Materials:

• Laboratory Notebook
• Various over-the-counter antacids (i.e. Tums, Mylanta Ultimate Strength Suspension, Maalox MS Suspension, Mylanta Supreme Suspension, Pepcid Complete Chewable Tablet, Mylanta Ultimate Strength Chewable Tablets, Nature’s Plus Licorice Root Extract and Michael’s Antisid)
• 0.05N Hydrochloric Acid (prepared from concentrated HCl)
• pH meter with pH indicating electrode and Silver / Silver Chloride reference electrode
• Magnetic Stirplate and magnetic stir bars (one stirbar per antacid product per trial)
• Various test glassware: 300mL glass beaker (one per antacid product per trial), 250mL graduated cylinder, two1L Volumetric flasks, 100mL graduated cylinder, 50mL volumetric pipet
• Mortar and pestle
• 5mL plastic syringe (without needle tip), one per Liquid antacid type
• scoopula
• weighing paper
• stopwatch
• pencil
• USP Purified Water
• purchased pH standards: pH = 4.0, 7.0 and 10.0

Safety Equipment

• Safety Glasses
• Lab Coat
• Safety Gloves

The control sample for this experiment is the 0.05 Normal Hydrochloric Acid. The variables in this experiment are the following antacid products: Tums, Mylanta Ultimate Strength Suspension, Maalox MS Suspension, Mylanta Supreme, Pepcid Complete, Mylanta Ultra Tabs, Nature’s Plus Licorice Root Extract and Michael’s Antisid. A pH meter that measures the Hydrogen ion concentration of solutions in pH units will be used to measure the change in pH of each antacid product addition over a range of 10 minutes, measured every 15 seconds.

Methods:

1. Check the pH meter for accuracy against purchased pH solutions 4.0, 7.0 and 10.0. If necessary, perform pH meter calibration per user manual.
2. Determine the smallest dose size for each antacid (dosage size is listed on product label, summarized in lab notebook).
3. Determine the cost of one dosage size, based on purchase price of sample and total amount of sample per antacid product.
4. Determine the concentration of acid to match stomach pH of 1.5 – 2 (see lab notebook).
5. Make enough 0.05N HCl to perform experiment. (Prepare a stock solution of 1N HCl a dilute stock as needed. (See lab notebook).
6. Measure 250mL of 0.05N HCl in a 250mL graduated cylinder and pour into 400mL glass beaker.
7. Place magnetic stir bar in beaker and place beaker on magnetic stir plate (in center of plate)
8. Set stir plate to speed 6-8 (chose the same speed for each sample to be consistent through the experiment)
9. Gently place the pH electrode in the beaker being very careful not to hit the bottom of the electrode with the spinning stir bar (Note: the pH meter should be turned ON, also note, the pH electrode is made if glass and the bulbous glass membrane at the bottom of the electrode is VERY thin and delicate.)
10. Measure initial pH of 250mL of 0.05N HCl and record the initial pH in Lab notebook.
11. Prepare sample for analysis (liquid samples: shake well and suck up one dose in syringe, solid sample: crush one dose with mortar and pestle to simulate chewing tablet, scoop out all of the sample onto weighing paper)
12. With stopwatch in one hand dump sample into beaker test beaker (containing the 250mL of 0.05N HCl) and start the stopwatch.
13. Record the pH values every 15 seconds for 600 seconds (10 minutes)
14. Repeat the procedure for each antacid product three times.
15. For each time point per antacid product, average the three pH readings.
16. Graph the average pH readings per antacid product (y-axis) vs. seconds (x-axis). If necessary, normalize pH values for differences in initial pH values to compare all samples on an equal scale.

Data Analysis:

The change in pH every 15 seconds over the 10 minute time period for each antacid will be recorded in data table in a lab notebook. The average of three pH measurements at each time point will be calculated. The calculated pH data for each antacid will be plotted on one graph. The graph will be used to determine which type of antacid (chemically formulated or homeopathic) neutralizes the most acid the quickest (produces the highest pH reading in the least amount of time showing the steepest slope) and which antacid product works the best overall (which antacid product produces the highest pH reading overall), taking price per unit does into consideration.