Glycerophosphate is interchangeable with inorganic phosphate in terms of safety and serum pharmacokinetics.

OBJECTIVE: The primary aim of the present investigation was to determine and compare the pharmacokinetic (PK) profiles of inorganic phosphate in serum and urine after intravenous administration of sodium glycerophosphate and inorganic sodium phosphate. Additionally, study product safety profiles were evaluated. SUBJECTS AND METHODS: In total, 27 healthy, white volunteers (17 male/10 female) were enrolled in this double-blinded, randomized, 2-sequence, crossover study and were assigned to receive an organic test drug (sodium glycerophosphate) and an inorganic reference preparation (sodium phosphate) on 2 occasions. Validated analytical methods were used, and concentrations of total inorganic phosphate in serum and urine were determined over 24 h following a single 4-hour continuous intravenous infusion of test and reference drugs at a dose of 80 mmol. Study days were separated by washout periods of 7 days. An analysis of variance, based on population means and 90% confidence intervals (CIs), was used for testing bioequivalence (BE; range 0.8-1.25) between investigational products. RESULTS: The geometric means of the ratio of the point estimates and corresponding 90% CIs for the area under the concentration-versus-time curve of inorganic serum phosphate from 0 to 24 h (AUC(0-24)), the phosphate's maximum concentration in serum (C(max)) and the total amount of inorganic phosphate excreted in urine over 24 h corrected for individual baseline values (Ae(0-24 bc)) were estimated. The test/reference ratios for inorganic phosphate were 1.04 (CI 1.00-1.07), 0.85 (CI 0.84-0.87) and 0.84 (CI 0.77-0.92) for AUC(0-24), C(max) in serum and Ae(0-24 bc) in urine, respectively. Hence, standard BE criteria were met for AUC(0-24) and C(max) in serum, while Ae(0-24 bc) marginally failed to demonstrate BE. After drug administration, a total of 15 subjects reported the occurrence of at least 1 treatment emergent adverse event (AE). All AEs were classified as mild to moderate in severity, and the two treatment groups were equally affected. No serious AEs occurred. CONCLUSION: The serum PK profiles of inorganic phosphate were almost superimposable following intravenous administration of equimolar doses of test and reference drugs. Thus, we conclude that the two study drugs are essentially similar in terms of serum PK profiles, safety and tolerability.

Efficacy and safety of current drug therapies for invasive aspergillosis.

Invasive aspergillosis (IA) is a potentially lethal infection that affects mostly immunocompromised patients. The therapeutic goals are to restore leucocyte function and to reduce the fungal burden by effective antifungal agents and, contingently, by surgery. Several drugs for the treatment of IA are currently licensed. The longest known among them is amphotericin B (AmB). In well-performed clinical trials, approximately 30-50% of participants treated with AmB showed complete or partial response. However, this drug is associated with considerable acute and chronic toxicity which was somewhat mitigated by the development of lipid-based formulations. In contrast, voriconazole (VRC) is better tolerated, penetrates well into the central nervous system and may be given intravenously and orally in a sequential manner. The overall rates of favourable response to VRC were similar to that for AmB. Most notably, double-digit rates of complete remission were observed in studies including extraordinarily high proportions of patients with proven IA and specific risk factors. Disadvantages of VRC include the genetically determined interindividual variability of pharmacokinetics and the potential for drug-drug interactions that may require therapeutic drug monitoring. The recently introduced caspofungin (CPF) offers an excellent safety profile, but underperformed in terms of efficacy against mold infections. Other antifungals such as itraconazole and posaconazole are presently recommended as second-line option for the therapy or prophylaxis of (non-)IA. The value of micafungin and anidulafungin remains to be investigated in randomized clinical trials. In guidelines released by relevant medical societies, VRC is recommended as the first choice in the treatment of IA. AmB, preferably given as a liposomal preparation, or combinatory antifungal regimens combining VRC or liposomal AmB with CPF are stated as alternative options.

Glycerophosphate does not interact with components of parenteral nutrition.

BACKGROUND/AIMS: The primary objective of this study was to determine and compare the pharmacokinetic (PK) profiles of inorganic phosphate in the serum after continuous administration of pure glycerophosphate and glycerophosphate contained in total parenteral nutrition (TPN) emulsions. This approach was selected to identify potential PK interactions between TPN components and glycerophosphate. METHODS: The serum PK profile of inorganic phosphate after continuous intravenous administration of a sodium glycerophosphate containing TPN emulsion was determined in 10 healthy, white (5 male/5 female) volunteers. A pure sodium glycerophosphate formulation served as reference. Standard criteria of bioequivalence were applied. Subjects were enrolled in the double-blinded study and were randomly allocated to receive the test and reference preparations on two occasions in a 2-sequence crossover study design. The volunteers received 1/3 of the maximum recommended body weight- (BW) adjusted intravenous daily dosage (13.3 ml/kg BW) of the test drug over a period of 8 h. The amount of total phosphate (0.101 mmol/kg) and duration of administration were identical for the test and reference drugs. Study days were separated by washout periods of at least 88 h. Serum concentrations of total inorganic phosphate were measured serially over a 36-hour period using a validated method. A statistical mixed ANOVA, based on population averages, was used for testing bioequivalence between these study preparations. RESULTS: The 90% confidence intervals (90% CIs) of inorganic phosphate in serum were calculated for the test/reference ratios of the area under the time-concentration curve from time 0 to 36 h (AUC0₋36), the maximum concentration (C(max)) and the concentration 5 min before the end of infusion (C(ss)) for a bioequivalence range from 0.80 to 1.25. The mean test/reference ratios fell completely within the 90% CIs with values of 1.016 (90% CI 1.005-1.028), 1.013 (90% CI 0.981-1.047) and 0.932 (90% CI 0.886-0.980) for AUC(0-36), C(max) and C(ss), respectively. In total, 3 mild adverse events in the reference group were detected after starting intravenous infusion, while no adverse events were observed in the test group after treatment. CONCLUSION: Primary PK parameters were within the defined bioequivalence range of 0.8-1.25. Thus, inorganic phosphate levels were essentially similar between the two investigational medicinal products tested in the present study. These findings confirm the concept that nutritional components of the test drug do not significantly interact with glycerophosphate. The two study preparations proved to be safe during the investigation.

A reappraisal of current dosing strategies for intravenous fosfomycin in children and neonates.

The rising incidence of multi-drug resistant bacterial pathogens has renewed interest in the long-known antibacterial fosfomycin. Not least because of its low toxicological potential, there is good clinical experience with intravenous fosfomycin for various Gram-positive and Gram-negative infections in the treatment of children and neonates. However, the current dosing recommendations for intravenous fosfomycin vary widely in paediatric patients. In the present review, we summarized available plasma pharmacokinetic data derived from neonates or children following intravenous administration of fosfomycin. Subsequently, we used this information for recalculation of different dosing strategies and simulated a variety of clinically applied dosing regimens. The percentage of time above the minimal inhibitory concentration (T>MIC) was calculated for each dosing strategy, as this pharmacokinetic-pharmacodynamic parameter was shown to be most predictive of antimicrobial and clinical success of fosfomycin treatment. Our data corroborate the current practice of selecting the dosage of intravenous fosfomycin primarily on the basis of bodyweight and age in paediatric patients. As with other 'time-dependent' antibacterials, a dosing interval of 6-8 hours should be preferred over 12 hours except for immature neonates. Given a T>MIC target of 40-70%, currently recommended dosing strategies appear to be insufficient in children aged 1-12 years, if pathogens with MICs of ≥32 mg/L are suspected and subjects are presenting with normal renal function. Likewise, the lowest recommended daily dose for neonates and infants (aged up to 12 months) of 100 mg/kg bodyweight of fosfomycin should be considered only for pre-term neonates with a postmenstrual age below 40 weeks.

The ability of fluconazole to penetrate into ventilated, healthy and inflamed lung tissue in a model of severe sepsis in rats.

BACKGROUND/AIMS: We measured the extracellular concentrations of fluconazole in lung tissue of septic and healthy rats. METHODS: A single intravenous dose of 6 mg/kg total body weight of fluconazole was administered intravenously to rats following insertion of microdialysis probes into lung tissue. Another probe was inserted into skeletal muscle and served as control. RESULTS: The mean peak concentration (C(max)), time to C(max), area under the concentration-versus-time curve from 0 to 6 h (fAUC(0-6)) and area under the concentration-versus-time curve from 0 to ∞ of unbound fluconazole for healthy lung were 11.0 ± 2.3 mg/l, 1.9 ± 1.5 h, 47.4 ± 8.6 mg·h/l and 233.7 ± 121.1 mg·h/l, respectively. The corresponding values for inflamed lung were 11.8 ± 1.7 mg/l, 1.5 ± 0.0 h, 52.9 ± 6.2 mg·h/l and 212.6 ± 79.7 mg·h/l, respectively. The mean apparent terminal elimination half-lives of fluconazole ranged from 12.3 to 22.4 h between compartments. The ratios of the fAUC(0-6) for lung to the fAUC(0-6) for plasma were 1.38 ± 0.39 and 1.32 ± 0.04 for healthy and inflamed lung, respectively. CONCLUSION: We provide evidence that free fluconazole levels in plasma, the extracellular space fluid of lung tissue and skeletal muscle are almost superimposable during inflammatory and normal conditions.

High extracellular levels of cefpirome in unaffected and infected lung tissue of patients.

OBJECTIVES: the objective of the present investigation was to measure the extracellular concentrations of cefpirome in unaffected and infected lung tissue of septic patients. METHODS: a single intravenous dose of 30 mg/kg total body weight of cefpirome was administered to eight patients every 12 h prior to insertion of microdialysis probes into lung tissue. RESULTS: the median (minimum, maximum) peak concentration (C(max)), time to C(max) (T(max)), area under the concentration-time curve from 0 to 4 h (AUC(0-4)) and AUC(0-∞) of unbound cefpirome for unaffected lung were 48 (32, 107) mg/L, 0.83 (0.17, 3.17) h, 117 (60, 177) mg ·â€Šh/L and 182 (80, 382) mg ·â€Šh/L, respectively. The corresponding values for infected lung tissue were 45 (6, 122) mg/L, 1.17 (0.83, 2.83) h, 92 (17, 253) mg ·â€Šh/L and 206 (49, 379) mg ·â€Šh/L, respectively. The median apparent terminal elimination half-lives (t(½z)) of cefpirome were 2.61, 3.05 and 3.39 h for plasma, unaffected lung and infected lung, respectively. The median ratios of the AUC(0)(-∞) for lung to the AUC(0)(-∞) for plasma were 0.63 (0.19, 1.55) and 0.46 (0.32, 0.98) for unaffected and infected lung, respectively. CONCLUSIONS: we provide strong evidence that cefpirome penetrates effectively into the extracellular space fluid of lung tissue. Under steady-state conditions, the median concentrations of cefpirome in plasma, unaffected lung and infected lung exceeded the MICs of the majority of relevant bacteria over the entire dosing interval of up to 12 h after intravenous administration of a dose of 30 mg/kg total body weight.

Coagulation factor VIII levels are associated with long-term survival - interactions with gender in a large hospital-based cohort.

INTRODUCTION: Elevated coagulation factor VIII activity has been associated with increased risk for both venous and arterial thrombosis. The current study evaluated the influence of Factor VIII levels and interactions with gender on all cause mortality in a large Austrian cohort. PATIENTS AND METHODS: During 1991 and 2003, 11203 individuals, first ever request for laboratory analyses of FVIII: C, age > or =18 years, were included in this study. The median observation period was 5 years covering a total of 46000 person-years. The death rate was 17.1%. RESULTS: Compared to individuals within the reference category (FVIII: C <94%) hazard ratios gradually increased from 1.4 (95% CI: 1.1-1.8) in the 152-170% category (5th decile) to finally 4.4 (95% CI: 3.5-5.5) in the >313% category (highest decile, all p < 0.05). The association between FVIII: C levels and mortality remained essentially unchanged when considering non-cancer mortality, all cause vascular mortality or mortality due to ischemic heart disease. Compared to males females with elevated FVIII: C had a worse outcome resulting in higher hazard ratios reaching 6.8 (95% CI: 4.6-9.9) within the highest decile compared to males (HR: 3.4 (95% CI: 2.6-4.5)). CONCLUSIONS: In our large patient cohort we might be able to demonstrate for the first time that FVIII: C plasma activity is strongly associated with all cause mortality. Additionally, FVIII: C appears to interact with gender. Especially in women FVIII: C might help identifying high-risk cohorts, which might benefit from individualized prevention strategies.

Rapid and sensitive determination of the antibiotic linezolid in low plasma volumes by high-performance liquid chromatography.

A rapid and sensitive method for the determination of linezolid by high-performance liquid chromatography (HPLC) with UV detection (251 nm) is presented. Linezolid is an important antibiotic against severe infections caused by multi-resistant bacterial pathogens. Scientific efforts continue investigating its effectiveness in different conditions and patient populations including children and newborns. Because plasma samples in a pediatric setting or from animal models are usually collected in low volumes, there is a necessity for a reliable and precise analytical method that is reliable and precise even at sample volumes below 50 microL. The presented method is suitable for plasma sample volumes of 20 microL and can be performed with basic HPLC equipment. Linezolid is extracted from plasma with 10% methanol-90% dichloromethane at neutral conditions and separated isocratically on a microbore ODS column using ammonium acetate buffer (pH 4.4, 0.5%, w/v) and acetonitrile (84:16, v/v) as the eluent. The method exerts linearity from 0.05-40 mg/L and meets commonly accepted specifications regarding accuracy and precision.

Linezolid concentrations in infected soft tissue and bone following repetitive doses in diabetic patients with bacterial foot infections.

The present study aimed at assessing unbound extracellular concentrations of linezolid in inflamed soft tissue and bone of diabetic patients suffering from severe bacterial foot infections. Linezolid was administered intravenously twice daily at a dosage of 600 mg. At steady-state conditions, the microdialysis technique was utilised to sample serially interstitial space fluid from inflamed subcutaneous adipose tissue and metatarsal bone from 0-8h post dose in three representative patients. Mean peak concentrations of free linezolid in plasma, healthy subcutis, inflamed subcutis and cancellous bone were 16.6+/-3.0, 15.5+/-2.5, 15.8+/-2.8 and 15.1+/-4.1mg/L, respectively. The degree of tissue penetration as expressed by the ratio of the area under the concentration-time curve of free linezolid from 0-12h (fAUC(0-12)) in tissue to the fAUC(0-12) in plasma was 1.32+/-0.09, 1.12+/-0.22 and 1.09+/-0.11 for healthy subcutis, inflamed subcutis and bone, respectively. Based on currently available pharmacokinetic/pharmacodynamic targets, we conclude that linezolid administered at 600 mg twice daily may be considered an effective treatment in diabetic patients suffering from bacterial foot infection complicated by osteomyelitis.

Soft tissue and bone penetration abilities of daptomycin in diabetic patients with bacterial foot infections.

OBJECTIVES: In the attempt to overcome increasing glycopeptide- and methicillin-resistant soft tissue infections, daptomycin is presently considered as an attractive alternative to the class of glycopeptides. However, daptomycin dosing and its ability to penetrate into inflamed target tissues are still a matter of controversy. Thus, in the present investigation, we set out to evaluate daptomycin's ability to penetrate into inflamed subcutaneous adipose tissue and bone in diabetic patients presenting with severe bacterial foot infection. PATIENTS AND METHODS: The microdialysis technique was utilized to collect interstitial space fluid from inflamed subcutaneous adipose tissue and metatarsal bone. Plasma and unaffected subcutaneous adipose tissue served as reference compartments. Serial sampling of specimens at steady-state was performed from 0 to 8 h post-dose in five patients (Group A) and from 8 to 16 h after study drug administration in another group of four patients (Group B). In all subjects, daptomycin was administered intravenously once daily at a dosage of 6 mg/kg body weight for 4 consecutive days at minimum. RESULTS: Equilibrium between free tissue and plasma concentrations was achieved approximately 2 h post-infusion. Under steady-state conditions, the degree of tissue penetration was assessed by the calculation of the ratio of free (f) AUC of daptomycin in plasma to the fAUC in tissues. The mean ratios of the fAUC0-16 tissue to the fAUC0-16 plasma were 1.44, 0.98 and 1.08 for healthy tissue, inflamed subcutaneous adipose tissue and bone, respectively. The corresponding ratios of the fAUCs from 0 to 24 h were 1.54, 1.06 and 1.17, respectively. CONCLUSIONS: With the reservation that pharmacokinetic-pharmacodynamic targets for daptomycin in tissues are currently not established, we conclude that daptomycin given at intravenous doses of 6 mg/kg body weight once daily may be considered an effective treatment regimen in diabetic patients suffering from bacterial foot infection and osteomyelitis.

Extracellular concentrations of fosfomycin in lung tissue of septic patients.

OBJECTIVES: The present investigation explored the ability of fosfomycin to penetrate lung tissue of septic patients by utilizing the microdialysis technique. METHODS: After microdialysis probe insertion into healthy and infected lung tissue, a single intravenous dose of 4 g of fosfomycin was administered. RESULTS: The mean C(max), T(max), AUC(0-4) and AUC(0-infinity) for healthy lung were 131.6 +/- 110.6 mg/L, 1.1 +/- 0.4 h, 242.4 +/- 101.6 mgxh/L and 367.6 +/- 111.9 mgxh/L, respectively. The corresponding values for infected lung were 107.5 +/- 60.2 mg/L, 1.4 +/- 0.5 h, 203.5 +/- 118.4 mgxh/L and 315.1 +/- 151.2 mgxh/L. The half-life of fosfomycin ranged from 2.2 to 2.7 h between compartments. The magnitude of lung tissue penetration, as determined by the ratios of the AUC(0-infinity) for lung to the AUC(0-infinity) for plasma, was 0.63 +/- 0.31 and 0.53 +/- 0.31 for healthy and infected lung, respectively. CONCLUSIONS: We conclude that fosfomycin achieves antimicrobially effective concentrations in infected lung tissue.

Lack of bactericidal antagonism or synergism in vitro between oxacillin and vancomycin against methicillin-susceptible strains of Staphylococcus aureus.

With the current high prevalence of infection caused by methicillin-resistant Staphylococcus aureus (MRSA) strains but in light of the general belief that beta-lactam antibiotics are more effective than vancomycin against infections caused by methicillin-susceptible S. aureus (MSSA) isolates, clinicians may utilize antistaphylococcal penicillins in combination with vancomycin for the empirical treatment of S. aureus infections. Vancomycin is considered to kill MSSA more slowly than oxacillin. Thus, we sought to evaluate the interaction of the combination of oxacillin and vancomycin on bacterial killing in vitro. Ten clinical isolates of MSSA isolated in the year 2000 were investigated. The killing observed at 24 h by vancomycin at 20 microg/ml, oxacillin at 16 microg/ml, or the combination did not differ (approximately 2.5 to 3.5 log10 CFU/ml). In a separate experiment, we assessed bacterial killing in a dynamic model simulating the free plasma concentration profiles expected following the administration of a combination of vancomycin at 1 g every 12 h and oxacillin at 1 g every 6 h. The time-kill profiles of these regimens against S. aureus ATCC 29213 were comparable to those observed in the fixed-concentration experiments. Using these methods, we found no evidence that vancomycin antagonized the bactericidal effect of oxacillin or that there was any benefit from use of the combination.

Dosing of daptomycin in intensive care unit patients with acute kidney injury undergoing extended dialysis--a pharmacokinetic study.

BACKGROUND: Daptomycin is a new intravenous cyclic lipopeptide antibiotic, licensed for the treatment of complicated skin and soft tissue infections caused by Gram-positive organisms including both susceptible and resistant strains of Staphylococcus aureus and for the treatment of various infections due to susceptible organisms, including serious and life-threatening Gram-positive infections, vancomycin-resistant enterococcal infections and right-sided endocarditis with associated bacteremia. Currently, no dosing recommendations exist for this drug for patients with acute kidney injury (AKI) undergoing renal replacement therapy. The aim of this study was to evaluate pharmacokinetics of daptomycin in critically ill patients with AKI undergoing extended dialysis (ED), a frequently used mean of renal replacement therapies in intensive care units (ICUs) around the world. Patients and methods. A prospective, single-dose pharmacokinetic study was performed in the medical and surgical ICUs of a tertiary care center. The aim was to investigate critically ill patients with anuric AKI being treated with ED and receiving daptomycin (n = 10). Daptomycin (6 mg/kg) was administered 8 h before ED was started. RESULTS: Key pharmacokinetic parameters like half-life in critically ill patients treated with ED were comparable to healthy controls. The dialyser clearance for daptomycin was 63 +/- 9 ml/min. Based on the amount of the drug recovered from the collected spent dialysate, the mean fraction of the drug removed by one dialysis treatment was 23.3%. CONCLUSION: Our data suggest that patients treated with ED using a high-flux dialyzer (polysulphone, 1.3 m(2); blood and dialysate flow, 160 ml/min; ED time, 480 min) and employing current dosing regimen, 6 mg/kg daptomycin every 48 h, run the risk of becoming significantly under dosed if one adheres to a twice daily dosing schedule that is recommended for patients on maintenance haemodialysis. Our data suggest that a daily dose of 6 mg/kg daptomycin is necessary in this special patient population to avoid under dosing, which may have detrimental effects in critically ill patients suffering from life-threatening infections.

The inflammatory response is influenced by FXIII VAL 34 LEU polymorphism in a human LPS model.

BACKGROUND: In sepsis, activation of coagulation and inhibition of fibrinolysis lead to microvascular thrombosis. The Val34Leu polymorphism affects the function of FXIII by increasing the rate of FXIII activation by thrombin, which results in an increased and faster rate of fibrin stabilization. Sepsis and multi-organ failure cause disturbance of the normal balance of inflammation and coagulation, one of the most frequent causes of death in ICU patients. Research in polymorphism has shown the possible influence of FXIII in coagulation and inflammation. METHODS: We analyzed the influence of the common FXIII Val34Leu polymorphism on inflammatory and coagulation parameters in human experimental endotoxinemia. Healthy volunteers (n = 62) received 2 ng endotoxin (LPS) per kg body weight as a bolus infusion over 2 min. We developed a new mutagenic separated PCR assay for determination of the FXIII promoter polymorphism. RESULTS: FXIII levels were higher for homozygous carriers of the FXIII polymorphism in comparison with wild-type 34 Val/Val and heterozygous 34 Val/Leu. Interestingly, persons homozygous for the FXIII Val34Leu polymorphism had lower monocyte and neutrophil counts throughout the observation period, yet prothrombin fragment 1+2 and D-dimer levels did not differ after LPS challenge. CONCLUSION: Our findings indicate that the common FXIII Val34Leu polymorphism is associated with differences in monocyte and neutrophil cell counts in response to systemic LPS infusion in humans.

High fosfomycin concentrations in bone and peripheral soft tissue in diabetic patients presenting with bacterial foot infection.

OBJECTIVES: Appropriate antimicrobial therapy and surgical intervention may be required in diabetic patients presenting with severe bacterial foot infection. Methicillin-resistant Staphylococcus aureus (MRSA) agents such as fosfomycin are increasingly in demand because of recent concern regarding vancomycin and daptomycin efficacy and constant use. Intravenous fosfomycin is approved for the therapy of severe soft tissue infections and is highly active against methicillin-susceptible S. aureus and MRSA. in the present study we investigated fosfomycin's ability to penetrate bone tissue in diabetic patients suffering from severe bacterial foot infection. PATIENTS AND METHODS: The well established microdialysis technique was utilized to determine fosfomycin concentrations in metatarsal bone in nine patients scheduled for partial bone resection due to bacterial foot infection and osteomyelitis. Plasma and unaffected subcutaneous adipose tissue served as reference compartments. RESULTS: After a single intravenous dose of approximately 100 mg of fosfomycin per kg of body weight, the mean C(max), T(max) and AUC(0-6) for bone were 96.4 mg/L, 3.9 h and 330.0 mg x h/L, respectively. The degree of tissue penetration as determined by the ratios of the AUC(0-6) for bone to plasma and for subcutaneous adipose tissue to plasma were 0.43 +/- 0.04 and 0.76 +/- 0.05, respectively. CONCLUSIONS: On the basis of relevant pharmacokinetic-pharmacodynamic indices, it seems that fosfomycin is an effective antibiotic for the treatment of deep-seated diabetic foot infections with osseous matrix involvement.

Multiple-dose pharmacokinetics of telithromycin in peripheral soft tissues.

Based on clinicians' expectations of high concentrations of telithromycin (TEL) in tissues, combined with its excellent in vitro antimicrobial characteristics, TEL is casually considered as a potential therapeutic option for the therapy of minor cases of soft tissue or bite-wound infections. To clarify this clinically important issue, the present investigation was carried out to measure the pharmacokinetic profile of TEL in the interstitial space fluid (ISF) of skeletal muscle and subcutaneous adipose tissue by means of the microdialysis technique in 10 healthy subjects following repetitive daily doses of 800 mg TEL. These data were compared with free concentrations of TEL determined in plasma. External controls for the present examination were the use of historic, single-dose data collected by our study group utilising identical methods and the same trial subjects. Despite an increase in the median half-life from ca. 3 h after a single dose to ca. 10h at steady-state conditions in all compartments, accumulation of TEL in ISF of soft tissues and plasma was clinically non-relevant. Median free peak concentrations in plasma, skeletal muscle and subcutis were 0.52, 0.13 and 0.19 mg/L, respectively. The median ratios of the tissue to plasma free areas under the concentration-time curves from 0 to 24 h (fAUC(0-24) tissue/fAUC(0-24) plasma) were 0.27 and 0.58 for muscle and subcutis, respectively (P>0.05). The present multiple-dose investigation of TEL is in line with a previous single-dose study confirming that TEL 800 mg/day may not be optimally effective in the therapy of soft tissue infections.

Concentrations of voriconazole in healthy and inflamed lung in rats.

By utilizing the microdialysis technique, we investigated the pharmacokinetic profile of voriconazole in the interstitium of the lungs and skeletal muscle tissue of rats after a single intravenous dose under healthy and inflammatory conditions. As expected, voriconazole penetrated excellently into the interstitium of tissues, and its levels were descriptively almost identical to free concentration-versus-time profiles in plasma.

Tigecycline has no effect on cytokine release in an ex vivo endotoxin model of human whole blood.

In previous studies, tetracyclines have been shown to decrease the release of cytokines in experimental settings of endotoxaemia. Tigecycline is the first member of the closely related glycylglycines and, due to its broad antimicrobial spectrum, it is considered useful in the treatment of sepsis. We therefore tested its ability to influence the concentrations of the proinflammatory cytokines interleukin (IL)-1beta, tumour necrosis factor-alpha (TNFalpha) and IL-6 in an established ex vivo model of human endotoxaemia. Whole blood from ten healthy volunteers was incubated with either saline (negative control), tigecycline (1 microg/mL [therapeutic concentration] or 100 microg/mL [supratherapeutic concentration]), lipopolysaccharide (LPS; 50 pg/mL, control) or a combination of tigecycline plus LPS (test group). Concentrations of IL-1beta, TNFalpha and IL-6 in the supernatant were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits. As expected, incubation with LPS significantly increased the cytokine concentrations in whole blood compared with baseline (P<0.05). The combination of tigecycline plus LPS did not exert any significant effect on the concentrations of IL-1beta, IL-6 and TNFalpha after 2h and 4h of incubation compared with LPS alone. These results indicate that proinflammatory cytokines remained unaffected by tigecycline in an established ex vivo model of systemic inflammatory response.

Orally administered rapamycin, dacarbazine or both for treatment of human melanoma evaluated in severe combined immunodeficiency mice.

OBJECTIVE: In this experimental study, the antineoplastic potential of orally administered rapamycin in human melanoma was evaluated and compared with dacarbazine (DTIC) as well as with the antineoplastic effect of the combination of both drugs. METHODS: The substances were tested using 2 human melanoma cell lines, 518A2, which is highly susceptible to DTIC, and 607B, which is moderately susceptible. A human melanoma severe combined immunodeficiency mouse xenotransplantation model was used. After development of palpable tumors, mice received oral rapamycin or saline over 18 days. Additionally, from treatment day 4 to 8, mice were randomly chosen to receive either DTIC or saline treatment. RESULTS: The oral rapamycin treatment (1.5, 7.5, 15 and 30 mg/kg body weight) had an antineoplastic effect, ranging from 35 to 78% tumor weight reduction compared with the saline group. In DTIC less sensitive 607B tumors, rapamycin treatment (15 and 30 mg/kg body weight) was superior to DTIC treatment (p < 0.05). DTIC monotreatment reduced tumor weight in 518A2 tumors by 85% on average, whereas in 607B xenografts, no significant tumor weight reduction was observed compared with the saline group (p > 0.05). The combination of rapamycin and DTIC was not superior to rapamycin monotreatment in any cell line. CONCLUSION: These data indicate that oral rapamycin exerts a relevant antineoplastic effect on human melanoma cells. This effect appeared to be more pronounced in DTIC less sensitive melanoma xenografts.