An HPLC method for the determination of diastereomeric prodrug RS-79070-004 in human plasma.

Ganciclovir is an antiviral nucleoside analogue approved for treatment and prevention of cytomegalovirus infections in immunocompromised subjects. RS-79070-194, a diastereomeric monovalyl ester of ganciclovir (hydrochloride salt), is under evaluation as a prodrug to increase the bioavailability of ganciclovir. An HPLC method with column switching has been developed and validated for quantification of the corresponding free base RS-79070-004 in human plasma. In the method, proteinaceous material in 0.25 ml of plasma is precipitated by trichloroacetic acid. An aliquot of the supernatant is analyzed by HPLC, with automated column switching to remove late-eluting materials that might interfere with the analyte peaks in subsequent runs. Detection of RS-79070-004 is by UV lambda = 254 nm). The peak areas for each isomer are summed to generate a value for total RS-79070-004. The method has a validated range of 0.0400-4.00 microg/ml and a lower limit of quantification of 0.0400 microg/ml. All intra- and inter-assay %CVs were < 7.5%, and all recoveries (accuracy) were within 6% of nominal values. No interference was observed by ganciclovir, caffeine, acetaminophen, or ibuprofen. Analyte stability in plasma and in the sample extracts is adequate for the specified collection, storage, and analysis conditions. The validated method has been successfully used to analyze clinical study samples.

Radioimmunoassay of ganirelix in plasma or serum.

A procedure for the radioimmunoassay (RIA) of ganirelix in plasma or serum at concentrations as low as 0.050 ng/ml is described. Antiserum was produced by coupling the N-terminus glycyl analog of ganirelix to BSA by a carbodiimide reaction and immunizing rabbits with this conjugate. The antiserum did not crossreact with LHRH or with various ganirelix peptide fragments. For RIA, 125I labeled ganirelix was used as the tracer and a double antibody procedure was used to separate the free and bound fractions. No purification of the analyte was required prior to RIA. Accuracy of the method was assessed by adding known quantities of ganirelix to ganirelix-free plasma and determining the ratio of measured to added analyte. Linear regression analysis for the concentration range 0.050-50.0 ng/ml yielded a regression equation of y = 0.97x + 0.18, r = 0.999, where x is the amount added and y is the amount measured. Additional validation was obtained from an in vivo study in which [3H]-ganirelix was administered to monkeys and plasma clearance profiles were determined by RIA and an HPLC-radiochemical method. The results were in agreement within experimental error of the two methods. Linear regression analysis of the comparative data gave the equation y = 0.92x + 33.7, r = 0.980, where x is the amount measured by RIA and y is the amount measured by HPLC-radiochemical analysis.

[Pseudomyxoma of the peritoneum. Apropos of 4 cases]. / Maladie gélatineuse du péritoine. A propos de quatre cas.

Peritoneal pseudomyxoma is a rare disease (400 published cases). In 60% of all cases, an ovarian tumor is the cause of the disease. The second cause is appendicular mucocele. We report about four personal cases after a longer time lapse. No clinical or biological sign is specific. Ultrasonography associated to CT may allow establishing the preoperative diagnosis. Peritoneal pseudomyxoma has several main features: it is insidious, recurrent, obstinate and severe. Recent work has shown that peritoneal pseudomyxoma is secondary to malignant mucosecretory tumors, mainly of ovarian (cystadenocarcinoma) or appendicular origin, with intraperitoneal cell implants. Surgery is the only treatment with proven effectiveness. The effectiveness of chemotherapy and radiation therapy has not been established.

Absorption and metabolism of nafarelin, a potent agonist of gonadotropin-releasing hormone.

Nafarelin, a potent gonadotropin-releasing hormone (GnRH) agonist, was absorbed rapidly into systemic circulation (time to reach peak concentration, 20 to 40 minutes) after intranasal but not after sublingual or vaginal administration. Serum elimination half-life was about 2 hours. Nasal absorption of nafarelin was increased by increasing the concentration of the drug in the dose solution and incorporating sodium glycocholate into the nasal formulation. An optimal formulation providing maximum nasal absorption of nafarelin was one containing 1.75 mg nafarelin per ml and 2% sodium glycocholate. Bioavailability of this nasal formulation relative to a single subcutaneous dose averaged 21%. The metabolism and excretion of nafarelin were determined in three subjects after subcutaneous administration of [14C]-nafarelin. Radioactivity was excreted in approximately equal amounts in urine and stool. Six metabolites accounted for most of the radioactivity in urine. Four metabolites were short peptide fragments of nafarelin and the other metabolites were naphthylalanine and 2-naphthylacetic acid.

Disposition of detirelix, a potent luteinizing hormone-releasing hormone antagonist, in rats and monkeys.

The disposition of detirelix, a potent luteinizing hormone-releasing hormone (LHRH) antagonist, was studied in rats and monkeys. After a single 300-microgram/kg intravenous dose in rats, the plasma elimination t1/2 was 1.6 hr and the plasma clearance was 3.3 ml/min/kg. In the monkey, the mean t1/2 and plasma clearance were 7.1 hr and 1.3 ml/min/kg, respectively, after an 80-microgram/kg intravenous dose. Long plasma t1/2 values of 18.7 and 31.6 hr were observed after single 0.2- and 1.0-mg/kg subcutaneous doses in the monkey, suggesting the possibility of subcutaneous depot formation at the injection site. Biliary excretion was the predominant route of elimination of detirelix in both species. Less than 10% of the detirelix was excreted renally. A major metabolite, isolated from the rat bile, was the 1-4 tetrapeptide fragment of detirelix. This metabolite was formed by enzymatic hydrolysis of the Ser4-Tyr5 bond, one of the only two peptide bonds in detirelix not containing a D-amino acid.

Radioimmunoassay of detirelix ([ N-Ac-D-Nal(2)1,D-p-Cl-Phe2,D-Trp3, D-hArg(Et)6(2),D-Ala10]-luteinizing hormone-releasing hormone) in plasma or serum.

A procedure for the radioimmunoassay (RIA) of detirelix in plasma or serum at concentrations as low as 0.15 ng/ml is described. Antiserum was produced by deacetylation of the N-terminus amino groups of detirelix and coupling this analog to bovine serum albumin with a carbodiimide and immunizing rabbits with the resultant conjugate. For RIA, 125I-labeled detirelix was used as the tracer and a double antibody procedure was used to separate the free and bound fractions. No purification of samples was required prior to RIA. Accuracy of the method was assessed by adding known quantities of detirelix to detirelix-free plasma and determining the ratio of measured to added analyte. Linear regression analysis for the concentration range 0.15-150.0 ng/ml yielded a regression equation of y = 0.88 X +1.46 and a correlation coefficient of 0.996. Additional validation was obtained from an in vivo study in which [14C]detirelix was administered to monkeys and plasma clearance profiles were determined by RIA and an HPLC-radiochemical method. The RIA results were in good agreement with those obtained by the HPLC method.

[Spontaneous intramural hematoma of the esophagus. Apropos of a case]. / Hématome intramural spontané de l'oesophage. A propos d'un cas.

Spontaneous intramural haematoma of the oesophagus is a rare condition which usually produces a clinical picture marked by chest pain, dysphagia and haematemesis of moderate severity. The authors report a new case in a woman aged 70 years, under anticoagulant treatment for viral meningitis and presenting with repeated vomiting. Endoscopy of the upper alimentary tract and oesophageal radiography showed a pseudotumoral appearance of the middle and lower portions of the thoracic oesophagus. Progress was favourable under medical management, with uncomplicated recovery. A review of the 38 cases previously published emphasizes in particular the favourable outcome and the conservative medical treatment of this condition.