Pharmaceutical compositions with constant erosion volume for zero order controlled release
December 13, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3870790 Sustained release therapeutic compositions Method and composition for the preparation of controlled long-acting pharmaceuticals Sustained release therapeutic compositions based on high molecular weight hydroxypropylmethylcellulose Prolonged release drug dosage forms based on modified low viscosity grade hydroxypropylmethylcellulose Sustained release propranolol tablet Pharmaceutical composition, in particular dermatological or cosmetic, comprising hydrous lipidic lamellar phases or liposomes containing a retinoid or a structural analogue thereof such as a carotenoid Controlled release tablet containing water soluble medicament Controlled release article with pulsatile release Oral osmotic system for slightly soluble active agents Patent #: 5284662 InventorsAssigneeApplicationNo. 166123 filed on 12/13/1993US Classes:514/365, 1,3-thiazoles (including hydrogenated)424/464, Tablets, lozenges, or pills514/781Cellulose or derivativeExaminersPrimary: Henley, III, RaymondAssistant: MacMillan, Keith D. Attorney, Agent or FirmForeign Patent References
International ClassesA61K 031/425A61K 047/00 A61K 009/20 AbstractAn erodible pharmaceutical composition providing a unique zero order controlled release profile is herein described. The erodible composition contains a therapeutically active substance having a solubility not greater than 80 mg/mL, a hydroxypropyl methylcellulose derivative and erosion modifiers depending on drug solubility and drug loading, such as lactose and polyoxyalkylene derivatives of propylene glycol, as well as other inert materials such as binders and lubricants. The hydroxypropyl methylcellulose derivative is most preferably a hydroxy-propylmethyl having a methoxy content of about 19-30% and hydroxypropyl content of 7-12%, a methoxy degree of substitution from 1.1 to 2.0, a molecular weight of approximately 20,000 to 26,000 daltons and a viscosity of a 2% w/w polymer solution at 25° C. ranging from 50 to 100 cps. The composition erodes with a constant erosion volume for a desired time period. When ingested, the matrix forms two layers, an outer layer of hydrated matrix which is eroding and an inner core of unchanged matrix. The composition provides a zero order release profile in part because the diffusion rate of the drug from the matrix is either negligible or is comparable to the erosion rate of the matrix and the drug concentration in the hydrated layer remains constant.Other References
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