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Biomedical subjects

I Wallin

Publications and source records attributed to I Wallin.

32 records · Page 2Linked to original sources
PubMed1988

Concentration of trimethylpsoralen in blood and skin after oral administration.

Trimethylpsoralen (TMP) concentrations were determined in blood and skin of 21 patients given oral TMP therapy and were compared to data obtained from 5 patients treated with TMP baths. The quantitative determination was performed by gas chromatography with selected ion monitoring. Concentrations of up to 5.6 ng/ml were detected in whole blood from orally TMP treated patients, with about the same concentrations in patients given TMP baths. Whole skin biopsies from patients ingesting TMP showed concentrations in 14 patients that ranged from 30 to 1250 ng/g skin, median value 85 ng/g. Large interindividual variations were observed. Stripped skin from 5 patients after TMP baths showed a somewhat higher median value of 160 ng/g and their entire skin had fairly high concentrations, with a median value of 390 ng/g, probably mostly bound to stratum corneum. Different concentrations in different parts of the skin may explain the difference in phototoxic capacity when the drug is given locally.

Administration, Oral↗
PubMed1984

Effect of food on pharmacokinetics of chlorambucil and its main metabolite, phenylacetic acid mustard.

The influence of food intake on the pharmacokinetics of chlorambucil (C) and its cytotoxic metabolite, phenylacetic acid mustard (PAM), has been studied in man after oral doses of chlorambucil. The administration of chlorambucil with food resulted in slower absorption than when fasting. However, the area under the plasma concentration-time curve (AUC) was unaffected. The mean ratio AUCPAM/AUCC was 2.8 (range 1.4-7.1) under fasting and 3.3 (range 1.3-7.4) under nonfasting conditions. The metabolite very probably plays an important role in the cytotoxic effects observed after administration of C, since calculations show that a major fraction of the metabolite is eliminated by alkylation reactions.

Adult↗
PubMed1983

Pharmacokinetics of chlorambucil in man after administration of the free drug and its prednisolone ester (prednimustine, Leo 1031).

The pharmacokinetics of chlorambucil has been investigated in a cross over study after oral administration of the free drug (10 mg) and its prednisolone ester (prednimustine, 100 mg). The bioavailability of chlorambucil was about five times lower when given as prednimustine as compared to administration of the free drug. The peak plasma concentration was about twice as high and it was obtained more rapidly when the free drug was given. No intact prednimustine could be detected in plasma.

Aged↗
PubMed1980

Determination of chlorambucil in plasma by GLC with selected-ion monitoring.

A GLC technique with selected-ion monitoring is described for chlorambucil determination in plasma using [2H]chlorambucil as the internal standard. Chlorambucil is extracted from plasma with methylene chloride at pH 3 and converted to a thiazane derivative by reaction with 0.1 M sodium sulfide at 80 degrees. The carboxylic group of the chlorambucil derivative is derivatized with allyl bromide using extractive alkylation. Analysis by selected-ion monitoring was performed by focusing at m/e 305 (M) and 313. The relative standard deviation was +/- 5% (n = 5) at the 10-ng/ml level.

Alkylation↗
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

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

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↗
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↗
PubMed1976

Plasma concentrations of griseofulvin in healthy volunteers and out-patients treated for onychomycosis.

Therapeutic failure of griseofulvin therapy are fairly common, espcially when toe nail infections are treated. The reasons for the failures remain largely unknown. The aim of the present investigation was to study whether pharmacokinetic factors may be responsible. At first, single-dose and steady-state pharmacokinetics of griseofulvin were analysed in volunteers by means of a gas-chromatographic technique. It was found that there was no difference in plasma levels of the three brands of griseofulvin commercially available in Sweden, whereas there was a singificant difference of absorption between individuals. The plasma half-life varied considerably from day to day in the same individual. In the second part of the investigation griseofulvin plasma concentrations were determined in 27 patients treated with griseofulvin for onychomycosis and related to the therapeutic result. All patients but one were initially improved but the therapeutic effect faded in 15 patients after 5-20 months of treatment ("partially healed" patients). In 11 patients the nail infections were clinically healed after 6-24 months. However, no statistically significant difference of the plasma griseofilvin levels could be demonstrated between the healed and partially healed groups. Some possible reasons for the therapeutic failure are discussed.

Adolescent↗
PubMedDate not supplied

Pharmacokinetic and metabolic studies of busulfan in rat plasma and brain.

Busulfan kinetics were studied in the rat plasma and brain after an I.P. dose of 14C-busulfan or busulfan (15 mg/kg). The distribution of busulfan to the brain was rapid and the ratio brain/plasma concentration was 0.74 during the time-course of busulfan. The elimination half-lives in plasma and brain were 3h for intact busulfan and 8h for the 14C-radioactivity. The radioactivity remaining in plasma and brain after 24h was mostly busulfan metabolites e.g. sulfolane, 3-hydroxysulfolane and tetrahydrothiophene-1-oxide as identified by gas chromatography-mass spectrometry. The protein binding to rat plasma was low (9.2 +/- 4.4%).

Animals↗