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Drug Dissolution II
N/A
40
Other
Graduate
10/02/2009

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Term
For some dosage forms, the size of the drug particles _______ as the drug dissolve.
Definition
decreases
Term
In Noyes-Whitney’s equation, ________ _______ is assumed to ________ _________during the process of dissolution.
Definition
surface area, remain constant
Term
Hixson and Crowell equation is a modified form of equation in which ...
Definition
the effect of changing surface area has been taken into account.
Term
According to Hixson-Crowell Cube root law, a drug powder consisting of uniformly sized particles, the dissolution rate depends on ....
Definition
the cube root of the weight of the particles.
Term
Methods used to determine rate of dissolution is largely dependent on ....
Definition
dosage form
Term
This method is used for what dissolution apparatus?
– Tablet or capsule is placed inside a stainless steel wire basket, which is rotated at a fixed speed whilst immersed in the dissolution medium that is contained in a wide mouthed cylindrical vessel.
Definition
Rotating Basket Method
Term
What is the Rotating Basket Method used for?
Definition
– Used for dissolution of capsules, suppositories and tablets that have low density and tend to float on the dissolution medium.
Term
This method is used for what dissolution apparatus?
– Dosage form is allowed to sink to the bottom of the dissolution vessel before agitation is commenced. The dissolution media is continuously stirred using a paddle.
Definition
Paddle Method
Term
The Paddle Method is used for what?
Definition
Used for tablets and capsules.
Term
Dissolution study is performed in an apparatus that consists of vessel for __________ __________, device for _______ the media and motor for keeping _________constant and _______ the stirring device.
Definition
dissolution medium, stirring,temperature, rotate
Term
Dissolution vessel is filled with ...
Definition
the dissolution media.
Term
Dissolution medium is selected based on ....
Definition
the drug or dosage form or as specified in the USP.
Term
________ or ________ are placed inside the dissolution vessel or stainless steel wire basket,
– The wire basket is rotated or medium is stirred using a paddle.
– Sample is collected periodically and analyzed for _______ ______
Definition
tablets or capsules, drug content
Term
The ________ ________ provide specific details of dissolution studies depending on the drug, dosage forms, coated and uncoated tablets.
Definition
USP monograph
Term
Rate of dissolution may be affected by several factors....
Definition
– Solubility
– Particle size
– Crystalline state
– Drug formulation
– Physiological factors
Term
Noyes-Whitney equation shows that the of a ________ _______drug is the factor that determine the dissolution of the drug.
Definition
aqueous solubility
Term
Dissolution of a drug can be increased by increasing the ...
Definition
solubility.
Term
The effective surface area of a drug can be increased by ______the particle size
Definition
reducing
Term
Because dissolution is thought to take place at the surface of the solute, the greater the surface area....
Definition
the more rapid the rate of drug dissolution.
Term
Different crystalline forms have different ...
Definition
aqueous solubility.
Term
What kind of drug dissolves more rapidly than the same drug in a crystalline form?
Definition
An amorphous drug
Term
Excipients in a drug product may alter ...
Definition
the rate of dissolution.
Term
tablet lubricants such as magnesium stearate may _______ the rate of dissolution.
Definition
reduce
Term
Excipients such as ________enhance dissolution of drug.
Definition
disintegrants
Term
What's the time it takes for nondigestable materials to pass through stomach?
Definition
15 min to 2 h
Term
Gastric emptying time greatly affects ....
Definition
drug dissolution
Term
Presence of food alters ________ of stomach contents thus affecting dissolution
Definition
viscosity
Term
________ varies in stomach depending on contents
Definition
ph
Term
________ _________in the fasted state and _______ with presence of food (3.5 or above)
Definition
low ph (1.2), increases
Term
Weakly acidic drugs will have limited solubility in a _____ pH environment, s a basic drug will dissolve _______
Definition
low, rapidly
Term
What is Quality Control Testing important for? Who provides its detailed guidelines?
Definition
Important for testing oral solid dosage forms, US Pharmacopeia
Term
Dosage form intended for a particular site of absorption must release __________ _________ to be absorbed into ________ ________
Definition
active ingredient, systemic circulation
Term
After dissolution drug, where is drug bsorbed into systemic circulation (Significance of Dissolution)
Definition
hepatic portal vein
Term
Define rate-limiting step (Significance of Dissolution)
Definition
itdetermines the rate at which the drug reaches systemic circulation
Term
In ________ drugs the absorption process is the rate limiting step(Significance of Dissolution)
Definition
hydrophilic
Term
In ______ drugs, dissolution is the rate limiting step
(Significance of Dissolution)
Definition
hydrophobic
Term
Case 1: High Solubility – High Permeability
Definition
Bioavailability not limited by dissolution
Term
Case 2: Low Solubility- High Permeability
Definition
Drug dissolution is rate limiting
Term
Case 3: High Solubility-Low Permeability
Definition
Permeability is rate limiting
Term
Case 4: Low Solubility-Low Permeability
Definition
Significant problems for oral drug delivery
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