A PRE-CLINICAL COMPARATIVE STUDY OF THE ANTI GASTRIC
ACID-SECRETORY AND ANTI-ULCEROGENIC EFFECT OF
ROXATIDINE AND RABEPRAZOLE USING A RAT MODEL.
Mehre Darakhshan Mehdi1, Somnath Maity2, Ranjita Santra3, Nandita Biswas4, Manisha Das5 and *Prithwijit Banerjee2
1
Assistant Professor, Department of Pharmacology, North Bengal Medical College, Sushrutanagar, Darjeeling.
2
Assistant Professor, Department of Pharmacology, College of Medicine and Sagore Dutta Hospital, Kamarhati, Kolkata.
3
Assistant Professor, Department of Pharmacology, School of Tropical Medicine, Kolkata.
4
Tutor, Department of Obstetrics and Gynaecology, North Bengal Medical College, Sushrutanagar, Darjeeling.
5
Associate Professor, Department of Pharmacology, College of Medicine and Sagore Dutta Hospital, Kamarhati, Kolkata.
ABSTRACT
Background & objectives: NSAIDS induced gastric ulcer is very common nowadays; a number of drugs are used to prevent NSAIDS
used ulcer. In this study we evaluated the antiulcerogenic effect i.e
prevention of Aspirin induced ulcer and antisecretory effect of
Roxatidine, the second generation H2 receptor antagonist and one of
the widely used proton pump inhibitor Rabeprazole in wistar rats.
Methods: The antisecretory effect of both drug and control is compared by pyloric ligation method. Free and total titrable acid is
measured and compared. The antiulcerogenic effect is compared by
aspirin (200mg/kg) induced gastric ulcer in wistar rats. Ulcer index of
both the drug and control is determined and compared. Result: In our study, Rabeprazole (20 mg/kg) was more effective than roxatidine
(5mg/kg) in reducing free and total titrable acids and in reduction of
ulcer (p<0.05). Both the drugs were superior to that of control (p<0.001). Interpretation & conclusion: Based on our findings, we presume that the anti-secretary and antiulcerogenic (i.e Prevention of NSAIDS induced gastric ulcer) properties of Rabeprazole is better than that
of roxatidine in animal model.
KEYWORDS: Aspirin; NSAIDS, Rabeprazole; Roxatidine, Ulcer index.
Volume 4, Issue 3, 1401-1407. Research Article ISSN 2277– 7105
Article Received on 22 Dec 2014,
Revised on 16 Jan 2015, Accepted on 10 Feb 2015
*Correspondence for
Author
Dr. Prithwijit Banerjee
Assistant Professor, Department of
Pharmacology, College of Medicine and Sagore Dutta Hospital,
INTRODUCTION
The relationship between nonsteroidal anti-inflammatory drugs (NSAIDs) and
gastroduodenal injury is well established.[1] Many factors such as gastric acid, pepsin
secretion, gastric microcirculation, prostaglandin E2 (PGE2) content, pro-inflammatory
cytokines interleukin(IL)-1 and tumor necrosis factor-α (TNF- α) , contribute to the formation
of gastric mucosal damage and subsequently to ulcer development [2-4]. Among the NSAIDs,
Aspirin and diclofenac are commonly associated with peptic ulcer disease.[5] Multiple agents,
including antacids, H2-receptor antagonists, and proton pump inhibitors, are currently
available for the treatment of gastric ulcers.[6] Proton pump inhibitors are the most potent
inhibitors of gastric acid secretion.[7] H2-receptor antagonists are other alternative to Proton
pump inhibitors and in some studies the H2 receptor antagonists have demonstrated
comparable efficacy to them.[8, 9] Roxatidine is the Second Generation H2-Receptor
antagonist has longer duration of action with greater 24 hour acid suppression10. Rabeprazole
is commonly used Proton Pump Inhibitor. Although, both the drugs have been frequently
used in various types of peptic ulcer diseases for quite some time, a head to head comparison
is still wanting. Therefore, we went ahead to take up this issue to compare the anti- gastric
acid secretory and anti-ulcerogenic effect of roxatidine and rabeprazole by using aspirin
induced gastric ulcer model of rat. This study can also serve as a platform for the future
clinical studies.
MATERIAL AND METHODS
All the experiments were approved by the Institutional Animal Ethics Committee for
conducting animal experiments.
Chemicals
Roxatidine 5mg/kg body weight was used as experimental drug while Rabeprazole 20mg/kg
body weight acted as active comparator. Aspirin 200mg/kg body weight was used as ulcer
inducing agent using gum acacia as vehicle. Suspensions of the individual drugs were made
before starting experiment, and kept in washed, dried bottles.
Experimental animals
Adult wistarWister rat of either sex weighed between 180-200 gm was housed separately.
The animals were left for 48 hrs to acclimatize to the animal room conditions. They were
maintained in standard laboratory conditions of temperature 22±2oc, humidity, 12 hours light
Pyloric Ligated Gastric Secretion
A total of 18Wistar wister rats were randomly divided into three groups (n = 6) and were
fasted for 36-48 hours with free access to water. One hour after oral administration of single
dose of vehicle (1ml saline) as control, roxatidine (5mg/kg) as experimental drug and
rabeprazole(20 mg/kg) as active comparator, the pylorus of each rat was tied under urethane
anesthesia (1.25 gm/kg of body weight I.M ) and abdomen incision were closed. Six hours
later, the animals were sacrificed, the abdomen opened and another ligature placed around the
esophagus close to the diaphragm. The stomach was removed and the gastric juice produced
by each was collected.
Free Acidity and Total Acidity
The gastric contents were centrifuged at 2000 rpm for 10 minutes. 1 ml of supernatant fluid
was taken with a pipette and diluted it to 10 ml with distilled water. PH of the solution is
determined with PH meter. The solution is titrated against 0.01N NaOH using topfers reagent
as an indicator to the end point till the solution turns to orange colour. The volume of NaOH
needed corresponds to free acidity. Then three drops of phenolphthalein was added and
titrated till definite red tinge appeared. The total volume of NaOH required, corresponds to
the total acidity. Acidity mEq/L/100gm can be expressed as
Acidity =
Aspirin Induced Gastric Ulcer Method
Animals were kept fasting for 24 hours before experiment. One hour before experiment the
control group of the animals were given 2 ml of normal saline. To the experimental group of
animals Rabeprazole was given 20 mg/kg of body weight orally Roxatidine was given in 5
mg/kg of body weight orally with the help of fine rubber catheter. Half an hour after this both
groups of animals received aspirin power suspended in 1% gum acacia in doses of 200 mg/kg
body weight. It was introduced in stomach through a fine rubber catheter. Neither food nor
water was allowed during this period. Six hours after aspirin administration wistar rats were
sacrificed with over dose of ether anaesthesia. Abdomen was opened with midline incision.
Stomach was freed of mesentery and removed. It was cut along the greater curvature and
washed under direct stream of cold water. Lesions were examined by necked eye. Ulcer in
each wistar rats was judged to be positive or negative on the basis of presence of absence of
Calculation of Ulcer Index
Ulcer index was then calculated from the glandular portion of the stomach by using a hand
held magnifying lens and a measuring tape.
Calculations:-
Ulcerindex is calculated as per R.K. Goyal.[11,12]
Ulcer Index = 10/X
Where X = Total mucosal surface ÷ Total ulcerated area
Measuring protocols
Each lesion was measured along its greatest length
Five petechiae, where present were considered equivalent to an area of 1sqmm
Total glandular area and total ulcerated mucosa were measured for calculation of the
ulcer index
RESULTS
In the present study effects of roxatidine the second generation H2 receptor antagonist is
compared with rabeprazole, one of the commonly used proton pump inhibitor with a view to
find out these agents, offered any protection against aspirin induced ulceration and their
effects on total and titrable acidity in pylorous ligation method. Both the drugs in tested doses
produced a decrease in ulcer index as compared to the control. Both the drugs i.e. roxatidine
and rabeprazole revealed to have protection against aspirin (200 mg/kg body weight) induced
ulcers in rats as well as decrease the output of total and titrable acids in comparison to
control. Maximum protection was seen in the rabeprazole treated group. The difference is
statistically significant both in prevention of aspirin induced gastric ulcer and antisectretory
effect.
Table 1: Effect of roxatidine (5mg/kg of body weight) rabeprazole (20 mg/kg of body weight) orally on gastric acid secretion in six hours pylorus ligated wistar rats.
P-value obtained by using ANOVA followed by Kruskal-Wallis test as post-hoc test
Table 2: Effect of roxatidine (5mg/kg of body weight) rabeprazole (20 mg/kg of body weight) orally on aspirin induced gastric ulcer in wistar rats.
Percentage of Wistar Rats ulcerated
Ulcer index (Mean + S.E.M.)
Aspirin (200 mg/kg body wt) 100 % 9.57 ± 0.53
Roxatidine (5 mg/kg body weight) 33.33 %*** 4.65 ± 0.24***
Rabeprazole (20 mg/kg body weight) 16.67 %*** 2.63 ± 0.32***
P value ***<0.001 in comparison
to control
<0.05 rabeprazole versus roxatidine
***<0.001 in comparison to control
<0.05 rabeprazole versus roxatidine
P-value obtained by using ANOVA followed by Kruskal-Wallis test as post-hoc test
DISCUSSION
NSAIDs have been shown to cause epigastric distress, heartburn, gastric ulceration and
haemorrhage in experimental animal and in human being. Aspirin and diclofenac are
frequently found to be responsible for the development of peptic ulcer disease.[5] Even low
dose aspirin has the potential to cause peptic ulcer in 10-40% patients and increases the risk
of upper GI bleeding by two fold.[13] The prevalence of peptic ulcer is around 20% among the
non-aspirin users; however the risk of upper GI bleeding is 4-6 times more in them.[13] The
use of NSAIDs is common in elderly population.[14] This is consistent with previous studies
and reflects that no dose is safe from gastrointestinal toxicity.[15, 16] Proton pump inhihitors
and H2 receptor blockers are the two frontline drugs used in prevention and treatment of
NSAIDs induced gastric injury or peptic ulcers. Among the Proton pump inhibitors the
Group
Volume of Gastric Juice In ml Mean ± SEM
TITRABLE ACIDITY Free acid ml 0.1N HCl/100
ml of gastric Juice
Total acid ml 0.1N HCl/ 100 ml of gastric juice
Control (2 ml Normal
Saline) 6.40 ± 0.08 46.48 ± 0.57 62.57 ± 0.66
Roxatidine (5 mg/kg
body weight) 3.19 ± 0.05*** 17.23 ± 0.09*** 27.92 ± 0.24***
Rabeprazole (20
mg/kg body weight) 1.9 ± 0.09*** 9.97 ± 0.27*** 15.79 ± 0.32***
P value ***<0.001 in comparison to control <0.05 rabeprazole versus roxatidine
***<0.001 in comparison to control
<0.05 rabeprazole versus roxatidine
***<0.001 in comparison to control
percent protection in ulcer index is maximum for rabeprazole than the other proton pump
inhibitors (viz Omeprazole and Lansoprazole),[17, 18] Roxatidine has longer duration of action
and amongst the newer H2 receptor blocker. Although H2-receptor antagonists are other
alternative to Proton pump inhibitors and it is reflected in some clinical study that they have
comparable efficacy in acid peptic disorder,[8, 9] our study demonstrated rabeprazole to be
more effective in prevention of aspirin induced gastric ulcer in animal model and it has better
antisecretory action than a second generation H2 receptor antagonist roxatidine. Rabeprazole,
being a direct inhibitor of the H+-K+ -ATPase pump (Proton pump) present on parietal cells
of the gastric mucosa, causes a more profound and prolonged acid suppression.[17, 18]
Roxatidine, on the other hand, is a competitive antagonist of histamine at the H2 receptor,
which in turn stimulates the proton pump to secrete acid. Since NSAIDS induced gastric
injury is very common health related problem now a days, and with increased incidence of
musculoskeletal disorder and ischaemic heart disease, where low dose aspirin is of paramount
importance, these agents play a crucial role in the prevention of gastric and duodenal ulcer
formation.
However, this is a pre-clinical experiment. In future, more detailed study involving human
subjects can provide us further insight about these agents.
Funding source: Self funded study.
Conflict of interest: None to the best of our knowledge.
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