Date of Award

1977

Degree Type

Thesis

Degree Name

Master of Science in Pharmacy

Department

Pharmacy

First Advisor

George E. Osborne

Abstract

The effective surf ace area of a parenteral drug in suspension, that which is exposed to body fluids at the injection site, is a major determinant of its in vivo absorption rate. Precise methods o f determining the effective surface area without disturbing the in vivo system have not been developed. A method to estimate the effective surf ace area of a subcutaneously injected suspension based on the urinary excretion of drug from solid disk implants of known surface area is presented. Standard curves for the mean surf ace area of from two to four subcutaneously implanted cylindrical disks of pure sulfadiazine versus cumulative urinary sulfadiazine excretion to 48 hours were developed or three test animals. By applying the urinary excretion data obtained following the subcutaneous injection of an aqueous suspension of sulfadiazine to the appropriate standard curve for area, a preliminary estimate of the apparent or effective in vivo surface area for the suspension formulation was obtained. Improvements in the experimental methodology which would control certain biopharmaceutical factors related to parenteral drug absorption from subcutaneous sites, and increase the statistical significance of the surf ace area estimate are suggested.

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