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83 Cards in this Set

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What is a generic name?
An established non-proprietary common name of active ingredient. (such as acetaminophen)
What is a chemical name?
Used by organic chemists and indicates structure. (ex. p-acetamidophenol or p-hydroxyacetaniline)
What is a brand name?
A privately owned trade name of a drug. (ex. tylenol)
What is "bioavailability"?
It is a reference to the rate and extent to which a drug is absorbed.
How are F and ka related to bioavailability?
F and ka are direct measures of bioavailability but are too variable to be useful for this purpose.
What are some indirect measures used to determine the bioavailability of a drug?
From and oral Cp verses t curve: The Cmax, tmax, and AUC are used (INDIRECT MEASURES).
What is Cmax a measure of?
(in oral Cp vs. t curve)
The rate and extent of absorption.
What is tmax a measure of?
(in oral Cp vs. t curve)
The rate of absorption.
What is the AUC a measure of?
(in oral Cp vs. t curve)
The extent of absorption.
If absorption is greater for one drug product that another, then more of the ? product should appear in the urine.
More of the first product.
For most drugs elimination is what?
First-order
How much time should be allowed for the collection of the amount of absorbed drug in the urine?
About 5 half-lives.
Au towards infinity is the total amount of what? What is this a measure of?
The absorbed drug that is ultimately excreted unchanged. It is a measure of the extent of drug absorption.
What does the idea of relative bioavailability compare?
This compares the extent of absorption of a test product (generic drug) with a standard reference product. It is the systemic availability of a drug in a given drug product relative to its availability in a standard formulation (such as the Reference Listed Drug).
If two products are given at the same dose how do you determine relative bioavailability?
Rel. Bioavail. = [AUC]test/[AUC]reference

OR

Rel. Bioavail. = (Du towards infinity)test/(Du towards infinity) reference
For two products, if the doses are not the same how do you determine relative bioavailability?
Rel. Bioavail. = ([AUC]test/test dose)/([AUC]reference/reference dose)

OR

Rel. Bioavail. = ([AUC]test/AUC reference)(reference dose/ test dose)
A high rel. bioavailability means what about two products?
They may be considered bioequivalent.
Bioavailability does not necessarily mean what?
It does not necessarily mean that either product is well absorbed.
What is absolute bioavailability a reference to?
It is a reference to the fraction of the oral dose (of an individual product) that is absorbed.
How do you figure out the absolute bioavailability for the same drug dose given po verses IV?
Absolute bioavailability = [AUC]oral/[AUC]iv
How do you figure out the absolute bioavailability for the same drug given at different doses po verses IV?
Absolute bioavailability = ([AUC]oral/AUCiv)(iv dose/ oral dose)
Bioavailability studies try to assure what?
That standards of effectiveness of a drug are met (such as identity, strength, and purity).
What does the FDA require for new generic products?
FDA requires in vitro and/or in vivo studies of bioavailability along with essential pharmacokinetic parameters are met. These are also reqd for new formulations of old drugs. These tests test for things such as half-life, rates of absorption, excretion and metabolism.
Data from bioavailability studies help determine appropriate what?
Dose regimens.
Bioequivalent drug products show what?
Similar bioavailability when studied under similar conditions.
How is bioequivalence demonstrated?
Bioequivalence is demonstrated by establishing that no 'statistical difference' exists among Cmax, tmax, and AUC for the test and reference products.
What is ANOVA aka?
Analysis of Variance
What is ANOVA used for?
ANOVA is a commonly used test (level of probability of > 0.05 and a power of 80% certainty). The avg parameter of the test product should be within 20% of that of the reference product.
How does the FDA define bioequivalence?
The RATE and EXTENT of absorption of the test drug DO NOT SHOW A SIG DIFFERENCE from the rate and extent of absorption of the reference drug when administered at the same molar dose of therapeutic ingredient under similar experimental conditions in either a single dose or multiple doses.

OR

Where there is NO DIFFERENCE IN THE EXTENT of absorption, but a SIG DIFFERENCE IN THE RATE of absorption that is intentional, reflected in the label and is medically significant.
What does the typical bioequivalency study consist of?
Typically single-dose (usually following an overnight fast), two treatment, randomized cross over design. A plasma sample is take just before the dose and at regular intervals thereafter. Food intervention studies and multiple-dose studies are sometimes performed.
What is the Latin square in a bioequivalent study?
Each subject receives each drug product only once, with sufficient time between product administrations to allow for:

1. Full description of Cmax, tmax, and AUC

2. Elimination of product from the body
What is a replicated crossover design in a bioequivalent study?
Estimates within-subject variance for both products. FDA recommends a four-period, two-sequence, two-formulation design.
What is a generic substitution?
Dispensing an unbranded product or a different brand in place of a prescribed product.
Generic substitutions have the ? dosage form, ? active ingredient, and ? manufacturers.
Generic substitutions have the same dosage form, same active ingredient, and different manufacturers.
Generic substitution has to be permitted by whom?
The prescriber.
What is the FDA published list of drug products?
The Orange Book ('Approved Drug Products with Therapeutic Equivalence Evaluations)
What does the letter A represent in the orange book?
Deemed therapeutically equivalent.
What does the letter B represent in the orange book?
Inadequate evidence of bioequivalence.
?-letter codes are used in the orange book.
Two-letter codes are used.
Define the term 'pharmaceutical alternatives'?
The same therapeutic entity but presented as different salts, complexes or esters. Also different dosage forms (eg. elixirs, caps, and tablets) and strengths by a single manufacturer.
Define the term 'pharmaceutical equivalents'?
Same active ingredient, same amount of it, same dosage form for the same route of administration. Must meet same uniformity, disintegration and dissolution rates where applicable. May differ in features such as packaging, shape, color, release mechanism, excipients and some labeling details.
The process of dispensing a pharmaceutical alternative in place of a prescribed product needs what?
Prescribe approval.
Define the term therapeutic alternatives.
Different active ingredients share same indications and used for same therapeutic objectives (ex. ibuprofen verses ASA)
Define the term 'therapeutic equivalents'?
Expected to have the same clinical effect and safety profile.
Therapeutic substitution involves the use of a what?
Therapeutic alternative.
The drug review process contrast what?
NDAs and ANDAs
What must NDAs have? What must ANDAs have?
NDAs must have animal and clinical data along with bioavailability data. ANDAs do not need these but must have bioequivalence data.
The biopharmaceutics classification system is used to predict what?
It is used to predict in vivo absorption based on solubility and permeability characteristics.
What is Jw?
Drug flux (mass/area/time)
What is Pw?
Permeability of membrane.
What is Cw?
Drug concentration at intestinal membrane surface.
What is the eqn to find Jw?
Jw = (Pw)(Cw)
Biopharmaceutics is the study of what relationship?
The study of the rel. between the nature and intensity of the biological effects produced in humans (or animals) AND the physicochemical properties of the drug formulation administered. Some authorities include pharmacokinetics as a branch or biopharmaceutics.
List 4 biopharmaceutic considerations?
1. The stability of the drug.

2. The release of the drug from the product.

3. The rate of dissolution or release at the site of absorption.

4. The systemic absorption of the drug.
List 5 formulation properties.
1. The type of dosage form.

2. The pharmaceutical process used in preparing dosage form.

3. The presence (or absence) of adjuncts with the drug.

4. The physical state, particle size and surface area of drug.

5. The chemical nature of the drug (salt, complex, ester, etc.)
A solid oral dosage form needs to ? to release the drug.
A solid oral dosage form needs to disintegrate to release the drug.
The USP has a standard ? test. This is a component of what?
The USP has a standard disintegration test. This is a component of the quality control process during tablet manufacture.
What does not have to satisfy USP disintegration criteria?
Chewable tablets, modified-release tablets and troches.
Describe the process of dissolution from the drug particle to the bulk solvent?
1. Dissolution at the particle surface.

2. Formation of saturated solution (stagnant layer) around particle.

3. Dissolved drug diffuses from stagnant layer to the bulk of the solvent (from region of high concentration to a region of low concentration).
The rate of dissolution (following ?) can control what?
The rate of dissolution (following disintegration) can control the rate of absorption.
In the GI tract, a drug would be considered to be dissolving in an ? medium.
Dissolving in an aqueous medium.
FDA dissolution tests may be used to to predict what?
Bioavailability.
The FDA uses dissolution tests to predict bioavailability. What does the USP do?
The USP also sets testing standards (a certain percentage of the labeled drug amount must dissolve in a specified period at the specified temperature) for the dissolution and release of many drugs.
What do dissolution tests help discover?
Possible problems with the product formulation, batch-to-batch variations. They can help predict in vivo performance.
What affects drug dissolution?
The physicochemical nature of a drug and the excipients used, as well as the manufacturing method.
What equation governs the rate of dissolution?
The Noyes-Whitney equation.

dC/dt = (DA/h)(Cs - C)

D = diffusion rate constant

A = surface area of the particle

Cs = concentration of drug in stagnant area

h = thickness of stagnant layer
What is the temperature in vivo? What does an increase in temperature result in?
37C. An increase results in a higher D (diffusion rate constant).
What kind of agitation occurs in vivo? What does an increase in agitation result in?
Mainly peristalsis. An increase in agitation results in a smaller h (thickness of stagnant layer).
What might excipients do?
Excipients may alter the medium in which the drug dissolves.
Give 4 examples of excipients that may alter the medium in which a drug dissolves?
1. Suspending agents make the medium more viscous and so decrease the dissolution rate.

2. Certain coating material form cross-links when they age and so decrease dissolution.

3. Lubricants repel water and so can reduce dissolution if present in large amounts.

4. Sodium Bicarb. (and some others) change the medium pH. For example, ASA will dissolve rapidly in such a reactive medium.
Excipients may be added to do what to the rate and extent of absorption?
They may be added to either retard or increase the rate and extent of absorption.
List 4 drug physciochemical properties.
1. pH and solubility.

2. pH and stability.

3. Particle size

4. Polymorphs
Describe the physicochemical property of 'pH and solubility'?
A basic drug is more soluble in the acidic medium of the stomach; an acidic drug is more soluble in the intestines. Excipients may be added to make modifications; buffering agents may be added to modify the release rate of a fast dissolving drug.
Describe the physicochemical property of 'pH and stability'?
pH may impact stability if a drug is decomposed via acid or base catalysis.
Describe the physicochemical property of particle size?
For poorly soluble drugs this is very important because dissolution occurs at the particle surface. Thus particle size and particle size distribution impact absorption.
Describe the physicochemical property of polymorphs?
Polymorphs have the same chemical structure but different physical properties. Some polymorphic forms may be more aqueous soluble than others.
List 6 drug product considerations?
1. Safety and efficacy

2. Desired Cp

3. Bioavailability

4. Dose

5. Route of administration

6. Compliance
Concerning the safety and efficacy of drugs what must excipients not add?
toxicity
How do you achieve the desired Cp for a drug product?
The formulation should be such that the release rate and the dose should help achieve the Cp (for acute illness drugs, the release rate should be high; for prophylactic drugs, ER forms could be appropriate).
How is bioavailability taken into consideration for a drug product?
Steps should be taken to preserve the stability of the drug (eg. use of enteric coating or buffers); for drugs subject to first pass effects, alternative routes of administration could be used of the dosage adjusted.
How is dose taken into consideration for a drug product?
This depends on the drug's potency and the Vd. Because of individual variations in pharmacokinetic parameters, different dose strengths of the product could be helpful. Additionally, tablets scored to facilitate breaking could be helpful.
What can result from different routes of administration?
A significant difference in responses.
What three things might be considered when dealing the compliance for a drug product?
1. Product size: Oddly shaped or large oral products could present swallowing difficulties with some patients.

2. Product Taste and Odor: should be agreeable to facilitate compliance

3. Extended-release products could aid compliance.