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Biomedical subjects

R T Calvert

Publications and source records attributed to R T Calvert.

10 recordsLinked to original sources
PubMed1979

The disposition of cyclophosphamide in a group of myeloma patients.

The disposition of cyclophosphamide and its alkylating metabolites was investigated in a group of myeloma patients with varying degrees of renal function impairment. No correlation between renal function and clearance of cyclophosphamide or its alkylating metabolites was found. No evidence of accumulation of cyclophosphamide or alkylating activity was found in four patients receiving radiolabelled cyclophosphamide. Renal function was found to be related to the reciprocal of the area under curve of alkylating activity, indicating that this area increased as renal function decreased. In view of the large nonrenal component of alkylating activity elimination and the large inter-subject variability, it is recommended that dose of cyclophosphamide is not altered in moderate impairment of renal function.

Alkylating Agents↗
PubMed1978

Bilirubin dynamics in the Gunn rat during phototherapy.

Bilirubin dynamics were studied in homozygous Gunn rats under normal room lighting conditions and under conditions simulating phototherapy. A kinetic model was developed for the formation, distribution, and elimination of bilirubin. The decrease in plasma bilirubin concentration during illumination with low intensity [300 footcandles (fc)] and high intensity (1000-1100 fc) light was studied. The plasma bilirubin concentration in the rats decreased under phototherapy until a new steady-state concentration was reached, the decline being more rapid under high intensity light conditions. Gunn rats were also injected with a tracer dose of 14C-bilirubin following a period during which the rats were illuminated with low or high intensity light. The distribution and elimination of the labeled bilirubin were followed under continuous illumination. The chosen kinetic model, when adapted to the set of data under investigation, fit all of the data concerning bilirubin kinetics in Gunn rats under continuous illumination.

Animals↗
PubMed1978

Bioavailability of griseofulvin from a novel capsule formulation.

The in vivo availability of griseofulvin from a novel formulation has been compared with the micronized powder. The formulation technique involves the conversion of the hydrophobic surface of the drug to a hydrophilic one by treatment with a film forming polymer. This enhances the wettability of the power, and increases its dissolution rate. The results of the in vivo study show the formulation technique has increased the rate and extent of bioavailability of griseofulvin when compared with the non-treated powder.

Biological Availability↗
PubMed1977

The effect of diphenhydramine alone and in combination with ethanol on histamine skin response and mental performance.

The effects of diphenhydramine and diphenhydramine plus ethanol on response to intradermal histamine and on mental performance were assessed in twelve male volunteers. A significant impairment of histamine skin response was found with diphenhydramine. This response was unaffected by ethanol. Ethanol improved performance with a tracking test compared with diphenhydramine alone, the effect was not potentiated by the combination. None of the treatments had a significant effect on a digit symbol substitution test. Co-administration of ethanol and diphenhydramine caused greater impairment of performance in a serial seven subtraction test than diphenhydramine alone. There was no correlation between central and peripheral effects of the antihistamine.

Adult↗
PubMed1977

Stability of phenylbutazone in presence of pharmaceutical colors.

The degradation of phenylbutazone was studied in the presence of lakes suitable for coloring the sugar coats of phenylbutazone tablets. The drug was degraded, in light, in the presence of erythrosine sodium. The degradation probably proceeds via singlet oxygen generated by the light-exicited dye. The degradation may be important in some quality control procedures and can lead, for example, to unusual results in dissolution rate testing.

Coloring Agents↗