In-vitro activity of fleroxacin against isolates causing complicated urinary tract infections and concentrations in seminal and prostatic fluid and in prostatic adenoma tissue

Is clindamycin a potential treatment for prostatitis?

Cutibacterium acnes has been associated with chronic prostatitis, which can potentially favor the appearance of tumors in the prostate. Prostatitis is difficult to treat, and the drug needs to be able to penetrate the prostate. The aim was to investigate the pharmacokinetics of clindamycin in the interstitial fluid of rat prostate using microdialysis. Microdialysis probes were recovered in vitro and in vivo. Clindamycin was administered at 80 mg/kg iv bolus for plasma and tissue pharmacokinetic experiments. A microdialysis probe was implanted in the prostate gland for collections over an 8-hour period. The pharmacokinetic parameters were determined by both compartmental and non-compartmental approaches. Penetration was determined as the ratio between the area under the curve and the time of the clindamycin measurement in the prostate. The recovery of the in vivo probes was 38.11 ± 1.14%. The plasma profile was modeled by a two-compartment pharmacokinetic model. Clindamycin presented a prostate/plasma ratio of 1.02, with free concentrations above the minimum inhibitory concentration for Cutibacterium acnes isolates. This was the first study that determined clindamycin free concentrations in the prostatic fluid of rats. These findings suggest that clindamycin may be an effective alternative for the treatment of prostatitis caused by Cutibacterium acnes.

Antimicrobial treatment of prostatitis

The aim of this review is to emphasize the role of antimicrobial treatment in prostatitis. Especially in chronic bacterial prostatitis, the selection of an appropriate antimicrobial agent with optimal pharmacokinetics for prostatic secretion and tissue is important. The theoretical background of drug penetration into the prostate is outlined, emphasizing the phenomenon of ion-trapping and the role of nonionic diffusion of weak acids, bases and amphoteric drugs across biological membranes with a pH gradient. Determination of drug concentrations in human prostatic secretion are problematic because of possible urinary contamination. Studies have been carried out mainly in healthy volunteers. The results have to be interpreted with caution, if not care was taken to rule out or at least identify urinary contamination. Analyzing the concentrations of various fluoroquinolones in prostatic and seminal fluid as well as in prostatic tissue, it becomes obvious that the fluoroquinolones differ not only in plasma concentrations but also in their penetration ability to these sites. In spite of intensive investigations, our knowledge is still limited concerning the mechanisms that govern the transport of antibiotic drugs into and their activity in the various prostatic compartments and how the findings can be applied clinically. Nevertheless, overall the concentrations at the site of infection of most of the fluoroquinolones with this indication should be sufficient for the treatment of chronic bacterial prostatitis and vesiculitis caused by susceptible pathogens.

A new method to estimate quantitatively seminal vesicle and prostate gland contributions to ejaculate

AIMS

We sought to optimize a quantitative noninvasive method to determine the concentration in their glands of origin of biochemical markers of compartments of the male genital tract as the first step towards validation of a novel method for estimation of drug concentrations in these male genital tract compartments.

METHODS

Sixty-eight men participated. We compared four collection devices to split ejaculate into fractions. Fractions were assayed for fructose and prostate specific antigen (PSA) as unique markers of the seminal vesicle and prostate, respectively. Seminal vesicle fructose and prostatic PSA were estimated using a linear regression method, based on fructose-PSA axis intercepts, and compared with an older method which solves a simultaneous series of equations.

RESULTS

A five-compartment collection device performed best with mean (95% confidence interval) PSA vs. fructose r(2) of 0.84 (0.71, 0.98, P < 0.001). Using resampling simulations, glandular PSA and fructose estimates were highly variable and often implausible when using only two fractions. Using our method, the prostate contributed 37-44% to the whole ejaculate and the seminal vesicle contributed 55-61%. The novel regression method was highly correlated (r(2) > or = 0.98) with older methods.

CONCLUSIONS

We developed a noninvasive quantitative method of male genital tract biochemical marker estimation using a five-compartment tray to collect three to five ejaculate fractions. Our novel regression method is quantitative and more fully developed than older methods. This noninvasive method for determining glandular marker concentrations should be useful to provide quantitative estimates of drug concentrations in these glands.

The role of antibiotics in chronic bacterial prostatitis

The role of antibiotic treatment in prostatitis is described. The selection of an appropriate antimicrobial agent with optimal pharmacokinetics for prostatic secretion and tissue is important, particularly in chronic bacterial prostatitis (CBP). The theoretical background of drug penetration into the prostate is outlined, emphasising the phenomenon of ion trapping and the role of non-ionic diffusion of weak acids, bases and amphoteric drugs across biological membranes with a pH gradient. Determination of drug concentrations in human prostatic secretion is problematic because of possible urinary contamination. Studies have been carried out mainly in healthy volunteers. The results must be interpreted with caution if no care was taken to rule out or at least to identify urinary contamination. Analysing the concentrations of various fluoroquinolones in prostatic and seminal fluid as well as in prostatic tissue, it becomes obvious that the fluoroquinolones differ not only in plasma concentrations but also in their penetration to these sites. In spite of intensive investigations, our knowledge is still limited regarding the mechanisms that govern the transport of antibiotics into and their activity in the various prostatic compartments and how these findings can be applied clinically. Nevertheless, the concentrations at the site of infection of most of the fluoroquinolones should be sufficient for the treatment of CBP and vesiculitis caused by susceptible pathogens.

Concentrations of gatifloxacin in plasma and urine and penetration into prostatic and seminal fluid, ejaculate, and sperm cells after single oral administrations of 400 milligrams to volunteers

Gatifloxacin (GTX), a new fluoroquinolone with extended antibacterial activity, is an interesting candidate for the treatment of chronic bacterial prostatitis (CBP). Besides the antibacterial spectrum, the concentrations in the target tissues and fluids are crucial for the treatment of CBP. Thus, it was of interest to investigate its penetration into prostatic and seminal fluid. GTX concentrations in plasma, urine, ejaculate, prostatic and seminal fluid, and sperm cells were determined by a high-performance liquid chromatography method after oral intake of a single 400-mg dose in 10 male Caucasian volunteers in the fasting state. Simultaneous application of the renal contrast agent iohexol was used to estimate the maximal possible contamination of ejaculate and prostatic and seminal fluid by urine. GTX was well tolerated. The means (standard deviations) for the following parameters were as indicated: time to maximum concentration of drug in serum, 1.66 (0. 91) h; maximum concentration of drug in serum, 2.90 (0.39) microg/ml; area under the concentration-time curve from 0 to 24 h, 25.65 microg. h/ml; and half life, 7.2 (0.90) h. Within 12 h about 50% of the drug was excreted unchanged into the urine. The mean renal clearance was 169 ml/min. The gatifloxacin concentrations in ejaculate, seminal fluid, and prostatic fluid were in the range of the corresponding plasma concentrations which were 1.92 (0.27) microg/ml at approximately the same time point (4 h after drug intake). The concentrations in sperm cells (0.195, 0.076, and 0.011 microg/ml) could be determined in three subjects. The good penetration into prostatic and seminal fluid, the good tolerance, and the previously reported broad antibacterial spectrum suggest that GTX may be a good alternative for the treatment of chronic bacterial prostatitis. Clinical studies should be performed to confirm this assumption.

Drugs in semen

Over the past 50 years, a decline in the quality of semen has been observed, possibly resulting in a reduction in male fertility. Among the factors affecting semen quality, exposure to drugs is of particular importance. It is known that drugs can be transported to the seminal plasma, which is made up of secretions from the various accessory genital glands. There is evidence that many drugs enter the male genitourinary tract by an ion-trapping process. Lipid solubility and the degree of ionisation of the drug, which depend on the pH of plasma and seminal fluid, are important factors in this process. To date, few studies have been conducted on this topic. Pharmacokinetic evaluation of the fluids of the male accessory gland have been performed in the case of chloroquine and caffeine only, while the effects of mesalazine (5-aminosalicylic acid), sulfasalazine, salicylate, propranolol, diltiazem, flunarizine, verapamil, caffeine and nicotine on sperm physiology and morphology have been examined. Although data from the literature are scarce and incomplete, it is evident that many drugs can be excreted into semen. These drugs may interfere with the most common semen characteristics, potentially resulting in a male-mediated teratogenic effect, or local and systemic responses in female recipients. Therefore, it may be advisable to include, in the processes of drug development, pharmacokinetic evaluation of a drug in the semen and analysis of standard microscopic parameters of the semen. This is particularly important for drugs known to concentrate in the semen.

Penetration of ciprofloxacin into prostatic fluid, ejaculate and seminal fluid in volunteers after an oral dose of 750 mg

To evaluate an effective dose for the treatment of bacterial prostatitis the concentrations of ciprofloxacin were measured in prostatic fluid, ejaculate and the cell-free seminal fluid of 15 healthy volunteers who received an oral dose of 750 mg. ciprofloxacin while in a fasting state. Venous blood samples were taken in all subjects at 1, 2, 3 and 4 hours. In 6 subjects blood samples were also taken after 8 and 12 hours. Urine was collected in all subjects during 0 to 4 hours and in the 6 subjects also during 4 to 8 hours and 8 to 12 hours. Prostatic fluid could be obtained in 10 subjects by prostatic massage 4 hours after drug intake. So as not to contaminate the urethra with ciprofloxacin the subjects were not allowed to void until 4 hours after drug intake. Iopamidol (3.162 gm.), a renal contrast agent, was administered intravenously concomitantly with oral ciprofloxacin intake. After 8 hours iohexol (3.235 gm.) was administered intravenously. These agents were measured in prostatic fluid, ejaculate and seminal fluid to assess the contamination of those fluids by urine. All drug measurements were done by high pressure liquid chromatography. The median plasma concentrations of ciprofloxacin were 2.1 mg./l. at 1 hour (maximum concentration), 0.9 mg./l. at 4 hours and 0.2 mg./l. at 12 hours. The median concentration in prostatic fluid was 0.23 mg./l. with a fluid-to-plasma concentration ratio of 0.23. The median concentration in the ejaculate (seminal fluid) after 4 hours was 7.4 mg./l. (6.6 mg./l.) and after 12 hours it was 2.0 mg./l. (1.9 mg./l.) with corresponding ejaculate (seminal fluid)-to-plasma concentration ratios of 8.4 (7.7) and 8.0 (6.6), respectively. Thus, ciprofloxacin is concentrated several-fold in ejaculate and seminal fluid but not in prostatic fluid. According to the results the concentrations of ciprofloxacin in prostatic fluid exceed the minimal inhibitory concentration-90% for Enterobacteriaceae but not for Pseudomonas, enterococci and staphylococci, whereas the concentrations in ejaculate and seminal fluid are sufficiently elevated to include the total spectrum of sensitive strains causing bacterial prostatis.

Penetration of ofloxacin into prostatic fluid, ejaculate and seminal fluid

The penetration of ofloxacin into prostatic fluid, ejaculate and seminal fluid was measured by a high-pressure liquid chromatography (HPLC) method after intravenous infusion (60 min) of 400 mg in six healthy male volunteers. The median concentration of ofloxacin in prostatic fluid was about one-third and that in ejaculate and seminal fluid about twice that in corresponding plasma. The results of the study indicate good penetration of ofloxacin into prostatic fluid, ejaculate and seminal fluid. Ofloxacin should thus be of value for the treatment of chronic bacterial prostatitis and vesiculitis.

The role of quinolones in the treatment of chronic bacterial prostatitis

Chronic bacterial prostatitis is a rare infection but difficult to treat. Usually co-trimoxazole has been used, yet with poor results. Because of their favorable pharmacokinetics and their broad antibacterial spectrum, the newer quinolones may be a good alternative. In contrast to beta-lactam antibiotics their concentrations in prostatic fluid, in prostatic tissue and in seminal fluid are relatively high in comparison to the corresponding plasma concentrations. For prostatic fluid measurements, however, possible urinary contamination has to be considered and identified otherwise falsely high levels are measured. A total of 23 studies with the newer quinolones (norfloxacin, ciprofloxacin, ofloxacin, pefloxacin, enoxacin, temafloxacin and rufloxacin) in the treatment of chronic bacterial prostatitis are available. However, the results of these studies are difficult to compare because not all investigators used the same diagnostic criteria and there was a considerable range of duration of treatment and of follow-up. Since the issue involved in the treatment of prostatitis is that of relapse, patients cannot be considered cured if they have been followed for one week or one month only. There were four studies among the 23 publications, i.e. one with norfloxacin and three with ciprofloxacin, which fulfilled the criteria of standardized prostatic localization and of long-term follow-up of at least six months. The results are promising, but further investigations, especially controlled studies, are needed in order to determine the role of the newer quinolones in the treatment of chronic bacterial prostatitis.

Concentrations of cefpodoxime in plasma, ejaculate and in prostatic fluid and adenoma tissue

Twenty-four healthy volunteers and 24 patients undergoing transurethral resection of the prostate received an oral dose of 200 mg of cefpodoxime as proxetil ester in a fasting state. At the same time 3.235 g of iohexol, a renal contrast medium, was injected intravenously to indicate possible urinary contamination of the prostatic fluid. The subjects were divided into three groups each. After 3, 6 and 12 h the cefpodoxime concentrations were measured in plasma, urine, prostatic fluid and ejaculate in volunteers and in plasma, prostatic fluid and prostatic adenoma tissue in patients by a bioassay as well as by an HPLC method. In general, the concentrations measured by bioassay were higher than those by HPLC. The median plasma concentrations (bioassay) in volunteers (patients) after 3, 6 and 12 h were 2.28 (2.34) mg/l, 0.95 (1.17) mg/l and 0.12 (0.28) mg/l, respectively. The median ejaculate concentrations after 6 and 12 h were 0.95 mg/l and 0.19 mg/l, respectively. Only in three volunteers and in one patient prostatic fluid concentration without urinary contamination could be measured after 3 h with a median fluid to plasma ratio of 0.10. The prostatic adenoma tissue concentrations (bioassay) after 3 and 6 h were 0.50 mg/kg and 0.24 mg/kg with tissue to plasma ratios of 0.30 and 0.26, respectively. After 3 h about half of the volunteers and after 12 h about half of the patients showed no detectable concentration in ejaculate (volunteers) and prostatic tissue (patients), respectively. It was concluded that the cefpodoxime should be administered 3 to 6 h prior to surgery if used for perioperative prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluoroquinolone antimicrobial agents

The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous system toxicities occurring most commonly, but only rarely necessitating discontinuance of therapy. In 17 of 18 prospective, randomized, double-blind comparisons with another agent or placebo, fluoroquinolones were tolerated as well as or better than the comparison regimen. Bacterial resistance has been uncommonly documented but occurs, most notably with P. aeruginosa and Staphylococcus aureus and occasionally other species for which the therapeutic ratio is less favorable. Fluoroquinolones offer an efficacious, well-tolerated, and cost-effective alternative to parenteral therapies of selected infections.

Developments in quinolones. Bacteriology, pharmacokinetics and initial clinical experience of several investigational quinolone derivatives

The properties of several new, investigational quinolones are reviewed. Desirable characteristics of new quinolones are improved activity against especially Gram-positive bacteria, longer elimination half-life, slower development of resistance, fewer side effects etc. Fleroxacin and lomefloxacin have entered phase III trials: their main advantage lies in improved pharmacokinetics. AM-1091, AT-4140 and T-3262 are still in early phases of development and show improved activity against Gram-positive bacteria. They also show a reduced penetration of the blood-brain barrier, probably resulting in fewer side effects in the central nervous system. AM-1091 shows incomplete cross-resistance with ciprofloxacin.

[Enoxacin concentration in seminal fluid, in prostate secretions and in prostatic adenoma tissue following oral administration or intravenous infusion]

In eleven volunteers and 39 patients undergoing transurethral resection of the prostate or bladder tumor, concentrations of enoxacin were measured in seminal fluid (volunteers), in prostatic fluid (volunteers, patients) and in prostatic adenoma tissue (patients) after oral (400 mg) administration and intravenous (428 mg) infusion (60 min) of enoxacin. Simultaneously 2.534 g of iothalamic acid was i.v. injected to identify possible urinary contamination. The concentrations of enoxacin in seminal fluid after 2-4 h and in prostatic tissue after about 1-4 h and 14-16 h exceeded plasma concentrations more than two-fold. The concentrations in prostatic fluid after 1-4 h were about half the plasma concentrations. Venous blood samples were taken after intravenous infusion at intervals of up to 24 h in a total of 14 patients. The mean plasma concentration of enoxacin decreased from its maximum of 6.9 mg/l at the end of infusion to 0.5 mg/l at 12 h after administration. A terminal half life of 6.65 h was calculated according to an open two-compartment model.