1. Formulations of Aspirin TP n°7

2. Experimental setup : a. Grind the aspirin pill in a mortar, then pour some ethanol in order to dissolve the pill. b. Filter. If necessary, rinse the mortar with ethanol over the filter. c. Pour few drops of iodized water on the residue (solid remaining in the filter), and also in the filtrate (liquid that is flowing).

3. Questions : a. Draw a schema of the filtration setup. Indicate the filtrate and the residue. b. Iodized water is used to test the presence of starch (« amidon »). The test is positive if the we get a dark blue coloration. What component of the excipient have we found ? Is it able to dissolve in alcohol ?

4. Experimental setup : a. Prepare two beakers : -beaker n°1 : with 20 mL of 1 mol.L -1 hydrochloric acid (H 3 O +,Cl - « acide chlorhydrique ») -beaker n°2 : with 20 mL of 1 mol.L -1 sodium hydroxide (Na +, HO - « hydroxyde de sodium ») b. In a mortar, grind one pill of « aspirine du Rhône 500mg ». Pour one half of the obtained powder into the beaker n°1 and the other half into the beaker n°2. c. Stir both beakers, measure the pH, and observe the appearance of the solutions.

5. Questions : a. Is Aspirin more soluble in beaker 1 or in beaker 2 ? b. As a consequence, is Aspririn more soluble in an acidic solution or in a basic solution ? c. In a basic solution, Apirin exists in its ionic form (A - ), whereas in an acidic solution, it is in its molecular form (AH). Wich one of these forms (A - or AH) can be called hydrosoluble ? d. The stomach's pH is about 2, whereas the intestine's pH is about 8. Which beaker represents the stomach ? the intestine ? e. What is the form of Aspirin in the stomach ? f. The mucous (surface of the stomach) contains lipids. The AH form of Aspirin is liposoluble. In stomach, where may Asprin be absorbed ? Why may it create ulcers (an ulcer is the loss of a part of the mucous)?

6. Experimental setup : a. Put a pill of pH8 aspirin in a beaker filled with about 20 mL of 1 mol.L -1 hydrochloric acid. b. Put a pill of pH8 aspirin in a beaker filled with about 20 mL of 1 mol.L -1 sodium hydroxide. c. Wait about 10 minuts, stir from time to time ; then observe the appearance of the pill and measure the pH of the solutions.

7. Questions : a. Does the covering of the pill dissolve in the acidic or in the basic beaker ? b. So, where will pH8 Aspirin be freed in our body? c. What will be the form (AH or A - )of Aspirin ? Is it hydrosoluble ? d. Tell one advantage and one disadvantage of pH8 compared to usual Aspirin.