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Biomedical subjects

A T Florence

Publications and source records attributed to A T Florence.

At least 91 records · Page 5Linked to original sources
PubMed1981

Non-ionic surfactants and gastric mucosal transport of paraquat.

The influence of a range of polyoxyethylated non-ionic surfactants upon the transport of [14C]-paraquat dichloride across rabbit isolated gastric mucosa was investigated. Paraquat was shown to cross the mucosal epithelium by passive diffusion. Certain members of the surfactant series enhanced transmucosal paraquat transfer at low surfactant concentrations (e.g. 0.001%) but the occurrence and magnitude of this effect was not dependent in a simple manner upon surfactant structure of physiochemical properties. At micellar concentrations the increase in paraquat transport was greatest with those surfactants possessing both ethylene oxide chains of 10-20 units and alkyl chains longer than C7-C9. The most effective absorption promoter was found to be Brij 36T (C12E10). At micellar surfactant concentrations the enhancement of paraquat transfer appeared, from histological evidence, to be related to the ability of the surfactants to solubilize membrane components and disrupt epithelial cells.

Animals↗
PubMed1980

In vitro heterogeneous degradation of poly(n-alkyl alpha-cyanoacrylates).

Methods by which in vitro heterogeneous phase degradation rates of the poly(n-alkyl alpha-cyanoacrylates) have been directly obtained are described. The data indicate that the rates of degradation in aqueous buffer solutions depend not only upon pH of the medium and length of the monomer alkyl side chain, but also critically upon polymer particle specific surface, particle size, polymer molecular weight, and molecular weight distribution. A modification of the currently held theory of degradation of these polymers is required, and postulated.

Buffers↗
PubMed1976

Effect of formulation of intramuscular injections of phenothiazines on duration of activity.

Trifluoperazine and pericyazine were formulated using both the hydrochloride and embonate salts, and some comparisons were made with the activity of fluphenazine salt and ester formulations. Simple solutions in polyethylene glycol, gelled aqueous solutions, nonaqueous suspensions, multiple emulsions, and microencapsulated preparations were formulated, and their duration of activity was tested in dogs. While the multiple emulsion system showed some promise, a nylon microcapsule system produced significant prolonged activity of the drug after deep intramuscular injection.

Animals↗
PubMed1976

Interfacial properties of polymethyl alpha-cyanoacrylate and polybutyl alpha-cyanoacrylate.

Several physical properties of two polyalkyl alpha-cyanoacrylates relevant to their use in pharmaceutical dosage forms have been investigated. Formation of polymer films at several oil-water interfaces reveals films of diverse morphology. The retardation of solute transfer across an oil-water interface caused by the presence of polymer films formed in situ from the monomers has revealed that the methyl derivative forms the more effective barrier to the test solute, gentian violet. The emulsion-stabilizing properties of the methyl polymer have been studied, and the film-forming properties of the monomers spread from benzene onto water surfaces have been examined using a surface balance.

Cyanoacrylates↗