion). For a target of ≥80% T>MIC, the PK/PD breakpoint was 4μg/mL for a dose of 1.2g (24-h continuous infusion). The probability of target attainment (PTA) could not achieve ≥90% at the usual biapenem dosage regimen (0.3g every 12h, 0.5-h infusion) when the MIC of the pathogenic bacteria was 4μg/mL, which most likely resulted in unsatisfactory clinical outcomes in Chinese patients with LRTIs. Higher doses and longer infusion time would be appropriate for empirical therapy. When the patient's symptoms indicated a strong suspicion of Pseudomonas aeruginosa or Acinetobacter baumannii infection, it may be more appropriate for combination therapy with other antibacterial agents.

The efficacy, safety, and pharmacokinetics of biapenem administered thrice daily for the treatment of pneumonia in the elderly

Biapenem has been widely used to treat bacterial pneumonia; however, there is little information concerning its efficacy and safety in elderly patients. Based on pharmacokinetic-pharmacodynamic theory, administration of biapenem thrice rather than twice daily would be expected to be more effective because of longer time above the minimum inhibitory concentration. In this study, we aimed to evaluate the efficacy, safety, and pharmacokinetics of biapenem (300 mg) administered thrice daily in pneumonic patients aged 65 years or older. Biapenem was effective in 22 of 25 patients, as assessed by the improvement in clinical symptoms and/or the eradication of the causative organisms, and caused no serious adverse events. The pharmacokinetic profile was established based on simulations using a modeling program. Among 17 patients whose causative organisms were detected, time above the minimum inhibitory concentration was estimated to be 100% in 16 patients, all of whom showed clinical improvement. The results of this study confirmed the efficacy and safety of 300 mg of biapenem administered thrice daily for the treatment of pneumonia in elderly patients.

[Personalized optimization of beta-lactam regimens based on studies of the pharmacokinetics-pharmacodynamics at the target sites]

Beta-lactam antibiotics are used for the treatment of various infections such as intra-abdominal infections and bacterial meningitis. Beta-lactams act at the infection site and their antibacterial effects relate to the exposure time during which the drug concentrations remain above the minimum inhibitory concentration for bacteria (T>MIC). The penetration into and exposure of beta-lactams at the target sites, such as the abdominal cavity and the cerebrospinal space, are therefore considered to be good indicators of their efficacies. However, earlier clinical research has focused primary on the drug concentrations in plasma. We therefore examined the pharmacokinetics-pharmacodynamics of beta-lactams at the target sites, and analyzed them using a population pharmacokinetic modeling and statistical technique called Monte Carlo simulation. This review summarizes our recent findings on carbapenem and cephem antibiotics in peritoneal and cerebrospinal fluids, and our new approaches to personalize and optimize beta-lactam dosing regimens based on their site-specific pharmacokinetic-pharmacodynamic profiles.