Oral bioavailability of trovafloxacin with and without food in healthy volunteers

Two studies determined the oral bioavailability of trovafloxacin (CP-99,219) in healthy volunteers under fasted and fed conditions. In a randomized, two-way crossover study, 12 fasting subjects received two 100 mg tablets of trovafloxacin and an equivalent dose of alatrofloxacin (CP-116,517), administered by i.v. infusion over 1 h. Alatrofloxacin, the L-Ala-L-Ala prodrug of trovafloxacin, is rapidly converted in the body to trovafloxacin. After the oral dose of trovafloxacin, the mean Cmax and AUC were 2.2 mg/L and 30.4 mg x h/L, respectively. After the infusion of alatrofloxacin, the Cmax and AUC of trovafloxacin were 3.2 mg/L and 34.7 mg x h/L, respectively. The mean T(1/2) after both treatments was about 11 h. The mean Cl and Vd(ss) of trovafloxacin after the infusion of alatrofloxacin were 1.32 mL/min/kg and 1.13 L/kg, respectively. The mean oral bioavailability of trovafloxacin was estimated to be 87.6% (range 64.8-122.1%). Another randomized, open, three-way crossover study was conducted in 12 healthy male volunteers to investigate the effect of food in the gastrointestinal tract on the bioavailability of trovafloxacin. Each subject received three 100 mg tablets after fasting overnight (treatment A) or after a standard breakfast (treatment B), or 300 mg as oral aqueous suspension after fasting overnight (treatment C). Mean Tmax after treatment B occurred 2.2 h later (3.6 h vs 1.4 h) than after treatment A. Mean Cmax and AUC were 2.3 and 2.6 mg/L and 38.2 and 39.5 mg x h/L after B and A, respectively. About 5% of the administered dose was recovered unchanged in the 24 h urine sample after all three treatments. Thus, the food reduced mean Cmax by 12% but had no appreciable effect on mean AUC. The mean bioavailability of trovafloxacin administered as treatment regimen B was 96.6% relative to that of treatment A. The respective mean bioavailabilities of trovafloxacin as treatments B and A were 91.3% and 94.5% respectively of that of treatment C. The results of these studies indicate that trovafloxacin has good oral bioavailability and that the ingestion of food is unlikely to have a clinically significant effect on the bioavailability of trovafloxacin.

Effect of Maalox and omeprazole on the bioavailability of trovafloxacin

To determine the effect of the concurrent administration of Maalox and omeprazole in the bioavailability of trovafloxacin (CP-99,219), an open, placebo-controlled, randomized, four-way crossover study was conducted in 12 healthy male volunteers. Each received treatments of three 100 mg trovafloxacin tablets in the morning 30 min after 30 mL of Maalox (A), 30 min after placebo (B), 2 h before 30 mL of Maalox (C) and 2 h after 40 mg of omeprazole (D). For treatments A and C, Maalox was also given at 22.00 h the night before the study day, 1 and 3 h after meals and at bedtime on the study day. For B and D, placebo and omeprazole, respectively, were also given at 22.00 h the night before the study day. After treatments A and C, mean area under the curve (AUC) was reduced by 66% and 28% (14.2 and 30.2 mg.h/L), respectively, and mean T(1/2) declined by 33% and 31% (8.3 and 8.5 h), respectively, relative to the values after B (42.1 mg.h/L; 12.4 h). The mean Kel-corrected relative bioavailabilities for A and C were 50% and 104%, respectively, suggesting a large reduction in the initial absorption of trovafloxacin with A. Treatment D had no appreciable effect on mean T(1/2) but mean AUC and Cmax were reduced by 18% and 32%, respectively, relative to B. The mean relative bioavailability after D was 82%. We conclude that the concurrent administration of trovafloxacin and aluminium- and magnesium-containing antacids should be avoided but that co-administration with omeprazole is unlikely to have a clinically significant effect on the extent of absorption of the antibiotic.

Penetration of trovafloxacin into cerebrospinal fluid in humans following intravenous infusion of alatrofloxacin

A single-dose study was conducted to determine concentrations of trovafloxacin (CP-99,219) achieved in the cerebrospinal fluid (CSF) relative to those in the serum of healthy subjects after intravenous infusion of alatrofloxacin (CP-116,517), the alanyl-alanyl prodrug of trovafloxacin. Twelve healthy subjects were administered single doses of alatrofloxacin at a trovafloxacin equivalent of 300 mg as an intravenous infusion over 1.0 h. CSF samples were taken by lumbar puncture at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 24 h after the start of the infusion; each subject was sampled at only one time point. Serum samples were taken from each subject at the time of CSF collection. A mean concentration of 5.8 microg of trovafloxacin per ml was present in serum 1.0 h after the start of the infusion. CSF/serum ratios ranged from 0.14 to 0.33 in the postdistribution phase (5 to 24 h postinfusion), with a mean ratio of 0.25. The most common adverse events were dizziness, nausea, and rash and were mild or moderate in intensity. The potency of trovafloxacin against susceptible organisms, coupled with its rapid penetration of CSF following the intravenous administration of alatrofloxacin, suggests that it may be useful in the treatment of bacterial meningitis in humans.

Excretion and metabolism of trovafloxacin in humans

The metabolism and excretion of trovafloxacin was investigated in four healthy male volunteers after a single oral administration of 200 mg of [14C]trovafloxacin (118 microCi). Mean values of 23.1 and 63.3% of the administered dose were recovered in the urine and feces, respectively, after 240 hr. The Cmax of total radioactivity and unchanged trovafloxacin in serum was 3.2 micrograms-equiv/ml and 2.9 micrograms/ml, respectively, and peaked in 1.4 hr. The mean AUC0-infinity for radioactivity and trovafloxacin was 58.2 micrograms-eq.hr/ml and 32.2 micrograms.hr/ml, respectively. This implied that unchanged trovafloxacin constituted 55% of the circulating radioactivity. Urine and fecal samples were analyzed by LC/MS/MS for characterization of the metabolites, and the quantity of each metabolite in the matrices was assessed by means of a radioactivity detector. The profile of radioactivity in urine showed three main metabolites that were identified as the trovafloxacin glucuronide (M1), N-acetyltrovafloxacin glucuronide (M2), and N-acetyltrovafloxacin (M3). The major fecal metabolites were M3 and the sulfate conjugate of trovafloxacin (M4). Analysis of circulating metabolites from pooled serum extracts obtained at 1, 5, and 12 hr indicated that M1 was the major circulating metabolite (22% of circulating radioactivity), whereas M2 and M3 were detected in minor amounts. The results of the present study revealed that oxidative metabolism did not play a significant role in the elimination of trovafloxacin, and phase II conjugation was the primary route of trovafloxacin clearance in humans.

Phase I pilot study of the effects of trovafloxacin (CP-99,219) on the pharmacokinetics of theophylline in healthy men

This study examined the effect of trovafloxacin (CP-99,219) on the pharmacokinetics and pharmacodynamics of a single dose of theophylline, when administered to steady-state concentrations. Twelve healthy, nonsmoking male volunteers participated. A 450-mg dose of theophylline was administered at 7:00 AM on day 1. On day 4, volunteers received 300 mg of trovafloxacin (CP-99,219) daily in the morning for 7 days. The 450-mg dose of theophylline was repeated on day 8 at 7:00 AM concomitantly with 300 mg of trovafloxacin. Theophylline concentrations in plasma and trovafloxacin in serum were determined using reverse-phase high-performance liquid chromatography. There was no significant difference between the geometric mean values for Cmax of theophylline, 6.42 micrograms/mL and 6.00 micrograms mL on days 1 and 8, respectively. A change (P = 0.032) in the geometric mean of the area under the concentration-time curve extrapolated to infinity (AUC0-infinity) for theophylline was noted for trovafloxacin was administered. Mean terminal phase elimination rate constants (Kes) were reduced (P = 0.001) by 13% after administration of trovafloxacin from day 1 to day 8. In general, changes in theophylline clearance of less than 20% are unlikely to be of clinical significance. In this study, oral administration of trovafloxacin in 300 mg doses to achieve steady-state concentration resulted in an 8.4% increase in the extent of systemic exposure (AUC0-infinity) to theophylline. Assuming that this AUC change is based on oral clearance and not absorption, one would not expect to see clinically significant changes in the pharmacokinetics of theophylline. No pharmacodynamic changes resulted from the pharmacokinetic changes of theophylline.

18F-labeling and biodistribution of the novel fluoro-quinolone antimicrobial agent, trovafloxacin (CP 99,219)

[18F]CP 99,219 [(1 alpha, 5 alpha, 6 alpha)-7-(6-amino-3-azabicyclo [3.1.0]hex-3-yl)-1-(2,4-difluorophenyl)-6-fluoro-1, 4-dihydro-4-oxo-1, 8-naphthyridine-3-carboxylic acid] was prepared by 18F for 19F exchange followed by reverse-phase HPLC purification. Studies of the effects of reaction time and temperature on 18F incorporation demonstrated that heating 1.0 mg of CP 99,219 in 0.5 cc of DMSO with 4.5 mg of K2CO3 and 24 mg of Kryptofix for 15 min at 160 degrees C results in the optimal compromise between radiochemical yield and purity. This method routinely provides radiochemical yields of 15-30% [EOS] with radiochemical purities of > 97%. Varying the concentration of CP 99,219 in the reaction mixture had no effect on yield. Biodistribution studies in rats demonstrated that significant concentrations of drug accumulate in most tissues. The tissues with the highest concentrations of drug were intestine, liver, kidney, and stomach.

Partial exchange transfusion in the treatment of severe falciparum malaria

BACKGROUND

Exchange transfusion as an adjunct to the treatment of severe falciparum malaria has been widely recommended, although there is no well-designed clinical trial to prove its efficacy. The amount of compatible blood required for total exchange is rarely available in areas endemic for malaria and the risks of the procedure including transfusion-related infections are high.

METHODS

Partial transfusion with four units of blood was given to a patient with severe falciparum malaria (80% parasitaemia) whose condition deteriorated on conventional treatment with intravenous quinine.

RESULTS

This brought about prompt clinical improvement and reduction in parasitaemia.

CONCLUSION

Partial transfusion with one or two litres of blood is a promising and viable alternative to total exchange transfusion.

Assessing pre-procedural subgingival irrigation and rinsing with an antiseptic mouthrinse to reduce bacteremia

In this controlled clinical study, the authors examined the effect of subgingival irrigation and rinsing with an antiseptic mouthrinse before ultrasonic scaling of a quadrant containing inflamed gingivae. The results showed that pre-procedural subgingival irrigation and rinsing can significantly reduce the level of bacteremia associated with ultrasonic scaling. These results support the American Heart Association's recommendation of adjunctive subgingival irrigation prior to invasive procedures in patients at risk of developing bacterial endocarditis.

Seroprevalence of five arboviruses in Zebu cattle in the Central African Republic

Sequential blood samples taken from 237 adult and 147 young Zebu cattle in the Central African Republic (CAR) were examined by enzyme-linked immunosorbent assay for the presence of antibodies to Rift Valley Fever (RVF), Dugbe (DUG), Crimean-Congo haemorrhagic fever (CCHF), Chikungunya (CHIK) and Wesselsbron (WSL) viruses. Antibodies to DUG and CCHF viruses were detected in 70% and 61% respectively, of the sera from adult cattle, probably due to common antigens. This hypothesis is supported by the fact that CCHF virus was isolated only 3 times from ticks, whereas DUG virus was isolated from almost all ticks. Ticks of the genus Hyalorama, the most important vectors of CCHF, are rare on Zebus in CAR. CCHF virus has a limited role in local human pathology, probably because its distribution is limited by the scarcity of its main vector and the immunological barrier resulting from the presence of antibodies to DUG virus. Antibodies to RVF virus were found in about 8% of adult cattle. Zebus do not play an important role in the spread of CHIK and WSL viruses among humans; these viruses were found in only one and 5, respectively, of the 183 cattle examined.

Keratitis, ichthyosis and deafness (KID) syndrome

Keratitis, ichthyosis, deafness (KID) syndrome is a genetically determined disorder. The present case is having marked photophobia, bilateral corneal ulceration with vascularisation, neurosensory deafness and skin changes.

Oligonucleotides as short as 7-mers can be used for PCR amplification

Amplification of DNA sequences using the polymerase chain reaction (PCR) requires as primers two oligonucleotides, which are carefully designed for length and G/C content. Such primers are generally between 18 and 30 bases long so that the primer sequences can amplify a unique sequence in the target genome; they should possess a minimal degree of secondary structure. We have tested the minimum length of G/C-rich and palindromic oligonucleotides to be used as primers in PCR. Oligonucleotides with sequences corresponding to the recognition sites of rare restriction enzymes were used on the DNA of vector constructs as model template DNA. Surprisingly, we found specific amplification with a low background over a wide range of temperatures for oligonucleotides as short as 7 nucleotides. This findings contradicts the previously reported empirical relationship between oligonucleotide length and ability to trigger amplification and points to the complex relationship between thermodynamic and kinetic criteria in relation to PCR. This technique should lead to new application in the cloning and screening of complex genomes.

Cell immunofluorescence and brain extract based dot-immunobinding assay in identification of arboviruses

Infected mouse brain homogenates were semi-purified and used in a dot-immunobinding assay to identify the corresponding arboviruses.

Neural network feature detector for real-time video signal processing

The application of artificial neural networks to real-time image processing tasks requires the use of dedicated, high performance hardware. A linear array processor called HANNIBAL has been developed which implements the backpropagation neural learning algorithm on-chip. This paper considers the design of a complete neural system which integrates HANNIBAL into an existing image processing environment. The goals for the design of the system have been set partly by the primary application, namely feature recognition, but mainly by the desire for a flexible, high performance hardware tool for the study and evaluation of range of neural image processing applications.

Reducing bacteria in dental aerosols: pre-procedural use of an antiseptic mouthrinse

This study, using a simulated office visit model, showed that the pre-procedural use of an antimicrobial mouthrinse produces a significant reduction in number of viable bacteria in a dental aerosol.

No effect of an antiaggregant treatment with aspirin in small cell lung cancer treated with CCAVP16 chemotherapy. Results from a randomized clinical trial of 303 patients. The "Petites Cellules" Group

BACKGROUND

Experimental, and more recently, clinical data have suggested the influence of hemostasis in the spread of malignant disease.

METHODS

To complete research in this type of coagulation and cancer, a multicentric randomized clinical trial was performed, including 303 patients with small cell lung cancer (SCLC), treated by the addition of aspirin at 1 g/day (a dosage at which aspirin is considered to be a platelet aggregation inhibitor) to combined chemotherapy.

RESULTS

Survival was not increased in the aspirin-treated group (P = 0.90). The analysis according to the extent of disease (limited or extensive disease) did not modify that conclusion.

CONCLUSIONS

This result does not confirm the hypothesis that, in SCLC, aspirin (a platelet aggregation inhibitor) reduces metastasis formation and local tumor thrombogenesis.

An improved clinical method for detecting meningeal irritation

Neck stiffness is the most important sign of meningitis. When the neck is flexed, the inflamed nerve roots and meninges of the cervical region get stretched. This causes protective muscle spasm manifesting as neck stiffness. Kernig's sign represents similar phenomena involving the distal spinal cord and related nerves. A manoeuvre that stretches the neural elements of the whole length of the spinal canal simultaneously will be a more sensitive test for meningeal irritation. Eliciting neck stiffness while the patient sits up with knees extended achieves this. This method is more sensitive, specific, and amenable to objective assessment.