Cestode zoonoses of aquatic animals.
The cestode zoonoses of Diphyllobothrium, and Spirometra and Sparganosis are discussed from the point of view of their transmission and epidemiology.
Animals↗
Biomedical subjects
M C Meyer
Publications and source records attributed to M C Meyer.
The binding of drugs by plasma proteins.
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Analgesics↗
Novel method for studying protein binding.
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Dialysis↗
Interactions of xanthine derivatives with bovine serum albumin. 3. Inhibition of binding.
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Acetates↗
Hatching of Diphyllobothrium sebago eggs in nature.
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Animals↗
Evaluation of criteria for the recognition of Diphyllobothrium species.
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Diphyllobothrium↗
Labor induction with a prenatal diagnosis of fetal macrosomia.
Since our institution has a low cesarean rate (14%), it was our hypothesis that the rate of cesarean delivery in patients who underwent induction for macrosomia would be similar to the cesarean rate in patients with similar birth weights who entered labor spontaneously. A retrospective analysis of cases seen from December 1993 to July 1995 revealed 53 nondiabetic patients who underwent induction for fetal macrosomia. These study patients were matched to the next nondiabetic patient delivering a child of equal or greater birth weight who entered labor spontaneously. Maternal demographics, labor characteristics, and neonatal outcome data were reviewed. There were no differences between the induction and spontaneous labor groups in maternal age, gestational age, rate of nulliparity, incidence of shoulder dystocia, Apgar scores, or vaginal birth after prior cesarean delivery. The cesarean delivery rate was higher in the induction group when compared to the spontaneous labor group (36% vs. 17%, P < 0.05) despite a lower birth weight in the induction group (4,102 +/- 374 g vs. 349 g, P < 0.05). Regional analgesia was administered more frequently in the induction group (38% vs. 53%, P < 0.05). An increased risk of cesarean delivery was observed in subjects undergoing induction for the indication of fetal macrosomia. These data support a plan of expectant management when fetal macrosomia is suspected.
Analgesia↗
Simultaneous determination of methenamine and formaldehyde in the urine of humans after methenamine administration.
Methenamine (hexamethylenetetramine) and its hydrolysis product formaldehyde are determined in the presence of each other in urine by a spectrophotometric method. Formaldehyde is assayed by a colour reaction with tryptophan, sulphuric acid and ferric chloride after precipitating methenamine by three treatments with mercuric chloride. Methenamine is indirectly analysed by hydrolysis to formaldehyde with dilute hydrochloric acid. Formaldehyde levels as low as 5.0 micrograms ml-1 in the presence of methenamine concentrations as high as 2.5 mg ml-1 can be assayed. Of practical significance is the feature that urine may be stored up to 1 weeks for analysis, by appropriate dilution and freezing, without excessive loss of methenamine or formaldehyde. The method was applied to the dtermination of the bioavailability of methenamine hippurate in ten human volunteers.
Biological Availability↗
HPLC determination of benzthiazide in biologic material.
An assay was developed for benzthiazide in plasma, urine and feces, using high performance liquid chromatography (HPLC). A reverse-phase column was employed, with quantitation af 280 nm, using polythiazide as an internal standard. In three of four human subjects who received a 50 mg benzthiazide tablet the plasma concentrations were below the 10 ng ml-1 sensitivity limit of the assay, and the urinary recovery averaged less than one per cent of the dose. One subject received a 50 mg dose as both a tablet and a solution; the urinary recoveries for these two doses were 1.7 and 10.4 per cent, respectively. Fecal samples, obtained from two subjects who received 50 mg tablets, were estimated to contain approximately 80 per cent of the administered dose.
Adult↗
Relative bioavailability of acetazolamide tablets.
Plasma acetazolamide concentrations were determined enzymatically after administration of three tablet dosage forms and a reference solution to 12 human subjects in a crossover study. Two of the tablet products represented different lots from the same manufacturer. There were no significant differences in area under the plasma level-time curves among the four treatments. However, significant differences were found among tablets in terms of peak plasma concentration and time to reach peak concentration. These apparent differences in rate of absorption were correlated with in vitro dissolution data obtained in pH 1.5 dissolution medium.
Acetazolamide↗
Plasma levels of ethaverine after oral administration to humans.
Fourteen healthy human subjects received a 200 mg oral dose of ethaverine hydrochloride as an elixir. Blood samples were obtained for 12 h after dosing. Plasma ethaverine concentrations were determined using a paired-ion, reversed-phase high performance liquid chromatographic method. Individual plasma concentration-time profiles were fitted to a two-compartment model with first-order absorption. The ethaverine was rapidly absorbed, based on a time of maximum plasma concentration of 0.75 h, a time-lag of 8.4 min, and an apparent first-order absorption half-life of 8.6 min. The mean terminal elimination half-life was 3.3 h.
Administration, Oral↗
Bioavailability of seven furosemide tablets in man.
A seven-way crossover study was conducted in 14 healthy male volunteers to evaluate the relative bioavailability of seven different marketed 40 mg furosemide tablets. Each dose was administered as a single tablet after an overnight fast, and blood samples were obtained for 16 hours. Plasma was assayed by HPLC. There were no statistically significant differences among the seven products for the mean peak concentration (1.01-1.29 micrograms/ml), mean time of peak (1.2-2.1 h) or mean area under the plasma concentration-time curves, which differed by less than 14 per cent. However, one product exhibited greater intersubject variability, and on this basis was considered inequivalent to the other six products. Furosemide is a potent and widely used diuretic. Currently the United States Food and Drug Administration (USFDA) has granted approval to at least twelve manufacturers of 40 mg furosemide tablets, based in part on bioavailability data obtained in human subjects. In addition, the USFDA has granted an 'AB' therapeutic equivalence evaluation to each of these products, which is understood by many to indicate the therapeutic equivalence and interchangeability of these products. The objective of the present investigation was to directly compare the bioavailability of seven 40 mg furosemide tablet products which had previously been approved by the Food and Drug Administration.
Adult↗
The absorption of sustained-release methylphenidate formulations compared to an immediate-release formulation.
A crossover study in 18 subjects evaluated the plasma concentration-time profile of two different 20 mg sustained-release (SR) methylphenidate (MPH) tablets administered before breakfast, compared to a 10 mg immediate-release (IR) tablet administered before breakfast and again 5 h later, before lunch. Plasma MPH concentrations were determined using a sensitive and precise gas chromatography-mass spectrometry method, incorporating a deuterated internal standard. The mean peak MPH concentration was 6.4 ng ml-1 for the IR product versus 4.6 ng ml-1 and 4.8 ng ml-1 for the two SR formulations. Peak concentrations occurred at 3.3 h after dosing with the SR products, compared to 1.5 h after the first dose of the IR product. The extent of absorption for the three products, as determined from areas under the plasma concentration-time curves, were within 5 per cent of each other. There was no significant difference in rate or extent of absorption between the two SR formulations.
Biological Availability↗
In vitro and in vivo evaluation of seven 50 mg and 100 mg nitrofurantoin tablets.
Four 50 mg and three 100 mg marketed nitrofurantoin tablets were studied in 14 healthy male subjects. Urine was collected 1, 2, 3, 4, 6, 8, 12, and 23 h after each dose, and nitrofurantoin was assayed by HPLC. The in vitro dissolution of the tablets was determined using USP Apparatus 1 and 2, with 0.1 N hydrochloric acid and pH 7.2 buffer as the dissolution fluids. One of the 50 mg tablets was more rapidly and completely absorbed than the other six products. The incidence of side-effects for this product was as low or lower than the other products. It was determined that the use of the USP Apparatus 1, at 100 rev min-1, with sampling of the pH 7.2 fluid at 30 min, provided for the best overall relationship between the urinary excretion and in vitro dissolution.
Administration, Oral↗
Influence of a standard meal on the absorption of a controlled release pseudoephedrine suspension.
The influence of a standard meal on the extent and rate of absorption of pseudoephedrine from a liquid controlled release (CR) formulation (Pennkinetic System) was studied in 16 normal male volunteers. Equivalent single doses of an immediate release reference syrup (IR-Sudafed) and the CR suspension were each studied under both fasted and postprandial conditions. AUC results showed no significant influence of food or formulation, indicating that the CR formulation was absorbed to the same extent as the IR product under all conditions. CMAX and TMAX tabulations under fasted conditions indicated that the CR preparation peaked at a lower level at a later time. Food diminished IR CMAXs but the CR suspension's CMAXs and TMAXs were apparently unaffected by food. This study indicates that this CR pseudoephedrine suspension releases drug independently of food intake.
Adolescent↗
Relative bioavailability of a controlled-release albuterol formulation for twice-daily use.
A two-way-crossover bioavailability study was completed with 15 healthy male volunteers to evaluate the relative bioavailability of an orally administered controlled-release (CR) formulation of albuterol as compared to the immediate-release (IR) formulation of albuterol. The CR formulation of albuterol used in this study was based mechanistically on the elementary osmotic pump. Each subject received one 8 mg CR tablet every 12 h for 8 consecutive days and one 4 mg IR tablet every 6 h for 8 consecutive days, with 7 days separating each phase. During day 8 of dosing, hourly blood samples (0-12 h) were collected after the morning dose and three additional samples were obtained 16, 20 and 24 h following this dose. Plasma concentrations were measured using a gas chromatography-mass spectrometry procedure. No statistically significant differences were observed in mean steady-state values for Cmax, Cmin, AUC(0-12 h) and peak-to-trough fluctuations (PTF) in comparing the two dosage formulations. Mean steady state Tmax values were 2.6 and 6.0 h for the TR and CR formulations, respectively. It was concluded that twice daily administration of the controlled-release formulation of albuterol provides an alternative to four times daily administration of conventional (immediate-release) albuterol tablets.
Adult↗
Propoxyphene bioavailability: an evaluation of ten products.
Ten commercial products containing 65 mg propoxyphene hydrochloride have been evaluated for their relative bioavailability in human subjects in a complete crossover study. No statistically significant (P greater than 0.05) differences were observed between the products in terms of plasma levels 1, 2, 3, 4, 6, 8, and 12 hours after administration; peak plasma levels; time to achieve peak plasma level; and area under the plasma level-time curve. Individual subjects exhibited considerable differences in the propoxyphene plasma levels, which were similar to the variability observed by others. The average estimated half-life of 3.61 hours was consistent with previously reported values, although it may have underestimated the true value because the low plasma levels remaining after 12 hours were not quantitated.
Adult↗
The influence of dosage form on papaverine bioavailability.
The bioavailability of sustained-release papaverine HCl dosage forms were compared to equivalent doses of the drug administered as an elixir and conventional compressed tablets to 12 healthy human subjects. Papaverine plasma levels were determined using a gas-chromatographic procedure. The drug was absorbed more rapidly and completely from the two nonsustained-release formulations. There was a large intersubject variability, and the plasma half-life of the drug was esstimated to be 1 hour. The area under the plasma level-time curve for the nine sustained-release products ranged from 18 to 64% relative to the area achieved by the papaverine elixir. It was concluded that the sustained-release dosage forms of papaverine included in each study group could be considered bioequivalent, but they exhibited inadequate bioavailability relative to either the elixir or the compressed tablet dosage form.
Administration, Oral↗