Antacids and the pH of the Stomach

 

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Project done by:      Selena Wang & Joelle Tan

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Introduction

 

      For our science fair, we conducted an experiment which involved testing different antacids in hydrochloric acid (after diluting it to the pH of the stomach) to see how the pH level would change and to observe what would happen to each of the antacids. Our hypothesis was that Tums would alter the pH of the HCl the most. However, we didn¡¦t have a hypothesis as to how the other antacids, Pepto-Bismol and Pariet would react, but we felt only the Tums tablets would work better in the HCl because they are composed of an ingredient that we easily identified as a base.

 

Purpose:

To find out how different antacids work and to determine how each affects the pH level of the stomach

 

Materials:

 

Inorganic Hydrochloric Acid (HCl)

Distilled Water

Tums Tablets

Pepto-Bismol

Pariet

Magnetic Stirrer

Magnetic Stir-Stick

3 Beakers/ Flasks

Graduated Cylinder

pH Meter

Balance

Fume Hood

Labelling Materials

Pipet

 

About the Materials:

 

Pipet

 

 

     A pipet is a device used for ¡§dropping¡¨ liquids into places. It is a very accurate and easy to use instrument.

Special Gloves

     These gloves were very special and didn¡¦t melt when used to hold very acidic or basic liquids. In addition, they were resistant to the heat and cold

Inorganic HCl

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       Inorganic HCl is different from organic HCl. It is specially formatted so that when it touches special types of materials, it won¡¦t melt.

Distilled Water

     This is water that has been boiled, and then re-condensed to purify it.

Graduated Cylinder

     This was used to measure liquids accurately.

Magnetic Stirrer

     There is a small magnet that is dropped into a flask containing liquid and put on a magnetic stirrer. This magnetic stirrer uses magnetic energy to make the small magnet in the flask spin, mixing the liquid.

Magnetic Stir-Stick

     There is a stick you can use to manually stir the liquid. It is also used to take the magnet out of the flask, after done using the magnetic stirrer.

Fume Hood

     This absorbs the dangerous fumes produced by whatever emitting substance.

pH Meter

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     This is an electrical device that measures pH very precisely, to a greater precision than a pH strip. The bubble at the end of the stick is really delicate, and one has to be careful not to jar it.

 

Fume Hood, HCl and pipet

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                                                                                                                 Gloves, Distilled water, pH meter

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Procedure:

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1.)   At the very beginning, we put on gloves.

2.)   We washed the pH meter with distilled water.

3.)   We calibrated the pH meter 2 times by using liquids that have standard pH of 4 and 7 because we were going to be measuring acidic liquids. (**could have used pH of 10 for calibration but we didn¡¦t because we didn¡¦t want it to be too basic)

4.)   We had to find out what amount of HCl and water would give us a pH of around 2.5 (average pH of the stomach).

5.)   We started measuring out (using graduated cylinder) 50 mL of water into a beaker. We went to the fume hood and using a pipet, added 100 uL of HCl. This didn¡¦t give us 2.5 so we had to add water and HCl until we got 2.5.

6.)   We came up with the solution that:

100 mL of water + 75 uL of HCl= a pH of 2.14 (which is close enough)

 

7.)   We made 300 mL of this diluted HCl solution and put it in equal amounts in 3 beakers

8.)   We added 1 tablet of Pariet in a beaker, 1 tablet of Tums to another and 15 mL of Pepto-Bismol to the last.

9.)   We immediately took observations. (see Chart I)

10.)           After 5 minutes, we took the pH of each liquid and washed the pH meter with distilled water after each one. (See Chart II) We also took observations.

11.)           After, we decided that we should simulate closer to the real volume of the stomach so we made 1200 mL more dilute HCl with a pH of 2.14 and added 400 mL to each liquid. We transferred each to a flask. Now, in each flask we had 500 mL of dilute HCl.

12.)           10 minutes after, we checked the pH level again and made observations. We washed the meter after each use.

13.)           While we waited for the antacids to dissolve, we washed all the beakers, took pictures and wrote ¡§possible errors.¡¨ (See ¡§Errors¡¨)

14.)           Repeat Procedure #12

15.)           After last check, the Tums was still dissolving, and we had to leave the lab so we used a magnetic stirrer to speed up the process. It took 20 minutes. Then we measured its pH and recorded it.

16.)           We weighed the samples of Pariet and Tums to see whether the indicated weight on the package was the actual weight. It wasn¡¦t, as we realized the weight of Pariet was 0.111 g not 10 mg. The Tums was 0.9g not 750 mg. After we did research, we found out that the number on the manufacturer¡¦s product is actually the amount of active ingredient.

17.)           Then we cleaned up the mess in the lab.

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                                                                            Tums

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 Observations & Data:

Text Box: Name of
Antacids
Text Box: Observations made after 0 minutes
Text Box: Observations made after 5 minutes
 
Text Box: Observations made after 25 minutes
Text Box: Observations made after 35 minutes

 

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Text Box: Observations made after 15 minutes
 

 

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Pepto-Bismol

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  It sunk to the bottom and was sticky and pink. It spread along the bottom and coated it. The water turned a pale pink right away. The Pepto-Bismol, along the bottom is bright pink.

 

 

 

 The pink colour didn¡¦t change. It hasn¡¦t dissolved yet.

 

 

 

 

 It has dissolved a little and isn¡¦t as gooey.

 

 

 

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The Pepto-Bismol along the bottom is a lighter pink. The water is a darker pink and it is becoming more uniform.

 

 

 

It is completely dissolved with a bit of pink residue at the bottom of the flask.

 

 

 

 

 

Pariet

 

 

 

Nothing changed. There was just a little pink tablet sinking to the bottom and staying there.

 

 

 

 

 

 

No Change

 

 

 

 

 

 

No Change

 

 

 

 

 

 

No Change

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The tablet still hasn¡¦t dissolved. After this measurement, we took the Pariet tablet out. It was hard and exactly the same as when we put it in.

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Tums

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It started to fizz as soon as we dropped it in the HCl. It sank to the bottom and continued fizzing.

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The water became cloudy as the tablet got smaller and continued fizzing. The tablet starts to dissolve.

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There is powder on the bottom of the beaker. The water was cloudier and the pill got even smaller. It is still fizzing.

 

 

It¡¦s still fizzing. The tablet is even smaller than before.

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The Tums is still dissolving. We decide that this is going to take a long time so we stir it with a magnetic stirrer until it¡¦s all dissolved and cloudy-white.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Discussion:

   

Name of Antacid Active Ingredient (s) What each did in our experiment Why? How does it work in the real stomach?
Pariet Rabeprazole Sodium Did not dissolve. Did not change the pH level      We realized that it didn't dissolve because it is enteric-coated, which means that it won't work (dissolve also)  until it gets to the small intestine. The small intestine has a pH of about 7-8 so probably the tablet needed those conditions to affect a change.

     We realized that it didn't affect the pH level because it is a proton pump inhibitor, preventing the parietal cells from secreting acid. This affects the cells, not the acid itself.

 Tums Calcium Carbonate Dissolved and changed the pH level      It neutralized the acid a lot and that's how it works in the human stomach as well. This gets rid of acid when one has an excess quantity so that one won't get ulcers and other acid-related problems.
 Pepto- Bismol Bismuth Subsalicyclate Pooled on the bottom and eventually dissolved a bit      Pepto-Bismol is supposed to coat the stomach. This is why it didn't change the pH a lot. It just coated the bottom of the flask we used. It provides a coating layer to prevent the secreted acid from eating away the stomach lining.

 

 

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**This information is taken directly from the manufacturers¡¦ websites.**

 

 

 

     Name of Antacid

 What is it used for..?

Side effects

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Tums

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*reliever of excess gas in the stomach and intestines (flatulence)

*Nausea

*reliever of heartburn (gastro oesophageal reflux disease)

 *Upset stomach (pain, burning, excess gas [dyspepsia] and nausea)

*Indigestion

 

 

 

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*Constipation

 

 

 

 

 

 

 

 

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     Pariet

 

 

 

 

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*Destroy bacteria in the gut that cause ulcers [ Helicobacter pylori] * reliever of gastro-oesophageal reflux disease

* reliever of excessive stomach acid secretions [due to tumor, enlargement of pancreas]

* reliever of active peptic ulcer

* Headache

*Cough

*Weakness or loss of strength [asthenia]

*Inflammation of the lining of the nose (rhinitis) causing a blocked or runny nose

*Difficulty in sleeping [insomnia]

*Infections

*Dizziness

*Inflammation of the throat (pharyngitis)

*diarrhea, constipation, nausea, vomiting or abdominal pain

*Rash

*Excess gas in stomach and intestines [flatulence]

*Inflammation of the liver (hepatitis)

*Dry mouth

*Chest pain

*Nervousness

*flushing skin (small blood vessels widen) [erythema]

*Blood disorders

*Pain in the muscles /joints

 

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Pepto- Bismol

 

*Nausea

*Upset stomach (pain, nausea, burning, excess gas [ dyspepsia]

*diarrhea

 

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*nausea and vomiting

*brain disorders [encephalopathy]

* rashes (skin)

*irritation to stomach lining/ movements of the gut

 

Background Information Digestion & the Stomach

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        Some of you may think, why is the digestive system so important, and how exactly does it work? Well, for starters, our digestive system plays a significant role in breaking down the food that we consume into smaller pieces for our body to use as ¡§nourishment.¡¨ When our food is converted to small pieces, our body may use these nutrients as energy, and distribute them amongst all the cells in our body. However, there is more to this process--- including the journey of food from the mouth to the anus, and ¡§the chemical breakdown of large molecules to small.¡¨ This whole process is called digestion.

 

        The digestive system consists of the digestive tract and supplementary organs that help digestion. The digestive tract is composed of the following: the mouth, esophagus, stomach, small intestine, large intestine, rectum and the anus. The supplementary organs that assist the digestive tract are the tongue, salivary glands, pancreas, gall bladder and the liver. Food travels down the digestive tract, by ¡§wave-like movements¡¨ called peristalsis,

 

The Digestion Journey and Stomach

       

        When food is put into our mouths, we chew and chomp the large pieces into small pieces vigorously. The salivary glands in our mouths help by assisting in the ¡§breakdown of chemicals,¡¨ so that we can swallow more easily. Our tongue pushes the mushy food [bolus] down our throat. Our nerves have ¡§full control of guiding¡¨ the small food bits down the 2nd organ in the digestive tract: the esophagus.

 

        Many refer to the esophagus as the ¡§stretchy pipe¡¨, as it well deserves the name, as its length is approximately 25 cm [10 inches]. This long pipe-like tube¡¦s function is basically to move the mashed up food particles from the throat to the stomach. Situated at the back of the throat is the windpipe and it controls the air circulation into and out of the body. Every time we swallow food, the epiglottis, ¡§a flap-like skin¡¨ covers the windpipe¡¦s opening to guide the food down the esophagus.

 

        Prior to reaching the stomach, the food meets a ¡§ring-like valve closing the passage between the organs¡¨ called the cardiac sphincter. The food slowly travels through this into the stomach. The cardiac sphincter ensures that the food goes down the stomach.

 

        The stomach can be described as a ¡§muscular and elastic pear-shaped¡¨ organ. Did you know that the stomach can adjust to different shapes and sizes, depending on how much food is consumed, and how the body is positioned? Its length is about 30.5 cm [12 inches] and its width is about 15.2 cm [6 inches]. Our stomach¡¦s gastric juices have a pH of 1-3, which is extremely acidic as it is filled with peptidase enzymes and hydrochloric acid.

The stomach has five layers: [from inner to outer] mucosa, submucosa, muscularis, subserosa and serosa. All of these layers have different duties to perform, and are all made up of different cells. The innermost layer, the mucosa is made of thin layer of muscle (muscularis mucosa), a layer of dead cells with mucous lining (epithelium) and the lamina propria. The second layer, the submucosa is made up of ¡§fibrous tissue¡¨ and it is sandwiched between the outer muscle layers and the mucosa layer. The ¡§musclaris externa¡¨ made of 3 layers of muscle.

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Hand-drawn picture of the layers

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The stomach is divided is divided into 4 subgroups--- the cardia, fundus, body and pylorus. The cardia is the junction where the esophagus is ¡§connected¡¨ to the stomach. The fundus is the place that ¡§curves above the rest of the stomach.¡¨ The body, is situated at the center, and has the greatest area. The pylorus is the junction where the small intestine and the stomach connect. There are muscles within the pylorus and the cardia that help with the movement and flow of the food.

 

              

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Hand-drawn picture of the stomach

              

              The ¡§chief cells¡¨ at the bottom of pits (oxynitic or fundic glands) formed by the epithelium of the stomach play vital roles in the making of pepsinogen, a ¡§precursor of pepsin.¡¨ Hydrochloric acid from the parietal cells (in the stomach lining) trigger this zymogen. [¡§In order to become an active enzyme, this zymogen (inactive enzyme) must undergo a biochemical change like a hydrolysis reaction. [decomposition of a chemical compound by reaction with water] Once a biochemical change occurs, the pepsinogen will be converted into pepsin, ¡§a digestive enzyme released by chief cells¡¨, responsible for the breakdown of ¡§peptide bonds between amino acids in proteins.¡¨ The pepsinogen when needed, will be secreted to protect the cells from digesting themselves. The hormone Gastrin within the stomach trigger the gastric glands to secrete pepsinogen and HCl. ¡§The secretion of gastrin is stimulated by food arriving in the stomach¡¨ and is very acidic. Gastric acid (HCl and other enzymes) will be secreted from gastric glands, made by parietal cells in the pit. The gastric acid is used to ¡§convert pepsinogen to pepsin, destroy living bacteria within food, and to ¡§stimulate hunger.¡¨ Mucus is the product of goblet cells in the lining of the stomach, used for protection against ¡§self- digestion¡¨ and the acidity of the HCl.

                                                                                         Hand-drawn picture of the parietal cells

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               Once the food been absorbed and broken down by the enzymes within the stomach, the stomach content (chyme) is moved down into the small intestine by peristalsis. With the joint work of the pancreas and the liver, food is ¡§broken into simpler molecules by enzymes¡¨ in the pancreatic juice and bile. The bile ¡§dissolves the watery¡¨ component of the fat and the pancreatic juice grinds down the protein, fat, and carbohydrates within our food.

 

               The small intestine further digests the chyme with the aid of pancreatic, bile and intestinal juices. Useful nutrients are absorbed and fiber (undigested food), and waste proceed further down the digestive system into the large intestine where it remains in the colon for a few days. The waste, or feces is then disposed out through the rectum.

 

 

Conclusion

 

      After we conducted the experiment and did research, we found that our hypotheses had been correct: the antacid Tums did change the pH of the HCl the most. We found that Tums contained calcium carbonate which neutralizes acidity, making the HCl more basic. Pariet did not change the pH as it involves the parietal cells within the stomach and the Pepto-Bismol didn't the change the pH level that much either, as it is meant to coat the lining of the stomach.

 

 

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Bibliography

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Internet Sources

 

1.)  National Institutes of Health [NIH]. ¡§Your Digestive System and How It Works.¡¨ Online. <http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/> May 2004.

 

2.)  University of Maryland Medical Center [UMMC]. ¡§ The Digestive System-Digestive Disorders.¡¨ Online.< http://www.umm.edu/digest/howworks.htm> (unknown month, date ) 2004.

 

3.)  The Nemours Foundation. ¡§The Real Deal on the Digestive System.¡¨ Online. <http://kidshealth.org/kid/body/digest_noSW.html> (unknown month, date) 1995-2006.

 

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9.)  Carter, J. ¡§Atoms, Molecules, Water, and pH.¡¨ Online. http://biology.clc.uc.edu/courses/bio104/atom-h2o.htm> 2 Nov. 2004.

 

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11.)  Ophardt, C. ¡§Acids and Bases in Rain, Lakes, Streams, and Household Products.¡¨ Online. < http://www.elmhurst.edu/~chm/onlcourse/chm110/labs/lab4H97.html> (unknown date) 2002.

 

12.)  Unknown author. ¡§Pariet.¡¨ Online. <http://www.netdoctor.co.uk/medicines/100002017.html> 1998-2005.

 

 

13.)  Unknown author. ¡§Tums.¡¨ Online. < http://www.netdoctor.co.uk/medicines/100002663.html> 1998-2005.

 

14.)  Unknown author. ¡§Pepto- Bismol.¡¨ Online. < http://www.netdoctor.co.uk/medicines/100002038.htmll> 1998-2005.

 

 

15.)  Murphy, Peter and Tipping, Paul. ¡§Gastrointestinal System- Relating structure to function.¡¨ Online. <http://www.uclan.ac.uk/facs/health/nursing/sonic/scenarios/scenario1GITlecture.htm> April 2005.

 

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17.)  Tamarkin, Dawn. ¡§Control of Stomach Activity.¡¨ Online. <http://distance.stcc.edu/AandP/AP/AP2pages/Units24to26/digestion/control.htm> (unknown date) 2004.

 

18.)  Unknown author. ¡§Protease.¡¨ Encyclopedia Wikipedia, 2006. Online. < http://en.wikipedia.org/wiki/Protease> 20 Feb. 2006.

 

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