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Biomedical subjects

H Ehrsson

Publications and source records attributed to H Ehrsson.

At least 73 records · Page 4Linked to original sources
PubMed1980

Degradation of chlorambucil in aqueous solution.

The stability of chlorambucil and its degradation product 4-[p-(2-chloroethyl-2-hydroxyethylamino)phenyl]butyric acid (I) was studied using reversed-phase high-pressure liquid chromatography. The degradation rate of chlorambucil was unaffected by pH between pH 5 and 10 but decreased at lower pH. The degradation rates of chlorambucil and I differed only slightly (pH < 6). The proteolytic properties of the compounds were studied using spectrophotometric and partition techniques.

Chemical Phenomena↗
PubMed1979

Liquid chromatographic determination of tetracycline in plasma and urine.

Tetracycline is extracted from plasma (0.50 ml) as an ion pair with tetrabutylammonium into chloroform-1-heptanol (9:1). After re-extraction into an acidic aqueous phase the separation is performed by reversed-phase liquid chromatography using LiChrosorb RP-2 as the support and acetonitrile-water-phosphoric acid as the mobile phase. The chromatographic system shows a high selectivity for the separation of tetracycline analogues. A high detection selectivity is obtained by the use of photometric detection at 357 nm. Analysis of urine is performed by direct injection of the sample into the liquid chromatograph. The precision in the determination of tetracycline in plasma was about 10% (relative standard deviation) at drug levels of 200 ng/ml and 200 microgram. Urine samples containing 20 and 200 microgram/ml of tetracycline were determined with a precision of 3%.

Chromatography, Liquid↗
PubMed1979

Reversed-phase liquid chromatographic determination of plasma levels of adriamycin and adriamycinol.

A method is given for the determination of adriamycin and its main metabolite, adriamycinol in plasma from cancer patients after administration of adriamycin as the free drug or as a complex with DNA. Adriamycin and adriamycinol are extracted in a column from 1 ml of plasma (pH 8.6) using a mixture of chloroform--1-heptanol (8:2). After re-extraction into phosphate buffer pH 2.2, the separation is performed as reversed-phase liquid chromatography on a LiChrosorb RP-2 (5 micron) column with a mobile phase of acetonitrile-water, acidified with phosphoric acid. The precision by quantitation with photometric detection was better than 5% within the range 50-300 ng/ml. Plasma levels of adriamycin and adriamycinol in a cancer patient are presented in this paper.

Chromatography, Liquid↗
PubMed1979

Effect of food on kinetics of 8-methoxsalen.

Kinetics of 8-methoxsalen were studied in 5 healthy subjects under fasting and nonfasting conditions. The plasma concentration-time data could be fitted to a zero order absorption one-compartment model. The area under the curve (AUC) values were higher (p less than 0.05) under nonfasting compared to fasting conditions, indicating higher relative bioavailability of the drug in the presence of food. No significant differences were observed in the lag-time for the start of the absorption, the apparent zero-order absorption rate constant, or the elimination rate constant. It is suggested that the drug should be taken in a standardized way in relation to food during the ultraviolet (UV) light treatment.

Biological Availability↗
PubMed1979

Liquid chromatographic monitoring of daunorubicin and daunorubicinol in plasma from leukemic patients treated with daunorubicin or the daunorubicin-DNA complex.

Fifteen patients with acute nonlymphocytic leukemia have been randomized for treatment with daunorubicin (1.0--1.5 mg/kg) either as the free drug (for 45 min or 4 h) or as the drug bound to a DNA carrier (for 5--6 h). The correlation between plasma kinetics of daunorubicin and its main metabolite daunorubicinol and the different administration schedules of daunorubicin has been studied by reversed-phase liquid chromatography. Plasma concentration kinetics of daunorubicin as well as the daunorubicin-DNA complex was biphasic in character. Maximum plasma level of daunorubicin was found during the infusion period. Its concentration decreased rapidly when the infusion stopped and was below the detection limit of the analytical method 2--4 h later. The data suggests a slower disposition of the duanorubicin-DNA complex compared with the free drug.

Animals↗
PubMed1979

Serum concentration and phototoxic effect of methoxsalen in patients with psoriasis.

The correlation between serum concentration of methoxsalen (8-methoxypsoralen; 8-MOP) and phototoxic effect using long-wave ultraviolet light has been studied in 5 psoriatic patients. The maximum serum concentration occurred between 0.5 and 2 hr after oral administration of 0.6 mg/kg of methoxsalen. The lowest value for the minimum phototoxic dose (MPD), i.e., highest photosensitivity, was obtained between 1 and 2 hr. There was a significant negative correlation between the logarithm of the serum concentration and minimum phototoxic dose (MPD) (r = 0.780). Hence, the degree of photosensitivity appears to be related to the serum level of methoxsalen.

Adult↗
PubMed1978

Liquid chromatographic determination of daunorubicin and daunorubicinol in plasma from leukemic patients.

A method is given for the determination of daunorubicin and its main metabolite, daunorubicinol, in plasma from leukemic patients after administration of daunorubicin as the free drug or as a complex with DNA. Daunorubicin and daunorubicinol are extracted from 2 ml of plasma (pH 8.1) using a mixture of chloroform and 1-heptanol (9:1). After re-extraction into phosphoric acid (0.1 M), the separation is performed as reversed phase liquid chromatography on a LiChrosorb RP-2 (5 micrometer) column with a mobile phase of acetonitrile-water, acidified with phosphoric acid. The precision, by quantitation with a photometric detector, was better than 2% within the range 20 ng/ml to 200 ng/ml. Some determinations of plasma levels of daunorubicin and daunorubicinol are presented.

Chromatography, Gas↗
PubMed1977

Determination of 8-methoxypsoralen in plasma by electron capture gas chromatography.

A method is given for the determination of 8-methoxypsoralen in human plasma at the low ng/ml level using gas chromatography with electron capture detection. 8-Methoxypsoralen was extracted from plasma with methylene chloride at pH 7.0. After addition of the internal standard, 8-butoxypsoralen, the psoralens were hydrolysed in sodium hydroxide and the aqueous phase was purified by extraction with methylene chloride and toluene. The aqueous phase was acidified and the re-lactonized psoralens were extracted with toluene and analysed. Some determinations of plasma levels of 8-methoxypsoralen after oral administration are presented.

Administration, Oral↗
PubMed1975

Determination of sulphonamides by electron-capture gas chromatography. Preparation and properties of perfluoroacyl and pentafluorobenzyl derivatives.

The derivatization of benzenesulphonamide, N-ethylbenzenesulphonamide and N-phenylbenzenesulphonamide with trifluoroacetic and heptafluorobutyric anhydride and pentafluorobenzyl bromide has been studied. A rapid quantitative acylation is obtained in benzene in the presence of trimethylamine. Pentafluorobenzylation is performed by the extractive alkylation technique using tetrabutylammonium as counter ion and methylene chloride as solvent. Less than 20 min are required for a quantitative derivatization. The derivatized sulphonamides have a hydrophobic character, making them very suitable for gas chromatography. Trifluoroacetylation and heptafluorobenzylation decreases it. The derivatives have a high electron-capture detector response (minimum detectable quantity, 1-2 X 10-minus 16 moles/sec). A standard curve is given for the determination of N-phenylbenzenesulphonamide as trifluoroacetyl derivative in the range 1.8-90 ng/ml.

Benzenesulfonates↗