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Biomedical subjects

E L Parrott

Publications and source records attributed to E L Parrott.

8 recordsLinked to original sources
PubMed1992

Effect of surfactants on release of a highly water-soluble medicinal compound from an inert, heterogeneous matrix.

The release from a matrix compressed from a physical mixture of procaine hydrochloride, chlorinated poly(propylene), lactose, and a surfactant was investigated. With nonionic and cationic surfactants incorporated in the matrix, the release of procaine hydrochloride was linearly related to the square root of time, and as the concentration of the surfactants increased, the release was faster. When an anionic surfactant (sodium lauryl sulfate) was incorporated in the matrix, the release of procaine hydrochloride was linearly related to the square root of time; however, the release pattern depended on the concentration of the anionic surfactant. As the concentration of sodium lauryl sulfate increased to 4%, the release progressively slowed to a minimum because of the formation of a poorly soluble complex between the cationic procaine and the anionic surfactant. As the concentration of anionic surfactant increased further, the release increased as the complex was micellarly solubilized.

Anions↗
PubMed1990

Release of highly water-soluble medicinal compounds from inert, heterogeneous matrixes. I: Physical mixture.

The release from a matrix compressed from a physical mixture of hydrogenated castor oil and ephedrine hydrochloride or procaine hydrochloride has been investigated. The effects on release of the concentration of medicinal compound, particle size of medicinal compound, agitation of dissolution medium, and porosity and tortuosity of the matrix are presented. An attempt is made to fit the experimental data to an acceptable diffusion model.

Castor Oil↗
PubMed1990

Release of highly water-soluble medicinal compounds from inert, heterogeneous matrixes. II: Melt.

The release from matrixes compressed from melts of hydrogenated castor oil and ephedrine hydrochloride or procaine hydrochloride has been studied and is compared with the release from matrixes prepared by compression of physical mixtures. In both, the release is dependent on the square root of time; however, the release is slower from the matrix prepared by the melt process. Parameters that affect the release are compared. The independence of release from stirring speed and the greater tortuosity of the matrix prepared by the melt process indicate that the release is by a matrix diffusion mechanism. In contrast, boundary layer diffusion is operative in the release from the matrixes prepared by compression of physical mixtures. It is demonstrated that for a given formulation, the method of processing may alter the mechanism and rate of release.

Castor Oil↗
PubMed1978

Effects of compression force, particle size, and lubricants on dissolution rate.

The effects of compression force, particle size, and lubricant concentration on the dissolution rates of compressed disks of salicylic acid, aspirin, and an equimolar mixture of aspirin and salicylic acid were investigated. Compression forces from 450 to 9100 kg had no effect on dissolution rates. With 5% starch incorporated into an equimolar mixture of aspirin and salicylic acid, the dissolution rates were independent of compression forces from 910 to 9100 kg. A 10-fold change of particle size of the materials being compressed did not affect the dissolution rates. An increase in the concentration from 0.1 to 5% of calcium stearate, glyceryl monostearate, magnesium stearate, and stearic acid progressively slowed the dissolution rate. An increase in the concentration from 0.1 to 5% talc and polyethylene glycol 4000 did not affect the dissolution rates. An increase in the concentration of starch from 0.1 to 5% progressively increased the dissolution rates.

Aspirin↗
PubMed1977

Rectal absorption of nitrofurantoin.

The adsorption in humans of nitrofurantoin from seven suppository bases was studied using urinary excretion measurements. Rectal absorption was poorer than GI absorption. The administration of 400 mg of nitrofurantoin in a polyethylene glycol-polysorbate 80 suppository base and in a polyethylene glycol-silica suppository based provided an adequate urinary concentration of nitrofurantoin. Persons who cannot tolerate orally administered nitrofurantoin due to gastric upset could receive nitrofurantoin therapy rectally.

Administration, Oral↗
PubMed1976

Dissolution of two-component solids.

The dissolution rates of compressed two-component mixtures were investigated. A good correlation between the composition of the solid and its observed dissolution rate was demonstrated by regression analysis. A model for dissolution was applied to compressed mixtures of aspirin-salicylic acid, aspirin-phenacetin, phenacetin-caffeine, and aspirin and caffeine (the last mixture complexes in solution).

Chemistry, Pharmaceutical↗
PubMed1975

Influence of particle size on rectal absorption of aspirin.

The rectal absorption of aspirin from theobroma oil suppositories was studied in seven human subjects using urinary excretion measurements. The effect of particle size on the excretion rate and cumulative amount of total salicylate excreted was demonstrated by the administration of a 600-mg dose as powdered aspirin and as aspirin disks having 0.023 as much surface as powdered aspirin. In vitro dissolution profiles of aspirin from the suppositories were studied. By the NF XIII Method II, the time required for 50% of the aspirin to dissolve from the suppository was 50 and 100 min for the powdered aspirin and the aspirin disks, respectively. In the bioavailability study, the diffusion equilibrium was attained at approximately 4-5 and 9-10 hr after the rectal administration of powdered aspirin and aspirin disks, respectively. No correlation was found between bioavailability and the dissolution profiles as determined by the USP XVIII dissolution method.

Adult↗