Page 59 - controlled drug delievery

2-B- Gas generating systems

– Floatability can be achieved by generation of gas bubbles through
incorporation of effervescent substance in the hydrophilic polymer (up to
8-10 hr floating time)

Gastric fluid

A-

B-

Semipermeable membrane:
Water permeable, CO2
impermeable

C-

D- Liquid sod alginate solution Gastric fluid Floating gel (raft)of or
containing carbonate/ Ca alginate Alginic acid
bicarbonate mixture. & Al acting as physical
hydroxide barrier in GORD