Hans W. Ruelius

Bifidus factor. IV. Preparations obtained from human milk

Abstract 1. 1. Cream, proteins, and salts can be removed from human milk with only small losses of bifidus activity. 2. 2. For the separation from lactose, processes have been developed using adsorption and elution on charcoal or fractional precipitation. 3. 3. The lactose-free, active concentrates upon hydrolysis gave acetic acid and four sugars, d -glucosamine, l -fucose, d -glucose, and d -galactose. All of the latter were identified through crystallized derivatives. Acetylation gave inactive chloroform-soluble, peracetyl compounds from which the bifidus-active N-containing oligo- and polysaccharides could be regenerated. 4. 4. By chromatography on charcoal and on paper, at least four different active components have been found. All of them contained N -acetyl-glucosamine units. All were levorotatory but one, which was lacking in l -fucose and was dextrorotatory. 5. 5. The nitrogen-free saccharides obtained from the lactose-free concentrates of human milk by chromatography did not show any bifidus activity.

Metabolism of diazepam in dogs: Transformation to oxazepam

Abstract On administration to dogs, diazepam is demethylated at the 1-nitrogen and through a novel metabolic pathway is hydroxylated at the 3-carbon of the seven-membered ring. The unhydroxylated demethylation product is excreted in the free form and the 3-hydroxy derivatives are excreted as the glucuronides. No unchanged drug can be detected in the urine. The major metabolite is oxazepam glucuronide.

Clinical pharmacokinetics of lorazepam; II. Intramuscular injection

A single dose of 4 mg of lorazepam was injected into the deltoid muscles of six healthy male volunteers. Multiple venous blood sampies were drawn during 48 hr after the dose and all urine was collected for 24 hr after the dose. Concentrations of lorazepam and its major metabolite, lorazepam glucuronide, were determined by electron‐capture gas‐liquid chromatography. Lorazepam was rapidly absorbed from the injection sire, reaching peak concentrations within 3 hr. Mean pharmacokinetic pamrameters for unchanged lorazepam were: apparent absorption half‐life: 21.2 min: elimination half‐life: 13.6 hr; volume of distribution: 0.9 L/kg; total clearance: 58.2 ml/min. Lorazepam glucuronide rapidly appeared in plasma, reached peak concentrations within 12 hr of the dose, then was eliminated approximately in parallel with the parent drug. Within 24 hr a mean of 47.6% of the dose was recovered in the urine as lorazepam glucuronide and less than 0.5% was recovered as unchanged lorazepam.

Metabolism and kinetics of oxaprozin in normal subjects

Absorption, biotransformation, excretion, and kinetics of Oxaprozin (4,5‐diphenyl‐2‐oxazolepropionic acid) were examined in subjects after an oral dose of 14C‐Oxaprozin alone as well as before, during, and after long‐term administration of unlabeled drug. A single dose of 14C‐oxaprozin was rapidly absorbed and the unchanged drug was essentially the only labeled substance in plasma. Recovery of radioactivity in excreta, mostly in urine, exceeded 90%. Major biotransformation routes were glucuronidatum of the carboxyl group and hydroxylation of the phenyl rings followed by glucuronidation. Administration of unlabeled Oxaprozin did not affect the absorption, qualitative, or quantitative metabolite profile, or recovery of l4C‐Oxaprozin. Following a single dose, the kinetic parameters for 14C and unchanged drug in plasma were nearly the same. A 2‐compartment model with first‐order elimination adequately describes kinetic disposition. The slow clearance (Clp), 0.08 to 0.12 l/hr, was almost entirely due to biotransformation and the plasma half‐lifes, which ranged from 49 to 69 hr, reflected the small Clp. The small volume of distribution (VDβ= 8 to 9 l) indicates limited extravascular distribution. Multiple doses of unlabeled drug, especially when given concurrently, increased the Clp of 14C‐oxaprozin. This effect is apparently related to decreased binding of high concentrations of Oxaprozin to plasma protein. As a result of increased Clp, steady‐state levels are only 40% of levels predicted from the single‐dose study.

Oxaprozin disposition in renal disease

Effects of renal disease on the disposition kinetics of oxaprozin, a nonsteroidal antiinflammatory analgesic, were assessed in 15 subjects who were normal, renally impaired, or who had been undergoing hemodialysis. Oral dose clearance (Cloral), volume of distribution at steady‐state (Vssd), and elimination half‐life (tl/2) did not substantially differ among the three groups. Mean fraction unbound oxaprozin in plasma (fup) increased from 0.08% in the normal group to 0.18% and 0.28% in the two azotemic groups. Consequently, unbound drug kinetic parameters, including intrinsic clearance (Clint) and Vssdu of unbound drug were reduced from 2.9 l/hr/kg and 193 l/kg in normal subjects to approximately 1.6 l/hr/kg and 91 l/kg in azotemic patients. The smaller volume of distribution is consistent with a decrease in oxaprozin tissue binding in azotemia. The decreased plasma and tissue binding and lower Clint suggest that, in the treatment of azotemic patients with rheumatoid arthritis, the dose of oxaprozin should begin at 600 mg once a day.

Protein binding of oxazepam and its glucuronide conjugates to human albumin

The binding of oxazepam and its glucuronide conjugates to human serum albumin (HSA), as well as the binding interactions of the drug and its metabolites, were examined by equilibrium dialysis and kinetic probe studies. Oxazepam and its S(+) glucuronide are bound to the HSA molecule with affinity constants of 3.5 X 10(5) M-1 and 5.5 X 10(4) M-1, respectively, which were independent of protein concentration over a range of 0.1 to 5.0 g/dl. The R(-) glucuronide bound weakly to albumin, with the binding parameter, N X K, increasing at lower albumin concentrations. Pre-acetylation of fatty acid free-HSA resulted in decreased binding of all three compounds, probably by altering the conformation of the binding sites. Kinetic probe studies with p-nitrophenyl acetate indicate that oxazepam and its S(+) glucuronide shared a common binding site on HSA, but that the R(-) glucuronide bound at another site. Oxazepam binding was unaffected by the presence of its glucuronide conjugates but was inhibited by fatty acids. The percentage of oxazepam bound to plasma proteins in patients with renal impairment (94%) was lower than in normal volunteers (97%). This lower binding can neither be attributed to lower albumin concentrations because of the large binding capacity of the protein and linearity of N X K nor to displacement by elevated concentrations of glucuronide conjugates, but it may be ascribed partly to increased plasma fatty acids.

Disposition of 14C-guanabenz in patients with essential hypertension.

Capsules containing either 16 or 32 mg of 14C‐guanabenz were given to 8 hypertensive patients. Maximum concentrations of guanabenz in plasma (1.2 to 5.2 ng/ml) were reached at 2 to 5 hr after dosing. 14C elimination into urine was 79.7 ± 10.6% (SD) and 76.7 ± 7.4% of the dose after the 16‐ and 32‐mg doses, respectively, while guanabenz accounted for less than 1% after either dose. Kinetic parameters for guanabenz were estimated by fitting the plasma and urinary data to a 2‐compartment model. After the 16‐mg dose, the elimination half‐life (t½) was 14 ± 5 hr, volume of distribution in the central compartment (Vc) was 5.0 ± 2.2 kl, and total plasma clearance (Clp) was 8 ± 4 l/min. After the 32‐mg dose, t½ was 12 ± 3 hr, Vc was 7.5 ± 1.8 kl, and Clp, was 17 ± 6 l/min. No statistically significant difference, except of total plasma clearance, was observed between any of the parameters followed after the 2 doses. (E)‐p‐Hydroxyguanabenz (unconjugated and as a glucuronide) was the major metabolite and accounted for 35.4 ± 3.0% of the urinary radioactivity. Minor amounts of guanabenz and 2,6‐dichlorobenzyl alcohol after β‐glucuronidase hydrolysis indicated that N‐glucuronidation and cleavage at the benzol carbon were minor metabolic pathways. The drug effectively lowered blood pressure in the hypertensive patients; no other significant effects were noted.

The presence of dl -, d - and l- norgestrel and their metabolites in the plasma of women

Abstract Women of childbearing potential were given single 1.5 mg oral doses of 14C- dl -, d - or l -norgestrel (Ng). Blood specimens were obtained at selected time intervals. Drug related entities in plasma were separated and quantitated by Chromatographic and radiochemical procedures. Neutral, glucuronide and sulfate fractions were obtained. The neutral fractions contained the largest percentage of the radioactivity at early time intervals. Of the two conjugate fractions, the sulfate fraction predominated at almost all times. Ng was the major component in plasma. Maximum concentrations of the drug in plasma were reached at two hours and were 14.7, 15.1 and 11.1 ng/ml for dl -, d - and l -Ng, respectively. Ng was still present at 24 hours after administration. Small amounts of a glucuronide and a sulfate of Ng were also observed, with the glucuronide being derived predominantly from the d -enantiomer and the sulfate predominantly from the l enantiomer. d-3α, 5β-Tetrahydronorgestrel and l -16β-hydroxynorgestrel were the major phase I metabolites following d - and l -Ng administration, respectively. Both existed mainly as glucuronide and sulfate conjugates. Following dl -Ng administration, both metabolites were found in measurable amounts. The results of these experiments provide information useful in circumventing problems associated with analytical methodologies — such as radioimmunoassays — which may be of limited specificity.

The conversion of d -norgestrel-3-oxime-17-acetate to d -norgestrel in female rhesus monkeys

Abstract Single intragastric 0.5 mg/kg doses of 14 C- d -norgestrel-3-oxime-17-acetate were given to female rhesus monkeys. Rapid absorption was evidenced by peak concentrations of radioactivity in plasma and whole blood within three hours. A multiphasic decline in concentrations of radioactivity then followed. At three and six hours after drug administration, two major metabolites, d -norgestrel and d -norgestrel-3-oxime, and at least five minor metabolites were detected in plasma fractions containing unconjugated metabolites. These accounted for approximately 40% of the plasma radioactivity. d -Norgestrel was also found in plasma fractions containing conjugated metabolites although the major conjugated biotransformation product was a glucuronide of d -3α,5β-tetrahydronorgestrel, previously shown to be the major metabolite of d-norgestrel in humans and the African green monkey. The presence of d-norgestrel was confirmed by chemical ionization mass spectrometric analysis. No d -norgestrel-17-acetate or d -norgestrel-3-oxime-17-acetate was detected in any plasma specimen. d -Norgestrel-3-oxime-17-acetate thus appears to be a “pro drug” that is rapidly deacetylated to d -norgestrel-3-oxime, which is then hydrolyzed to d -norgestrel. Further metabolism of the d -norgestrel was indicated by comparing the plasma metabolite patterns obtained after administration of either d -norgestrel-3-oxime-17-acetate or d -norgestrel to female rhesus monkeys.

A Specific and Highly Sensitive Method for the Determination of Protriptyline in Body Fluids and Tissues

Abstract Protriptyline, a tricyclic antidepressant, was converted to its heptafluorobutyramide using heptafluorobutyrylimidazole as the acylating agent. Conditions for the gas chromatography of the derivative and its quantitation by an electron capture detector were established. The smallest detectable amount of the protriptyline derivative was 0.05 nanogram. Isolation and purification procedures were devised which permit the determination of the drug in biological materials without interference from reagents, drug metabolites or naturally occurring substances. Protriptyline extracted from plasma, erythrocytes, urine and tissues was determined in concentrations as low as 10 nanograms/ml.