Abstract
This study was undertaken to find a means for a long lasting and uniform release of the male hormone, testosterone. The rate of release of testosterone was determined over periods up to 4 months. The factors which affect the rate of testosterone release were studied and a mechanism for the release of testosterone was proposed.
The first means providing a constant release of testosterone was the use of silicone rubber membrane around testosterone cylinders. It was found that a constant rate of release was reached after an initial unsteady state period ranging from 1 to 2 weeks.
It was theorized that a water layer had formed between the membrane and testosterone cylinder. This layer caused the concentration inside the capsule to be that of saturated water.
Several testosterone cylinders were coated with especially prepared membranes. These membranes were made by dissolving testosterone and silicone rubber in a mixture of tetrahydrofurane and toluene. It was hoped that an amount of testosterone might be incorporated into the silicone rubber matrix. The samples were run and the permeabilities determined. The permeability showed little or no increase over the range of 10–30% testosterone.
Next, a membrane was prepared by mechanically mixing testosterone and silicone rubber. The amount of testosterone ranged between 5 and 200%, by weight. A definite increase in the permeability was observed with an increase in the percentage of testosterone.
The second method of obtaining a uniform rate of release of testosterone was by mechanically mixing testosterone and silicone rubber and molding a sheet. After an initial unsteady state a constant rate of release was obtained and such rate of release increased with higher percentages of testosterone in the sheets.