pharmceutics exam 2 (1-45: 2013) (46-90: 2018)
A liquid or gaseous carrier transports the solute in convection and transport of the solute depends upon the flow properties of the carrier.
A. true
Complexing drug molecules with cyclodextrin molecules is a technique that in some cases may increase the apparent solubility of the drug.
A. true
Drug C is known to be 99% protein bound and 100% bioavailable when given by the oral route. If 500 mg of Drug C was administered to a normal patient and given time to reach systemic circulation, then approximately 5 mg of Drug C would be present in the plasma in the unbound state.
A. true
One of the strengths of the osmotic pressure driven table (OROS or osmotic pump) is that Fick's law applies and we are able to obtain a rate that is based upon the square root of time release.
A. true
When an ion-exchange resin is used in an oral controlled release formulation, the resin that is used is typically not soluble in water.
A. true
When most drugs form complexes with another molecule, the drug-molecule complex will almost always be inactive at the intended site of action.
A. true
a 10% solution is more concentrated than 1:20 solution
A. true
For typical immediate release oral tablet, the dissolution rate is constant from time = 0 until all the solid has dissolved.
B. false
In intestinal absorption, most drugs usually undergo active transport from a region of low concentration in the GI tract to a region of high concentration in the systemic circulation.
B. false
The Noyes Whitney equation above can be set to represent sink conditions by letting D=O.
B. false
USP dissolution data is commonly used to determine the storage conditions for sterile parenteral products
B. false
The formation of a drug complex could alter:
D. All of the above a. The apparent aqueous solubility of the drug b. The stability of the drug c. The partitioning characteristics of the drug
Drug A has an oral bioavailabilty of 50% and is 80% bound to plasma proteins. If a patient receives a one time oral dose of 100 mg, approximately how many milligrams of drug would be unbound in the blood stream?
a. 10 mg
The decreasing dissolution rate in zone B cane best be described as due to:
a. A decrease in the amount of solid present
Five mL of a concentration solution (10% w/v) of drug z from a glass vial was added to 250 mL of normal saline. Thirty minutes after the addition, a hospital pharmacist measured the level of the diluted drug z when the normal saline was contained in a plastic polyvinyl chloride (PVC) intravenous (IV) bag. The pharmacist calculated that the amount of drug z in the plastic IV was 20% to 30% of what she measured when drug z was diluted in 250 mL of normal saline contained in a glass bottle. The best explanation for this:
a. Drug Z absorbed strongly into the plastic bag because it has a greater affinity for the plastic than it does for water.
*** Which one of the following is most correct about a contact angle measurement of a liquid on a solid flat surface?
a. If the contact angle is less than 10° and greater than 5°, then the solid material is easily wetter by the liquid
which one of the following is most correct for a drug compound a weak acid that is under basic conditions?
a. If the pH of the solution is greater than the pKa value by 2 units then the ratio of the unionized form of the drug to the ionized form of the drug is 1:100
if we are 2 pH units below pKa for a weakly basic drug molecule, then which of the following is most correct concerning the effect of pH upon the partition coefficient.
a. Kd= (BH+)o/(BH+)w
Which one of the following is most accurate in regard to Physical Adsorption?
a. Physical Adsorption is when the adsorbate attaches to the adsorbent by utilizing weak forces such as van der Waals
There are two major types of diffusional release system, they are:
a. Reservoir and matris systems
Which one of the following is NOT true about the passive transport of solutes by diffusion?
a. The movement of solute molecules is driven by the temperature differential between the donor and receiving compartments __________________________________________________ IS TRUE ABOUT PASS. TRANS. OF SOLUTES BY DIFF.: b. Thermodynamics dictates that systems will find the lowest energy state. This means that solute molecules will move from an area of high concentration to an area that has a lower concentration. c. The movement of solute molecules is by random Brownian motion d. No "extra" energy is needed because thermodynamics insures that driving force is provided for the direction movement of the solute movement
Which one of the following is NOT true for anionic surfactants?
a. The polar end has both a positive and negative charge _________________________________________________ IS TRUE FOR ANIONIC SURFACTANTS: b. The polar end has only a negative charge c. Widely used in pharmacy and cosmetics d. Unpleasant taste, some skin irritation
Which one of the following is NOT true about DuNouy Ring Method?
a. This method can only be used to measure surface tension and can not be used to measure interfacial tension _________________________________________________ IS TRUE OF DUNUOY RING METHOD: b. The surface tension is directly proportional to the force required to detach the ring from the surface of the liquid c. The surface of the liquid is brought into contact with the ring and the ring is pulled away from the surface of the liquid d. This method can be used to measure both surface tension and interfacial tension
which one of the following is NOT true?
a. every specification for all approved drug products that are sold in the US are listed in the USP monographs
for drug X in a capsule, the calculated zero order, degradation rate constant is 2 mg/hr, what is the half life in hours fora capsule that contains 20 mg of drug X
a. five hours
As a result of the change in the variable referred to in question #9 by stirring, the dissolution rate for the system would:
a. increase
**equation** which one of the following is NOT true for the equation given above?
a. k is the diffusional release rate constant
**graph** in the dissolution profile above, which formulation has the fastest dissolution rate at time =2.5 hours?
a. the film coated tablets.
Referring to the system described in question #11, which would tend to have the faster dissolution rate?
a. the smaller particles
which of the following us NOT true about the solubility of drugs that are weak acids
a. the solubility remains relatively constant with increasing pH at pH values close to the pKa (pH > pKa by less than 1 unit) ______________________________________________ IS TRUE OF WEAK ACID SOLUBILITY: b. the solubility remains relatively constant with decreasing pH at pH values much lower than the pKa (pH < pKa by 2 units or more) c. solute-solute attractions have to be broken for the drug to go into solution d. solute-solvent interactions have to be formed in order for the drug to go into solution
**graph** referring to the graph above, which one fo the following answers is most correct?
a. this is an example of a base catalyzed hydrolysis reaction
A membrane is a physical barrier that separates two or more regions.
a. true
Mass transport is the movement of molecules from one region to another as a result of a specific driving force.
a. true
drug Z is known the be 100% bioavailable and 90% bound to proteins. drug X is known to be 90% bioavailable and 0% bound to proteins. if a 500mg dose of each drug was administered orally the amount of free (unbound) drug in the blood stream would be approximately 50mg for both drug Z and drug X
a. true
in some cases cyclodextrin complexes can be formed with drug molecules in order to enhance their aqueous solubility or increase stability?
a. true
in the delsym product mentioned above, the drug is reversibly bound to the resin in order to avoid toxic effects of the drug
a. true
mathematically, zero-order and pseudo zero-order reaction rate models are treated in an identical fashion
a. true
regarding the scenario described in question 27 eventually the dissolution rates in beaker A and beaker B will be essentially the same
a. true
sink conditions occur if the concentration of drug in the donor compartment is so much higher than in the receptor compartment that the concentration in the receptor compartment can be ignored.
a. true
the bioavailability of a drug in solution given by IV injection is essentially 100% but when administer by an other route the bioavailability may be less than 100%
a. true
the pharmaceutical drug manufacturer has a list of specifications for both the release and stability of each approved drug product
a. true
when using cyclodextrin molecules to form drug complexes, formulators take advantage of the fact that they have hydrophilic exteriors and relatively hydrophobic interiors
a. true
based on the information given above it can be determined that the bioavailability of Drug A via the oral and rectal routes is 100%
b false
**henderson-hasselbalch equation for weak acid** compound X is weak acid with a pKa of 5.0 what is the ratio of the ionized to unionized forms for compound X at a pH of 7.0?
b. 100 to 1
If Drug A from question #7 is given as a one time IV dose of 100 mg, approximately how many milligrams of drug would be unbound in the blood stream? (Use Noyes - Whitney Eq)
b. 20 mg
100mg of a drug is administered orally and 75mg of drug is found to enter systemic circulation. additional data reveals that 10% of the drug is also protein bound. given these data the oral bioavailability of the drug is approximately:
b. 75%
Drug Z is known to be 90% protein bound to albumin. Your patient becomes hypoalbuminemic (low albumin) and this results in Drug Z being only 80% protein bound. This would result in:
b. A drastic increase in the unbound blood concentration and the need to reduce the dose.
**salting out equation** which one of the following drugs will "salt out" (form a precipitate) first if they are all dissolved in the same solution and NaCl (the given Ks values are for NaCl) is added to the solution?
b. Drug B, Ks= -0.478, MW= 271
**graph** The plot below is of the amount of drug that is diffused (released) with time. This plot (release profile) is typical for which system:
b. Matrix system
Which one of the following is NOT true about surface tension?
b. The surface tension of water is increased when surfactants with HLB values > 9 are added to water __________________________________________________ TRUE OF SURFACE TENSION: a. There is a spontaneous movement of molecules from the surface into the bulk phase c. The surface behaves as though it is under tension and the force of tension per unit length of surface is the surface tension d. The surface tension of water can be decreased by adding surfactant molecules to water
**graph** Referring to the graph above, which one of the following answers is most correct?
b. This is an example of base catalyzed hydrolysis reaction
**graph** considering the dissolution profile above, the dissolution rate between t50 and t75 is
b. decreasing
According to the Noyes - Whitney equation, if we were not maintaining sink conditions and Cs = Cb we could increase the dissolution rate for the system by decreasing the particle size therefore increasing the surface area.
b. false
If you have large particles and small particles of the same drug molecule, the smaller particles would tend to have higher aqueous solubility.
b. false
a drug with high aqueous solubility will always have a faster dissolution rate than a drug with lower aqueous solubility
b. false
all cyclodextrin-drug complexes are irreversible.
b. false
beaker A and beaker B both contain 500mg of the same drug. breaker A contains the drug as one immediate release tablet. beaker B contains the same tablet but it has been divided into three separate pieces. the Noyes-Whitney equation predicts that beaker A will have the fastest initial dissolution rate
b. false
drug A is administered orally and the plasma concentration vs time curve has an AUC of 45. when the same drug is administered rectally it produces an AUC of 45 as well. based on this data it can be determined that drug A has the same oral and rectal bioavailability
b. false
if a beaker containing a completely saturated solution fo drug is stirred, the dissolution rate will increase
b. false
if a drug is administered orally and 90% of the dose is protein bound, we can determine that the bioavailability of the drug is approximately 10%
b. false
second-order reaction rates are commonly seen by the pharmacist when modeling for drug degradation. the mass balance equation is integrated to give the concentration of drug as a function of the reciprocal of time.
b. false
with hydrolysis, the stability of the drug solution is usually independent of the solution pH
b. false
with ion-exchange resins used in products such as delsym, the exchange resin itself is soluble in water.
b. false
If the dissolution of a tablet formulation is being studied, which variable in the Noyes - Whitney equation would be affected by agitating or stirring the system?
b. h
**graph** The initial increase in dissolution rate in zone A can best be described as due to:
b. increase in the surface area of the solid
The following are considered to be commonly used accelerated testing conditions that are used to quickly give the scientists information on the stability of drug tablets.
b. temperature and humidity conditions that are much higher than normally encountered in a room
**graph** given the dissolution profile above, which formulation has dissolved the most after 2.5 hours?
b. the uncoated tablets
**graph** in the dissolution profile above, which formulation has the fastest dissolution rate at time =1 hour?
b. the uncoated tablets
**graph** given the dissolution profile above which formulation has dissolved the most after 1 hour?
b. the uncoated tablets
the plot below is of the concentration of the original drug compounds vs time in days. it is known that the concentration of the drug is decreasing because it is undergoing chemical decomposition. the plot indicates that the degradation (decomposition) of the drug can be best described by which one of the following models:
b. zero-order reaction rate model
the eye product "GreatEye" is a solution of the drug Isogreat that has a concentration of 10mg/mL and a first order decomposition rate constant of 1.1x10^-3 hr^-1. what is the half life in days?
c. 26 days
**plot** The plots below are of the concentration of the original drug compound versus time in days. It is known that the concentration of the drug is decreasing because it is undergoing chemical decomposition. The plots indicate that the degradation (decomposition) of the drug can be best described by which one of the following models:
c. A first-order reaction rate model
Which one of the following is NOT true about Fick's law of diffusion?
c. Fick's law indicates that the rate of diffusion increases in direct proportion to increases in the thickness of the synthetic membrane __________________________________________________ IS TRUE OF FICK'S LAW: a. The process of diffusion can be quantitatively described using Fick's law of diffusion b. Fick's law of diffusion is an important model of the diffusion process that is used frequently in pharmaceutics d. The diffusion coefficient is a measure of the ease of permeability of molecules across the barrier
Which one of the following is NOT true about micelles formed from surfactants?
c. Micelles are usually long and linear in form, allowing drug molecules to "tunnel" through to the water and air surface interface _________________________________________________ IS TRUE OF MICELLES FORMED FROM SURFACTANTS: a. The critical micelle concentration (CMC) is that concentration in which micelles are formed b. Micelles are aggregates of 50 or more surfactant molecules d. Micelles are usually spherical in shape
Which one of the following is NOT true about synthetic membranes?
c. Synthetic membranes have a bilayer of lipids that fill the spaces between protein complexes called corneocytes __________________________________________________ IS TRUE OF SYNTHETIC MEMBRANES: a. Synthetic membranes used in pharmaceutical applications are made from polymeric material b. Synthetic membranes can be sheets that are nonporous or porous c. Synthetic membranes have a bilayer of lipids that fill the spaces between protein complexes called corneocytes
The rate limiting barrier to a drug diffusing through natural membranes is usually considered to be:
c. The lipid portion of the membranes
When surfactants are dispersed in the bulk mixture of oil (immiscible with water) and water, which one of the following is NOT true about surfactants in general?
c. The polar part of the surfactant will stay in the oil side of the interface _________________________________________________ IS TRUE OF SURFACTANTS IN GENERAL: a. The polar part of the surfactant will stay in the water side of the interface b. The lipophilic part of the surfactant molecule is located in the oil d. The interfacial tension will be lowered
**equation for weak bases ** when p H is within +/- 2 units of the pKa which one of the following is NOT correct?
c. as [H+] is increased, the apparent partition coeff is increased because more of the weak base in in the non-ionized state ______________________________________________ IS CORRECT: a. as the pH is increased, the apparent partition coefficient is increased because more of the weak base is in the non-ionized state b. as the pH is decreased the apparent partition coeff is decreased because more of the weak base is in the ionized state d. as the [H+] is increased, the apparent partition coefficient is decreased because more of the weak base is in the ionized state
which one of the following is most correct?
c. factors that influence the absorption of a drug include the partition coefficient of the drug, the water solubility of the drug, and the molecular weight of the drug
the two most common types of chemical decomposition reactions that occur with drug molecules are:
c. hydrolysis and oxidation
which one of the following is NOT true concerning the equation?
c. the apparent solubility is independent of intrinsic solubility when Ka approaches [H+] ________________________________________________ IS TRUE OF EQUATION: a. at low pH the apparent solubility and the intrinsic solubility are nearly the same b. at high pH the apparent solubility is greater than the intrinsic solubility d. the biggest change in apparent solubility occures when [H+] approaches the Ka of the solute
which one of the following is NOT true aobut the partition coeff. of a compound?
c. the partition coefficient is a ratio, so a large partition coeff means that the concentration in the organic layer is high compared to a compound with a smaller partition coefficient ________________________________________________ IS TRUE OF PARTITION COEFF: a. the partition coefficient for non-electrolytes is equal to their concentration in the organic phase divided by their concentration in the water phase b. the partition coefficient for strong electrolytes approaches zero d. the solvent used as the organic phase in determining partition coeff as used in pharmacy is usually 1-octanol
A capsule that contains 20 mg of Drug X is emptied into 100 mL of normal saline solution and completely dissolved (assume the final volume is 100 mL). The first order rate constant now is calculated to be 0.0003 hour-1 (or 0.003/hr). At what time, in hours, will the concentration of the drug X in normal saline be equal to 0.1 mg/mL.
d. 231 hrs
what is the T90 value in days for the product GreatEye?
d. 4 days
A decomposition (degradation) product occurs when:
d. A drug molecule's structure is changed at the molecular level. The can occur by breaking molecular bonds and/or forming new molecular bonds
give that the degree of dissociation of a weak acid solute in water is affected by the pH of the solution, which of the following is NOT correct?
d. At high pH, the total solubility is essentially equal to the solubility of HA
**plot** The plot below is an Arrhenius plot of the degradation rates of drug Y in a tablet. The plot indicates that:
d. The numerical value of Ea/R is equal to 10036
Which of the following is NOT true regarding cyclodextrins?
d. They are long linear polymers _________________________________________________ IS TRUE REGARDING CYCLODEXTRINS: a. They are donut-shaped molecules of D-glucopyranose b. They have an outer surface that is hydrophilic c. They have an interior surface that is relatively non-polar
For the following equation (derived from the law of mass action): dc/dt = Rate = k(A)a(B)b, which one of the following is the most correct?
d. a + b is equal to one or a first order reaction rate model
Dissolutions studies can be used to:
d. all of the above a. Assess batch to batch quality b. Determine product stability/shelf life c. Guide in the development of formulations
For two formulations of the same drug to be bioequivalent, they must have:
d. all of the above a. similar peak blood concentrations b. similar times to peak blood concentrations c. similar AUC's from blood concentration vs time profiles
Which of the following statements best describes bioavailability (F)?
d. fraction of the administered drug that reaches the systemic reduction
which one of the following is NOT true in regard to the quality of pharmaceutical drug products?
d. pharmaceutical manufacturers are not responsible to establish specifications for their drug product as long as an expiration date is not assigned
photochemical decomposition is:
d. the composition of the drug molecule that occurs when it is exposed to light
Photochemical decomposition is:
d. the decomposition of the drug molecule that occurs when it is exposed to light
the plot below is an Arrhenius plot of the degradation rates of drug Y in a tablet. assume that the gas constant R=1.987 cal/deg mole. the plot indicates that:
d. the numerical value of Ea is equal to 10,036
**graph** what is likely causing the change in the dissolution profile above?
e. a and b only a. an increase in the concentration of drug in the bulk of the solution (increase in Cb with non-sink conditions) b. a decrease in the total amount of drug remaining in the solid state
Ion-exchange resins work by using a resin that is highly water-soluble but forms irreversible bonds with the drug molecule to control release rate.
false
Molecular complexes held together by van der Waals forces are very strong and difficult to break.
false
Non-reversible complextion of a drug molecule with another non-drug molecule will almost always result in no activity at the receptor site.
true
