Search PubMed⌕ Search

Biomedical subjects

L H Block

Publications and source records attributed to L H Block.

100 records · Page 6Linked to original sources

Aqueous solubility of 14C-triamcinolone acetonide.

The blue tetrazolium colorimetric assay has often been employed in the analysis of corticosteroids. However, the reaction between blue tetrazolium and corticosteroids partly depends on the apparent pH of the system. In an earlier study of the temperature dependence of the solubility and dissolution of triamcinolone acetonide in aqueous dissolution media (distilled water and 0.2-1.0 M potassium chloride solutions), pH was not considered. To determine the reliability of the data previously reported, the solubility of 14C-triamcinolone acetonide was determined by a radioisotopic method. The results of the analyses, using a liquid scintillation counting system, indicate that the steroid solubility is generally about 20% lower than that reported previously.

Carbon Radioisotopes↗

Hydrogen peroxide permeation across liposomal membranes: a novel method to assess structural flaws in liposomes.

Hydrogen peroxide permeation across large multilamellar vesicles of defined and complex lipid composition was shown to obey precise kinetic relationships for the activity of the occluded catalase. Careful assay conditions precluded simultaneous peroxidative damage to the lipids. The kinetic data was consistent with a barrier role for the bilayer for hydrogen peroxide permeation. More interestingly, hydrogen peroxide permeation across liposomes of complex lipid mixtures exhibited osmotic inhibition of permeation of hydrogen peroxide. On the other hand, purified egg lecithin vesicles did not exhibit any effect of external osmolality on hydrogen peroxide permeation in an experimentally defined non-lytic zone of external osmolarity. These results argue in favour of a heterogeneous, heteroporous structure of bilayers with complex lipid composition.

Animals↗