OROS tablets

J Richard, JM Cardot, J Godbillon. Stable isotope methodology for studying the performance of metoprolol Oros tablets in comparison to conventional and slow release formulations. EurJ DrugMetab Pharmacokinet 19 375—380,1994. 

Richard, 1., Cardot, J. M., and Godbillon, J., Stable isotope methodology for studying the performance of metoprolol Oros tablets in comparison to conventional and slow release formulations, Eur. J. Drug Metab. Pharmacokinet., 19 375-380, 1994. Veng-Pedersen, R, Theorems and implications of a model independent elimina-tion/distribution function decomposition of linear and some nonlinear drug dispositions. 1. Derivations and theoretical analysis, J. Pharmacokinet. Biopharm., 12 627-648, 1984. 

Osmotic Control. Several oral osmotic systems (OROS) have been developed by the Alza Corporation to allow controUed deHvery of highly water-soluble dmgs. The elementary osmotic pump (94) consists of an osmotic core containing dmg surrounded by a semi-permeable membrane having a laser-drilled deHvery orifice. The system looks like a conventional tablet, yet the outer layer allows only the diffusion of water into the core of the unit. The rate of water diffusion into the system is controUed by the membrane s permeabUity to water and by the osmotic activity of the core. Because the membrane does not expand as water is absorbed, the dmg solution must leave the interior of the tablet through the smaU orifice at the same rate that water enters by osmosis. The osmotic driving force is constant until aU of the dmg is dissolved thus, the osmotic system maintains a constant deHvery rate of dmg until the time of complete dissolution of the dmg. 

Acutrim 16 Hour Steady Control Tablets. Acuttim is an appetite suppressant diet aid available without a prescription and marketed by CIBA Consumer Pharmaceuticals. The active ingredient is phenylpropanolamine hydrochloride [154-41 -6] a sympathomimetic amine (see Antiobesity drugs). Acutrim dehvers its dosage at a precisely controlled rate for up to 16 hours. This is achieved through the OROS technology. 

The manufacture of this system utilizes essentially the same process as the one inherent in the manufacture of OROS. The complicating factors are that a bilayer tablet press is required and the tablet must be oriented during the laser drilling operation to ensure that the drug-containing layer is directed toward the laser beam. 

Nitroglycerin, the prototype of the nitrates is characterized by a rapid onset and short duration of action. It is usually administered sublingually (via the oro-mucosal route), which allows a rapid and efficient absorption and avoids the strong first pass effect after oral administration. Nitroglycerin is available as tablets, capsules (for sublingual administration) but also as transdermal preparations, sprays, and ointments. 

In other indications such as hypertension, the OROS technology (oral osmotic system developed by ALZA) has already proven its value, and therefore it seemed appropriate to use this technology with its typical, virtually constant, release rate (zero-order kinetics) for once-daily opioid tablets. Such a morphine tablet is already available, but is not yet on the market, and a hydromorphone OROS is currently being clinically developed by Knoll. 

The ORO 5 Push-Stick technology is designed to deliver high doses of poorly water-soluble or slowly dissolving drugs at a controlled rate [50,52], The basic system consists of two layers, typically in a capsule-shaped tablet surrounded by a semipermeable membrane however, the system... 

FIGURE 6.39 Effect of pH and stirring on the release of KC1 from elementary osmotic pump tablets (OROS ). [Graph reconstructed from data by F. Theeuwes, J. Pharm. Sci., 64, 1987 (1975).]... 

Baldi R Lansoprazole oro-dispersible tablet pharmacokinetics and therapeutic use in acid-related disorders. Drugs 2005 65(10) 1419-1426. 

Drug delivery systems of once-daily products (Concerta, Metadate CD, Ritalin LA, Adderall XR) provide 8 to 12 hours of symptom control. Concerta uses an oral osmotic (OROS) controlled-release delivery system, while other preparations use combinations of immediate-release or extended-release beads containing drug. Concerta is a nondeformable tablet and it should not be given to children with gastrointestinal narrowing due to the risk of obstruction. Older wax-matrix sustained-release products (e.g., Ritalin SR)... 

Kasliwal N, Negi JS, Jugran V, Jain R. Formulation, development, and performance evaluation of meto-clopramide HCl oro-dispersible sustained release tablet. Archives of Pharmacal Research. October 2011 34(10) 1691-1700. PubMed PMID 22076769. 

From Equations 28 and 29 it may be concluded that zero-order release may be obtained if the permeability characteristics of the semi-permeable membrane are controlled, namely the area, thickness, the diffusion coefficient of water across the membrane, and a saturated concentration of drug is maintained within the tablet core (by the correct choice of drug salt and inclusion of excipients). In the original OROS system the semi-pcrmcable membrane was composed of cellulose acetate and the osmotic pressure of the core was controlled by the inclusion of salts. If a non-saturaled drug solution is present in the tablet core non zero-order release occurs (a.47, a. 159). 

In the OROS system, solid drug—present alone or with an osmotic driving agent—is surrounded by a semipermeable membrane having one delivery orifice (Figure 9). During pump operation, water from the environment is continuously imbibed across the semipermeable membrane, by osmosis, to produce the fluid drug formulation. The membrane s structure does not allow expansion of the tablet s volume ... 

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