Progestin permeation through polymer membranes IV: Mechanism of steroid permeation and functional group contributions to diffusion through hydrogel films
✍ Scribed by G. M. Zentner; J. R. Cardinal; J. Feijen; Suk-Zu Song
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- English
- Weight
- 698 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0022-3549
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✦ Synopsis
Hydrogel films were prepared from hydroxyethyl methacrylate, both with (Film II) and withouth (Film I) 5.25 mole% of ethylene glycol dimethacrylate. Permeation, diffusion, and partition coefficients for progesterone, testosterone, nandrolone, norethindrone, 17 alpha-hydroxyprogesterone, estradiol, and hydrocortisone were determined. A solute permeation model was proposed based on the separation of a domain (B) composed of "bulk-like" water and a doman (A) composed of polymer, interfacial water, and bound water present in the films. The separate contributions from the "pore" and "solution-diffusion" mechanisms to the total permeability were calculated from the model. Steroid permeabilities through Films I and II were analyzed in accordance with this model. Permeation of Film II occurred via the solution-diffusion mechanism. Permeation of Film I occurred predominately by the pore mechanism with a small contribution (approximate 20%) from the solution-diffusion mechanism. The latter contribution was dependent on the solubility of the solute within the A domains of the hydrogel film. Functional group contributions to permeation of Film II were ascribed to either steric or hydrogen bonding effects.