Progestin Permeation through Polymer Membranes II: Diffusion Studies on Hydrogel Membranes

Progestin Permeation Through Polymer Membranes V: Progesterone Release from Monolithic Hydrogel Devices

“…This conclusion is consistent with previous results (8,9). Previous work (8,9) demonstrated that the pore mechanism dominates progesterone permeation in hydrogels of the type utilized in the present study. However, drug incorporation is not without effect on the transport properties of the matrix.…”

“…This conclusion is consistent with previous results (8,9). This conclusion is consistent with previous results (8,9).…”

“…The water content of the hydrated films was determined as described previously (8). Prior to these permeation experiments, the films were depleted of the initial drug load by placing them in a large volume of water.…”

Immobilization of Arthrobacter simplex in Thermally Reversible Hydrogels: Effect of Gel Hydrophobicity on Steroid Conversion

“…The partition coefficient is related to the chemical composition of the gel matrix and its water content, while the diffusion coefficient is dependent upon the water content (porosity), the pore sizes, and pore interconnections and distribution (tortuosity) as well as the size of the substrate molecule. Normally, these two parameters (partition and diffusion) show opposing trends for the transport of water-insoluble solutes through hydrogel membranes, because of the tendency for such solutes to partition in the polymer phase and to diffuse mainly through the water pores (Kim et al, 1980;Zentner et al, 1978). It has also been known that the transport of a solute across the hydrogel membrane occurs via two routes, a pore diffusion mechanism through the pore fluid (free water) and a partition diffusion mechanism through the polymer matrix.…”

Progestin Permeation Through Polymer Membranes III: Polymerization Solvent Effect on Progesterone Permeation Through Hydrogel Membranes

“…Diffusion and partition experiments were conducted as described previously (8,9). Film thicknesses, -0.07 cm, were measured on the water-swollen hydrogels using a lightwave micromete+.…”