Biochemical outcome following external beam radiation therapy with or without androgen suppression therapy for clinically localized prostate cancer.

CONTEXT: Combined treatment using radiation therapy (RT) and androgen suppression therapy (AST) is used to treat men with clinically localized adenocarcinoma of the prostate, but outcome using this combined therapy compared with RT alone is not known. OBJECTIVE: To determine the relative efficacy of RT plus AST vs RT alone among men with clinically localized prostate cancer. DESIGN, SETTING, AND PATIENTS: Retrospective cohort study of 1586 men with prostate cancer who were treated between January 1989 and August 1999 using 3-dimensional conformal RT with (n = 276) or without (n = 1310) 6 months of AST. MAIN OUTCOME MEASURE: Relative risk (RR) of prostate-specific antigen (PSA) failure (defined according to the American Society for Therapeutic Radiology and Oncology consensus statement), by treatment and high-, intermediate-, or low-risk group based on serum PSA level, biopsy Gleason score, and 1992 American Joint Commission on Cancer clinical tumor category. RESULTS: Estimates of 5-year PSA outcome after RT with or without AST were not statistically different among low-risk patients (P =.09), whereas intermediate- and high-risk patients treated with RT plus AST had significantly better outcomes than those treated with RT alone (P<.001 and =.009, respectively). The RR of PSA failure in low-risk patients treated with RT plus AST was 0.5 (95% confidence interval [CI], 0.3-1.1) compared with patients treated with RT alone. The RRs of PSA failure in intermediate-risk and high-risk patients treated with RT plus AST compared with RT alone were 0.2 (95% CI, 0. 1-0.3) and 0.4 (95% CI, 0.2-0.8), respectively. CONCLUSIONS: Our data suggest a significant benefit in 5-year PSA outcomes for men with clinically localized prostate cancer in intermediate- and high-risk groups treated with RT plus AST vs those treated with RT alone. Results from prospective randomized trials currently under way are needed to validate these findings. JAMA. 2000;284:1280-1283

Comparison of usefulness of estradiol vaginal tablets and estriol vagitories for treatment of vaginal atrophy.

BACKGROUND: Atrophic vaginitis is a common condition. This study compared the usefulness of estradiol vaginal tablets (EVT) and estriol vagitories (EV) in treatment of atrophic vaginitis. METHODS: Ninety-six postmenopausal women with symptoms of atrophic vaginitis were treated for 24 weeks with either EVT or with EV. Patients used the medication daily for the first 2 weeks of the study, and twice-weekly thereafter. RESULTS: Both EVT and EV were effective in treating vaginal atrophy and patients in both treatment groups experienced a significant improvement in vaginal symptoms such as itching, irritation, dryness, and dyspareunia. At the end of the study three (6%) EVT treated women reported leakage and none needed to use sanitary towels. Among the EV treated women 31 (65%) reported leakage and 14 (29%) required sanitary protection. Furthermore, 90% in the EVT group perceived the medication as hygienic compared to 79% in the EV group, and 49% in the EVT group indicated that the product was easy to use compared to 28% in the EV group. Endometrial thickness was increased (1.1 mm with EVT and 0.5 mm on EV) in both treatment groups during the first 2 weeks of the study, but returned to baseline levels when the frequency of drug application was reduced to twice-weekly. CONCLUSIONS: Estradiol vaginal tablets provides an effective alternative to traditional forms of local estrogen therapy.

Studies on anabolic steroids. V. Sequential reduction of methandienone and structurally related steroid A-ring substituents in humans: gas chromatographic-mass spectrometric study of the corresponding urinary metabolites.

The biotransformation of methandienone (17 beta-hydroxy-17 alpha-methylandrosta-1,4-dien-3-one) in human adults, more particularly the sequential reduction of its A-ring substituents, was investigated by gas chromatography-mass spectrometry. Two pairs of 17-epimeric tetrahydro diols resulting from the stereoselective reduction of the delta 4- and 3-oxo groups and of the delta 1-function were characterized. The major diols were 17 alpha-methyl-5 alpha-androstane-3 alpha,17 beta-diol and 17 alpha-methyl-5 beta-androstane-3 alpha,17 beta-diol, which were both excreted in the conjugate fraction in a 1:3.8 ratio. The immediate metabolic precursors of the 5 beta-diol, namely 17 beta-hydroxy-17 alpha-methyl-5 beta-androsta-1-en-3-one and 17 alpha-methyl-5 beta-androsta-1-en-3 alpha,17 beta diol and their corresponding 17-epimers, were also identified in post-administration urine samples. These data indicated that reduction of methandienone A-ring substituents proceeds according to the sequence. delta 4-, 3-oxo- and delta 1-. The A-ring reduction products of the structurally related steroids mestanolone, 17 alpha-methyltestosterone and oxymethone were also characterized and provided further analytical and metabolic evidence supporting the proposed route of methandienone A-ring reduction. It was also demonstrated using synthetic 17 beta-sulfate conjugates of methandienone and 17 alpha-methyltestosterone that their corresponding 17-epimers are formed by nucleophilic substitution by water of the labile sulfate moiety. The steroidal metabolites were identified on the basis of their characteristic mass spectral features and by comparison with authentic reference standards. Metabolic pathways accounting for the occurrence of the metabolites of interest in post-administration urine samples are proposed.

Studies on anabolic steroids. III. Detection and characterization of stanozolol urinary metabolites in humans by gas chromatography-mass spectrometry.

The metabolism of stanozolol (17 beta-hydroxy-17 alpha-methyl-5 alpha-androstano[3,2-c]pyrazole), an androgenic-anabolic steroid widely used in sport for the purpose of enhancing performance, was investigated in humans. The analysis method was based on the use of solid-phase extraction on the Sep-Pak C18 cartridge, enzymic hydrolysis of steroid conjugates and high-resolution gas chromatograph-mass spectrometric (GC-MS) analysis of trimethylsilylated steroid extracts. After administration of a single 20-mg oral dose, twelve metabolites including unchanged stanozolol were recovered predominantly from the conjugated steroid fraction and characterized by GC-MS. In the unconjugated fraction, 16 alpha-hydroxystanozolol, 17-epistanozolol, stanozolol and 3'-hydroxy-17-epistanozolol were the most abundant metabolites. In the aglycone fraction, 16 alpha- and 16 beta-hydroxystanozolol, stanozolol and 3'-hydroxystanozolol were the most abundant metabolites. Other metabolites resulted from regioselective hydroxylation of stanozolol at C-4, whereas other were 17-epimers of 3'- and 16 alpha-hydroxystanozolol. Further hydroxylation leading to the formation of four isomeric dihydroxylated metabolites was also observed. They were tentatively assigned the structures of 3',16 alpha-, 4 beta,16 alpha-, 3',16 beta- and 4 beta,16 beta-dihydroxystanozolol. The mass spectral features of their bis-N,O-trimethylsilyl derivatives obtained under electron-impact ionization are presented. The effect of pH on the relative recovery of some of these metabolites is also presented. The usefulness of this analytical methodology for the detection and identification of stanozolol urinary metabolites in doping-control situations is demonstrated. The metabolism of stanozolol is also discussed, and metabolic pathways accounting for the formation of its biotransformation products are proposed.

Studies on anabolic steroids. II--Gas chromatographic/mass spectrometric characterization of oxandrolone urinary metabolites in man.

The metabolism of 17 alpha-methyl-17 beta-hydroxy-2-oxa-5 alpha-androstan-3-one (oxandrolone) in man has been investigated by gas chromatography/mass spectrometry. After oral administration of a 10 mg dose to man, five metabolites were detected in the free fraction of the urinary samples. Oxandrolone, the major compound excreted in urine, was detected within 72 h after administration. During this period 35.8 and 8.4% of the administered dose was excreted as unchanged oxandrolone and 17-epioxandrolone, respectively. In addition, minute amounts of 16 alpha- and 16 beta-hydroxyoxandrolone and a delta-hydroxy acid resulting from the hydrolysis of the lactone group of oxandrolone were detected in the urine samples 8-60 h after administration. Furthermore, the susceptibility of oxandrolone to hydrolysis was investigated under several pH conditions. Extraction and fractionation of steroidal metabolites was achieved by using C18 and silica Sep Pak chromatography. The mass spectra of the metabolites are presented and major fragmentation pathways discussed.

Studies on anabolic steroids. I. Integrated methodological approach to the gas chromatographic-mass spectrometric analysis of anabolic steroid metabolites in urine.

The analytical and methodological imperatives for large-scale and routine gas chromatographic-mass spectrometric screening of anabolic steroid urinary metabolites are described. Several aspects of their isolation, enzymatic hydrolysis, derivatization and metabolism in humans are discussed. Gas chromatographic-mass spectrometric data illustrating artifacts arising from enzymatic hydrolysis of 3 beta-ol-5-en steroids, and describing new metabolites of boldenone, methanedienone and stanozolol, as well as the conversion of norethisterone into 19-nortestosterone metabolites through de-ethylation at C-17, are presented. The analytical approach developed for gas chromatographic-mass spectrometric screening of anabolic steroids is based on the sequential selection-ion monitoring of specific and discrete ion groups characteristic to the steroids of interest under high-resolution chromatographic conditions. The major analytical and methodological requirements necessary to provide irrefutable evidence, in the case where the presence of a synthetic anabolic steroid or a testosterone to epitestosterone ratio higher than 6:1 is suspected in a given urine specimen, are also discussed.

Comprehensive screening procedure for diuretics in urine by high-performance liquid chromatography.

A rapid and reliable screening procedure using high-performance liquid chromatography for the detection of 23 diuretics (belonging to five different pharmacological groups) in urine has been developed. Two aliquots of 2-ml urine samples were extracted separately under acidic and basic conditions. The acidic and basic extracts were pooled, evaporated to dryness and reconstituted in methanol. The methanolic extract was injected onto a Hewlett-Packard Hypersil ODS C18 (5 microns) column (column I) and a Hewlett-Packard LiChrosorb RP-18 (5 microns) column (column II; an alternative column). The same gradient mobile phase was used for both columns. A diode array ultraviolet detector was set to monitor the signal to the integrator (Chem Station) at 230 and 275 nm. Recovery studies of the 23 diuretics were performed under acidic and basic conditions. The overall lower limits for detection on column I using both extraction procedures ranged from 0.5 to 1.5 micrograms/ml of urine (average 1.0 micrograms/ml). Amiloride, ethacrynic acid and probenecid could not be detected below 5 micrograms/ml of urine. No interference from the biological matrix was apparent. Amiloride could be detected in urine 4 h after oral administration of 15 mg of amiloride to a healthy volunteer, when the sample was extracted under alkaline conditions. The suitability of the screening method for the analysis of urine samples was tested by studying the variation with time of chlorthalidone, furosemide, probenecid, acetazolamide, quinethazone, spironolactone, bendroflumethiazide, bumetanide, triameterene and hydrochlorothiazide concentrations in the urine of normal human volunteers after minimum single or multiple (probenecid) doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Gas chromatographic/mass spectrometric analysis of 19-nortestosterone urinary metabolites in man.

A sensitive and highly specific method based on capillary column gas chromatography/mass spectrometry has been developed for the detection of 19-nortestosterone (17 beta-hydroxy-4-estren-3-one) metabolites in urine. After intramuscular administration of 19-nortestosterone decanoate to man, urine samples were collected during several days and treated with Helix pomatia digestive juice. The free steroids were extracted and converted into O-methyl-oxime-trimethylsilyl or the trimethylsilyl ether derivatives and analysed by capillary column gas chromatography/mass spectrometry (GC/MS). Three isomeric metabolites were detected and identified as 3 alpha-hydroxy-5 alpha-extran-17-one (19-norandrosterone), 3 alpha-hydroxy-5 beta-estran-17-one (19-noretiocholanolone) and 3 beta-hydroxy-5 alpha-estran-17-one (19-norepiandrosterone). Packed column GC/MS was also employed in the selected ion monitoring mode for the specific detection of 19-norandrosterone, the most abundant urinary metabolite of 19-nortestosterone. These gas chromatographic/mass spectrometric methods are highly specific tests which can be used on a routine basis for the confirmation of 19-nortestosterone administration to athletes as well as for therapeutic monitoring following administration of the drug.

Comparative bioavailability of two oral formulations of flurazepam in human subjects.

The systemic availability of an investigational oral formulation of flurazepam was compared to that of a commercially available product whose therapeutic efficacy has been well established by usage. The experiment was designed to dissociate formula on factors from all other sources of variation including differences between subjects, sexes, sequences of administration, experimental periods, as well as sex by sequence, sex by period, and sex by formulation interactions. Systemic availability was assessed by conventional pharmacokinetic techniques. Pharmacokinetic interpretation and statistical analysis of plasma concentrations of flurazepam and its major blood metabolites namely N-1-hydroxyethylfurazepam and N-1-desalkylflurazepam as a function of time and of systemic availability indicators revealed a nearly identical biopharmaceutical behaviour for the two preparations. A significant difference could be seen in the plasma levels of N-1-desalkylflurazepam between male and female subjects. The results collectively indicate a very similar biopharmaceutical performance of the two oral formulations of flurazepam.

The effect of buffering on oxyphenbutazone absorption kinetics and systemic availability.

A systemic availability study comparing an investigational buffered tablet formulation of oxyphenbutazone and a commercially available product, the efficacy of which has been well established by usage, is reported. The experiment was designed to dissociate formulation factors from all other sources of variation including differences between subjects, sexes, sequences of administration, experimental periods, as well as sex by sequence, sex by period, and sex by formulation interactions. Systemic availability was assessed by conventional pharmacokinetic techniques. Results show that buffering of a tablet formulation consistently increased the rate and degree of absorption. Although the relative magnitude of bioavailability indicators is slightly different according to the method of calculation, the estimates are always higher with the buffered formulation. No statistical difference was observed for plasma concentration-time profiles between sexes. The wide range of observed concentrations over the time interval of this study confirms other reports of individual variations in handling oxyphenbutazone. The differences noted between the two formulations may be attributed to faster dissolution rate characteristics and better dispersion of oxyphenbutazone. Some aspects of the clinical relevance of this situation are discussed briefly.

Comparative biopharmaceutical performance of imipramine formulations in man.

The systemic availability of an investigational liquid formulation of imipramine was compared to that of a commercially available tablet (Tofranil) whose therapeutic efficacy has been established by usage. The experiment was conducted under controlled conditions and a balanced 2-by-2 crossover design was used to dissociate the significance of formulation effects from subject, group, and experimental period sources of variation. Pharmacokinetic interpretation and statistical analysis of plasma concentrations as a function of time and of systemic availability indicators reveal a nearly identical biopharmaceutical behavior for the two preparations. Significant differences (P less than 0.05) were found in the cumulative area under the plasma concentration--time curve (AUC) up to 4 hours after administration and the availability lag time, but not in the maximum plasma concentration, the time at which this concentration is reached, the first-order availability rate constant, and the AUC to infinity. These results collectively indicate a very similar biopharmaceutical performance, where the differences in the early AUC values are partly attributable to a longer availability lag time for the tablet formulation.

An integrated methodological approach to the computer-assisted gas chromatographic screening of basic drugs in biological fluids using nitrogen selective detection.

This paper presents the methodological aspects of a computerized system for the gas-chromatographic screening and primary identification of central nervous system stimulants and narcotic analgesics (including some of their respective metabolites) extracted from urine. The operating conditions of a selective nitrogen detector for optimized analytical functions are discussed, particularly the effect of carrier and fuel gas on the detector's sensitivity to nitrogen-containing molecules and discriminating performance toward biological matrix interferences. Application of simple extraction techniques, combined with rapid derivatization procedures, computer data acquisition, and reduction of chromatographic data are presented. Results show that this system approach allows for the screening of several drugs and their metabolites in a short amount of time. The reliability and stability of the system have been tested by analyzing several thousand samples for doping control at major international sporting events and for monitoring drug intake in addicts participating in a rehabilitation program. Results indicate that these techniques can be used and adapted to many different analytical toxicology situations.

Determination of loxapine in human plasma and urine and identification of three urinary metabolites.

1. A g.l.c. method for quantitative determination of loxapine (2-chloro-11-(4-methyl-1-piperazinyl)dibenz(b,f)(1,4)oxazepine), in human plasma and urine is described. 2. Preliminary pharmacokinetic data on plasma concn of loxapine over 12 h from five psychiatric patients who received a total average dose of 80 mg of loxapine succinate per day orally for twelve weeks are presented. 3. In addition to unchanged loxapine, three urinary metabolic products, namely aromatic ring-hydroxy loxapine, desmethyl loxapine and loxapine-N-oxide, were identified using g.l.c.--mass spectrometry.

Quantitative determination of plasma oxyphenbutazone by gas-liquid chromatography with selective nitrogen detection.

A sensitive and specific gas chromatographic method, using the nitrogen-phosphorus detector for the detection and determination of oxyphenbutazone extracted from plasma is described. The method involves extraction and back-extraction steps followed by derivatization of both oxyphenbutazone and the internal standard with trifluoroacetic anhydride. The procedure permits the rapid and specific routine determination of oxyphenbutazone in plasma with a detection limit of 0.5 microgram/ml. The procedure is linear over the range of concentrations encountered after administration of a single oral therapeutic dose. No interference from the biological matrix is apparent. The suitability of the method for the analysis of biological samples was tested by studying the variation with time of oxyphenbutazone plasma concentrations in normal human volunteers over a period of several biological half-lives.

Gas chromatographic determination of amitriptyline, nortriptyline and perphenazine in plasma of schizophrenic patients after administration of the combination of amitriptyline with perphenazine.

A specific and sensitive gas-chromatographic technique using a common extraction procedure for the quantitative determination of amitriptyline, endogenous nortriptyline and perphenazine in plasma of schizophrenic patients receiving therapeutic doses of a combination of amitriptyline and perphenazine (Etrafon) has been developed. The lower limits of detection are 20 ng/ml for amitriptyline, 1 ng/ml for nortriptyline and 5 ng/ml for perphenazine. Amitriptyline is estimated with a flame ionization detector. Nortriptyline is quantitated using an electron capture detector after converting it to its heptafluorobutyryl derivative by reaction with the appropriate anhydride. Perphenazine is also determined using an electron capture detector after forming its stable, trimethylsilyl derivative by reaction with N,O-bis-(trimethylsilyl)-acetamide. In individual patients, the steady-state plasma levels ranged from 44 to 215 ng/ml for amitriptyline, from 49 to 270 ng/ml for nortriptyline and from less than 5 to 20 ng/ml for perphenazine. Steady-state plasma levels data on amitriptyline, nortriptyline and perphenazine in 23 patients treated with Etrafon are presented.

Pharmacokinetics of intravenous amikacin after rapid and slow infusion with special reference to hemodialysis.

The pharmacokinetics of amikacin, a recently introduced aminoglycoside structurally related to kanamycin, were determined in healthy volunteers after rapid and slow constant-rate intravenous administration of a 7.5 mg/kg dose. The elimination profile of amikacin can be described by two compartment open model kinetics. Peripheral distribution of the drug is extremely rapid, and beta-phase concentrations decay with a half-life averaging about 2 hours, while inter-compartmental equilibrium is achieved in a little over 30 minutes. The volume of distribution averages about 25% of body weight. During hemodialysis, amikacin extraction from the blood reaches 97% +/- 17% (mean +/- 95% confidence interval) that of creatinine and 89% +/- 20% that of blood urea nitrogen. A method of administration adapted to the kinetic properties of the antibiotic is proposed.

Metabolic interaction between amitriptyline and perphenazine in psychiatric patients.

1. Steady-state plasma level samples of sixty-five schizophrenic patients from two psychiatric hospitals assigned to three treatment groups (amitriptyline 150 mg/day, perphenazine 20 mg/day and a combination of amitriptyline and perphenazine at 150 mg and 20 mg/day) were assayed for amitriptyline (AT), endogenous nortriptyline (NT) and perphenazine (PPZ) using gas-liquid chromatography. 2. Results reveal that AT and NT levels are independent of sex and hospital environment. 3. PPZ significantly increased the steady-state NT plasma levels, probably through inhibition of the hydroxylation biotransformation pathway, but had no effect on AT levels, thus indicating that PPZ has no influence on the desmethylation pathway, or alternatively, the hydroxylation of AT.

Pharmacokinetics of netilmicin in renal insufficiency and haemodialysis.

The pharmacokinetics of intravenously administered netilmicin, an investigational aminoglycoside antibiotic, were studied in 38 patients with creatinine clearance ranging from 150 to Oml/min/1.73m2 in order to determine the influence of kidney function status on the disposition of the antibiotic. The serum disappearance of netilmicin followed first order kinetics and the elimination rate constant decreased proportionally with decreasing renal function. Half-lives averaged 2.2 hours in normal individuals (creatinine clearance greater than 80ml/min/1.73m2) and reached 42 +/- 10 hours (mean +/- SD) in virtually anephric patients. The elimination rate constant lowered proportionally with decreasing renal function. Several linear relationships between pharmacokinetic parameters and renal function indicators were defined. A clinically useful correlation indicates that the half-life may be approximated as 3 times the serum creatinine concentration and may be used for adjustment of dosage of netilmicin in the treatment of patients with impaired renal function. During haemodialysis, netilmicin extraction from the blood reaches 75 +/- 14% (mean +-/ 95% confidence interval) of that of creatinine and 88 +/- 19% of that of blood urea nitrogen.

Nanogram-range determination of plasma imipramine by gas-liquid chromatography using a selective nitrogen/phosphorus detector.

A sensitive and specific gas chromatographic method for the quantitative determination of plasma concentrations resulting from a single normal therapeutic dose of imipramine has been developed and is descriged. After extraction into a mixture of n-heptane/isoamyl alcohol (98.5:1.5), imipramine is well separated from its main metabolite, desmethylimipramine, and both compounds are detected using a selective detector operating in the N/P mode. The procedure permits the rapid routine quantitative analysis of relatively small plasma volumes (1-2 ml) containing as little as 1-2 ng of imipramine. No interference from the biological matrix is apparent. The suitability of the method for the analysis of biological samples was tested by studying the time of course of imipramine plasma concentrations in normal human volunteers, after administration of a single therapeutic dose.