Problems experienced when swallowing solid oral dosage forms in older Japanese patients with dysphagia: A cross-sectional study

AIMS

We aimed to assess the difficulty in taking solid oral dosage forms (SODFs) among older people with dysphagia and clarify the relationship between difficulty in swallowing SODFs and swallowing function.

METHODS AND RESULTS

Outpatients from a dysphagia clinic aged ≥65 years were asked yes-or-no questions about the applicability of eight items regarding difficulty in taking SODFs. Additionally, a videofluorographic swallowing study (VFSS) was performed to assess their swallowing function. The Kruskal-Wallis test and Spearman's rank correlation coefficient were used to analyze the relationship between difficulty in taking SODFs and swallowing function.

RESULTS

Among the 93 participants, the average number of SODFs consumed was 5.8 ± 3.1. In the questionnaire, the average number of "yes" answers was 2.2 ± 2.2, and 65 patients (71.0%) answered "yes" to at least one question. Additionally, no significant relationship was observed between the perceived difficulty in swallowing SODFs and VFSS findings.

CONCLUSION

Approximately 70% of participants reported subjective difficulty in taking SODFs, showing that patients uniformly reported perceived difficulty in taking SODFs regardless of actual swallowing function. The results of this study suggest that patients must be questioned thoroughly about their SODFs use, regardless of the objective severity of their dysphagia.

Animal species difference in the uptake of dimethylarsinous acid (DMA(III)) by red blood cells

The animal species difference in the metabolism of arsenic was studied from the viewpoint of the mechanism underlying its distribution in the form of dimethylated arsenic in red blood cells (RBCs). Dimethylarsinic (DMA(V)) and dimethylarsinous (DMA(III)) acids were incubated with rat, hamster, mouse, and human RBCs, and the uptake rates and chemical forms of arsenic were determined. Although DMA(V) was practically not or taken up slowly by RBCs of all the present animal species, DMA(III) was taken efficiently in the order of rat > hamster > human, RBCs of mice taking it up less efficiently and with a different pattern from the former three animals. Further, although DMA(III) taken up by rat RBCs was retained, that by hamster ones was effluxed in the form of DMA(V). The uptake of DMA(III) and efflux of DMA(V) took place much more slowly in human RBCs than rat and hamster ones. The uptake of DMA(III) by RBCs was inhibited on the oxidation of glutathione with diamide. Incubation of DMA(III), but not of DMA(V), with a hemolysate produced a high molecular weight complex, which increases in the presence of glutathione, suggesting that DMA(III) taken up by RBCs is retained through the formation of a complex with protein(s) specific to animal species, and effluxed from RBCs after being oxidized to DMA(V). These results indicate that DMA is taken up by RBCs in the form of DMA(III), and that the uptake and efflux rates are dependent on the animal species, the effluxed arsenic being DMA(V). The present results suggest that the uptake of DMA by RBCs is an additional contributing factor to the animal species difference in the metabolism of arsenic in addition to the reduction and methylation capacity in the liver.

Exchange of endogenous selenium for dietary selenium as 82Se-enriched selenite in brain, liver, kidneys and testes

Male Wistar rats were fed a diet containing selenium (Se) in the form of 82Se-enriched selenite at the adequate concentration of 0.2 microg Se/g diet, i.e. a Se-deficient diet (<0.03 microg Se/g) fortified with 82Se-enriched selenite, from 5 weeks of age for 20 days, and the systemic disposition of the labelled Se and exchange of endogenous naturally occurring Se for the labelled Se were monitored in four organs. Features characteristic of each organ in terms of Se metabolism were revealed by plotting the disposition of 82Se and exchange of endogenous Se for 82Se against the number of days of feeding 82Se-selenite. Labelled Se amounted to 83.7, 80.8, 73.2 and 41.9% of the total Se in the liver, kidneys, testes and brain, respectively, after feeding 82Se-selenite for 20 days, suggesting that the disposition and exchange were most efficient in the liver but least efficient in the brain. However, when the weight gain of the four organs during the feeding period was taken into consideration, the apparent higher exchange was concluded to be caused by weight gain, i.e., more efficient uptake of the labelled Se by proliferating cells than non-proliferating cells in the liver, kidneys and testes. On the other hand, the uptake and exchange in non-proliferating cells were greater in the brain than in the other organs, especially in the late observation period. The relative metabolic turnover rates of selenoproteins were shown to be easy to determine from the relative exchange rates of endogenous Se for exogenous Se in the distribution profiles of Se obtained by the HPLC-ICP MS method.

[Mesh and glue technique as a new sealing technique for the use of expanded polytetrafluoroethylene dura substitute: the experimental studies of its tolerance for pressure and long-term histological changes]

Expanded polytetrafluoroethylene (ePTFE) as a dural substitute is sometimes associated with leakage of cerebrospinal fluid through the suture line. We have developed a new technique to seal the suture line with an absorbable mesh and fibrin glue. It is named as the mesh-and-glue technique. In this paper, the basic background of the efficacy of this technique was examined using in vitro and in vivo experimental models. The sealing effect was estimated on water leakage through 1 cm of suture line on the ePTFE sutured with 4-0 braided nylon at intervals of 2mm. The burst pressure of the non-sealed, conventional fibrin glue, simple glue spray, mesh-and-glue, and mesh-and-glue combined with spray was 2.8 +/- 0.4, 4.3 +/- 1.2, 64.4 +/- 21.4, 142.7 +/- 22.2 and 406.1 +/- 29.7 cm H2O respectively. It was worth noting that mesh-and-glue combined with the spray method can tolerate even arterial pressure. It was also observed that mesh-and-glue can seal a small dural defect. Long-term pathological changes of the mesh-and-glue was examined in a murine craniotomy model. Implanted mesh and fibrin glue was gradually transformed into a tight connective tissue firmly adhering to the surrounding structure within two months. These experimental results well support the clinical efficacy of the mesh-and-glue technique. This technique can also be applied to seal the arachnoid membrane after spinal surgery or to seal the suture line of arteriotomy in carotid endoarterectomy.

Speciation of metabolites of selenate in rats by HPLC-ICP-MS

The metabolic pathway for and metabolites of selenium (Se) administered intravenously to rats in the form of selenate at a dose of 0.3 mg Se kg-1 body weight were studied by speciating Se in the bloodstream, liver and urine by HPLC-inductively coupled argon plasma mass spectrometry. Selenate was not taken up by red blood cells (RBCs) and disappeared from the bloodstream much faster than selenite, without any change in its chemical form before it disappeared from the plasma. Selenium excreted into the urine after the administration of selenate showed different patterns from those of selenite in both amounts and chemical forms. With the selenate group, the concentration of Se in urine was highest at 0-6 h and the chemical species of Se was selenate at 0-6 h; thereafter a monomethylselenol-related Se compound (MMSe*) and trimethylselenonium ions (TMSe) appeared, selenate not being excreted after 6 h. On the other hand, in the selenite group, the concentration of Se peaked at 6-12 h, and the chemical species of Se were MMSe* and TMSe. Selenate was reduced in vitro on incubation in either a liver homogenate or supernatant fraction, although much more slowly than in the whole body. Selenate was not reduced by glutathione or dithiothreitol. The results suggest that in contrast to selenite, which is taken up by and reduced in RBCs, and then transferred to the liver, approximately 20% of the selenate administered to rats was excreted into the urine without any change in its chemical form with the present dose, and the major portion of selenate was taken up by the liver, reduced and then utilized for the synthesis of selenoproteins or excreted into the urine after being methylated.

Copper increases in both plasma and red blood cells at the onset of acute hepatitis in LEC rats

Ceruloplasmin is excreted mostly in the apo-form in Wilson's disease patients and Long-Evans rats with a cinnamon-like coat color (LEC rats), an animal model for Wilson's disease, and hence the concentration of Cu in the plasma is low. However, it increases toward and at the onset of acute hepatitis in LEC rats, the increased Cu in the plasma being bound to ceruloplasmin, metallothionein and albumin. Changes in the concentration of Cu in red blood cells (RBCs) were monitored with age for the first time together with that in the plasma in LEC rats. Cu in the RBCs was found to increase to a 5-7 times higher level than that in the plasma toward the onset and peaked at the onset, the pattern being similar to that in the plasma. The source of the Cu increase in the RBCs was discussed, and it was assumed that the so-called free Cu ions that leak from the damaged hepatocytes are bound to albumin and/or taken up by the RBCs.

Effects of dietary selenium species on Se concentrations in hair, blood, and urine

The effects of the chemical species and concentration of selenium (Se) in diets on the concentrations of Se in hair, blood serum, red blood cells (RBCs), and urine were studied to gain an insight into the toxicological and nutritional significance of different chemical forms of Se. Male Wistar rats were fed an Se-deficient diet (Se, less than 0.03 microgram/g) for 3 weeks, and then an Se-adequate (Se, 0.2 microgram/g) or Se-excess diet (Se, 2.0 micrograms/g), including seleno-L-methionine (SeMet) or selenite for up to 12 weeks. Hair, blood, and urine specimens were obtained every two weeks, and the concentrations of Se and its distribution in serum and urine on a size-exclusion column were determined. The concentrations of Se in hair, serum, and urine attained constant levels 2 weeks after a change of in the dietary Se concentration irrespective of the chemical species, the levels being dependent on the chemical species and the concentration. Specifically, in hair and serum, selenite gave the lowest constant levels irrespective of the dose, while SeMet resulted in higher levels than selenite in a dose-dependent manner. The two major selenoproteins in serum exhibited comparable concentrations. On the other hand, in urine, the concentration of Se was dependent on the dose but not on the chemical species. The results could be explained by regulated metabolism of selenite, and both nonregulated and regulated aspects of the metabolism of SeMet.

Binding of selenium (administered as selenite) to albumin after efflux from red blood cells

The role of albumin in the metabolism of inorganic selenium (Se) was studied in vivo and in vitro using a HPLC-ICP-MS method. Although Se injected in the form of selenite binds selectively to albumin after being reduced to selenide and then being effluxed into the plasma, Se was shown to be metabolized normally in the absence of albumin. The reduced form of Se, selenide, bound selectively to albumin but only to a percentage of it. The thiol group and the intermolecular disulfide group at the 34th cysteinyl residue of albumin were not responsible for the selective binding of Se to albumin. Selenide was suggested to be bound to a disulfide not a thiol group, i.e., to one of the 17 disulfide bonds in a conformationally different isoform of albumin.

Selective uptake of selenite by red blood cells

Both organic and inorganic forms of selenium (Se) can be utilized in the body, and the biotransformation of selenite into an organic form of Se in the bloodstream is the first step for the utilization of inorganic Se. Selenite injected intravenously into rats was shown to be taken up rapidly and selectively by red blood cells (RBCs) through the anion-exchange carrier. The uptake of selenite by RBCs was inhibited by 4,4'-diisothiocyano-2,2'-stilbene disulfonate, a specific inhibitor of the anion-exchange carrier (band 3 protein). The uptake was also inhibited by chromate owing to the glutathione deprivation in RBCs, which was confirmed by the inhibition by azodicarboxylic acid bis(dimethylamide). The presence of hydrogencarbonate in the incubation solution slightly retarded the uptake of selenite by RBCs. Although Se effluxed into the plasma was bound selectively to albumin, plasma proteins (albumin) did not accelerate the uptake process. Based on these results, the rapid and selective uptake of selenite by RBCs was explained by the selective and efficient uptake through the anion-exchange carrier, followed by reduction by glutathione.

Effect of ecdysterone on histamine release from rat peritoneal mast cells

Ecdysterone dose-dependently inhibited anti-IgE-induced histamine release from mast cells. Moreover, the rate and extent of histamine release from mast cells induced by Concanavalin A (Con A) are significantly diminished in samples incubated with ecdysterone. Ecdysterone inhibited both the initial and gradual rise in fluorescent response by anti-IgE and Con A. The effects of ecdysterone on the fluorescence response was correlated with the inhibition of histamine release. These results suggest the possibility that the inhibition of histamine release from rat mast cells by ecdysterone might be due to inhibition of Ca2+ mobilization from intracellular Ca2+ storage.

Actinoplanones C, D, E, F and G, new cytotoxic polycyclic xanthones from Actinoplanes sp

Our previous finding of strong cytotoxic polycyclic xanthones, actinoplanones A (1) and B (2), in the culture broth of Actinoplanes sp. R-304 stimulated us to isolate further five new cytotoxic polycyclic xanthones which were named actinoplanones C (3), D (4), E (5), F (6) and G (7) from the broth. Actinoplanones C (3) and G (7) showed very strong cytotoxicity against HeLa cells at less than 0.00004 microgram/ml dosage (IC50). The structures of 3-7 were varieties of 1 for the N-2 and C-4 substituents. All or several actinoplanones showed strong antimicrobial activities against bacteria and the rice blast fungus. Actinoplanone A (1) was tested for cytotoxicity against various tumor cells and for inhibitory effect on HeLa cell macromolecular synthesis, and 1 exhibited strong cytotoxicity against the cells and inhibitory action on DNA synthesis.

Actinoplanones A and B, new cytotoxic polycyclic xanthones from Actinoplanes sp

Two new cytotoxic polycyclic xanthones, actinoplanones A (1) and B (2) were isolated from the culture broth of Actinoplanes sp. R-304 by monitoring their bioactivity against HeLa cells. Compound 1 was extremely cytotoxic (IC50 0.00004 micrograms/ml) against HeLa cells. The structures of 1 and 2 were established mainly by analyses of 2D heteronuclear correlation NMR experiments. The absolute configurations of the asymmetric carbons of the compounds have been assigned to be 9R, 24S, 25R and 27S by circular dichroism spectra and NMR analysis using chiral derivatives (esters of alpha-methoxy-alpha-(trifluoromethyl)acetic acid).

The development of a radioimmunoassay for formoterol

The development of a radioimmunoassay (RIA) for the beta 2-stimulant formoterol is described. The sensitivity of the method is 0.1 ng/ml in plasma and urine, when a 1-ml sample is used. The cross-reactivity of the antiserum with formoterol glucuronide was 30%. Since formoterol is metabolized extensively to formoterol glucuronide in rats, dogs and humans, extraction with ethyl ether prior to the radioimmunoassay was carried out. Satisfactory agreement was obtained for levels of formoterol in plasma and urine when they were determined by RIA and gas chromatography-mass spectrometry. The concentration of formoterol was determined in dog plasma and human urine after oral administration of formoterol fumarate to dogs (61 mcg/kg) and humans (40 mcg).

[6-week intravenous toxicity test of cefpiramide in rhesus monkeys]

A subchronic toxicity of cefpiramide (CPM) was studied in rhesus monkeys. The drug was administered intravenously to 4 groups of 2 males and 2 females each at a daily dose of 0, 100, 300 mg/kg and 1,000 mg/kg, respectively, for 6 weeks. Vomiting and diarrhea were observed at every dose of CPM, more frequently at the beginning of the treatment period. In addition, salivation was observed at 300 mg/kg or more and a transient subdued mood and inappetence at 1,000 mg/kg. A slight decrease of body weight was noted in a female given 1,000 mg/kg. There were no treatment-related changes in fecal occult blood test and electrocardiograms. Ophthalmological examinations showed no abnormalities being attributable to the treatment. A transient or slight anemia was observed in 2 monkeys receiving 1,000 mg/kg. Examination of bone marrow revealed no abnormalities. There were no effects on plasma biochemical parameters. In urinalysis, a female in the 1,000 mg/kg group showed a glycosuria. Kidneys of 3 animals given 1,000 mg/kg were pale at necropsy. Liver and kidneys were heavier in some animals at 300 mg/kg or more and at 1,000 mg/kg, respectively. Histological examination revealed a multifocal degeneration and regeneration of the proximal renal tubular epithelium in all animals receiving 1,000 mg/kg. No treatment-related changes were encountered in other organs and tissues. From these results, the maximum non-effective dose level of CPM was considered to be 300 mg/kg.

[26-week intravenous toxicity test of cefpiramide in cynomolgus monkeys]

A chronic toxicity of cefpiramide (CPM) was studied in Cynomolgus monkeys. Groups of 4 males and 4 females were given daily doses of 100, 300 mg/kg or 600 mg/kg by intravenous administration for 26 weeks. Another group of 4 males and 4 females was given physiological saline and served as the control. In CPM groups, diarrhea or soft feces was observed after the commencement of administration at every doses. The frequency of these signs decreased as the study progressed and animals at lower doses returned to normal earlier. There were no treatment-related changes in body weights, fecal occult blood and electrocardiograms. A female in the 600 mg/kg group died after 13 weeks of treatment. The cause of death was assumed to be an acute myocardial necrosis resulting from thromboarteritis. It was not considered to be treatment-related. Ophthalmological examination revealed no abnormalities attributable to the treatment. Erythrocyte counts, hemoglobin and hematocrit values decreased in 3 animals receiving 600 mg/kg of the drug. The changes, however, were transient at least in 2 of these animals. There were no effects on plasma biochemical and urinalysis parameters. Small yellow spotes were noted in the renal cortex of 2 monkeys in the 600 mg/kg group at necropsy. Liver and kidneys were slightly heavier in animals receiving 600 mg/kg. Histopathological examinations revealed focal nonsuppurative interstitial nephritis in 1 animal given 300 mg/kg and 5 animals given 600 mg/kg. No treatment-related changes were observed in other organs and tissues. From these results, the maximum non-effective dose level of CPM was considered to be 100 mg/kg.

Animal pharmacokinetics and toxicology of cefotetan--a new cephamycin antibiotic

In animal pharmacokinetic studies the biological half-lives of cefotetan were 13.0 min in mice, 15.9 min in rats, 30.5 min in rabbits, 55.5 min in dogs and 77.9 min in rhesus monkeys. The acute intravenous LD50 values (g/kg) were 6.4 and 5.0 in male and female mice, respectively, and 8.5 and 6.8 in male and female rats, respectively. Six-month repeated dose studies of 30 to 1000 mg/kg per day intraperitoneally in rats and 100 to 600 mg/kg per day intravenously in rhesus monkeys showed no notable organ toxicity. A teratogenicity study in rats indicated that cefotetan had no adverse effects on fetal and postnatal development. The nephrotoxicity of cefotetan in rabbits was considerably less than that of cefazolin.

Disposition and metabolism of formoterol fumarate, a new bronchodilator, in rats and dogs

1. The disposition and metabolism of formoterol fumarate, a highly potent beta 2-adrenoceptor stimulant, were studied in rats and dogs. 2. After oral administration of [3H] formoterol fumarate to dogs, unchanged formoterol accounted for greater than 60% of the plasma radioactivity immediately after dosage; greater than 20% was due to the unchanged drug until 12 h after dosage. In contrast, only 1-3% of the radioactivity was present as unchanged drug in rat plasma. After i.v. dosage, unchanged drug was much higher in both species. The elimination half-life of formoterol was 4-6 h in dogs and 1.7 h in rats. 3. In both species, 36-45% of the dose was excreted in urine and 50-56% in faeces in 72 h, irrespective of the administration route. Biliary excretion after oral dosage amounted to 65 and 31% in rats and dogs, respectively. 4. T.l.c. before and after enzymic hydrolysis revealed that the drug was excreted in urine and bile of rats mostly as a conjugate. Dog urine also contained the conjugate but the unchanged drug was much higher than in rats. The conjugated metabolite was purified from rat urine and identified as the 2-O-glucuronide. The glucuronide was the only metabolite detected in the urine and bile of rats and in the urine of dogs.

Quantitative determination of the beta-adrenoceptor stimulant formoterol in urine by gas chromatography mass spectrometry

A method for the quantitative determination of the beta-stimulant formoterol in urine, using a gas chromatograph--mass spectrometer, is described. Formoterol can be analyzed after the addition of a deuterium-labelled internal standard and conversion to a mixed bis-pentafluoropropionyl-methyl derivative for selected ion monitoring. The detection limit was 5 ng/ml. Urinalysis after the oral administration of formoterol fumarate, using a combined enzymic hydrolysis method, revealed that the drug was conjugated with glucuronic acid in rats, dogs and humans.

Metabolic fate of nicardipine hydrochloride, a new vasodilator, by various species in vitro

1. The metabolic fate of nicarpidine hydrochloride by rats, dogs and monkeys in vitro has been compared with previously reported in vivo studies. 2. The rate of metabolism of the drug in rat liver was 1.76 mumol/g tissue per 20 min, while the values in the intestine, kidney, lung and blood were less than 0.1 mumol/g tissue per 20 min, suggesting that the first-pass effect observed in vivo was due mainly to metabolism of the drug in the liver. 3. The rates of liver metabolism were 1.76, 0.45 and 0.55 mumol/g tissue per 20 min in rats, dogs and monkeys, respectively. This species difference correlates well with the differences in plasma clearance values, which were 197, 37 and 27 ml/min per kg in rats, dogs and monkeys, respectively, after i.v. administration of nicardipine hydrochloride (0.4 mg/kg). 4. Urinary metabolites were qualitatively similar, but the proportions of each were slightly different, among rats, dogs, monkeys and humans. The most abundant urinary metabolite was derived from debenzylation of the N-benzyl-N-methylaminoethyl ester side-chain in dogs and humans, and from hydrolysis of the same side-chain to the carboxylic acid, together with oxidation of the dihydropyridine nucleus to pyridine, in rats and monkeys. The metabolites produced in vitro were also qualitatively similar in the animal species examined. 5. More than 90% of the drug was reversibly bound to the plasma protein at 0.1 microgram/ml in the three animal species and humans. The extent of binding decreased with increased drug concentration in rats and humans, but not in dog and monkeys.

Application of the stable isotope technique to the elucidation of the saturation phenomenon of nicardipine hydrochloride metabolizing enzyme activity in dogs

The pharmacokinetics of 2-(N-benzyl-N-methylamino)ethyl methyl 2,6-dimethyl 4-(m-nitrophenyl)-1, 4-dihydropyridine-3, 5-dicarboxylate hydrochloride (nicardipine hydrochloride) was studied in dogs by using two deuterium labelled compounds (N-[2H3]methyl and N-[2H7]benzyl derivatives). The biological isotope effect of the [2H7]derivative, which was calculated from the half-lives in vivo and the metabolic rates in vitro, was 1.37 and 1.36, respectively, suggesting that debenzylation in the liver was one of the rate limiting steps of elimination of the drug, while the [2H3] derivative did not show this effect. The [2H3] derivative was administered orally or intravenously to dogs 2 h after oral administration of the non-labelled compound, and the plasma concentration of the [2H3] derivative was determined by the selected ion monitoring method. The biological half-lives, AUC and systemic availability increased with increasing doses of non-labelled nicardipine hydrochloride, while plasma clearance decreased, suggesting that the hepatic enzyme activity metabolizing the drug was partly saturated by the drug or its metabolites.

Comparative pharmacokinetics of nicardipine hydrochloride, a new vasodilator, in various species

1. The pharmacokinetics of a new potent vasodilator, 2-(N-benzyl-N-methylamino)-ethyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride (nicardipine hydrochloride), were studied after oral and i.v. dosage to rats, dogs, monkeys and humans. 2. The plasma half-life and volume of distribution in humans after i.v. administration did not change with dosage in clinical range. In rats and dogs these parameters increased with higher doses, probably because of the potent vasodilative effect of the drug. 3. The plasma clearance in dogs and humans was not affected by dosage, but in rats tended to increase slightly with higher doses. 4. Systemic availability after oral administration was low in spite of excellent absorption, indicating a marked first-pass effect. Increased systemic availability with increased dose indicates that the metabolic activity of the liver may become partly saturated with the drug or its metabolites. 5. Disappearance of the drug from the plasma after i.v. administration was fastest in rats > dogs approximately monkeys > humans. The terminal half-life of the drug after i.v. administration to humans was about 1 h.

Simplified determination of lorazepam and oxazepam in biological fluids by gas chromatography-mass spectrometry

Lorazepam and oxazepam in plasma and urine were measured by gas chromatography-mass spectrometry. Oxazepam was used as an internal standard in the assay of lorazepam and vice versa. After removal of interfering substances with n-hexane, the drugs were extracted with benzene and converted to N1,O3-bistrimethylsilyl derivatives. Glucuronide forms of the drugs were extracted after hydrolysis with beta-glucuronidase. A common fragment ion at m/e 429 was used to monitor the two drugs. The sensitivity was 2 ng/ml for both drugs, which was sufficient to determine plasma and urine concentrations after therapeutic doses to humans.

Simultaneous determination of griseofulvin and 6-desmethylgriseofulvin in plasma by electron-capture gas chromatography

Two methods have been developed for the simultaneous determination of griseofulvin and its major metabolite 6-desmethylgriseofulvin in plasma using electron-capture gas chromatography. The first method was based on the quantitative reversion of the 6-desmethyl metabolite to griseofulvin by diazomethane. Plasma extract was chromatographed both before and after treatment with diazomethane, the former being the measure of griseofulvin and the latter representing the sum of the two compounds. In the second method, plasma extract was treated with diazobutane and griseofulvin and the butylated metabolite were separated by gas chromatography. The sensitivity for griseofulvin was 20 ng/ml by both methods and that for the metabolite was 20 ng/ml and 40 ng/ml by the first and the second method, respectively. The concentrations of the metabolite as well as griseofulvin were determined in dog and human plasma after oral administration of griseofulvin.

Quantitative determination of nifedipine in human plasma by selected ion monitoring

A highly sensitive and specific method for the determination of nifedipine in plasma is described. Nifedipine was oxidized to its pyridine analogue with nitrous acid and determined by selected ion monitoring. Deuterium labeled nifedipine was used as an internal standard. Plasma levels as low as 5 ng ml-1 were measured. The usefulness of the method was demonstrated by obtaining plasma concentration curves for humans after an oral dose of 10 mg.

The effect of carboxyl substituent on the metabolism of aromatic aldehydes

1. The effect of a carboxyl substituent on the metabolism of aromatic aldehydes has been examined in several species of animals. 2. Phthalaldehydic acid was exclusively reduced to the corresponding alcohol in mice, rats, rabbits, dogs and man. The oxidized metabolite phthalic acid was not detected appreciably in any species. 3. Iso- and terephthalaldehydic acid were oxidized to the corresponding dicarboxylic acids in rats and dogs. The reduced metabolites were not detected. 4. The aldehyde group of o-formylphenoxyacetic acid and o-formylphenoxypropionic acid was largely reduced to the corresponding alcohol in rats, rabbits and dogs. In contrast, oxidation to the carboxylic acid predominant over the reduction in mice. In the former three species, the amount of the minor metabolite carboxylic acid was larger with o-formylphenoxypropionic acid than with o-formylphenoxyacetic acid. 5. 1,8-Naphthaldehydic acid, m- and p-formylphenoxyacetic acid were mainly oxidized to the corresponding carboxylic acids in rats. 6. It was concluded that aromatic aldehydes bearing a carboxyl group in the ortho position, attached either directly or indirectly to the benzene nucleus, tend to be reduced to the corresponding alcohols in animals.

Absorption, excretion and metabolism of a new dihydropyridine diester cerebral vasodilator in rats and dogs

1. After oral administration of [14C]dihydropyridine diester, the plasma concn. of radioactivity was similar in rats and dogs, reaching a maximum at 0-5 to 1 h and decreasing with a half life of about 3-5 h. The plasma concn. of unmetabolized drug in dogs was 10 times higher than in rats. Radioactivity in rat tissue was high in liver, kidney and lung after both oral and intravenous administration. 2. In both species, 66-72% of radioactivity was excreted in faeces and 23-29% in urine in 48 h, regardless of the route of administration. Biliary excretion in rats after oral dosage amounted to 65%. 3. Eight metabolites were identified from urine of dogs and rats. They were derived from one or several of the following pathways: I, debenzylation of the N-benzyl-N-methylaminoethyl side chain; II, reduction of the 3-nitro group on the phenyl substituent; III, oxidation of the 1,4-dihydropyridine ring to the corresponding pyridine; IV, oxidative removal of the N-benzyl-N-methylamino group yielding a carboxylic acid; V, hydrolysis of the N-benzyl-N-methylamino-ethyl ester to the corresponding carboxylic acid; VI, hydroxylation of the 2-methyl group of the 1,4-dihydropyridine ring to hydroxymethyl.

Synthesis of DL- and D-gluco-hept-3-ulose

DL-gluco-Hept-3-ulose was synthesised by oxidation of tri-O-isopropylidene-meso-glycero-gulo-heptitol with methyl sulphoxide-phosphorus pentaoxide, and subsequent hydrolysis. D-gluco-Hept-3-ulose (3) was synthesised by oxidation of one of the two isopropylidene derivatives from perseitol (D-glycero-D-galacto-heptitol), which is presumed to have the 2,2:4,5:6,7 structure, followed by hydrolysis. The crude product from the reduction of DL-gluco-hept-3-ulose with sodium borohydride showed two peaks corresponding to meso-glycero-gulo-heptitol and perseitol on g.l.c. of the trimethylsilyl derivatives. Isolation and acetylation of the latter heptitol revealed it to be racemic perseitol. Oxodation of DL-gluco-hept-3-ulose with oxygen in alkali followed by treatment with ferric acetate-hydrogen peroxide gave products with chromatographic behaviour characteristic of arabinonolactone and erythrose. Treatment of DL-gluco-hept-3-ulose with 2,4-dinitrophenylhydrazine gave a 1-deoxy-2,4-dinitrophenylosazone.