SPL Set ID: c5950dba-d92b-46a0-993f-af9f9ddb52bf

Oxybutynin chloride extended-release tablets are an antispasmodic, muscarinic antagonist. Each Oxybutynin chloride extended-release tablet contains 5 mg, 10 mg, or 15 mg of oxybutynin chloride USP, formulated as a once-a-day controlled-release tablet for oral administration. Oxybutynin chloride is administered as a racemate of R- and S-enantiomers. Chemically, oxybutynin chloride is d,l (racemic) 4-diethylamino-2-butynyl phenylcyclohexylglycolate hydrochloride. The empirical formula of oxybutynin chloride is C 22 H 31 NO 3 •HCl. Its structural formula is: Oxybutynin chloride is a white crystalline solid with a molecular weight of 393.9. It is readily soluble in water and acids, but relatively insoluble in alkalis. Oxybutynin chloride extended-release tablets also contain the following inert ingredients: black iron oxide, cellulose acetate, colloidal silicon dioxide, dextrose, hypromellose, lactose, magnesium stearate, mannitol, polyethylene glycol, propylene glycol, tartaric acid, titanium dioxide, triacetin. Chemical Structure System Components and Performance Oxybutynin chloride extended-release tablets use osmotic pressure to deliver oxybutynin chloride at a controlled rate over approximately 24 hours. The system, which resembles a conventional tablet in appearance, comprises an osmotically active core surrounded by a semipermeable membrane. The unitary tablet core is composed of the drug and excipients (including the osmotically active components). There is a precision-laser drilled orifice in the semipermeable membrane on the side of the tablet. In an aqueous environment, such as the gastrointestinal tract, water permeates through the membrane into the tablet core, causing the drug to go into suspension and the osmotic components to expand. This expansion pushes the drug out through the orifice. The semipermeable membrane controls the rate at which water permeates into the tablet core, which in turn controls the rate of drug delivery. The controlled rate of drug delivery into the gastrointestinal lumen is thus independent of pH or gastrointestinal motility. The function of Oxybutynin chloride extended-release tablets depends on the existence of an osmotic gradient between the contents of the core and the fluid in the gastrointestinal tract. Since the osmotic gradient remains constant, drug delivery remains essentially constant. The biologically inert components of the tablet remain intact during gastrointestinal transit and are eliminated in the feces as an insoluble shell. USP Dissolution Test 3.