PubMed Health⌕ Search

Biomedical subjects

P J Morrison

Publications and source records attributed to P J Morrison.

125 records · Page 7Linked to original sources
PubMed1979

Plasma cinnarizine levels resulting from oral administration as capsule or tablet formulation investigated by gas-liquid chromatography.

1 A gas chromatographic assay for the estimation of therapeutic concentrations of cinnarizine in plasma is described. 2 Cinnarizine (75 mg) was administered orally to twelve healthy subjects in the form of capsules and tablets on two separate occasions. No difference was found in the plasma levels or absorption of cinnarizine from these formulations. 3 The mean plasma elimination half-life of cinnarizine was 3.24 h.

Administration, Oral↗
PubMed1978

Comparison of the effect of drugs upon some commonly used measures of bowel transit time.

1 To study the effect of drugs on methods of assessment of gut transit time a double-blind study of the effect of single doses of placebo, oxyphenisatin, anthracene purgatives, (+)-norpseudoephedrine and a combined preparation of (+)-norpseudophedrine and senna was carried out in ten normal volunteers. Gut transit time was assessed by dye and radio-opaque marker methods. 2 It was possible to demonstrate the effect of the anthracenes but not oxyphenisatin on gut transit time. 3 More sophisticated statistical techniques were required to demonstrate the retarding effect of the sympathomimetic amine and its reversal by senna. 4 Statistical analysis shows that assessment of intestinal transit time by dye or pellet methods gives identical information.

Adult↗
PubMed1977

Plasma prednisolone levels from enteric and non-enteric coated tablets estimated by an original technique.

1 A quantitative thin layer chromatographic technique for the estimation of plasma prednisolone levels has been devised with a minimum level of estimation of 10 ng/ml. 2 A comparative study of the absorption of 5 and 10 mg prednisolone from enteric and non-enteric coated tablets (5 mg) was carried out in healthy subjects. 3 Mean plasma half-life and peak plasma concentrations obtained from the non-enteric coated preparation agree well with previous studies in normal subjects reported by other investigators using competitive protein binding or radioimmunoassay techniques. Intersubject variability in bioavailability was noted. 4 Enteric coating increased the lag time before prednisolone appeared in the blood but did not alter the bioavailability of prednisolone compared to the equivalent dose of the non-enteric coated tablet.

Adult↗
PubMed1975

Electron paramagnetic resonance spectra of catalase in mammalian tissues.

The relatively small number of paramagnetic species and the high concentration of catalase in mammalian liver and blood make it possible to directly study this enzyme in frozen whole tissue. The EPR spectra of catalase are dependent on the heme environment and in human blood only catalase A, gxy = 6.48, 5.36 is observed whereas in liver a second spectrum, catalase B, gxy = 6.80, 5.07 can also be seen. Using rapid freeze techniques it has been shown that in rat liver catalase A corresponds to the in vivo steady state and that after death this is largely converted into catalase B. Data from the perfusion of rat livers with oxygenated and deoxygenated blood and dextran solutions together with results from in vitro studies of catalase are interpreted as indicating that catalase B results from the interaction of catalase with an organic acid, most probably formic acid, that the acid is a peroxidative substrate for catalase in vivo and that peroxidation of the acid is not the major role for catalase in rat liver. Catalase binding with other small molecules in intact liver has been demonstrated by perfusion with nitrite-containing dextrans and by intraperitoneal injection of 3-amino-1,2,4-triazole.

Amitrole↗
PubMed1975

Effects of acute and chronic stress on plasma corticosterone levels in the pregnant and non-pregnant mouse.

Plasma corticosterone levels were measured in the pregnant and non-pregnant mouse after acute and chronic stress. Acute surgical stress in the non-pregnant mouse increased plasma corticosterone from a mean resting level of 2-3 to 50-6 mug/100 ml 1 h after operation. By 24 h after operation, levels had fallen back to 7-6 mug/100 ml. In the pregnant mouse an acute surgical stress on day 14 or pregnancy increased plasma corticosterone levels to 525 mug/100 ml 1 h after surgery from a resting value of 80 mug/100 ml, with a return to resting levels by 24 h. During the chronic stress of 24 h restraint, plasma corticosterone levels in the non-pregnant mouse reached a peak (81-0 mug/100ml) 1 h after the start of restrain and were still raised (mean 24-0 mug/100 ml) after 24 h. In the pregnant restrained mouse a peak value of 733 mug/100 ml was seen at 1 h, with levels maintained at around 500-600 mug/100 ml during the next 16 h of restraint. Increased levels of 268 mug/100 ml were still present at 24 h. After the chronic stress of 24 h food deprivation, plasma corticosterone levels in the non-pregnant and pregnant mice were raised after 7 h to levels slightly lower than those observed in the restrained groups, and at 24 h levels in the respective restrained and food-deprived groups were similar, suggesting that food deprivation is a powerful chronic stressor in the mouse. During chronic stress in the pregnant mouse where plasma corticosterone levels of around 600 mug/100 ml were maintained fro some hours, protein binding studies indicated that 10 mug/100 ml was free, unbound corticosterone. The physiological and pathological consequences of such high levels of free corticosterone during stress in pregnancy are discussed.

Animals↗
PubMedDate not supplied

Bioavailability of phenylbutazone from a new enteric-coated formulation with superior dissolution characteristics.

The bioavailability of an improved formulation of enteric-coated phenylbutazone with faster dissolution, more consistent in vitro rate of drug release and improved stability was compared in 8 normal subjects at doses of 100 and 200 mg with commercially available Butacote. Phenylbutazone was more rapidly absorbed from the new formulation and higher plasma concentrations were achieved at shorter intervals after dosing. Drug elimination rate was unaffected by reformulation and despite faster absorption the total amounts of drug reaching the circulation from the new and commercial products were similar. It was concluded that replacing Butacote by the new formulation would provide the same therapeutic benefit.

Adult↗