Synthesis and inhibitory activity towards human leukocyte elastase of new 7alpha-methoxy and 7alpha-chloro (2-acyloxymethyl) cephem derivatives.

Some new cephem derivatives of types 4 and 5, viewed as analogues of type I esters in which the atomic sequence of the C-2 ester group is formally inverted, were synthesised and tested in vitro for their inhibitory activity towards human leukocyte elastase and porcine pancreatic elastase. An examination of the inhibition data obtained for the new type 4 and 5 derivatives, while exhibiting a considerable reduction in their activity against porcine pancreatic elastase, indicated that these compounds still maintain an appreciable inhibitory activity against human leukocyte elastase. On this basis the new type of C-2 substitution appears to contribute to the research of new, potentially interesting, cephalosporinic human leukocyte elastase inhibitors.

Synthesis, inhibitory activity towards human leukocyte elastase and molecular modelling studies of 1-carbamoyl-4-methyleneaminoxyazetidinones.

Some monocyclic beta-lactam derivatives of type 3 (MAOAs) in which the leaving group (LG) on the C(4) is a methyleneaminoxy moiety, were synthesised and tested in vitro and in vivo for their inhibitory activity towards human leukocyte elastase (HLE). Some compounds showed an appreciable in vitro inhibitory activity against this enzyme. Effects on the anti-HLE activity due to the nature of the substituents R and R(1) present on their LG were observed and rationalised by means of molecular modelling techniques. The results of in vivo pharmacological tests indicated that MAOAs, while showing an inhibitory activity on the haemorrhage induced by HLE, did not exhibit any effects due to the R and R(1) substituents.

Synthesis and antimicrobial properties of cephalosporin derivatives substituted on the C(7) nitrogen with arylmethyloxyimino or arylmethyloxyamino alkanoyl groups.

Some 7-aminocephalosporanic acid (7-ACA) derivatives substituted on the C(7) nitrogen with 2-(arylmethyloxyimino)propionyl (3a-f), 2-(arylmethyloxyamino)propionyl (4a-d) and (arylmethyloxyamino)acetyl (2a-d) moieties were synthesized by reaction of the appropriate acylating agents with 7-ACA protected as a t-butyl ester, followed by removal of the t-butyl protecting group. The new compounds, tested in vitro for their antimicrobial activity against Gram-positive and Gram-negative bacteria, proved to possess a modest activity directed only against Gram-positive microorganisms.

Synthesis and HIV-1 inhibitory properties of new tetrahydrobenzoquinazolinedione and tetrahydrobenzocycloheptenuracil derivatives and of their thioxo analogues.

Some new tetrahydrobenzoquinazolinediones 2a-4a, tetrahydrobenzocycloheptenuracils 5a, 6a and their thioxo analogues 2b-6b were synthesized within a project aimed at obtaining new HIV-1 tricyclic inhibitors whose scaffold includes a pyrimidine and a phenyl ring, which are present in various HIV-1 non-nucleoside inhibitors. Among the tetrahydrobenzoquinazolinediones 2a-4a, compounds 3a and 4a, in which the tricyclic system is respectively in an angular or linear arrangement, proved to possess a HIV-1 inhibitory activity which was in the micromolar range, while compound 2a, in which the tricyclic system is in the angular arrangement opposite to that of 3a, was found to be completely inactive. As regards the tetrahydrobenzocycloheptenuracil derivatives (5a and 6a), only 5a showed an inhibitory activity similar to that of 3a and 4a. Furthermore, all thioxo analogues 2b-6b were found to be devoid of any activity.

New N-substituted 7-aminocephalosporanic acid derivatives as potential agents against Streptococcus pneumoniae. Synthesis and in vitro activity.

The synthesis and the antimicrobial properties of a new series of cephalosporinic beta-lactam antibiotics is described. The data reported in the present paper show the potential of this type of substituted cephalosporins as new anti Gram-positive antibiotic drugs. In fact, all compounds tested showed a good in vitro antibacterial activity against the most relevant Gram-positive pathogens including resistant species that currently represent unmet medical need. On the contrary, the new synthesized compounds were found to be completely devoid of any activity on Gram-negative bacteria up to a concentration of the single agent of 128 microg/ml.

L-Asparagine depletion in plasma and cerebro-spinal fluid of children with acute lymphoblastic leukemia during subsequent exposures to Erwinia L-asparaginase.

BACKGROUND: Monitoring L-asparagine (L-ASN) plasma levels could provide information useful for determining whether the dosage or schedule of L-asparaginase (L-ASE) administration is adequate. Very few data are available on depletion caused by the Erwinia chrysanthemi (E. chrysanthemi) product. Since it has been suggested that L-ASN depletion may have been overestimated in the past due to residual L-ASE activity, samples in this study have been analyzed after deproteinization with sulphosalicylic acid. Patients undergoing subsequent exposures to L-ASE derived from E. chrysanthemi have been investigated. PATIENTS AND METHODS: Fifty-four children with newly diagnosed acute lymphoblastic leukemia (ALL) at our institution entered this study. L-ASE was given at conventional doses (10,000 IU/sqm) every three days during the induction phase (8 doses, first exposure) or twice a week (4 doses, second exposure) during the reinduction phase. High-dose L-ASE (i.e., HD-L-ASE 25,000 IU/sqm) was given weekly, for a total of 20 doses, as a second or third exposure during the reinduction and/or maintenance phases. To determine the plasma levels of L-ASN, samples were deproteinized with sulphosalicylic acid, stored at -80 degrees C and then analyzed by HPLC after precolumn derivatization with o-phthaldialdehyde. The CSF samples were analyzed by the same procedure. An experiment was carried out to detect in vitro L-ASE deactivation in patients' plasma. RESULTS: L-ASN plasma depletion was observed in 80% of the cases during the first exposure to conventional doses of L-ASE and only in 25% of the cases during the second or third exposures to either conventional or high doses of L-ASE. A correlation was found between plasma and CSF L-ASN levels. Activity inhibitory to L-ASE was found in the plasma of patients not depleted during L-ASE treatment and was not found in the plasma of those in whom L-ASN plasma depletion was obtained. CONCLUSIONS: L-ASN plasma depletion is regularly obtained in the majority of patients during the first exposure to conventional doses of E. chrysanthemi L-ASE. Conversely, in most cases depletion does not occur during subsequent exposures. Studies should be performed to evaluate whether L-ASE derived from different species or conjugated with polyethylene-glycole are effective in obtaining L-ASN plasma depletion in patients previously treated with Erwinia C. L-ASE. The clinical impact of L-ASN depletion should also be investigated in large cohorts of patients.

Clinical pharmacology of chronic oral etoposide in patients with small cell and non-small cell lung cancer.

We aimed to evaluate the pharmacokinetics and pharmacodynamics of etoposide given chronically by the p.o. route to patients with small cell and non-small cell lung cancer. Single daily p.o. doses of 100 mg etoposide were given for 21 consecutive days every 4 weeks to 39 previously untreated patients with small cell lung cancer and 10 patients with non-small cell lung cancer. Bioavailability was studied after one i.v. and one p.o. dose of 100 mg etoposide given 48 h before and on day 1 of treatment, respectively. Etoposide plasma levels were measured using the HPLC method. Inter- and intrapatient variability of the area under the curve of the concentration versus time (AUC) during the first cycle were evaluated using a limited sampling model; the variability of etoposide plasma concentrations (Ecs) during the first cycle was assessed by weekly blood samples taken 24 h after dosing. The overall bioavailability of etoposide (mean +/- SD) was 67% +/- 22% and was not affected by fasting. A much higher inter- than intrapatient variability of both the AUC and 24-h Ec determined on days 8, 15, and 22 was found. Neutropenia was dose limiting and of varying degrees (mean +/- SD of absolute neutrophil count nadir at the first cycle: 1.5 +/- 1.2 x 10(3)/microliter). Neutropenia WHO grade >/=3 occurred in 38% of the patients after the first cycle. Pharmacodynamic analyses showed a significant relationship between the mean 24-h Ec and neutropenia, expressed as log- of absolute neutrophil count nadir or as a relative decrease of neutrophils. A correlation between a critical value of mean 24-h Ec (0.34 microgram/ml) and a high probability of achieving a greater than 80% decrease in absolute neutrophil count was found. Two pharmacodynamic models (one previously described and one developed in this study) were used to evaluate the possibility of predicting neutropenia on the basis of individual etoposide pharmacokinetics and baseline absolute neutrophil count. Pharmacokinetic studies have shown a high interpatient variability and a relatively low intrapatient variability of AUC and 24-h Ec. The application of the pharmacodynamic models and mean 24-h Ec cutoff values has proven statistically valid to predict the occurrence of severe neutropenia. However, it remains to be demonstrated in a prospective manner whether the application of pharmacokinetic/ pharmacodynamic knowledge can improve the overall therapeutic outcome of chronic p.o. treatment with etoposide.

Synthesis and beta-adrenergic activity of a series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives.

In an attempt to change the beta-adrenergic properties of completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives, from antagonist to agonist, while still retaining the beta 2-selectivity, we described, in a previous paper, the synthesis of a series of such derivatives possessing a hydroxy or methoxy group linked to the aliphatic substituent present on the oximic carbon. However, pharmacological tests indicated that these compounds maintain the competitive antagonism on beta receptors. In this paper, the synthesis and the results of functional tests on isolated preparations are reported for a new series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives in which either the hydroxy or the methoxy group is linked to a phenyl ring present on the oximic carbon. The results obtained are then discussed, taking into account the conformational and reactivity properties of these compounds, determined by means of theoretical calculations.

High-performance liquid chromatographic assay for the determination of the novel etoposide derivative dimethylaminoetoposide (NK611) and its metabolites in urine of cancer patients.

A simple, reproducible and specific urine assay for the novel epipodophyllotoxin derivative dimethylaminoetoposide (NK611, I) its picro form (III), the N-demethyl metabolite (II) and its picro form (IV) is reported. The method involves the addition of Pr-NK611 as internal standard, chloroform extraction and HPLC separation on a Nova-Pak C18 column with a mobile phase of acetonitrile-0.05 M KH2PO4 (pH 6.4) (23:77, v/v). UV detection was used with absorbance monitored at 205 nm and the limit of quantification was 100 ng/ml. The intra- and inter-day precisions were within the ranges 1.1-3.4% and 1.9-2.4% for all analytes and the accuracy was 101-107%. The extraction recovery was more than 88% for I, II and IV and more than 83% for III. The assay is applicable to the urinary monitoring of I-IV in clinical pharmacokinetic investigations.

Phase I clinical and pharmacokinetic study of oral etoposide phosphate.

PURPOSE: To determine the bioavailability (F) and the pharmacokinetic profile of both etoposide and its prodrug, etoposide phosphate, after oral and intravenous administration of etoposide phosphate, and to determine the maximum-tolerable dose (MTD) of oral etoposide phosphate administered daily for 5 consecutive days every 3 weeks. In addition, we sought to develop and validate two limited-sampling models (LSMs) to predict the etoposide area under the curve (AUC) 24 hours after administration of oral and intravenous etoposide phosphate. PATIENTS AND METHODS: In the F part of the study, patients were assessed for pharmacokinetic studies after one oral and one intravenous administration of the same dose of etoposide phosphate. Etoposide phosphate and etoposide plasma concentrations were assayed by high-performance liquid chromatography (HPLC). To develop LSMs after oral and intravenous administration, patients were randomized between the training and validation data sets. In the phase I part of the study, which followed the F part, the dose of etoposide phosphate was escalated from 50 mg/m2/d for etoposide equivalents for 5 days to 220 mg/m2/d for 5 days. RESULTS: Forty adult patients with solid tumors or lymphoma entered the study and 35 were assessable for toxicity. The MTDs were defined as 175 mg/m2 and 220 mg/m2 in previously treated and untreated patients, respectively. Neutropenia was dose-limiting, with high interpatient variability. Within 15 minutes after intravenous administration, etoposide phosphate was no longer detectable in plasma, and it was never detectable after oral administration. Plasma concentrations and pharmacokinetic parameters of etoposide following etoposide phosphate were comparable to those reported for etoposide. The relative F (mean +/- SD) of etoposide after oral etoposide phosphate was 76 +/- 27%, with a range of 37% to 144%. CONCLUSION: The clinical and pharmacokinetic results of this study confirm the prodrug hypothesis of etoposide phosphate. Although firm conclusions cannot be drawn, the F of oral etoposide phosphate seems to be comparable to or only slightly better than that of oral etoposide.

Synthesis and beta-adrenergic activity of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives.

In a previous paper, it had been found that completely aliphatic 3-(methylene aminoxy)propanolamine derivatives showed a good beta-blocking adrenergic activity directed prevalently towards beta 2-tracheal receptors. In an attempt to change the beta-adrenergic properties of these compounds from antagonist to agonist, while still retaining the beta 2-selectivity, a series of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives were designed in which either a hydroxylic or a methoxylic group was present on the aliphatic portion linked to the oximic carbon. The synthesis of the new compounds and their beta-adrenergic activity, evaluated by means of functional tests on isolated preparations, are described and discussed; the results obtained are then rationalised on the basis of their conformational and reactivity characteristics, determined by means of theoretical methods.

Determination of L-asparagine in biological samples in the presence of L-asparaginase.

The antileukaemic efficacy of L-asparaginase is related to the ability of the enzyme to induce the complete disappearance from plasma of L-asparagine, an amino acid essential to lymphoblastic leukaemia cells. It is not feasible to monitor L-asparagine plasma levels in patients under L-asparaginase treatment using the usual analytical procedures as the enzyme continues the hydrolysis of L-asparagine after blood sampling and during plasma extraction. A method was therefore developed for the determination of L-asparagine in patients receiving L-asparaginase. Sulphosalicylic acid is added to blood samples to deproteinize and inactivate L-asparaginase rapidly. The samples are then analysed by HPLC using a Novapack C18 column and fluorescence detection. With the same method L-asparagine is determined in blood cells and, by difference, plasma levels are calculated. This method is highly specific and sufficiently simple and sensitive for clinical use.

Chronic oral etoposide in small-cell lung cancer: clinical and pharmacokinetic results.

AIMS: To evaluate antitumour activity, toxicity, pharmacokinetics, and the pharmacodynamic relationship with neutropenia of chronic oral etoposide (E) in patients (pts) with small-cell lung cancer (SCLC) previously untreated with chemotherapy. PATIENTS AND METHODS: Twenty-seven (14 extensive-, 13 limited-stage) pts receiving 100 mg daily of oral E for 21 days every 4 weeks. CBC with differential repeated every week. E plasma levels determined by HPLC method (sensitivity limit: 0.1 microgram/ml) with evaluation during the first cycle of weekly 24-hour drug concentrations. RESULTS: Among 25 evaluable pts, 60% (95% CI: 39%-79%) overall response, 144 and 217 days of median PFS and survival. Dose-limiting non-cumulative neutropenia of high interpatient variability. Linear reduction (30% per week) of absolute neutrophil counts (ANC) up to the 3rd week, recovering the following week. Risk factors for neutropenia (age, PS, serum creatinine and albumin) not identified. High inter-patient variability of 24-hour E plasma levels. A weak correlation between mean 24-hour E plasma levels and ANC nadir or relative decrease of ANC, but higher relative decrease of ANC in pts with 24-hour E plasma levels of > 0.32 microgram/ml. CONCLUSIONS: Chronic oral E is effective in SCLC pts previously untreated with chemotherapy. Careful hematological monitoring is essential to avoid severe myelosuppression. The degree of neutropenia might be related to the maintenance of a critical drug concentration level for a critical period of time.

A limited sampling model for the pharmacokinetics of etoposide given orally.

A limited sampling model of etoposide after oral administration to estimate the area under the plasma concentration-time curve from 0 to 24 h (AUC) by determination of the drug plasma levels at only two time points was developed by a multiple regression analysis on a training data set of 15 patients receiving oral doses ranging from 54 to 90 mg/m2. The equation describing the model is AUC (micrograms ml-1 h) = 5.183 (micrograms ml-1 h) + 1.193 (h) x C1h (micrograms/ml) + 8.439 (h) x C4h (micrograms/ml) (R2 = 0.93, P = 0.0001), where C1h and C4h represent the plasma etoposide concentrations at 1 and 4 h, respectively. The model was validated prospectively on a test data set of 13 patients receiving oral doses ranging from 52 to 87 mg/m2 and, additionally, on a data set of 7 patients receiving oral doses ranging between 176 and 200 mg/m2, investigated in a previous study. Validation on both test data sets gave a relative mean predictive error of 0.1% and a relative root mean square error of 15.8% and 16.7%, respectively. The present study shows that it is possible to obtain a good estimate of the plasma AUC after oral administration of etoposide using a two-time-point sampling model. The model can be used to monitor the etoposide AUC in patients receiving chronic oral treatment.

The hemodynamic effects of intravenous ranitidine in intensive care unit patients: a double-blind prospective study.

The hemodynamic effects of intravenous ranitidine were studied in a prospective double-blind fashion in postoperative intensive care unit patients to determine if this H2 blocker produced the same transient fall in mean arterial pressure and systemic vascular resistance known to occur with cimetidine infusion. We found no statistically significant hemodynamic changes from baseline associated with infusion of 50 mg ranitidine over a 5-minute period. The different chemical ring structure of ranitidine and its effect on H2 vascular and cardiac receptors may account for these observations.

Cardiopulmonary effects of the head-down tilt position in elderly postoperative patients: a prospective study.

We studied the use of the head-down tilt position (Trendelenburg) in elderly postoperative patients in the intensive care unit to determine its effect upon cardiac and pulmonary function. Twenty-two patients (mean age 68.4 years) were placed in a 12 degrees head-down tilt position for 15 minutes. No deterioration was shown in any measured cardiac parameter; mean arterial pressure, cardiac index, and right and left ventricular stroke work increased significantly (P less than .05). Further, there were no observed changes in arterial or venous oxygenation, or in venous admixture. Because of the uncertain effect of the head-down tilt position upon cerebral blood flow, the routine use of this position is not recommended for the treatment of hypotension or during cardiopulmonary resuscitation. The results of this study, however, show that the cardiopulmonary effects are well tolerated if the position is required, as during central venous access procedures.

Effects of sodium bicarbonate in canine hemorrhagic shock.

We studied the use of sodium bicarbonate administration in a canine model of hemorrhagic shock to determine its effect on hemodynamics, arterial and venous blood gases, respiratory gases, and blood lactate levels. Thirteen dogs were anesthetized, paralyzed, mechanically ventilated, and hemodynamically monitored. Hypotension was induced and maintained at a mean arterial pressure of 40 to 45 mm Hg using controlled hemorrhage and reinfusion. After 2.5 h of shock, the dogs were randomized into two groups: one group (n = 6) received NaCl infusion; the other (n = 7) received sodium bicarbonate (1 mEq/kg followed by a continuous infusion of 2.5 mEq/kg.h for 2.5 h). CO2 production was increased in the alkali group, but there was no statistically significant difference between groups in any measured hemodynamic, blood gas, or respiratory gas variable. These included heart rate, BP, cardiac output, arterial and venous pH, CO2 production, and bicarbonate levels. Blood lactate levels, however, in the bicarbonate treated animals were significantly (p less than .01) higher than in the group treated with NaCl alone (10.1 +/- 3.2 vs. 5.1 +/- 1.2 mEq/L). These results are similar to the effects of bicarbonate found in other models of lactic acidosis, and suggest that bicarbonate therapy may have limited usefulness in the treatment of lactic acidosis.