The effect of glucose and copper on the stability of diatrizoic acid.

Hypaque Sodium Oral Solution is used as a X-ray contrast agent. The active ingredient is diatrizoate sodium. Several bottles of drug product were found to contain elevated levels of inorganic iodide, ranging from 0.

Assay and purity analysis of diatrizoate sodium in drug product by LC.

An LC procedure was developed to separate diatrizoate sodium from three known impurities. These impurities are 2,4- and 2,6-diiodo-3,5-diacetamidobenzoic acid (DDZA), and the free amine (5-acetamido-3-amino-2,4,6-triiodobenzoic acid). The separation was achieved using a Hamilton, PRP-X100, anion exchange column.

Binding constant determination of WIN 22169, a novel polymeric ligand.

WIN 22169 is a co-polymer containing approximately 11 repeating units of polyoxyethylene and diethylenetriamine pentaacetic acid (DTPA). WIN 66368, a magnetic resonance imaging (MRI) contrast agent, is the gadolinium III complex of WIN 22169. WIN 22169 has been characterized with respect to its equivalent weight, acidity constants and excess acid or base, as well as its metal ion binding constants.

An LC method for measuring complex formation equilibria by competitive chelation.

A method, entailing the use of a competitor ligand, is described for measuring complex formation constants by HPLC. The log of the formation constant of Gd(III) 2,6-bis(aminomethyl)pyridinetetraacetate was determined to be 18.6, a previously unreported value.

The effect of mobile phase modifiers on the simultaneous LC elution of a gadolinium complex and free ligand.

A liquid chromatographic method was developed for simultaneous separation of a gadolinium complex and corresponding ligand using a reversed-phase anion-exchange column. The effect of mobile phase pH, EDTA and chloride ion concentration, added to the mobile phase as counter-ions, on the elution of a metal complex and ligand were investigated. Decreasing the mobile phase pH from 9.

Benzoyl peroxide solubility and stability in hydric solvents.

Saturated solubility and reaction rate constants for the decomposition of benzoyl peroxide in solution and suspension were determined for use in formulation development. The solvents studied included ethanol, propylene glycol, and cosolvent mixtures of PEG 400 and water. The solubility of benzoyl peroxide was inversely related to the solvent polarity, with greater solubility occurring with semipolar solvents.

Distribution and fate of diethyl malonate and diisopropyl fluorophosphate on pig skin in vitro.

The in vitro distribution and fate of [14C]diethyl malonate and [14C]diisopropyl fluorophosphate were evaluated on normal and heat-treated pig skin. The extent of hydrolysis from the skin surface, skin, and receptor fluid was determined. A significant skin-mediated hydrolysis (15-35% of applied dose) was observed for diethyl malonate in normal skin, but not in heat-treated skin.

Percutaneous penetration in the hairless dog, weanling pig and grafted athymic nude mouse: evaluation of models for predicting skin penetration in man.

The human skin grafted congenitally athymic (nude) mouse, pig skin grafted nude mouse, hairless dog, and weanling Yorkshire pig were evaluated as models for predicting skin penetration in man. Nine radiolabelled compounds previously tested on man were applied topically (4 micrograms/cm2) to each model. These compounds included caffeine, benzoic acid, N, N-diethyl-m-toluamide, three steroids, and three insecticides.

Evaluation of animal models for predicting skin penetration in man.

The human skin grafted athymic nude mouse, pig skin grafted athymic nude mouse, hairless dog, and weanling Yorkshire pig were evaluated as models for predicting skin penetration in man. Nine radiolabeled compounds previously tested on man were applied topically (4 micrograms/cm2) to each animal. These compounds included caffeine, benzoic acid, N,N-diethyl-m-toluamide, three steroids, and three insecticides.