*Co esponding au ho : Shwe a Goga e
Copy igh © 2025 Au ho (s) e ain he copy igh o his a icle. This a icle is published unde he e ms o he C ea i e Commons A ibu ion License 4.0.
Syn hesis and e alua ion o amide p od ugs o me enamic acid o colon a ge ing
Shwe a Goga e * and Vishal Gup a
Depa men o Pha maceu ical chemis y, Mansa o a Global Uni e si y, Bilkisganj, Seho e, M.P.
GSC Biological and Pha maceu ical Sciences, 2025, 32(03), 294-303
Publica ion his o y: Recei ed on 09 Augus 2025; e ised on 19 Sep embe 2025; accep ed on 22 Sep embe 2025
A icle DOI: h ps://doi.o g/10.30574/gscbps.2025.32.3.0363
Abs ac
P od ug app oach is one o he impo an app oaches o a ge ing d ugs o colon. P od ug design has pa ed a way o
o e come he undesi able p ope ies associa ed wi h he exis ing d ug and success ul si e-speci ic d ug deli e y o
a ied o gans and issues. Colon-speci ic d ug deli e y h ough colon-speci ic p od ug ac i a ion may be accomplished
by he u iliza ion o high ac i i y o ce ain enzymes a he a ge si e ela i e o non- a ge issues o p od ug o d ug
con e sion. Fo he p esen s udies me enamic acid was selec ed because o being cu a i e agen s o mos p e alen
colon disease namely in es inal bowel disease due o any eason. An i-in lamma o y he apy, a p esen , in ol es use o
co icos e oids, as all NSAIDs a e abso bed in he s omach and hey do no each o colon. Mos o he NSAIDs ha e ee
ca boxylic acid g oups, al hough, i is impo an o hei ac i i y bu hey can be a ge ed o colon ia o ma ion o
mu ual p od ugs ( amide). Hyd oly ic enzymes o s omach o ileum do no hyd olyze such mu ual p od ugs. Abso p ion
o he NSAIDs p ima ily akes place in he s omach and ollowed wi h jejunum due o lipophilici y o he unionized o m.
Thus, hey do no each o he colon and also ulce ogenic which can also be a oided by o ma ion o hei mu ual
p od ugs. O dina y ea men o IBD equi es equen in ake o an i-in lamma o y d ugs a highe doses. Mos o hese
d ugs a e apidly abso bed om small in es ine wi h e y small ac ion ac ually eaching he si e o ac ion i.e. colon.
In e ac ion wi h non- a ge ed si es leads o signi ican ad e se e ec s. The e o e, ou o he need o o e come his
o midable ba ie o GIT, colon- a ge ed deli e y has e ol ed as an ideal d ug deli e y sys em o he opical ea men
o local diseases o colon like in lamma o y bowel disease. Minimizing d ug-induced side e ec s and mo ali y a e he
main challenges du ing managemen o IBD.
Keywo ds: Colon-speci ic d ug deli e y; Ulce a i e coli is; Me enamic acid; P od ug; An i-in lamma o y ac i i y
1. In oduc ion
The o al ou e is conside ed o be mos con enien o adminis a ion o d ugs o pa ien s. O al adminis a ion o
con en ional dosage o ms no mally dissol es in he s omach luid o in es inal luid and abso b om hese egions o
he GIT depends upon he physicochemical p ope ies o he d ug. I is a se ious d awback in condi ions whe e localized
deli e y o he d ugs in he colon is equi ed o in condi ions whe e a d ug needs o be p o ec ed om he hos ile
en i onmen o uppe GIT. Dosage o ms ha deli e d ugs in o he colon a he han uppe GIT p o e s numbe o
ad an ages. O al deli e y o d ugs o he colon is aluable in he ea men o diseases o colon (ulce a i e coli is, c ohn’s
disease, ca cinomas and in ec ions) whe eby high local concen a ion can be achie ed while minimizing side e ec s ha
occu because o elease o d ugs in he uppe GIT. The colon is a ac ing in e es as a si e whe e poo ly abso bed d ug
molecule may ha e an imp o ed bioa ailabili y. Also, he colon has a longe e en ion ime and appea s highly
esponsi e o agen s ha enhance he abso p ion o poo ly abso bed d ugs. Apa om e a ding and a ge ing dosage
o ms, a eliable colonic d ug deli e y could also be an impo an s a ing posi ion o he colonic abso p ion o pe o ally
applied, undiges ed, unchanged and ully ac i e pep ide d ugs. The p esence o colonic mic o lo a (en e obac e ia) ha
is esponsible o speci ic enzyma ic ac i i y. The colonic bac e ia a e p edomina ely anae obic in na u e and sec e e
GSC Biological and Pha maceu ical Sciences, 2025, 32(03), 294-303
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enzymes ha a e capable o me abolizing subs ances such as ca bohyd a es and p o eins ha escape he diges ion in
he uppe GI ac .1,2
Ea lie colon was conside ed as a black-box ac ing as a si e o p oduc ion and empo a y s o age o exc e a and
esponsible o abso p ion o elec oly es and wa e . Bu , because o challenging issue o ea ing local pa hologies o
colon, i has eme ged as an o gan o signi icance o a ge -speci ic deli e y o d ugs. The e a e many a ibu es o colon
ha can be explo ed and exploi ed o si e-speci ic deli e y o d ugs such as :Less hos ile en i onmen , nea neu al pH,
less di e si y and in ensi y o enzyma ic ac i i ies han s omach and small in es ine, long colonic ansi (20-30 h) o
ex ended abso p ion window, highly esponsi e o abso p ion enhance s, unique mic obial lo a and enzymes,
minimized sys emic exposu e o d ugs, educed isk o i s -pass me abolism, mo e chances o d ug being a ailable in
i s e ec i e concen a ion, lowe dosing and p e alence o sys emic side e ec s and A ac i e si e o d ugs which a e
hyd ophilic o poo ly abso bed om uppe GIT.3,4
2. Colonic mic o lo a and sec e ed enzymes:
Ou o he 100 illion mic oo ganisms esiding in he GIT, maximum anae obic popula ion is ound in la ge in es ine
which is in ol ed in e men a ion o ca bohyd a es/p o eins ha escape diges ion in he uppe GIT. D ugs and
xenobio ics a e ex ensi ely me abolized by di e se a ay o enzymes sec e ed by colonic mic obio a. As we a el om
s omach o la ge in es ine, he popula ion o bac e ia goes on inc easing om 102-104 c u/ml in s omach and 105-107
c u/ml in lowe small in es ine o he maximum o 1011-1012 c u/ml in he colon whe e, 102-104 imes mo e anae obic
bac e ia han ae obes a e ound. Tha is he eason why he occu ence o oxida i e me abolism is compa a i ely a e
in he colon as compa ed o li e . The educ i e and hyd oly ic pa hways domina e he me abolic scene in he colon.
The concen a ion o p o eoly ic enzymes is also low in colon ha makes i a p omising si e o deli e y o p o eins and
pep ides. Sudden inc ease in he popula ion o bac e ia and ela ed ise in he concen a ion o sec e ed enzymes in he
colon is conside ed as a non-con inuous e en which is no dependen on GI ansi ime. This is a p e e able se up ha
can be u ilized as a igge ing mechanism o he ac i a ion o a colon-speci ic d ug deli e y sys em. The a ious
enzymes ca alyzing educ ion eac ions in colon a e azo educ ases (azo compounds), ni o educ ases (a oma ic and
he e ocyclic ni o compounds), sul oxide educ ases (sul oxides), hyd ogenases (alipha ic double bonds and ca bonyl
g oups) and N-oxide educ ase (N-oxides). Glycosidases, glucu onidases, N-acyl amidases, sul a ases and es e ases
sec e ed by he colonic mic o lo a a e in ol ed in hyd olysis o β-glycosides and glucu onides, amides wi h amino acids,
sul a es and sul ama es and es e s o ca boxylic acids wi h polysaccha ides espec i ely.5-7
The colon a ge ed d ug deli e y is de eloped o he e ec i e managemen o IBD (Ulce a i e coli is, C ohn’s disease),
local pa hologies, ch ono he apy (as hma, hype ension, ca diac a hy hmias, a h i is o in lamma ion), g ea e
esponsi eness o he abso p ion enhance s, less enzyma ic ac i i y, si e o deli e y o delica e d ugs (P o eins and
Pep ides), o al deli e y o accines as i is ich in lymphoid issues.8
2.1. P od ug o ma ion o colon a ge ing
This app oach in ol es he o ma ion o p od ug o a ge ing d ugs o colon. I in ol es he o ma ion o a co alen
linkage be ween d ug and ca ie in such a way ha upon o al adminis a ion he moie y emains in ac in he s omach
and small in es ine. The p oblem o s abili y o ce ain d ugs om he ad e se en i onmen o he uppe GIT can be
elimina ed by p od ug o ma ion, which is con e ed in o pa en d ug molecule once i eaches in o he colon. Si e
speci ic d ug deli e y h ough si e speci ic p od ug ac i a ion may be accomplished by he u iliza ion o some speci ic
p ope y a he a ge si e, such as al e ed pH o high ac i i y o ce ain enzymes ela i e o he non- a ge issues o
he p od ug-d ug con e sion.9,10
2.2. E alua ion Techniques o CDDS
In- i o e alua ion, no any s anda dized es ima e me hod is accessible o assessmen o CDDS because an ideal in- i o
model should acqui e he in- i o en i onmen o GIT such as pH, s i ing, bac e ia, enzymes, olume, enzyme ac i i y,
and o he componen s o ood. Gene ally, hese ci cums ances a e inclined by he die , physical s ess, and hese ac o s
make i ha d o plan a s anda din- i o model. In i o models used o CDDS a e:
2.2.1. In i o dissolu ion es
Dissolu ion o con olled- elease o mula ions employed o colon-speci ic d ug deli e y a e mainly ha d, and he
dissolu ion echniques desc ibed in he USP canno ully imi a e in- i o si ua ion such as hose ela ing o bac e ial
en i onmen , pH and mixing o ces. Dissolu ion es s desc ibing o CDDS may be ca ied ou using he conse a i e
baske me hod. Pa allel dissolu ion s udies in di e se bu e s may be unde aken o dis inguish he beha iou o
GSC Biological and Pha maceu ical Sciences, 2025, 32(03), 294-303
296
o mula ions a di e en pH le els. Dissolu ion es s o a colon- speci ic o mula ion in di e en media simula ing pH
ci cums ances and imes likely o be s umble upon a di e en loca ions in he gas oin es inal ac ha e been s udied.
The media chosen we e examined o simula e gas ic luid, pH 6.8 o simula e he jejunal egion o he small in es ine,
and Ph 7.2 o simula e he ileum segmen . En e ic- coa ed capsules o CDDS ha e been examined in a g adien
dissolu ion s udy in h ee bu e s.11-14
2.2.2. In i o enzyma ic es s
Incuba ion o ca ie d ug sys em in e men e holding app op ia e medium o bac e ia (B. o a us and S ec ococcus
accium). The quan i y o d ug p oduced a dissimila ime in e als a e de e mined. D ug elease s udy is comple ed in
bu e medium con aining enzymes (dex anase, ezypec inase), o a o guinea pig o abbi cecal con en s. The quan i y
o d ug p oduced in a pa icula ime is done, which is p opo ional o a e o dep i a ion o polyme .15
2.2.3. In i o e alua ion
A numbe o animals such as guinea pigs, a s, dogs, and pigs a e used o sc eening he deli e y o d ug o colon because
hey look like he ana omic and physiological ci cums ances as well as he mic o lo a o human GIT. While deciding a
model o es ing he CDDS, compa a i e model o he colonic diseases should also be measu ed. Guinea pigs a e
mainely used o expe imen al IBD model. The dis ibu ion o azo educ ase and glucou onidase po en ial in he GIT o
a and abbi is ai ly equi alen o ha in he human.16,17
3. Me hodology
3.1. Physicochemical Cha ac e iza ion o d ug and p od ugs
3.1.1. Mel ing Poin De e mina ion
The mel ing poin s o he d ug and he syn hesized conjuga es we e de e mined by open capilla y ube using Toshniwal
Mel ing Poin Appa a us and e o s a e unco ec ed.18
3.1.2. Thin Laye Ch oma og aphy
The pu i y o he syn hesized de i a i es was ensu ed by subjec ing o hin laye ch oma og aphy. I was ca ied ou
on silica gel p ecoa ed pla es o Me ck wi h ace one: chlo o o m: ace ic acid (3:2:1). as sol en sys em used o p od ugs
and iodine apou s and UV ligh we e used as de ec ing agen o isualiza ion. All syn hesized de i a i es ga e b own
spo . R alues we e calcula ed om he TLC pla es.19
3.1.3. Pa i ion coe icien de e mina ion
Pa i ion coe icien was de e mined in oc anol/ phospha e bu e (pH 7.4) a 37± 1ºC. n-Oc anol and wa e we e
mu ually sa u a ed wi h each o he p io o use. A p od ug (10 mg) was dissol ed in n-oc anol (10 mL) and 10 mL
dis illed wa e was slowly added o i and he oc anol- wa e mix u e was shaken o 24 h on a w is shake o each
dis ibu ion equilib ium. The wo laye s we e sepa a ed by sepa a ing unnel and aqueous laye was es ima ed by
JascoV-530, UV- Visible double beam spec opho ome e a p e-de e mined λmax.20
3.2. Syn hesis o mu ual amide p od ugs o me enamic acid wi h amino acids
3.2.1. Syn hesis o amino acid me hyl es e hyd ochlo ide:
F eshly dis illed hionyl chlo ide (0.05mol + 30% excess: 5 mL) was slowly added o me hanol (100 mL) wi h cooling
and amino acid (0.1mol) was added o i . The mix u e was e luxed o 7-8 h a 60-70°C wi h con inuous s i ing on
Radley’s six s a ion pa allel syn hesize s. Excess o hionyl chlo ide and sol en was emo ed unde educed p essu e
on a o a y e apo a o gi ing c ude es e which was i u a ed wi h 20 mL po ions o cold e he a 0°C, un il dime hyl
sulphi e was comple ely emo ed and d ied unde high acuum. I was ec ys allized om ho me hanol by slow
addi ion o 15-20 mL o e he ollowed by cooling a 0°C. C ys als we e collec ed on he nex day, washed wice wi h
e he : me hanol mix u e (5:1; / ) ollowed by pu e e he and d ied unde acuum o gi e pu e p oduc .21
3.2.2. Con e sion o AAME. HCl o amino-acid me hyl es e (AAME)
To suspension o (0.025mol) in 30 mL chlo o o m, TEA (0.05mol) was added wi h s i ing a 0ºC o 30min. The sol en
was dis illed o unde acuum and he d y esidue o es e was used as such o coupling s ep.22
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3.2.3. Syn hesis o mu ual amide p od ugs o me enamic acid wi h amino acids by CDI coupling
Me enamic acid (0.001mol) was dissol ed in DCM (10 mL) and o his solu ion CDI (0.0015 mol) was added a oom
empe a u e wi h s i ing o 2-4 h. AAME (0.001 mol) in DCM (10 mL) was hen added o he abo e solu ion and
e luxed a 45ºC o 16-20 h. The comple ion o eac ion was moni o ed by TLC using DCM: n-hexane: TEA (0.8.0.2:0.05;
/ / ). The eac ion mix u e was washed wi h dis illed wa e (3 x 10 mL) and sa u a ed solu ion o sodium bica bona e
(2 x 10 mL). The o ganic laye was sepa a ed and d ied o e anhyd ous sodium sulpha e. The esidue ob ained upon
e apo a ion o o ganic laye was ec ys allized wi h e hanol. Pu i ica ion o p od ugs o me enamic acid wi h amino
acids was achie ed by column ch oma og aphy using e hyl ace a e: hexane (80:20; / ).23,24
3.3. In i o elease s udies o syn hesized mu ual p od ugs
The weighed amoun o p od ug (10 mg) was ans e ed o 100 ml olume ic lask and olume was made up o 100
ml wi h PBS (pH 7.4) o ob ain a s ock solu ion o 100 µg/ml. F om his 1 ml was wi hd awn each ime and aken in 10
ml olume ic lask. Volume was made up o 10 ml sepa a ely wi h SGF, SJF, SIF and SCF, espec i ely. These solu ions
we e scanned be ween 220-380 nm on Shimadzu 1700 UV double beam spec opho ome e . Same p ocedu e was
ollowed o SIF and a ecal ma e .25,26
3.4. Pha macological sc eening o d ugs and p od ugs
3.4.1. An i In lamma o y Ac i i y
In he p esen s udy, he an i-in lamma o y ac i i y o d ugs and p od ugs we e de e mined by hind paw oedema
me hod using ca ageenan (0.1 ml, 1 % w/ ) as phlogis ic agen . Wis a albino a s (150-200 g) we e di ided in o
di e en g oups, each comp ising o six animals, including a con ol and a s anda d g oup. The ini ial olume o igh
hind paw o a was measu ed by ple hysmome e wi hou adminis a ion o d ug. A 1 % sodium ca boxy me hyl
cellulose (CMC) suspension con aining d ug (100 mg) was p epa ed and a olume o his suspension con aining an
equi alen dose (Me enamic acid-50 mg/kg/body w ) was adminis e ed o ally o he s anda d g oups. Simila ly
equi alen quan i y o each p od ug was adminis e ed o he es g oups. A e 30 min o adminis a ion o he d ug o
p od ugs, ca ageenan solu ion in no mal saline was injec ed in o he plan e su ace o igh hind paw o each animal.
The olume o swelling o igh hind paw o each a was measu ed a e 0.5, 1, 2, 4 and 6 h. The mean inc ease in he
olume o he igh hind paw o a s was compa ed wi h con ol and s anda d. The pe cen inhibi ion o paw oedema
was calcula ed as
Pe cen age inhibi ion = (1-V /Vc) x100
whe e V - mean ela i e change in paw oedema olume in es g oup, Vc – mean ela i e change in paw oedema olume
in con ol g oup.27,28
3.4.2. Ulce ogenic Ac i i y
Gas oin es inal oxici y o he d ugs and p od ugs was measu ed and compa ed wi h he pa en d ug by measu ing
mean ulce index. Wis a albino a s we e di ided in o di e en g oups, each comp ising six animals, including a con ol
and s anda d g oup. The con ol g oup was adminis e ed o ally by 2 % acacia suspension. Tes compounds and
s anda d we e adminis e ed o ally (a 10 imes highe dose) as a suspension wi h 2 % acacia daily o 5 days. The a s
we e as ed a e he adminis a ion o las dose, he ea e hey we e sac i iced by decapi a ion and he s omach was
emo ed, opened and washed wi h dis illed wa e . The lesions on he gas ic mucosa we e coun ed by isual
examina ion using a binocula magni ie . Ulce s g ea e han 0.5 mm we e eco ded. The mean ulce index (UI) was
calcula ed by se e i y o gas ic mucosal lesions which a e g aded as g ade 1: less han1 mm e osions, g ade 2: 1-2 mm
e osions and g ade 3: mo e han 2 mm e osions. The UI was calcula ed as.29,30
UI = [1× (numbe o lesions o g ade 1) + 2× (numbe o lesions o g ade 2) + 3× (numbe o lesions o g ade 3)]/10
3.5. TNBS induced expe imen al coli is model
3.5.1. Induc ion o Coli is
Ra s we e as ed o 24 h be o e expe imen a ion. Ra s we e ligh ly anes he ized wi h ke amine and xylazine (20mg/kg
and 5mg/kg, i.m.). A polye hylene ca he e wi h 2 mm diame e was inse ed h ough he ec um in o he colon o a
dis ance o 8 cm. Fo ulce a i e coli is induc ion, TNBS dose was 150 mg/kg o body weigh o TNBS in e hanol, 50%
solu ion) was in used in o he colon o all a s (excep he no mal con ol g oup) h ough he ca he e , held in place o
30 sec. The ca he e was le in place o ew seconds hen gen ly emo ed. Fo 3 days he a s we e housed wi hou
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ea men o main ain he de elopmen o a ull in lamma o y bowel disease model wi h ull access o ood and wa e
ad libi um. The animals o s anda d and es g oups ecei ed o ally sul asalazine and p od ugs espec i ely, once daily
o i e con inuous days. The no mal con ol and coli is con ol g oups ecei ed only 1% ca boxy me hylcellulose
ins ead o ee d ug o p od ug.31
3.5.2. Assessmen o colonic damage by clinical ac i i y sco e:
The animals o all g oups we e examined o weigh loss, s ool consis ency and ec al bleeding h oughou he 11 days
s udy. The clinical ac i i y sco e was de e mined by calcula ing he a e age o he abo e h ee pa ame e s o each day,
o each g oup and was anging om 0 (heal hy) o 4 (maximal ac i i y o coli is).32
3.6. Measu emen o MPO ac i i y in TNBS-induced coli is
The ac i i y o in es inal MPO, was measu ed using he me hod o K awisz , wi h mino modi ica ions. B ie ly, in es inal
issue samples (app oxima ely 50-100 mg) we e homogenized on ice using a poly on (13, 500 pm, one minu e) in a
solu ion o 0.5% HTAB in 50 mM po assium phospha e bu e (HTAB, pH 6.0, 1 mL pe 50 mg issue). The esul ing
homogena e was subjec ed o h ee apid eezing (70°C) and (imme sion in wa m wa e , 37°C) cycles. The samples
we e hen cen i uged (4000 pm, 15 minu es, 4°C) o emo e insoluble ma e ial. The MPO con aining supe na an (0.1
mL) was assayed spec opho ome ically a e addi ion o 2.88 mL phospha e bu e (50 mM, pH 6.0) con aining 0.167
mg/mL o-dianisidine hyd ochlo ide and 10 µL 0.0005% hyd ogen pe oxide. The kine ics o abso bance changes a 470
nm was measu ed. Sample enzyme ac i i y was calcula ed wi h a s anda d cu e o known MPO uni ac i i y. One uni
o MPO ac i i y, de ined as he quan i y o enzyme able o con e 1 µmol o hyd ogen pe oxide o wa e in one minu e
a oom empe a u e, was exp essed in mU/100 mg o issue.33
4. Resul s:
4.1. Cha ac e iza ion o me enamic acid p od ugs
Table 1 Physicochemical cha ac e iza ion o amide p od ugs
P od ug
Colou
Mel ing
poin (oC)
Yield (%)
R
alue
Log P
MA1
Yellow
155-157
67
0.54
1.86
MA2
Yellow
166-168
57
0.56
1.06
MA3
Yellow
171-172
74
0.46
0.96
MA4
Yellow
178-179
68
0.49
0.73
Spec al da a o amide p od ug o me enamic acid
• Spec al da a o amide p od ug o me enamic acid-Isoleucine (MA1)
IR (KB , cm-1): 3420 (NH s ), 2920 and 2857 (CH s .), 1670 (CO s . o es e ), 1620, 1586, 1470 and 1407(C=C o
a oma ic ing), 1260 (OCH3), 756 (1,2-o ho, disubs i u ed);
1H NMR (δ, ppm) (DMSO): 8.37-8.20 (m, 4H, a oma ic ing), 7.91-7.73 (d, 3H, CH in ing), 4.35 (d, 1H, CONH), 3.82 (1H,
NH in ing), 3.30 (s, 3H o OCH3), 2.176(s, 3H, o CH3), 1.21 (d, 2H o CH2).
• Spec al da a o amide p od ug o me enamic acid-Cys eine (MA2)
IR (KB , cm-1): 3439 (NH s .), 2945 and 2821 (CH s .), 2552(SH s .), 1686 (CO s . o es e ), 1610, 1576, 1480 and
1405(C=C o a oma ic ing), 1263 (OCH3), 750 (1,2-o ho, disubs i u ed);
1H NMR (δ, ppm) (DMSO): 8.38-8.22 (m, 4H, a oma ic ing), 7.89-7.75 ( , 3H, CH in ing), 3.33 (d, 1H, CONH), 2.89 (1H,
NH in ing), 2.81 (s, 3H o OCH3),2.54( , 1H, SH), 2.49(s, 3H, o CH3), 2.42 (d, 2H o CH2).
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• Spec al da a o amide p od ug o me enamic acid-Glu amic acid (MA3)
IR (KB , cm-1): 3446 (NH s . o amide), 2952 and 2832 (CH s .), 1689 (CO s . o es e ), 1617, 1566, 1476 and 1401(C=C
o a oma ic ing), 1254 (OCH3), 757 (1,2-o ho, disubs i u ed);
1H NMR (δ, ppm) (DMSO): 8.35-8.18 (m, 4H, a oma ic ing), 7.90-7.87 ( , 3H, CH in ing), 4.35 (d, 1H, CONH), 3.68 (1H,
NH in ing), 3.35 (s, 3H o OCH3), 2.19(s, 3H, o CH3), 1.19 (d, 2H o CH2).
• Spec al da a o amide p od ug o me enamic acid-Aspa ic acid (MA4)
IR (KB , cm-1): 3486 (NH s .), 2971 and 2812 (CH s .), 1697 (CO s . o es e ), 1602, 1561, 1435 and 1409(C=C o
a oma ic ing), 1243 (OCH3), 754 (1,2-o ho , disubs i u ed);
1H NMR (δ, ppm) (DMSO): 8.32-8.16 (m, 4H, a oma ic ing), 7.99-7.74 ( , 3H, CH in ing), 3.44 (d, 1H, CONH), 2.76 (1H,
NH in ing), 2.73 (s, 3H o OCH3), 2.33(s, 3H, o CH3), 2.22 (d, 2H o CH2).
4.2. Hyd olysis s udies o me enamic acid p od ugs
Table 2 Pe cen age elease o d ugs on hyd olysis in SIF
Time
(min)
P od ug Hyd olyzed in SIF (%)
MA1
MA2
MA3
MA4
15
0.00
0.00
0.00
0.00
30
1.01
1.09
1.10
1.02
45
2.12
2.20
2.40
2.33
60
3.11
3.12
3.19
3.17
75
4.21
4.22
4.31
4.11
90
5.34
5.71
5.40
5.72
105
7.00
7.43
7.37
7.31
120
7.89
7.91
7.93
7.88
240
9.48
8.97
9.98
9.96
360
10.12
10.18
10.11
10.01
Table 3 Pe cen age o d ug eleased in a ecal ma e
Time (min)
MA1
MA2
MA3
MA4
15
0.00
0.00
0.00
0.00
30
13.1
11.2
14.2
16.8
45
24.2
22.2
25.5
27.6
60
33.1
35.1
39.7
40.3
75
38.8
37.8
46.2
48.8
90
44.3
42.3
53.3
58.2
105
53.3
53.3
68.2
69.2
120
63.8
61.8
73.1
75.4
240
76.6
75.6
79.9
83.6
360
86.3
87.2
88.2
91.6
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The minimum e e sion was obse ed a gas ic pH (SGF, pH 1.2) sugges ing he s abili y o syn hesized p od ugs in
gas ic pH, bo h in as ed and ed s a e. Howe e , a highe pH alues i.e. in SIF ep esen ing in es ine, he pe cen age
e e sion was signi ican ly highe , he eby making he ee d ug a ailable o abso p ion in he in es ine. A much highe
alue was obse ed in a ecal ma e due o he enzyme dependan hyd olysis aking place in colon.
4.3. Pha macological s udy o amide p od ugs:
4.3.1. An i In lamma o y Ac i i y
The pe cen age an i in lamma o y ac i i y o me enamic acid and i s p od ugs we e de e mined.
Table 4 An i in lamma o y ac i i y o amide p od ugs
G oup
T ea men
Pe cen age an i-in lamma o y ac i i y
0.5 h
1 h
2 h
4 h
6 h
I
No mal
% CMC
nil
nil
nil
nil
nil
II
Me enamic acid
48.0 ± 1.1
62.0 ± 1.2
60.6 ± 2.1
56.1 ± 1.2
42.3 ± 1.5
III
Sul asalazine
42.0 ± 1.2
50.1 ± 1.0
59.0 ± 1.3
68.1 ± 2.3
72.4 ± 1.2
IV
MA1
45.0 ± 1.1
62.5 ± 1.7
67.4 ± 1.1
70.7 ± 1.1
71.3 ± 2.2
V
MA2
42.0 ± 1.5
50.1 ± 1.8
54.4 ± 1.7
58.3 ± 1.0
66.5 ± 1.3
VI
MA3
41.0 ± 1.0
54.3 ± 1.3
61.4 ± 1.4
65.9 ± 1.4
70.8 ± 1.3
VII
MA4
40.0 ± 1.0
52.3 ± 1.3
59.4 ± 1.4
63.9 ± 1.4
71.8 ± 1.3
Values we e exp essed as mean ± SD o 6 obse a ions. Compa ison be ween G oup II Vs Tes G oups P < 0.05,
4.3.2. Ulce ogenic Ac i i y
The ulce index o he p od ugs was eco ded o obse e he ex en o gas oin es inal side e ec s and he mean ulce
index was de e mined
Table 5 Resul s o ulce ogenic ac i i y
G oups
Ulce index ± S.D.
No mal Con ol
0.6 ± 0.12
Diseases Con ol
28.4 ± 1.6
S anda d (Sul asalazine)
5.4 ± 0.15
Me enamic acid
45.6 ± 1.8
MA1
5.8 ±0.13
MA2
5..2 ± 0.2
MA3
5.8 ±0.97
MA4
5.7 ± 0.17
The mean ulce index o s anda d d ug me enamic acid was ound o be mo e han p od ugs. The minimized side e ec
ob ained in he p od ugs migh be due o he inhibi ion o di ec con ac o ca boxylic acid g oup o he d ug o he
gas ic mucosa which is mainly esponsible o he damage.
GSC Biological and Pha maceu ical Sciences, 2025, 32(03), 294-303
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4.3.3. De e mina ion o Clinical ac i i y sco e a e
Table 6 Clinical ac i i y sco e a e
GROUPS
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 9
Day 10
Day 11
HC
0±00
0±00
0±00
0±00
0±00
0±00
0±00
0±00
0±00
0±00
0±00
DC
0±00
0.7±1.3
1±1.73
1.6±1.5
1.6±1.5
1.8±1.7
3.1±1.0
3.2±1.0
3.3±1.1
3.3±1.1
3.33±1.15
Me enamic acid
0±00
0.6±1.1
1.0±1.7
1.6±1.5
2±1.73
2.7±1.3
3.0±1.0
2.3±0.5
1.9±0.6
1.3±1.1
0.99±1.1
SLZ
0±00
0.3±0.6
0.8±0.9
1.8±0.8
2.7±0.6
2.8±0.8
2.4±0.5
1.6±1.13
1.1±1.0
0.7±0.75
0.38±0.6
MA1
0±00
0.6±1.1
1.5±1.5
2.1±0.8
2.7±1.0
3±1
2.6±0.5
2.1±0.50
1.5±1.0
1.1±0.83
0.7±1.1
MA2
0±00
0.7±1.3
1±1.73
1.5±1.5
2.1±1.0
2.6±0.8
2.5±0.7
1.8±1.01
1.2±1.1
0.8±1.07
0.66±0.7
MA3
0±00
0.7±1.2
1.0±1.8
2.1±0.8
2.3±0.6
2.3±0.6
2.1±0.9
1.4±1.1
0.9±1.1
0.5±0.86
0.43±0.5
MA4
0±00
0.6±1.1
1.4±1.5
2±0.88
2.7±0.6
3.0±1.0
2.8±1.0
2±1.20
1.6±1.2
1.2±1.17
0.53±0.9
A e age o six eadings; Two-way ANOVA ollowed by Bon e oni’s es , s a is ical signi icance conside ed a P<0.01; compa ing o disease con ol.
4.3.4. De e mina ion o myelope oxidse (MPO) ac i i y
The his ologic ea u e o IBD is ma ked by he p esence o in lamma o y cells; neu ophils, lymphocy es and his iocy es.
The mo e acu e he illness, he p ominen he neu ophil componen o he in lamma o y in il a e. A he p esen ime,
in es inal and colonic in lamma ion is e alua ed ei he quan i a i ely o quali a i ely by his ological examina ion. The
de e mina ion o myelope oxidase ac i i y in he in es ine is a simple biochemical assay ha can be used o quan i a e
in lamma ion.
Table 7 MPO ac i i y o p od ugs
S. No.
G oups
MPO ac i i y
1
HC
18.453 ± 1.659
2
DC
122.735 ± 1.982
3
Me enamic acid
60.714 ± 1.681
4
SLZ
36.215 ± 1.611
5
MA1
47.059 ± 1.993
6
MA2
39.744 ± 1.400
7
MA3
37.490 ± 1.967
8
MA4
53.933 ± 1.251
A e age o six eadings is p esen ed; s a is ical signi icance was conside ed a P<0.01; s disease con ol.
5. Conclusion
P od ug design concep is a pa o d ug disco e y p ocess which was ini ia ed o imp o ing d ug he apy, in which a
unique subs ance is c ea ed o ha e desi able pha macokine ic cha ac e s in o de o op imize pha macologically
po en s uc u es which ul ima ely lead o he design o be e d ugs. The li e a u e has e ealed a lo o success ul wo k
on p od ugs o dec easing he oxici y and also a ge ing he d ug o a ious pa s o he body. Li e a u e a ailable in
he ield on colon a ge ing indica es he di icul y in he ea men o in lamma o y bowel diseases (IBDs) which is a
common symp om o all he diseases o colon, iz., ulce a i e coli is, c ohn’s disease, i i able bowel synd ome and
colon cance due o ailu e o he d ug o each a he si e o ac ion i.e. colon in app op ia e concen a ion. As mos o
he d ugs a e abso bed in he uppe gas o-in es inal ac like NSAIDs which a e p ima ily abso bed in he s omach,
he ea men o IBD had e e been a g ea p oblem due o non a ailabili y o hese d ugs in he dis al in es inal egion.
In he p esen esea ch, i was en isaged o syn hesize mu ual p od ugs o me enamic acid wi h amino acids o deli e
GSC Biological and Pha maceu ical Sciences, 2025, 32(03), 294-303
302
hem e ec i ely o colon wi hou hei abso p ion a uppe pa o GIT. This concep will no only a ge he d ugs o
colon bu also a oid gas ic i i a ion and will maximize he he apeu ic a ailabili y ha will ul ima ely esul in
lowe ing o he doses.
Release s udies sugges ha d ugs s a eleasing om p od ug in he dis al in es inal egion and an app eciable elease
was obse ed in colon. Thus, p od ugs a e no abso bed due o hei highe molecula weigh om uppe GIT. As a
esul , he p od ug and eleased d ugs emain in he GIT only. This showed he p od ug (MA4) a e be e han d ug.
Aboli ion o unwan ed abso p ion o d ugs will lowe he doses, hus inc easing he he apeu ic u iliza ion o d ugs.
Compliance wi h e hical s anda ds
Disclosu e o con lic o in e es
No con lic o in e es o be disclosed.
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