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level: Level 1 of Chapter 9: MODIFIED-RELEASE DDS

Questions and Answers List

level questions: Level 1 of Chapter 9: MODIFIED-RELEASE DDS

Question	Answer
products usually are enteric-coated tablets or capsules designed to pass through the stomach unaltered, later to release their medication within the intestinal tract.	Delayed-release
products are designed to release their medication in a controlled manner, at a predetermined rate, duration and location to achieve and maintain optimum therapeutic blood levels of drug.	Extended-release
are commonly taken only once or twice daily, compared with counterpart conventional forms that may have to be taken three or four times daily to achieve the same therapeutic effect.	Extended-release tablets & capsules
Typically, extended-release products provide an 1) __ of drug that promptly produces the desired therapeutic effect, followed by 2) __of additional amounts of drug to maintain this effect over a predetermined period.	1 immediate release 2 gradual release
Drug-candidates for extended-release products have the following characteristics:	1 They exhibit neither very slow nor very fast rates of absorption and excretion. 2 They are uniformly absorbed from the gastrointestinal tract. 3 They are administered in relatively small doses. 4 They possess a good margin of safety. 5 They are used in the treatment of chronic rather than acute conditions.
1 The rate of drug release from solid dosage forms may be modified by the technologies described below: Modifying drug dissolution by __ of biologic fluids to the drug through the use of barrier coatings. __ from dosage forms	1 controlling access 2 controlling drug diffusion rates
In these systems, the drug is distributed onto beads, pellets, granules, or other particulate systems.	Coated beads, granules, or microspheres
In Coated beads, granules, or microspheres, Using conventional pan coating or air suspension coating, a solution of the drug substance is placed on small inert nonpareil seeds or beads made of sugar and starch or on __	microcrystalline cellulose spheres (more durable).
Small spheroid compressed tablets 3 to 4 mm in diameter may be prepared to have varying drug release characteristics.	Multitablet system
In multitablet system, Each capsule may contain __, some uncoated for immediate release and others coated for extended drug release.	8 to 10 minitablets
a process by which solids, liquids, or even gases may be enclosed in microscopic particles by formation of thin coatings of wall material around the substance.	Microencapsulation
1 This additive material concentrates the gelatin into tiny liquid droplets 2 Advantages of Microencapsulation	1 coacervates 2 administered dose of a drug is subdivided into small units that are spread over a large area of the GI tract which may enhance absorption by diminishing localized drug concentration.
By this process, the drug substance is combined and made into granules with an excipient material that slowly erodes in body fluids, progressively releasing the drug for absorption.	Embedding drug in slowly eroding or hydrophilic matrix system
In Embedding drug in slowly eroding or hydrophilic matrix system, 1 This is commonly used 2 forms gel layer after ingestion	1 Hydrophilic cellulose polymers 2 Hydroxypropyl methylcellulose (HPMC)
By this method, the drug is granulated with an inert plastic material such as polyethylene, polyvinyl acetate, or polymethacrylate, and the granulation is compressed into tablets. expended in feces (the tablet matrix)	Embedding drug in inert plastic matrix
Example product of Embedding drug in inert plastic matrix	1 Gradumet (Abbott)
1 Certain drug substances when chemically combined with certain other chemical agents form chemical complexes that may be only slowly soluble in body fluids, depending upon the pH of the environment. 2 This slow dissolution rate provides the __ of the drug. 3 Salts of tannic acid, tannates, provide this quality in a variety of proprietary produces by the trade name __	1 Complex formation 2 extended release 3 Rynatan
A solution of a cationic drug may be passed through a column containing an __, forming a complex by the replacement of hydrogen atoms.	Ion-exchange resins
In Ion-exchange resins, 1 Release is greater in the __ 2 Examples of drug products of this type include	1 acidity of the stomach 2 hydrocodone polistirex, chlorpheniramine polistirex suspension, phentermine resin capsules.
1 The pioneer oral osmotic pump drug delivery system is the __, developed by __. 2 The system is composed of a core tablet surrounded by a semipermeable membrane coating have a __ diameter hole produced by __.	1 OROS system, Alza 2) 0.4 mm, laser beam
1 In Osmotic Pump, the drug release rate may be altered by: 2 In Osmotic Pump, drug release is not affected by: 3 Osmotic Pump Example:	1 -Changing Surface area -Thickness or composition of the membrane -Changing the diameter of the drug release 2 GI Acidity, Alkalinity, Fed conditions, or GI motility 3 Gastrointestinal Therapeutic system (GITS), Adalat GITS