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Michaelis and menten equation related to active diffusion of drugs absorption - YouTube
Channel: unknown
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Hi today we are going to learn about Michaelis
and Mentent equation I will be not deriving
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this equation in this lecture you can go and
get YouTube videos for that you have plenty
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of videos where the people are there in Michelson
menten equation today I'm not going to delete
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this I am explain this equation in context
of biopharmaceutics that to in absorption
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will try to see what this my colleagues and
mentat equation explain about active absorption
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if any drug is undergoing active absorption
how this how can we explain that absorption
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pattern by taking Michael is mental equation
Equation now soldiers write the equation the
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equations is velocity is equal to maximum
velocity into concentration divided by Michael
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is Mentent constant + concentration is the
equation which is being derived previously
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ok I'm not going to do this equation I will
be explained what is the contacts in terms
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of absorption so in this this graph in this
grafi have three parts ok first part is take
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this is a linear line then curve and this
is ok so we have first part here this one
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second part here this work so this is the
first part this is a second part and remaining
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is third part of this graph has three parts
hereNobles try to see a case 1 case 2 and
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Kesari what happens in case of absorption
in case of active absorption ok absorption
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through carrier mediated system so case 1
let se case 1 what is happening here is what
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is happening here is we can take it has like
a KTM is much much greater than concentration
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km is much much greater than the concentration
in such case what happens to the equation
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so equation adjust write the equation because
you are came is much much greater than the
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concentration we can neglect this concentration
camp Lassi will become km and we can write
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the equation as we both are constant maximum
velocity and also your Michael is meant it
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is also a constant so we can write it has
a velocity is equal to constant into valuable
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asset e change in concentration by changing
that is equal to K not check this equation
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how this equation is is a what this equation
is representing it is a present thing first
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order ok so rate of reaction is directly proportional
to the concentration that what this equation
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is representing to draw the graph of this
equation in the Michael is Mentent equation
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the first part is represented by this equation
first part in the cystic here I told this
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part this first part is represented by by
your case 1 ok this one this part is being
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represented by a lawyer this part the first
part is been represented by your first case
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what is saying is what it says I will try
to do the full graph here to avoid the confusion
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ok something this graph will look like this
something now this equation represents the
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first part of the Michael is Mentent graph
this part but it says velocity is increasing
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what the time has concentration increases
the velocity is also increases so what is
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happening here has the concentration of the
drug increases the absorption rate of the
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drug is also increases what do you mean by
this is assume that you have a membrane and
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it assume that there is a git you have a membrane
here ok in this membrane we have active carrier
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carrier mediated system in this membrane we
have carrier mediated system I like this in
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this membrane we have carrier mediated system
analyst at this Academy at systems are 15
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number assume just one thought experiment
will try to do here we have that this carrier
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mediated systems are 15 number floor level
increase the drug concentration is in the
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GIT so here it is blood and this is it inside
the ok slowly increases if I increase if I
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give 10 molecules of drugs year this if I
get and molecules of drugs because the Carriers
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are 15 number all the molecules are been observed
then if I increase further 20 again all the
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molecules are observed if I increase the concentration
2:30 all the molecules will observe because
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the carrier system here is 50 ok all the molecules
will get absorb has the concentration is increased
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so that what this equation is a present case
one if came is much much more than concentration
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in that case that Michael easement equation
is like this and it is showing our it is a
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modified in the form of first order reaction
and also there is a straight line we can see
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here this line is explained by this particular
equation so what is happening has the concentration
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increases absorption rate also increases it
is directly proportional to the concentration
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and we called as a first order that what is
explain in first part first order kinetics
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ok next will try to see the case 2 second
case your km as well as concentration both
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are significant
ok no that significant you can't ignore both
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in such case what happens if your equation
will remain has such because both are important
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for recreational remind her so what does it
indicate is neither the velocity is dependent
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on the concentration not the velocity is not
dependent on the concentration it is showing
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mix Rada previous it is showing first order
now it is showing mixer it is both it is dependent
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9 it is not dependent both zero order of this
part is been explained in the graph of the
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Michael is Mentent equation here this particular
part is explain by this equation so when came
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and C constant and as well as concentration
are significantly court is not both the terms
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in such case what happens this particular
equation remain has it and it explains the
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velocity at the deep end and dependent on
the concentration not it is independent of
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the concentration it is showing mix border
so what is happening here that what this equation
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is saying ok no will see what is happening
here is again will take GIT here and we have
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blood and we have some actively absorbing
pieces ok so if I increase the drug cost carrier
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mediated system how many have 50 molecules
of career immediate system in number 15 number
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their present in the Azeem in the GIT ok so
now in the first case we increase the drug
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concentration till 30 or 40 like that ok now
when the concentration reaches 250 then beyond
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that 5556 ok are you can still 6870 what is
happening here the 50 molecules see here the
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drug molecules is 50 and all the 50 molecules
will go and attached to the carrier mediated
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system because they are also in 15 number
and all the drug is been absorbed initially
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it is first order all how many molecules are
that month molecules are observed if I further
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increase the concentration 255 what happens
here you molecules will go there ok and you
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are actively absorbing species that is a carrier
mediated system it will take a few molecules
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of carrier mediated is it after leaving the
drug in the blood they will come back and
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again pickup the molecules which are present
in the GIT flow process only few will come
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back ok so slowly there will be limiting which
is going to occur and we can clearly see here
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just shift is both it is initially dependent
that is faster and has the concentration increases
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from 55 60 70 it will ship to zero order means
in this case when the concentration and constant
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are significant advances the concentration
is in medium level then what happens medium
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in the sense what compared to the concentration
of your act to actively observing this is
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a carrier mediated system air cancellation
is slightly more than the carrier mediated
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system in such case we can observe both first
order has a second order that we called as
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mixed da ok we call it has a mixture that
what happens in the case to search role in
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there is a shift and we get a curved in the
Michael is melted and the third case is case
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number 3 is if concentration is much much
more than what happened initial concentration
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is less than came then we have concentration
and came are both significant concentration
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is much much more than can higher molecules
of drugs are there in git I will see first
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in the equation C by concentration is much
much more hence KMC can be written as she
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came plus two because came is very less we
can take this came play CSC so if you modify
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the equation for velocity is equal to BMC
by see again this year will get cancelled
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so velocity is equal to VM what is V M it
is a constant maximum velocity is a constant
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term means what velocity is dependent on nothing
here it is zero order zero order means what
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if you keep on increase the concentration
of drug there is no significant change in
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the drug absorption even the increase the
concentration of the drug there is no significant
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change in the drug absorption because here
the saturation of your carrier mediated system
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is going to Aakar I will tell you in this
example we have git lining then blood here
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and we have carrier mediated system that are
we assume that are 50 in number ok if we increase
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our concentration 200 I let se 200 molecules
initially we start with the 1020 and we now
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reach to 200 because concentration of drug
is much much more what happens within this
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250 molecules will go and join will form a
bond with your carrier mediated system and
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it is being carried through a 50-50 molecule
will absorb now I'll increase the concentration
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to 300 then also only 50 molecules will go
wind and again 50 molecule of the no I can
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I will increase the concentration to 400 then
also the rate of absorption is 50 molecules
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only so what is happening here only 50 molecules
are observing even though I am increasing
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the concentration that indicate zero order
this can be represented in the equation like
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this what are the plateau are say the velocity
is not changing what the time even though
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there is increase in the concentration because
concentration is more you are carrier mediated
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system is getting saturated what are the Carriers
we have only 15 number we have that it is
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getting saturated the number 50 what I am
saying is best for your imagination OK where
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are you thought experiment so this is how
we need to understand the Michael is Mentent
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equation in terms of biopharmaceutics RD Kansas
active absorption ok mixed order kinetics
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be called as a mixed order kinetics because
while the drug is undergoing active absorption
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in such case your passive diffusion I cancel
linear kinetics is not observed ok because
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in passive diffusion whether the rate of absorption
is dependent on the concentration are independent
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of the drug concentration but in case of your
active diffusion active absorption your rate
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of absorption is dependence and Independence
will be keep on changing initially it will
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be dependent then it will turn to mixed and
then it will become independent ok as increase
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the drug concentration that what the rate
of absorption will be keep on changing its
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dependency entry card is a mixture or nonlinear
pharmacokinetics because it is known as active
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career know this particular thing I explain
about absorption you can apply this to excretion
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also you can apply this to metabolism also
can apply this to protein binding also distribution
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also wherever there is environment of enzyme
is there are protein is there are wherever
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there is a formation of drug 14 complex is
going to occur in such case we can apply this
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Michael is meant it equation in Ada me also
ok I explained about only absorption we can
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apply this to distribution metabolism and
elimination also how we need to understand
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this ok I hope you understand
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