Evaluation of the efficacy and safety of biapenem against pneumonia in the elderly and a study on its pharmacokinetics

Although biapenem is used in the treatment of pneumonia, the clinical data on elderly patients are yet insufficient. Therefore, the purpose of this study was evaluating the efficacy and safety of biapenem against pneumonia in the elderly and its pharmacokinetics. The subjects were patients 65 years of age or older with pneumonia. Biapenem (300 mg) was administered once to three times per day. For some cases, the drug concentrations in plasma were measured chronologically. The clinical efficacy was evaluated in reference to the improvement in subjective symptoms and objective opinion. The primary outcome was efficacy rate at the end of treatment. Biapenem was effective in 17 of 20 subject cases (85.0 %). Regarding safety, although 4 cases experienced hepatic dysfunction and 1 case had nausea, these effects were not severe in all cases and administration was continued. There was no deterioration of renal function associated with biapenem. In 13 cases in which the trough value of biapenem was measured, there were no unacceptable side effects and the trough values were generally low. It is believed that biapenem (300 mg once to three times a day), even when taken by elderly people, does not accumulate and that the dosage is safe and appropriate. The changes in the predicted concentrations calculated with the pharmacokinetic-pharmacodynamic (PK-PD) software, which is based on previously reported population pharmacokinetic parameters, and those in the measured concentrations approximately matched. It is useful to plan biapenem administration using the PK-PD software when performing antibiotic chemical treatment.

[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.

Determination of total cefozopran concentrations in human peritoneal fluid by HPLC with cefepime as an internal standard: Comparative pharmacokinetics in the fluid and plasma

A simple, rapid and precise HPLC method using ultrafiltration to remove protein was developed to determine total cefozopran concentrations in human peritoneal fluid in the same manner as in human plasma, irrespective of the amount of protein. The recovery of cefozopran after ultrafiltration in peritoneal fluid was higher than that in plasma, because the protein content in peritoneal fluid was lower than that in plasma. Furthermore, it was found that an internal standard with a similar protein-binding ratio to cefozopran could revise the cefozopran loss by ultrafiltration in plasma and peritoneal fluid samples irrespective of the amount of protein. Therefore, it was concluded that cefepime may be used as an internal standard. Cefozopran and cefepime were detected by measuring their ultraviolet absorbances at 235 nm. The calibration curve obtained for cefozopran in peritoneal fluid was linear from 0.2 to 200 microg/ml. The intraday and interday precisions were less than 5.77% (CV), and the accuracy was between 96.3% and 108% above 0.2 micro/ml. The lower limit of detection was 0.05 micro/ml in peritoneal fluid, which was the same as that in plasma. The assay has been applied to therapeutic drug monitoring of cefozopran in both plasma and peritoneal fluid and has contributed to peritoneal pharmacokinetic studies in patients.

Real-time therapeutic drug monitoring of cefozopran in plasma using high-performance liquid chromatography with ultraviolet detection

A simple, rapid, and precise HPLC method using ultrafiltration to remove plasma protein was developed to determine cefozopran concentrations in human plasma for real-time therapeutic drug monitoring. Plasma was separated by centrifugation at 4 degrees C from blood collected in heparinized vacuum tubes. Cefozopran and an internal standard were detected by ultraviolet absorbances at 235 nm with no interfering plasma peak. The calibration curve of cefozopran in human plasma was linear from 0.2 to 200 microg/ml. The limit of detection was 0.05 microg/ml. The assay was applied to febrile neutropenia patients in a clinical setting.

High-performance liquid chromatography with ultraviolet detection for real-time therapeutic drug monitoring of meropenem in plasma

A simple, rapid, and precise high-performance liquid chromatography (HPLC) method using ultrafiltration to remove plasma protein was developed to determine meropenem concentrations in human plasma in a clinical setting. Plasma was separated by centrifugation at 4 degrees C from blood collected in heparinized vacuum tubes, and meropenem was stabilized by immediately mixing the plasma with 1M 3-morpholinopropanesulfonic acid buffer (pH 7.0) (1:1). Ultrafiltration was used for plasma deproteinization. Meropenem was detected by ultraviolet absorbance at 300 nm with no interfering plasma peak. The calibration curve of meropenem in human plasma was linear from 0.05 to 100 microg/mL. Intraday and interday precision was less than 7.17% (CV), and accuracy was between 97.7% and 106.3% over 0.05 microg/mL. The limit of detection was 0.01 microg/mL. The assay has been clinically applied to a real-time therapeutic drug monitoring in pediatric patients and pharmacokinetic studies.