04 GIT anatomy and phyisiology new.pptx

8/20/2019 04 GIT anatomy and phyisiology new.pptx

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BIOPHARMACEUTICS

&PHARMACOKINETICS


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GIT: Anatomy andPhysiology The enteral system consists of the

alimentary canal from the mouth tothe anus.

Th ma!o" #hysiologi$ #"o$sss thato$$%" in th GI systm a":

' s$"tion(' digstion

)' a*so"#tion


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' S$"tion

Secretion + in$l%ds th t"ans#o"t o,-%id.

l$t"olyts. ##tids and #"otins intoth l%mn

o, th alimnta"y $anal'


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' S$"tion

En/yms in sali0a and #an$"ati$s$"tions a" in0ol0d in thdigstion o, $a"*ohyd"ats and

#"otins' Oth" s$"tions s%$h as m%$%s.

#"ot$t th linings o, th l%mn o, th

GIT'


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(' 1igstion

Digestion + *"a2do3n o, ,ood$onstit%nts into

small" st"%$t%"s in #"#a"ation ,o"

a*so"#tion'

Food constituents are mostly

absorbed in the proximal area(duodenum) of the small intestine.


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)' A*so"#tion

Absorption + nt"y o, $onstit%nts ,"omth l%mn o, th g%t into th *ody4 may* $onsid"d as th nt "s%lt o, *oth

l%mn5to5*lood and *lood5to5l%mnt"ans#o"t mo0mnts'


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Im#o"tant:

1"%gs administ"d o"ally #ass th"o%gh0a"io%s #a"ts o, th nt"al $analin$l%ding th o"al $a0ity. so#hag%s. and

0a"io%s #a"ts o, th GIT' Rsid%s0nt%ally 6it th *ody th"o%gh than%s'


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Im#o"tant:

Th total t"ansit tim. in$l%ding gast"i$m#tying. small intstinal t"ansit and$oloni$ t"ansit "angs ,"om 7'8 to 9 days

Ki"3an & Smith ;


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Im#o"tant:

Small intstin t"ansit tim SITT="angs ,"om 3 to 4 ho%"s ,o" mosthalthy s%*!$ts' I, a*so"#tion is not

$om#ltd *y th tim a d"%g la0sth small intstin. a*so"#tion may *""ati$ and in$om#lt +ABSORPTION>IN1O>


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Im#o"tant:

Th small intstin is no"mally ?lld 3ithdigsti0 !%i$s and li@%ids. 2#ing thl%mn $ontnts -%id'


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Im#o"tant:

In $ont"ast. th -%id in th $olon is"a*so"*d. and th l%minal $ontntin th $olon is ith" smisolid o"

solid. ma2ing ,%"th" d"%g dissol%tion""ati$ and di$%lt'


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Im#o"tant:

Th la$2 o, th sol%*ili/ing $t o,th $him and digsti0 -%id$ont"i*%ts to a lss ,a0o"a*l

n0i"onmnt ,o" d"%g a*so"#tion'


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Th no"mal #hysiologi$ #"o$sss o, thalimnta"y $anal may * a$td *y:

' dit

(' $ontnts o, th GIT

)' Ho"mons

8' 0is$"al n"0o%s systm

9' 1isas dia""ha. in-ammato"y *o3ldisas=

' 1"%gs anti$holin"gi$s=


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Im#o"tant:

Th%s d"%gs gi0n *y th nt"al "o%t,o" systmi$ a*so"#tion may *a$td *y th anatomy. #hysiologi$

,%n$tions and $ontnts o, thalimnta"y t"a$t'


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Im#o"tant:

Mo"o0". th #hysi$al. $hmi$al and

#ha"ma$ologi$ #"o#"tis o, th d"%gitsl, 3ill also a$t its o3n a*so"#tion,"om th alimnta"y $anal'


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Rasons 3hy GIT o"s an $inta*so"#tion systmD

' $o#io%s *lood s%##ly

(' nti" lngth o, GIT is lind 3ithm%$o%s mm*"an

m%$o%s mm*"an is "i$h in *lood0ssls and 3ill ,a$ilitat a*so"#tion o,d"%g4 it s$"ts m%$in 3hi$h is a highm3 #olysa$$ha"id that may *ind d"%gs


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Rasons 3hy GIT o"s an $inta*so"#tion systmD

)' th" a" a"o%nd F57 lit"s o,-%idday

#"od%$d *y o" s$"td into th GIT4

and5( lit"s $om ,"om th ,ood and

-%id

inta2'8' GIT is #",%sd *y $a#illa"y nt3o"2that

allo3s $int a*so"#tion and


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Bio#ha"ma$%ti$al 1ata o, thGast"ointstinal T"a$t

Part pH Remarks

Oral Cavity 7Has an average length of 15-20cm and its main secretion issaliva 1!500ml"day# $hichcontain ptyalin! a salivaryamylase and can digeststarches% &t also secretes m'cin$hich is a glycoprotein that mayinteract $ith dr'gs% (illi isa)sent%


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Part pH Remarks

*tomach 2-+1%5-2

,asting

Presence of food

*ecretion histamine H2# gastrin

.astrin reg'lated )y stomach

distention presence ofpeptides and amino acids


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Part pH Remarks

*tomach/asic dr'gs are sol')iliedrapidly )y stomach acid

mptying is inf'enced )y foodcontent and osmolality


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Part pH Remarks

'oden'm +-+%5

Presence of )icar)onate

3rypsin! chymotrypsin car)o4ypeptidase proteins toamino acids

mylase CHO

Pancreatic lipase

fats to fattyacids


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Part pH Remarks

'oden'mComple4 fl'id medi'm helpsdissolve dr'gs $ith limiteda6'eo's sol')ility

ster prodr'g are hydrolyed

Protein dr'gs are 'nsta)le d'e

to proteolytic enymes


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Part pH Remarks

&le'm 7 cid dr'gs $ill dissolve d'e to)icar)onate secretion

,ats and hydropho)ic dr'gs aredissolved )y )ile secretion


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Part pH Remarks

Colon 5%5-7

ack microvilli

(ery limited dr'g a)sorption d'eto visco's and semisolid nat'reof l'men contents

8'cin l')ricant and

protectant


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Part pH Remarks

Colon3heophylline metoprolol area)sor)ed

)sor)ed at this region are goodcandidates for s'stained releasedosage forms

ero)ic aero)icmicroorganisms $hichmeta)olies dr'gs -dopa andlact'lose#


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Part pH Remarks

Rect'm 7 *'perior hemorrhoidal vein

8iddle hemorrhoidal vein

&nferior hemorrhoidal vein


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T it ti , 1 i th


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T"ansit tim o, 1"%g in thGI T"a$t Pha"ma$ologi$ #"o#"tis o, th d"%g

Ty# o, dosag ,o"m #hysi$o$hmi$al#"o#"tis=

Physiologi$ ,a$to"s + 3ith ,ooddigsti0,d stat= o" ,astdint"digsti0 stat=

Mi ti M t C l


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Mig"ating Moto" Com#l6MMC= Alt"nating $y$ls o, #"o#%lsi0

mo0mnt that m#tis th %##" GIt"a$t to th $$%m

Mi ti M t C l


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Mig"ating Moto" Com#l6MMC=

& && &&&&( ,eeding

90-+0 20-:0 10-200-5

&nterdigestive fasted# state igestive fed# state

Mi ti M t C l


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Mig"ating Moto" Com#l6MMC= Bil s$"tion *gins at #has II

Onst o, #a"ti$l & m%$%s dis$ha"g mayo$$%" d%"ing th latt" #a"t o, #has II

M%$%s & #a"ti$l dis$ha"g $ontin%s at#has III


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%n$tions o, Gast"i$ Motility

To allo3 th stoma$h to s"0 as a"s"0oi" ,o" th la"g 0ol%m o, ,oodthat may * ingstd at a singl mal

To ,"agmnt ,ood into small" #a"ti$ls tomi6 $hym 3ith gast"i$ s$"tion so thatdigstion $an *gin

Em#ty gast"i$ $ontnts into thd%odn%m at a $ont"olld "at gast"i$m#tying tim=

a$to"s that a$t gast"i$


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a$to"s that a$t gast"i$m#tying ol%m + la"g 0ol%m. g"at" initial

,ollo3d *y slo3 m#tying

atty a$ids + %nsat%"atd J sat%"atd.

8C $hain o" mo" J sho"t & mdi%m$hain D emulsifed by bile acid &lecithin in bile

Ca"*ohyd"ats + hy#"osmola"

D P"otins + hy#"osmola" D



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a$to"s that a$t gast"i$m#tying Osmoti$ #"ss%" + "at o, m#yting

may in$"as at lo3" $on$' thnd$"as at high" $on$'

Physi$al stat o, gast"i$ $ontnts +small" #a"ti$ls D

A$ids D 5 lo3 M> J high M>

neutralized by pancreatic & duodenalsecretions



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a$to"s that a$t gast"i$m#tying Al2ali + in$"asd at lo3 $on$' =.

d$"asd at high $on$' 9=

1"%gs5 anti$holin"gi$ D. na"$oti$

analgsi$ mo"#hin= D.mto$lo#"amid D. thanol D

Body #osition + lying on th l,t sid D

is$osity + mo" 0is$o%s

D



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a$to"s that a$t gast"i$m#tying Emotional stats + agg"ssi0st"ss,%l

stat D. d#"ssionD

Bil salts 5 D

E6"$is 5 D 1isas stats + hy#othy"oidism 0s

hy#"thy"oidism D. dia*ti$s D


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Slo3 in gast"i$ m#tying dlay int"ansit to th d%odn%m delay inabsorption delay onset of action


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Intstinal Motility

1"%gs m%st ha0 a s%$int tim"sidn$ tim= at th sit ,o" o#tim%ma*so"#tion

1ia""ha a*so"#tion o, a d"%gD Small intstin t"ansit tim SITT=

d"%g 3ill ta2 a*o%t 4! hours ,astd

stat= & !"# hours ,d stat= to #assth"o%gh th stoma$h & SI


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Intstinal Motility

Mo%th5to5an%s t"ansit tim L $3.3 ho%"s

Man $olon t"ansit tim L 3$ ho%"s


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P",%sion o, GI t"a$t

Im#o"tant in $a""ying th d"%g intosystmi$ $i"$%lation

S#lan$hni$ $i"$%lation "$i0s a*o%t

(F o, th $a"dia$ o%t#%t and isin$"asd a,t" mals

Som d"%gs 'g' *lomy$in #"#a"d in

$hylomi$"ons= $an * a*so"*d inlym#hati$ $i"$%lation and *y#ass ?"st5#ass $t


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E$t o, ood on GI d"%g a*so"#tion

1lay in gast"i$ m#tying

Stim%lation o, *il -o3

Chang in #H o, th GI t"a$t

An in$"as in th s#lan$hni$ *lood -o3

Chang in th l%minal mta*olism o,d"%g s%*stan$

Physi$al o" $hmi$al int"a$tion o, thmal 3ith th d"%g #"od%$t


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Rd%$d a*so"#tion 3ith ,ood

Tt"a$y$lin

Pni$illin G

Isonia/id

Amo6i$illin

As#i"in

Ri,am#in

%"osmid

Phna$tin

1layd a*so"#tion 3ith


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1layd a*so"#tion 3ith,ood As#i"in

A$tamino#hn

Nit"o,%"antoin

1igo6in

S%l?so6a/ol

C#h"adin

C,a$lo"

S%l,adia/in

In$"asd a*so"#tion 3ith


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In$"asd a*so"#tion 3ith,ood 1i$o%ma"ol

G"iso,%l0in

Phnytoin

Mto#"olol

O6a/#am

P"o#"anolol

Hyd"ala/in


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Not a$td 3ith ,ood

Tho#hyllin

P"dnison

Chlo"#"o#"amid

Mt"onida/ol

P"o#ylthio%"a$il


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E$t o, ,ood on GI d"%g a*so"#tion

Ca%s

Calo"i$ $ontnt

Mal 0ol%m

Mal tm#"at%" E$t 1"%g #"od%$t t"ansit tim %minal dissol%tion

1"%g #"ma*ility

Systmi$ a0aila*ility


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1A R$ommndation

High5$alo"i and high5,at mals $to, ,ood on th *ioa0aila*ility and*io@%i0aln$ o, d"%g #"od%$ts


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Pni$illin. tt"a$y$lin and $"tainhyd"o#hili$ d"%gs ha0 d$"asda*so"#tion 3ith ,ood

G"iso,%l0in a" a*so"*d *tt" 3ith,ood $ontaining high ,at $ontnt

Bil in$"as a*so"#tion o, ,at sol%*ld"%gs th"o%gh mi$ll ,o"mation


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Som *asi$ d"%gs $inna"i/in= 3ithlimitd a@%o%s sol%*ility $an %nd"go"a#id dissol%tion and *tt" a*so"#tion

in th #"sn$ o, ,ood

a$id s$"tion#H


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Gn"ally. *ioa0aila*ility o, d"%g is*tt" in a ,astd stat and 3ith a la"g"0ol%m o, 3at"

1"%gs "yth"omy$in. i"on salts. as#i"in &NSAI1s= a" gi0n 3ith ,ood to "d%$gast"i$ i""itaion a*so"#tion "at is"d%$d *%t th 6tnt & $a$y is th

sam Una*so"*d anti*ioti$ in th GI t"a$t D

D

S%staind5"las ta*lt and dia""ha


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Ent"i$5$oatd ta*lt 0s nt"i$5$oatd*adsmi$"o#a"ti$ls in th #"sn$ o,,ood D D d"%g a*so"#tion

ood $an a$t th intg"ity o, thdosag ,o"m tho#hyllin $ont"olld5"las ta*lt= *ioa0aila*ility mo" "a#idin th ,d5stat than ,astd5stat dos

d%m#ing G"an%ls 5( mm in si/= and ta*lts

that asily disintg"ats in th #"sn$

o, ,ood

D D


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E$t o, ,ood on GI d"%g


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E$t o, ,ood on GI d"%ga*so"#tion

Timing o, ta2ing th mds in "lation tomals H(5 *lo$2"s

atty ,oods 3hi$h may dlay stoma$h

m#tying

D D timing o, d"%gs that a"snsiti0 to a$id

#H in "lation to d"%g dissol%tion tt"a$y$lin and sodi%m *i$a"*onat

ood may nhan$ a*so"#tion o, d"%gs*yond ( ho%"s a,t" mals 'g'$,#odo6im #"o6til=


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Timing o, d"%g inta2 in "lation to ,ood

Th"a#%ti$ goal

Physi$o$hmi$al #"o#"tis o, th d"%g#2a. sol%*ility. #a"ti$l si/. sta*ility in

gast"i$ #H= 1osag ,o"m s%staind5"las ta*lt.

sol%tion. nt"i$5$oatd ta*lt=

Cha"a$t" o, th d"%g gast"i$ i""itant= 1"%g int"a$tionin$om#ati*ilitis 'g'

tt"a$y$lin anta$ids=


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1o%*l5#a2 #hnomnon

Us%ally sn in administ"d singl doso, ,astd #atints

a"ia*ility o, stoma$h m#tying

a"ia*ility in intstinal motility P"sn$ o, ,ood

Ent"oh#ati$ "$y$ling

ail%" o, a ta*lt dosag ,o"m

*l 2 h


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1o%*l5#a2 #hnomnon

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04 GIT anatomy and phyisiology new.pptx