Rate-limiting membranes and devices

The use of rate-limiting membranes to control the movement of dmgs from a reservoir has been referred to above. Implants of silicone rubber or other appropriate polymeric material in which dmg is embedded can be designed by choice of polymer, membrane thickness and porosity, to release dmg at preselected rates. The Progestasert device (Fig. 8.34c) is designed to be implanted into the uterine 

Reproduced from A. Gopferich ef al., in Formulation and Delivery of Proteins and Peptides (ed. J. L. Cleland and R. Langer), ACS Symposium Series no. 567, ACS, Washington, 1 994. 

---