Oros Colon Targeting:
Hard gelatin capsule
This has one osmotic agent or
it consists of as many as five to six push pull osmotic unit filled in a hard gelatin
capsule. After coming in association with the aqueous environment, gelatin
capsule dissolved and the enteric coating avoids entry of fluids from stomach
to the system, when system pass into the small intestine the enteric coating liquefies
and water is absorbed into the core thus causing the push compartment to swell.
At the same time flow-able gel is formed in the drug compartment, which is
pushed out of the orifice at a rate, which is precisely controlled, by the rate
of water transport across the semi permeable membrane
is used as a one or two times a day formulation for site specific delivery of
drugs to the colon.
Monolithic osmotic system:
It consists of a simple dispersion of water-soluble agent in a polymer
matrix .When the system comes across with the aqueous environment water imbibition
by the active agent’s results in distortion of the polymer matrix capsule
encapsulating the drug this delivering it to the outside environment. Mostly this
process proceeds at the external environment of the polymeric matrix, but slowly
heads towards the inside of the matrix in a sequential manner, but this system is
not succeeded if more than 20 –30 volumes per liter of the active agents are combined
in to the device cross this level, significant contribution from the simple
leaching of the substance take place
Osmotic Matrix Tablet (OSMAT):
in aqueous media forming semi permeable
This type of system employs the swellings property of hydrophilic
polymer, which swells and gels in aqueous medium making a semipermeable
membrane in situ. The rate of drug delivery from this system is influenced by
the insertion of osmogent with a matrix delivery of drug from OSMAT don’t rely
on agitation & is low cost method.
Evaluation aspects of osmotic DDS
Angle of repose
Effect of Ph.