Prostatic Pharmacokinetic/Pharmacodynamic Evaluation of Ampicillin-Sulbactam for Bacterial Prostatitis and Preoperative Prophylaxis.

This study aims to define the penetration of ampicillin and sulbactam into prostate tissue, develop a prostatic pharmacokinetic model of each drug, and assess the appropriateness of ampicillin-sulbactam regimens for the treatment of prostatitis and the prophylaxis of postoperative infection, based on a pharmacokinetic and pharmacodynamic simulation. Subjects were prostatic hyperplasia patients prophylactically receiving a 0.5-hour infusion of 1.5 g (1:0.5 g) or 3 g (2:1 g) ampicillin-sulbactam before transurethral resection of the prostate. Ampicillin and sulbactam concentrations in plasma and prostate tissue were measured. The prostate tissue/plasma ratios of both ampicillin and sulbactam were approximately 0.37 (area under the drug concentration-time curve), and penetration was similar. The prostatic population pharmacokinetic model, which included a covariate analysis, adequately predicted prostate tissue concentrations in our patient population. For therapeutic use, aiming for a bactericidal target of 50% of time above minimum inhibitory concentration (T > MIC) in prostate tissue, 3 g ampicillin-sulbactam 4 times daily achieved ≥90% expected probability against only Enterococcus faecalis in typical patients with a creatinine clearance (CLcr ) of 30 mL/min. For prophylactic use, aiming for a bacteriostatic target of 30% T > MIC, 3 g ampicillin-sulbactam 4 times daily achieved ≥90% expected probability of attaining the bacteriostatic target against E. faecalis and Proteus species when CLcr was 30 mL/min. Based on prostatic simulations, the present study provides helpful recommendations for the treatment of bacterial prostatitis and preoperative prophylaxis in prostatectomy.

Clinical pharmacokinetics of flomoxef in prostate tissue and dosing considerations for prostatitis based on site-specific pharmacodynamic target attainment.

Flomoxef is used to treat bacterial prostatitis; however, its prostatic pharmacokinetics have not been fully clarified. Flomoxef (500 or 1000 mg) was administered to patients with benign prostatic hypertrophy (n = 54). After a 0.5-h infusion, venous blood samples were drawn at time points of 0.5-5 h, and prostate tissue samples were collected at time points of 0.5-1.5 h during transurethral resection of the prostate. The drug concentrations in plasma and prostate tissue were analyzed pharmacokinetically and used for a stochastic simulation to predict the probability of attaining pharmacodynamic target in prostate tissue. Showing dose linearity in the prostatic pharmacokinetics, flomoxef rapidly penetrated into prostate tissue, with a prostate/plasma ratio of 0.48-0.50 (maximum drug concentration) and 0.42-0.55 (area under the drug concentration-time curve). Against the tested populations of Escherichia coli, Klebsiella and Proteus species isolates, 0.5-h infusion of 1000 mg three times daily achieved a ≥90% expected probability of attaining the bactericidal target (70% of the time above the minimum inhibitory concentration [MIC]) in prostate tissue. The site-specific pharmacodynamic-based breakpoint (the highest MIC at which the target-attainment probability in prostate tissue was >90%) values were 0.25 mg/L (MIC for 90th percentile of E. coli and Klebsiella species) for 500 mg four times daily and 0.5 mg/L (MIC90 of Proteus species) for 1000 mg four times daily. These results help to fully characterize the prostatic pharmacokinetics of flomoxef, while also helping to rationalize and optimize the dosing regimens for prostatitis based on site-specific pharmacodynamic target attainment.

Effects of live yeast supplementation on serum oxidative stress biomarkers and lactation performance in dairy cows during summer.

This study aimed to evaluate the effects of live yeast (Saccharomyces cerevisiae) (LY) supplementation on serum oxidative stress biomarkers, antioxidant vitamin levels, and lactation performance in dairy cows during summer. A total of 16 lactating cows weighing 707.5 ± 13.1 kg (mean ± standard error) were enrolled and randomly assigned to either supplemented (n=8) or control group (n=8). In the supplemented group, the cows were administered with LY product at 10 g/day per cow from mid-July to mid-September for 8 weeks. The serum levels of derivatives of reactive oxygen metabolites in the supplemented group were lower (P<0.05) at week 6. The serum retinol and blood glucose concentrations in the supplemented group were higher (P<0.01) at week 8. LY supplementation did not affect physiological responses, such as rectal temperature, respiratory rate, protein and cholesterol metabolism, and lactation performance. During the study period, daily average milk yield decreased in both groups. The reduction rates of milk yield in the supplemented and control groups were 17.6 and 20.0%, respectively. These results suggest that LY supplementation may reduce oxidative stress and improve carbohydrate metabolism in lactating dairy cows during summer.

Clinical pharmacokinetics and pharmacodynamic target attainment of pazufloxacin in prostate tissue: Dosing considerations for prostatitis.

The present study examined the clinical pharmacokinetics of pazufloxacin in prostate tissue and estimated the probability of target attainment for tissue-specific pharmacodynamic goals related to treating prostatitis using various intravenous dosing regimens. Patients with prostatic hypertrophy received prophylactic infusions of pazufloxacin (500 mg, n = 23; 1000 mg, n = 25) for 0.5 h prior to transurethral prostate resection. Drug concentrations in plasma (0.5-5 h) and prostate tissue (0.5-1.5 h) were measured by high-performance liquid chromatography and used for subsequent noncompartmental and three-compartmental analysis. Monte Carlo simulation was performed to evaluate the probability of target attainment of a specific minimum inhibitory concentration (MIC) in prostate tissue: the proportion that achieved both area under the drug concentration over time curve (AUC)/MIC = 100 and maximum concentration (Cmax)/MIC = 8. Prostatic penetration of pazufloxacin was good with mean Cmax ratios (prostate tissue/plasma) of 0.82-0.99 and for AUC, 0.80-0.98. The probability of reaching target MIC concentrations in prostate tissue was more than 90% for dosing schedules of 0.25 mg/L for 500 mg every 24 h (500 mg daily), 0.5 mg/L for 500 mg every 12 h (1000 mg daily), 1 mg/L for 1000 mg every 24 h (1000 mg daily), and 2 mg/L for 1000 mg every 12 h (2000 mg daily). Importantly, the 2000 mg daily regimen of pazufloxacin produced a profile sufficient to have an antibacterial effect in prostate tissue against clinical isolates of Escherichia coli and Klebsiella pneumonia with MIC values less than 2 mg/L.

Penetration of piperacillin-tazobactam into human prostate tissue and dosing considerations for prostatitis based on site-specific pharmacokinetics and pharmacodynamics.

This study aimed to investigate the penetration of PIPC-TAZ into human prostate, and to assess effectiveness of PIPC-TAZ against prostatitis by evaluating site-specific PK-PD. Patients with prostatic hypertrophy (n = 47) prophylactically received a 0.5 h infusion of PIPC-TAZ (8:1.2-0.25 g or 4-0.5 g) before transurethral resection of the prostate. PIPC-TAZ concentrations in plasma (0.5-5 h) and prostate tissue (0.5-1.5 h) were analyzed with a three-compartment PK model. The estimated model parameters were, then used to estimate the drug exposure time above the minimum inhibitory concentration for bacteria (T > MIC, the PD indicator for antibacterial effects) in prostate tissue for six PIPC-TAZ regimens (2.25 or 4.5 g; once, twice, three times or four times daily; 0.5 h infusions). Prostate tissue/plasma ratio of PIPC was about 36% both for the maximum drug concentration (Cmax) and the area under the drug concentration-time curve (AUC). Against MIC distributions for isolates of Escherichia coli, Klebsiella species and Proteus species, regimens of 4.5 g twice daily and 2.25 g three times daily achieved a >90% probability of attaining the bacteriostatic target for PIPC (30% T > MIC) in prostate tissue; regimens of 4.5 g three times daily and 2.25 g four times daily achieved a >90% probability of attaining the bactericidal target for PIPC (50% T > MIC) in prostate tissue. However, against Pseudomonas aeruginosa isolates, none of the tested regimens achieved a >90% probability. PIPC-TAZ is appropriate for the treatment of prostatitis from the site-specific PK-PD perspective.