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Biomedical subjects

L A Luzzi

Publications and source records attributed to L A Luzzi.

At least 19 recordsLinked to original sources
PubMed1991

Cosolvency of dimethyl isosorbide for steroid solubility.

Dimethyl isosorbide (DMI), which is currently under investigation for its potential use as a pharmaceutical vehicle and drug permeation enhancer, is a water-miscible liquid with relatively low viscosity. The solubilization behavior of DMI as a cosolvent for nonpolar drugs was characterized via dielectric constant measurements of binary solvent systems containing DMI and either water, propylene glycol (PG), or polyethylene glycol (PEG). Evidence from the dielectric constant profiles and NMR studies suggest that DMI undergoes complexation with water and PG, but not with PEG, through hydrogen bonding interactions. The solvent complexation exhibited a major effect on the solubilities of prednisone, dexamethasone, and prednisolone in the mixed solvent systems. Maximum solubility of each drug was found to occur near a DMI/water or DMI/PG concentration ratio of 1:2. In the DMI-PEG mixed system, while there is no apparent interaction between DMI and PEG molecules, the solubility of prednisone was found to increase with decreasing dielectric constant.

Dexamethasone↗
PubMed1977

Protein binding of benz[a]anthracene and benzo[a]pyrene.

Fluorometric studies on the binding of benz[a]anthracene and benzo[a]pyrene to human serum albumin are described. The protein molecule appears to have one binding site for the hydrocarbons, but all of the sites on the protein are not fully occupied even in relatively large hydrocarbon concentrations. Equilibrium studies showed that both hydrocarbons bind to the protein to the same extent. Evidence for the energy transfer from the tryptophan residue of the protein to bound hydrocarbons is examined. By using Förster's theory, the mean distance between the tryptophan residue and bound ligand was found to be 15,2 A for benz[a]anthracene and 19.6 A for benzo[a]pyrene. It is concluded that the two hydrocarbons may bind to the same general area on the protein molecule near the tryptophan residue but at different sites. The structural differences of the hydrocarbons, which may greatly affect their orientations on the protein molecule, affect mainly the selection of the binding site rather than the binding equilibrium.

Benz(a)Anthracenes↗
PubMed1975

Drug-biomolecule interactions: fluorescence studies on interaction of aminonaphthalenesulfonic acid derivatives with serum albumins.

The binding of the three aminonaphthalenesulfonic acid derivatives to human and bovine serum albumins was studied by measuring the fluorescence enhancement of the compounds. The number of binding sites of human and bovine serum albumins for these compounds appears to be one and two, respectively, under the experimental conditions. As the molar ratio of the fluorescent compounds to bovine serum albumin increased, the binding sites appeared to increase for the compounds. The quenching of the native fluorescence of albumin was examined by the successive addition of methanolic solutions of these compounds. 1-Anilinonaphthalene-8-sulfonate quenched the protein fluorescence to a greater extent than the other compounds studied, indicating that 1-anilinonaphthalene-8-sulfonate molecules are bound more closely to the tryptophan residues of albumin. The finding that the three compounds did not quench the fluorescence of tryptophan dissolved in water indicates no direct molecular interaction between tryptophan and the three fluorescent probes. The driving force for binding may be due to the structural characteristics of the amino acid sequence surrounding the tryptophan residues.

Anilino Naphthalenesulfonates↗