This document summarizes screening methods for antiulcer agents, including both in vivo and in vitro methods. It begins with an introduction to peptic ulcers and classifications of antiulcer drugs. In vivo screening methods described include the pylorus ligation model in rats, ethanol-induced gastric ulcer model, water immersion stress model, and indomethacin-induced ulcer model. The key in vitro screening method discussed is the H+/K+-ATPase inhibition assay to measure inhibition of proton pump activity. The document provides details of procedures and evaluations for each screening model. It concludes with references for further information.

1. SCREENING OF ANTIULCER AGENTS
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Dr. V.V.P.F’S COLLEGE OF PHARMACY
AHMEDNAGAR (2018-2019 )
GUIDED BY
Prof. Dr.P.M.GAIKWAD
M.Pharm, Ph.D
(Head, Dept of
Pharmacology)
PRESENTED BY
Miss. Joshi Uttara L.
M.Pharm (sem 1st )
(Pharmacology)
Roll no.08

2. Contents
• Introduction
• Symptoms of peptic ulcer
• Classification
• Screening methods
1. In vivo methods
2. In vitro methods
• Reference
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3. Introduction
• Peptic ulcer is one of the most common
gastrointestinal diseases.
• The drug has been use to prevention of stress ulcer.
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4. Symptoms of Peptic Ulcer
• Burning abdominal pain
• Nausea
• Vomiting
• Pain in stomach
• Weight loss
• Constipation
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5. PATHOPHYSIOLOGY
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6. Classification of Anti-Ulcer Drug
1) H2 receptor antagonist
e.g. Cimetidine , Ranitidine , Famotidine
2) Proton pump inhibitors -
e.g. Omeprazole ,Pantoprozole,Lansoprazole
3) Anticholinergics
e.g. pirenzepine , Telenzepine, Propanthalin
4)Prostaglandin analogues:Misoprostal ,Enprostil
5) Antacids
Syatemic:Sodium bicarbonate
Nonsystemic:Mg hydroxide
6) Ulcer protective
e.g. Sucralfate
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7. 7)Ulcer Healing drugs : carbenoxolone
sodium
8)Anti H pylori drugs: Amoxicillin,
Clarithromycin,Metronidazole,tinidazole,
Tetracycline.
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8. PROTON PUMP INHIBITORS
- Most effective drugs in antiulcer therapy.
- Prodrug requiring activation in acid environment .
- Activated forms binds irreversibly to H+K+ ATPase
and inhibit it.
- Eg –Omeprazole
Pantoprazole
- The parietal cell of the stomach is activated by
histamine acetylcholine and gastrin.
- In addition to the direct action of gastrin and
acetylcholine on the parietal cell these two agents
may release histamine form a histamine form
storage in the gastric mucosa.
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9. MECHANISM OF ACTION
- Prodrugs inactive at neutral pH .
- At pH < 5 rearranges to two charged cationic forms t that
bind covalently with SH groups of H+/K+ATPase and
inactivate it irreversible.
- Also inhibits gastric mucosal carbonic anhydrase.
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10. Screening methods
• In vitro method
1) Gastric binding assay .
2) H+/K+ ATPase
inhibition assay
• In vivo methods
1) Pylorus ligation in rats
2) Stress ulcer model .
3) Histamine induced
gastric ulcer .
4) Acetic acid induced
gastric ulcer
5) Ethanol induced
gastric ulcer
6) Indomethacin induced
ulcers in rats 10

11. In vitro methods
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12. 1) H+/K+ -ATPase inhibition assay
• Proton pump > final step in the synthesis of acid by
parietal call.
Procedure –
Incubation of guinea pig gastric mucosa
buffer ATP and test compound
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13. Add malachite green (colorimetric agent )
after 30 minutes
Add 15% sodium citrate after 10 sec . For 45
minutes
Released of orthophosphate from ATP quantified by
colorimeter at 570 nm
Evaluation:
• Percentage inhibition of H⁺/K⁺-ATPase is calculated.
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14. In vivo method
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15. 1) Pylorus ligation in rats
• Purpose –
 A simple and reliable method for production of
gastric ulceration in the rat.
Based on ligature of the pylorus has been
published by shay et al 1945 .
The ulceration is caused by accumulation of
gastric the stomach
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16. Midline abdominal incision is given
Ligation of pylorus
Test compounds are given either orally or
injected S.C.
About 17-19 hours after pyloric ligation
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PROCEDURE
Wistar Rat are saturated for 48 hrs. access to
water

17. 17
Rats are sacrificed and stomachs are
dissected out
volume of gastric acid pH no. of ulcer index
and severity is noted.

18. Evaluation
• ID50 values can be calculated by probit analysis.
• An Ulcer Index (UI) is calculated.
• UI = UN+US+UP × 10-1
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Where,
Un=Average number of ulcer per animal,
Us= Average of severity score ,
Up= Percentage of animal with ulcer

19. 2)Ethanol Induced mucosal damaged
in Rats
PURPOSE
Intra gastric application of absolute ethanol is a
reproducible method to produce gastric lesions in
experimental animal
• These lesion can be at least partially inhibited by
various drugs such as some prostaglandins
• The protective effect against various irritants has
been called cytoprotective activity.
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20. Wistar Rat are saturated for 18 hrs. access to water
After 30 min 99.80% alcohol is given orally.
Rate are sacrificed and stomach dissected out
A circular full thickened area is cut
Evaluated using a light transmission densitometer.
The optical density of the test tissues is
determined.
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PROCEDURE

21. EVALUATION
 The significance of differences in optical density
Test drug is given orally.
.
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22. 22
Principle:
•Exposure of cold conditions to restrained
animals
•Accelerates the occurrence of gastric ulcers.
•Shortens the immobilization time
3) Water immersion induced stress model

23. PROCEDURE
Stress induced ulcers were induced by force swimming
in the glass cylinder (height 45cm diameter 35cm)
containing water up to 350C maintained at 350C for 3 hrs
(Wistar rat) Animals were fasted 24 hrs prior to the
experiment
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24. All stomachs were opened along the greater
curvature ulcer index and % inhibition was calculated.
After the drug treatment (standard/test) animals
were allowed to swim for 3hrs then animal were
dissected stomachs were removed
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25. 25
Principle:
NSAID induced gastric damage ; by blocking COX
enzyme, endogenous prostaglandin production
inhibited
4) Indomethacin induced ulcer model

26. PROCEDURE
All the animals were fasted 36 hours before administration of
indomethacin
The animals were divided into groups. each rat was administered
with the 20mg/kg indomethacin orally.
30 min prior to the administration of the indomethacin
standard/test drug was administered.
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27. By titrating with 0.01M NAOH using phenolphthalein as
an indicator.
Gastric juice estimated for pepsin
Ulcer index and % inhibition were calculated
The rats were anaesthetized with ether 1 hour latter the
stomach was incised through the greater curvature and
examined for the number of lesion under the dissecting
microscope
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28. Reference:
1) H.G. Vogel and W.H. Vogel ,“ Drug Discovery and evaluation
pharmacological assay ”, Springer , New York.
Page no-1236-1242.
2) K.D. Tripathi Medical Pharmacology Sixth edition,
Page no-151-161.
3) S.k.kulkarni,̏ Text Book of Practical Pharmacology ̋,6th edition ,
Vallabh Prakashan,
Page No-107 -108
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29. 29
4. Datta GK, Sairam K, Priyambada S, Debnath PK, Goel RK:
Antiulcerogenic activity of Satavari mandur-An ayurvedic
herbomineral preparation. Indian J Expl Biol 2002; 40:1173-77.
5.Mishra L.Wagnar H. Lipid derivatives from mucona pruriens
seeds Indian journal of chemistry 2006,45(B):801-804
6.Chopra RN ,Nayar SL , Chopra IC Glossry of indian
medicinal Plants ,CSIR , New Delhi 1956 .

30. Thank you
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