Page 49 - controlled drug delievery

5- Osmotically controlled Systems.

• These are based on the combination of:
i. Osmotically active substance (drug and/or excipient)
ii. A semipermeable membrane (permeable to water but not to drug)

• Type I: one compartment osmotic pump (OROS®)

Drug out
Laser drilled orifice

Water

Rigid Semipermeable membrane Osmotic core :
E.g. Cellulose triacetate membrane Drug +osmotic agent

Polyvinyl chloride
Polyvinyl acetate