Pharmaceutics Kinetics

Front 1

Pharmaceutics relates to

a. physics- motion
b. chemistry- chemical change
c. both - physical chemistry

Back 1

C. physical chemistry

Front 2

Change per unit time

Back 2

Rate

Front 3

metabolism, degradation, (changes in chemical structure)
fall under ________

Back 3

Reactions

Front 4

absorption, distribution, excretion, (changes in location/transport events)
fall under ______

Back 4

processes

Front 5

law of mass action

Back 5

rate of the reaction is proportional to the product of the molar concentrations of the reactants each raised to an exponent equal to the number of moles taking part in the reaction

Front 6

order is equal to the sum of the ________

Back 6

exponents

Front 7

rate of change is proportional to the quantity of one reactant

Back 7

first order

Front 8

rate of change is constant

Back 8

zero order

Front 9

rate of change is proportional to the quantity of 2 reactants, or the square of the quantity of 1 reactant

Back 9

second order

Front 10

what does the symbol k stand for?

Back 10

specific rate constant

Front 11

A = A0-kt
what order?
units on answer?

Back 11

zero order process

quantity/time

Front 12

lnA = lnA0-kt

order?

Back 12

first order process

1/time

Front 13

T1/2 = 0.693/k

order?

Back 13

first order half life

Front 14

T90 = 0.1A0/k

Back 14

zero order shelf life

Front 15

T1/2 = A0/2k
units?

Back 15

zero order half life

moles/L/S

Front 16

T90 = 0.105/k

Back 16

first order shelf life

Front 17

dependent variable = _axis
independent variable = _axis

Back 17

Y
X

Front 18

second order units

Back 18

1/ quantity x time

Front 19

A + B --> P

if B remains constant while A is changing it would be __ order

Back 19

first

Front 20

why are stability studies done on drugs?

Back 20

determine susceptibility of a drug molecule to commons modes of degradation

Front 21

common modes of pharmaceutical degradation
how do we prevent?

Back 21

Hydrolysis- tight packages
oxidation- anti oxidants, tight seal
photolysis- amber bottles

Front 22

a dosage form can be modified to stop or slow down degradation by...

Back 22

inhibition- stop
retardation- slow down
combination of both

Front 23

what factors affect the rate of a reaction and degradation?

Back 23

pH
catalysts
additives (surfactants, complexing agents, solvents, salts)
Temperature

Front 24

how does temperature affect the rate of a reaction?

Back 24

reactions depend on interactions of molecules, collisions.
increasing temp increases movement

Front 25

the energy of activation is the amount of energy required to bring the reactants to a transition state or ____ ____

Back 25

activated complex

Front 26

collision theory of activation rates

Back 26

freq factor is proportional to rate

activation energy is inverse to rate

Front 27

average shelf life

Back 27

2 years

use an accelerated method to test drugs (increase temp etc)

Front 28

actual shelf life is determined at ___

Back 28

room temp
25 degrees C

Front 29

universal value R

Back 29

1.987 cal/deg/mol

Front 30

kinetic phenomena

Back 30

Degradation
Drug disposition (where it moves)

Front 31

drug response is proportional to ____ _______

Back 31

plasma concentration

dose determines drug response

Front 32

the noyes whitney eq assumes that

Back 32

surface area is a constant

Front 33

a condition in which a drugs dissolution concentration bulk is negligible because as soon as drug is released it is taken away, making the concentration much lower than the saturated stagnant layer

Back 33

sink conditions

Front 34

dissolution rate can be controlled by

Back 34

increasing SA by comminution (size reduction)
agitation (spreading out stag layer h)
dissolution coefficient can be changed w/ different polymorphs

Front 35

hixon crowell cube root eq is used to...

k-2kCsMo^1/3 /dp

Back 35

overcome the flaw in noyes eq by accounting for a change in SA over time

Front 36

Dissolution limited absorption would be due to..

how can it improved?

Back 36

drug would be lipophilic and hard to dissolve in aqueous conditions
but would pass through lipophilic barrier easily (permeability)

Use the salt form!

Front 37

what are the 3 mechanisms of drug transport?

Back 37

active- requires energy to go against conc. gradient. ABC carrier

Passive- no energy, High --> Low

Facilitative- requires a carrier

Front 38

3 types of cellular transport

Back 38

endocytosis- particles
phagocytosis- particles (eating)
Pinocytosis- liquids (drinking)

Front 39

passive modes of transport
2

Back 39

Diffusion- molecules move at random because of their own K energy, want equilibrium. ex cell wall

Convection- flow within fluid, ex blood

Front 40

ficks first law

Back 40

flux (amount moving through an area over time) is proportional to the concentration gradient

Front 41

diffusion across membrane used with ____ device
M=PSCd t

M=PSCd (t+tb) ?
M=PSCd (t-tl) ?

Back 41

reservoir

burst effect

lag effect

Front 42

diffusion through a ____ device

M=kt^1/2

Back 42

matrix

Front 43

why are pharmaceutical solutions isotonic to our body?

Back 43

if they werent isotonic they would cause cells (RBC) to either take in water and burst or lose water.
they would become denatured

Front 44

isotonicity depends on grams
true or false?

Back 44

false, it depends on the number of moles

Front 45

solution with the same amount of solute as bodily fluid (osmotic pressure close to .9% NaCl w/v)

Back 45

isotonic solution

Front 46

what pharm. solutions are isotonic?

Back 46

enemas
opthalmic solutions
nasal sprays
most parenteral