Bioavailability assessment of a liquid prednisone preparation.

To assess the relative bioavailability of a recently developed liquid prednisone preparation, prednisolone pharmacokinetics were evaluated after the administration of three separate steroid preparations. On 3 study days, each 2 wk apart, 12 healthy subjects received in random order: prednisone liquid, prednisone tablet, and prednisolone sodium phosphate. Plasma samples were collected over a 12 hr study period and analyzed for prednisolone concentration by high-pressure liquid chromatography.

Rapid elimination of quinidine in pediatric patients.

The oral absorption and elimination of quinidine in pediatric patients was studied. Single oral doses of quinidine sulfate were administered to 13 patients ranging in age from 4 to 22 years of age. Serum quinidine concentration reached a peak within 30 minutes to two hours after drug administration.

Dose- and time-related effect of troleandomycin on methylprednisolone elimination.

Effects of varying doses of troleandomycin (TAO) on methylprednisolone disposition were examined in five steroid-dependent asthmatic patients. The characteristic reduction in methylprednisolone elimination in the presence of TAO after a 40 mg IV methylprednisolone was also present after methylprednisolone doses as low as 4 mg. In patients receiving continuous TAO on an every-other-day basis, inhibition of methylprednisolone elimination was impaired to a greater extent on the "day on" TAO than on the "day off" TAO Methylprednisolone elimination on the day off TAO was still slower than that before TAO, however, TAO on a multiple-dose schedule resulted in greater reduction of methylprednisolone elimination than after a single TAO dose.

Steroid-specific and anticonvulsant interaction aspects of troleandomycin-steroid therapy.

Troleandomycin (TAO) is a macrolide antibiotic that has an apparent "steroid-sparing" effect when used in the treatment of severe steroid-dependent asthmatic patients. Recent observations demonstrated the effect of TAO on inhibiting methylprednisolone elimination, possibly contributing to its beneficial effects. Prednisolone and methylprednisolone disposition were studied before and 1 wk after initiation of TAO therapy in three patients.

High gentamicin trough concentrations in neonates of less than 28 weeks gestational age.

77 newborns, ranging from 25.5 to 43 weeks gestational age (GA) and receiving gentamicin, were studied prospectively over 4 months. Peak and trough serum concentrations were obtained on days 1, 3, and 5 of therapy.

Intrasubject variation in sustained-release theophylline absorption.

Intrasubject variability in the absorption characteristics of two sustained-release theophylline products was examined. Eight healthy, nonsmoking, adult volunteers received a single 250 mg Slo-Phyllin Gyrocap on two separate study days and a single 300 mg Theo-dur tablet on two other study days. Plasma samples were collected over a 24-hr period after each dose and were assayed for theophylline content.

Effect of erythromycin base on theophylline kinetics.

Because of several recent reports describing altered theophylline elimination in the presence of salts of erythromycin, the effect of a 10-day course of erythromycin base on theophylline kinetics was studied in eight healthy adult men. Theophylline (4 mg/kg) was given on four separate study days: (1) prior to starting erythromycin, (2) on the third day of erythromycin administration, (3) on the tenth day of erythromycin administration, and (4) 2 weeks after the course of erythromycin was completed. Mean theophylline kinetic parameter values on each of the 4 study days were: apparent volume of distribution (Vd), 0.

Prednisolone metabolism and excretion in the isolated perfused rat kidney.

The isolated perfused rat kidney was used to identify factors responsible for the renal elimination of prednisolone (Pn). Pn was recirculated at initial concentrations varying from 100 to 1000 ng/ml for 90 min. Perfusate and urine samples were assayed for Pn and prednisone by HPLC.

Beta-adrenergic receptors of human polymorphonuclear leukocytes.

125I-iodohydroxybenzylpindolol (IHYP) is a beta-adrenergic antagonist used as a ligand for the characterization of beta-adrenergic receptors in various cell preparations. Since IHYP may be adsorbed to surfaces such as test tubes and pipet tips, it is necessary to measure the actual free concentration of IHYP in the incubation solution. With this modification, the number of beta-adrenergic receptors in human peripheral PMNs can be determined with greater precision.

The effect of troleandomycin on methylprednisolone elimination.

Troleandomoycin (TAO), a macrolide antibiotic, has an apparent "steroid-sparing" effect when used in the treatment of severe steroid-dependent asthma. This study was designed to investigate the effect of TAO on methylprednisolone elimination. Pharmacokinetic studies were performed before and 1 wk after starting TAO in 10 severe steroid-dependent asthmatics.

Isoproterenol excretion and metabolism in the isolated perfused rat kidney.

[3H]isoproterenol excretion and metabolism were studied in the isolated perfused rat kidney using a one-pass, non-recirculating perfusion system with constant infusion rates of [3H]isoproterenol. The [3H]isoproterenol (U/P) to inulin (U/P) ratio was approximately 15 indicating extensive tubular secretion. A major renal metabolite, 3-O-methylisoproterenol, appeared in the urine and renal vein perfusate and also accumulated in the renal tissue.

Paradoxical behavior of serum digoxin concentrations in an anuric neonate.

Serum digoxin values were determined in a newborn infant with severe heart failure and renal failure. The half-life of digoxin in the serum appeared to change, possibly the result of prolonged distribution and/or absorption owing to circulatory insufficiency, or to the accumulation of cross-reacting metabolites of digoxin in the serum. No clinical toxicity was apparent, and no cardiac arrhythmia was observed.