cardura xl - Medication Listings

CARDURA XL contains doxazosin which is a quinazoline compound with the chemical name 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(1,4-benzodioxan-2-ylcarbonyl) piperazine methanesulfonate. The empirical formula for doxazosin mesylate is C 23 H 25 N 5 O 5 • CH 4 O 3 S and the molecular weight is 547.6. It has the following structure: CARDURA XL is an extended-release tablet for oral use and is designed to deliver 4 or 8 mg of doxazosin as the free base. Each 4 and 8 mg tablet contains 5.1 and 10.2 mg doxazosin mesylate (includes a 5% overage) to ensure the labeled dose of 4 and 8 mg doxazosin as the free base (equivalent to 4.9 and 9.8 mg of doxazosin mesylate), is delivered. The inactive ingredients for CARDURA XL are black iron oxide, cellulose acetate, hypromellose, Macrogol ® , magnesium stearate, pharmaceutical glaze, polyethylene oxide, red ferric oxide, sodium chloride and titanium dioxide. CARDURA XL System Components and Performance CARDURA XL is similar in appearance to a conventional tablet. It consists, however, of an osmotically active drug core surrounded by a semipermeable membrane. 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. The membrane surrounding the tablet is permeable to water, but not to drug or osmotic excipients. As water from the gastrointestinal tract enters the tablet, pressure increases in the osmotic layer and “pushes” against the drug layer, resulting in the release of drug through a small, laser-drilled orifice in the membrane on the drug side of the tablet. CARDURA XL utilizes GITS (Gastrointestinal Therapeutic System) which is designed to provide a controlled rate of delivery of doxazosin into the gastrointestinal lumen which is independent of pH or gastrointestinal (GI) motility. The function of CARDURA XL depends upon 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. The biologically inert components of the tablet remain intact during GI transit and are eliminated in the feces as an insoluble shell. Doxazosin Mesylate Structural Formula