DESCRIPTION
Immediate Release Capsules and Extended Release
Tablets
Nifedipine is an antianginal drug belonging to a class
of pharmacological agents, the calcium channel blockers.
Nifedipine is 3,5-pyridinedicarboxylic acid, 1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-,dimethyl
ester, C17H18N2O6.
Nifedipine is a yellow crystalline substance, practically
insoluble in water but soluble in ethanol. It has a molecular
weight of 346.3.
Immediate Release Capsules
Procardia capsules are formulated as soft gelatin capsules
for oral administration each containing 10 mg or 20 mg
nifedipine.
Inert Ingredients in the Formulations Are:
Glycerin; peppermint oil; polyethylene glycol; soft gelatin
capsules (which contain yellow 6, and may contain red
ferric oxide and other inert ingredients), and water.
The 10 mg capsules also contain saccharin sodium.
Extended Release Tablets
Procardia XL is a trademark for nifedipine GITS. Nifedipine
GITS (Gastrointestinal Therapeutic System) Tablet is formulated
as a once-a-day controlled-release tablet for oral administration
designed to deliver 30, 60, or 90 mg of nifedipine.
Inert Ingredients in the Formulations Are:
Cellulose acetate; hydroxypropyl cellulose; hydroxypropyl
methylcellulose; magnesium stearate; polyethylene glycol;
polyethylene oxide; red ferric oxide; sodium chloride;
titanium dioxide.
System Components and Performance: Procardia
XL extended release tablet is similar in appearance to
a conventional tablet. It consists, however, of a semipermeable
membrane surrounding an osmotically active drug core.
The core itself is divided into two layers: an "active"
layer containing the drug, and a "push" layer
containing pharmacologically inert (but osmotically active)
components. As water from the gastrointestinal tract enters
the tablet, pressure increases in the osmotic layer and
"pushes" against the drug layer, releasing drug
through the precision laser-drilled tablet orifice in
the active layer.
Procardia XL extended release tablet is designed to provide
nifedipine at an approximately constant rate over 24 hours.
This controlled rate of drug delivery into the gastrointestinal
lumen is independent of pH or gastrointestinal motility.
Procardia XL depends for its action on the existence of
an osmotic gradient between the contents of the bi-layer
core and fluid in the GI tract. Drug delivery is essentially
constant as long as the osmotic gradient remains constant,
and then gradually falls to zero. Upon swallowing, the
biologically inert components of the tablet remain intact
during GI transit and are eliminated in the feces as an
insoluble shell.
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