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.
