Antacid

It deals with Ideal properties, acid neutralizing capacity , branded antacids and compounds

1. By Dr.N.Gopinathan M.Pharm Ph.D Assistant Professor Faculty of Pharmacy Sri Ramachandra Medical college and Research institute ( Deemed University) Chennai, Tamilnadu India. Antacid introduction

2. In stomach the gastric acid is secreted by the parietal cells of gastric mucosa. These cells contain receptors for the three stimulants of acid secretion. They are Gastrin from G-Cell Histamine from Entero Chromaffin Like cells Acetyl choline from vagal efferents .

3. Entero chromaffin Like cell

4. Parietal cell

5. The histamine released from the ECL cells binds to the H2 receptors present in the stomach. It increases the intra cellular cyclic AMP cAMP . Gastrin and acetyl choline acts by increasing the cytosolic calcium. Both cAMP and cytosolic calcium activates protein kinase and stimulate the HCl secretion via H+ / K+ ATP ase which is present in the surface of parietal cells.

6. The secreted H+ ion combines with the Cl - from plasma leads to the formation of HCl . The carbonic anhydrase enzyme is also catalyses the formation of carbonic acid which in turn undergo dissociation into bicarbonate and H+ ion. These H+ ions also used for the production of HCl by proton pump. Acetyl choline stimulate the acid secretion by directly acting on muscarinic M3 receptors or through M1 receptor.

7. Gastrin stimulate the acid secretion from ECL cell which are the major source of histamine release needed for acid secretion. Gastric acid secretion and peptic ulcer formation is depicted in the diagram

8. Before the discovery of H2 receptor antagonists and proton pump inhibitors, antacids are primarily used therapeutic agents for the treatment of gastro oesophagul reflux, peptic ulcer and dyspepsia.

9. Antacids are weak bases that neutralize the excess gastric hydrochloric acid there by raising the PH of stomach contents, decreasing the acid load delivered to the deuodenum and reduce the pepsin activity. These agents also increase the mucosal defense by the stimulation of prostoglandin production and partly by forming a protective layer against gastric mucosa.

10. The dose of antacid is meq or mmol of their neutralizing capacity. Factors which controls the capacity of antacid activity are Formulation [ liquid formulation is most effective than chewable tablet] Gastric emptying Duration of action[ insoluble antacids are relatively longer acting]

11. Antacid

12. Definition .

13. When there is too much acid or protective mechanisms are inadequate, the lining of the stomach, duodenum or esophagus may become damaged by the acid, giving rise to inflammation and ulcerations and their various gastrointestinal symptoms such as nausea, abdominal pain, and heartburn

14. systemic Buffer Non buffer Sodium bi carbonate Aluminium hydroxide Magnesium hydroxide miscellaneous Alginate

15. Buffer type Antacid They have a slow onset of action but longer duration of action and increases the PH up to 3.5 to 4. Aluminium hydroxide, magnesium trisilicate and magaldrate are acting as buffer type non systemic antacids. They are poorly absorbed from GI tract and do not interfere systemic acid base balance nor do they elevate urinary PH these are two types.

16. They do not interfere systemic acid base balance nor do they elevate urinary PH these are two types.

17. Non buffer type They are powerful type of antacid with fast onset of action and raises the gastric PH 7 Calcium carbonate and magnesium hydroxide Calcium carbonate reacts with gastric hydrochloric acid to neutralize and gives calcium chloride, which further react with intestinal bicarbonates and stearates to give calcium carbonate and calcium stearate which leads to constipation.

18. Miscellaneous antacids Simethicone and sodium alginate are the examples for miscellaneous antacids. Simethicone has the water repellent properties, so it act as an antifoaming agent by t his way it reduces gastric flatulence. Sodium alginate is a colloidal carbohydrate. It is used along with H2 receptor antagonist for the management of heart burn and gastroeasophageal reflux disease.

19. Recent antacid preparations contain buffer type antacids with sodium alginate. Antacids should not be used in congestive cardiac failure since it contains sodium ions.

20. Ideal properties of antacid Cheaper Exert action gradually Longer duration of action No side effect Insoluble in water

21. Ideal properties of antacid Not to be absorbed- systemic alkalosis It should inhibit pepsin/ proteolytic enzyme Should not cause alkalosis The reaction between antacid and gastric acid should not yield large amount of gas

22. Antacids are a class of drugs used to treat conditions caused by the acid that is produced by the stomach . The stomach naturally secretes an acid called hydrochloric acid that helps to break down proteins.  The stomach, duodenum, and esophagus are protected from acid by several protective mechanisms.

23. When there is too much acid or protective mechanisms are inadequate, the lining of the stomach, duodenum or esophagus may become damaged by the acid, giving rise to inflammation and ulcerations and their various gastrointestinal symptoms such asnausea ,  abdominaL pain , and heartburn

24. Antacids reduce acidity by neutralizing (counteracting) acid, reducing the acidity in the stomach, and reducing the amount of acid that is refluxed into the esophagus or emptied into the duodenum

25. Antacid to be taken with meal It is important to note that when antacids are taken on an empty stomach they provide acid reduction for 20 to 40 minutes only because the antacid is rapidly emptied into the duodenum. When taken after a meal, (approximately 1 hour afterwards) antacids reduce acid for at least three hours since food from the meal slows emptying of the antacid (and food) from the stomach. 

26. Precaution Antacids (for example, calcium carbonate) when consumed in high doses and for long periods of time may cause acid rebound. Acid rebound is a condition in which the stomach produces even more acid after the consumption of foods and drinks . High-dose calcium carbonate and sodium bicarbonate when taken together can cause a condition called milk-alkali syndrome. Its symptoms include headache, nausea, irritability, and weakness,  hypercalcemia  (high blood calcium levels), and reduced function of the kidneys . Extensive use of aluminum-containing antacids may cause hypophosphatemia (low phosphate levels in the blood), which in severe cases could lead to muscle weakness, anorexia, and osteomalacia  

27. Antacids containing aluminum hydroxide should be used with caution in patients who have recently suffered massive upper gastrointestinal bleeding. For patients with conditions such as high blood pressure,  chronic heart failure, renal failure and those who have sodium or salt-restricted diets, it is important to pay attention to the sodium level in sodium-based antacid preparations such as sodium bicarbonate Antacids should not be given to children under six years of age.

28. Side effect Antacids may cause dose-dependent rebound hyperacidity and milk-alkali syndrome . Antacids that contain aluminum hydroxide may cause constipation, aluminum-intoxication, osteomalacia , and hypophosphatemia . Antacids that contain magnesium have a laxative effect that may cause diarrhea, and in patients with renal failure they may cause increased magnesium levels in the blood, because of the reduced ability of the kidneys to eliminate magnesium from the body in the urine . Antacids that contain magnesium trisilicate and magnesium hydroxide when taken with some other medications (such as tetracycline) will bind to the drugs, and reduce their absorption and effects.

29. Gelusil ®  Antacid & Anti-Gas Tablets PRODUCT INFORMATION Active ingredients (in each tablet): Purpose:Aluminum hydroxide dried gel 200 mgAntacidMagnesium hydroxide 200 mgAntacidSimethicone 25 mgAnti -gas. USES Relieves: Heartburn Sour stomach Acid indigestion Bloating, pressure, and discomfort commonly referred to as gas Do not take more than 12 tablets in a 24-hour period, or use the maximum dosage for more than 2 weeks, except under the advice and supervision of a physician. Chew 2 to 4 tablets. Repeat hourly if symptoms return, or as directed by a physician. Children under 12 years of age: ask a doctor Each tablet contains: magnesium 95 mg Store at 59° to 77°F (15° to 25°C) Tamper Evident: Do not use if blister or printed Gelusil ®  foil seal is broken See end panel for lot number and expiration date

30. Gas forms when you swallow too much air or when your body doesn't digest certain foods properly. Everyone gets it and most people pass it 13 to 21 times a day. 1  In normal people, about 50% of the gas passed from the rectum comes from swallowed air. 2 Gas is a source of abdominal bloating and discomfort, too. Many people who have heartburn experience gas as well.

31. Acid rebound Acid rebound is when a large amount of stomach acid rises into the esophagus several hours after taking an antacid. Acid rebound occurs most often with antacids that contain calcium carbonate. 2 Gelusil ®  doesn't contain calcium carbonate and hasn't been shown to be associated with acid rebound. 3

32. ENO eno  was invented in the 1850s by James Crossley Eno (1827-1915).Each 5g of Eno powder contains: Sodium bicarbonate  2.32g Citric acid  2.18 g Anhydrous sodium carbonate  0.50 g Total  sodiumcontent , 0.85g

33. Antacid By Dr.N.Gopinathan M.Pharm Ph.D Assistant Professor Faculty of Pharmacy Sri Ramachandra Medical college and Research institute ( Deemed University) Chennai, Tamilnadu India.

34. Antacid to be taken with meal It is important to note that when antacids are taken on an empty stomach they provide acid reduction for 20 to 40 minutes only because the antacid is rapidly emptied into the duodenum. When taken after a meal, (approximately 1 hour afterwards) antacids reduce acid for at least three hours since food from the meal slows emptying of the antacid (and food) from the stomach. 

35. Precaution Antacids (for example, calcium carbonate) when consumed in high doses and for long periods of time may cause acid rebound. Acid rebound is a condition in which the stomach produces even more acid after the consumption of foods and drinks . High-dose calcium carbonate and sodium bicarbonate when taken together can cause a condition called milk-alkali syndrome. Its symptoms include headache, nausea, irritability, and weakness,  hypercalcemia  (high blood calcium levels), and reduced function of the kidneys .

36. Precaution Extensive use of aluminum-containing antacids may cause hypophosphatemia (low phosphate levels in the blood), which in severe cases could lead to muscle weakness, anorexia, and osteomalacia   Antacids containing aluminum hydroxide should be used with caution in patients who have recently suffered massive upper gastrointestinal bleeding.

37. Precaution For patients with conditions such as high blood pressure,  chronic heart failure, renal failure and those who have sodium or salt-restricted diets, it is important to pay attention to the sodium level in sodium-based antacid preparations such as sodium bicarbonate Antacids should not be given to children under six years of age.

38. Side effect Antacids may cause dose-dependent rebound hyperacidity and milk-alkali syndrome. Antacids that contain aluminum hydroxide may cause constipation, aluminum-intoxication, osteomalacia , and hypophosphatemia . Antacids that contain magnesium have a laxative effect that may cause diarrhea, and in patients with renal failure they may cause increased magnesium levels in the blood, because of the reduced ability of the kidneys to eliminate magnesium from the body in the urine . Antacids that contain magnesium trisilicate and magnesium hydroxide when taken with some other medications (such as tetracycline) will bind to the drugs, and reduce their absorption and effects.

39. Milk Alkali Syndrome High-dose calcium carbonate and sodium bicarbonate when taken together can cause a condition called milk-alkali syndrome. Its symptoms include headache, nausea, irritability, and weakness,  hypercalcemia  (high blood calcium levels), and reduced function of the kidneys.

40. GELUSIL -Antacid & Anti-Gas Tablets Active ingredients (in each tablet): Aluminum hydroxide dried gel 200mg Magnesium hydroxide 200 mg Simethicone 25 mg Anti-gas.

41. GELUSIL USES Relieves: Heartburn Sour stomach Acid indigestion Bloating, pressure, and discomfort commonly referred to as gas

42. GELUSIL Do not take more than 12 tablets in a 24-hour period, or use the maximum dosage for more than 2 weeks, except under the advice and supervision of a physician. Chew 2 to 4 tablets. Repeat hourly if symptoms return, or as directed by a physician. Children under 12 years of age: ask a doctor

43. GELUSIL Each tablet contains: magnesium 95 mg Store at 59° to 77°F (15° to 25°C) Tamper Evident: Do not use if blister or printed Gelusil ®  foil seal is broken See end panel for lot number and expiration date

44. Gelusil MPS Active ingredients (in each tablet): Aluminum hydroxide dried gel 250 mg Magnesium hydroxide 250 mg Dimethicone 25 mg-Anti-gas. Magnesium trisilicate - 50 mg MPS- Methyl Poly Siloxane

45. Digene gel Magnesium hydroxide-185 mg Activated poly dimethyl siloxane-50mg Sodium carboxymethyl cellulose – 100 mg Dried aluminum hydroxide gel- 830 mg

46. Digene tablet Dried aluminium hydroxide gel 300 mg Magnesium Aluminium silicate hydrate- 50 mg Magnesium hydroxide- 25 mg Activated poly dimethyl siloxane - 25 mg

47. Other formulation Aciguard - magnesium hydroxide and activated poly dimethyl siloxane Aludrox gel- Aluminium hydroxide gel Dimol - Activated dimethicone . Galson S- Magaldrate and simethicone Galson SD- Magaldrate and simethicone domperidone

48. Polycid Gel Oxetacaine – 10 mg Aluminium Hydroxide – 291mg Magnesium hydroxide- 98 mg 5ml

49. ENO eno  was invented in the 1850s by James Crossley Eno (1827-1915).Each 5g of Eno powder contains: Sodium bicarbonate  2.32g Citric acid  2.18 g Anhydrous sodium carbonate  0.50 g Total  sodiumcontent , 0.85g

50. Acid rebound Acid rebound is when a large amount of stomach acid rises into the esophagus several hours after taking an antacid. Acid rebound occurs most often with antacids that contain calcium carbonate. 2 Gelusil ®  doesn't contain calcium carbonate and hasn't been shown to be associated with acid rebound. 3

51. Gas forms when you swallow too much air or when your body doesn't digest certain foods properly. Everyone gets it and most people pass it 13 to 21 times a day. 1  In normal people, about 50% of the gas passed from the rectum comes from swallowed air. 2 Gas is a source of abdominal bloating and discomfort, too. Many people who have heartburn experience gas as well.

52. Antacid compounds

53. Sodium bi carbonate baking soda NaHCO3

54. Preparation Ammonia soda process or solvay process Introduced by Brunner and Mond Strong brine [ Brine solution – high concentration of Nacl ] solution passed through carbonating water saturated with Ammonia It is again saturated with carbon di oxide under pressure

55. During the process ammonia react with carbon di oxide to produce Ammonium bi carbonate . This undergoes double decomposition with NaCl , leads to the formation of sodium bi carbonate as precipitate which is less soluble in brine solution. The above prepared sodium bi carbonate is separated by simple filtration and dried at room temperature. It does not comply with Indian Pharmacopoeia. Hence it is heated to get anhydrous sodium carbonate and evolves CO2.

56. This sodium carbonate is dissolved in pure water and CO2 is passed through the pure solution up to saturation to yield pure Sodium bi carbonate.

57. The second method of preparing it by bubbling carbon di oxide in to the sodium hydroxide. The solution is concentrated and dried.

58. Assay Substance dissolved in water add methyl orange and titrate it against 0.5 N HCl . The end point is yellow to orange colour . Methyl orange – yellow in alkaline and orange in acid medium.

59. use Systemic Alkalizer Antacid For preparing buffer In treatment of burns , insects bites etc. It is one of the constituent of oral rehydration salt

60. Aluminuim hydroxide gel

61. It is an aqueous suspension of hydrated aluminum oxide together with various amount of aluminum carbonate and bi carbonate. A hot solution of potash alum is slowly added to a hot solution of sodium carbonate with constant stirring during this reaction CO2 is evolved. After the complete evolution of CO2 the precipitate of aluminum hydroxide is prepared by filtration.

62. Preparation of Aluminum hydroxide gel

63. Precaution Alum solution to be added to sodium bi carbonate solution not vice versa otherwise precipitate will occur. Aluminum hydroxide is washed with hot water not with boiling water because later cause the decomposition of aluminum hydroxide.

64. Acid Neutralizing capacity Dissolve the required amount of sample in water add100 ml of 0.1 M HCl stir well maintain the temperature at 37 C measure the PH at time interval of 10, 15, and 20 minute. The PH of the solution is not more than 1.8, 2.3 and 3 respectively.

65. To this add 0.5 ml of 0.5 M HCl Stir well at 37 C Titrate with 0.1M NaOH to reach the PH 3.5. Not more than 50 ml of NaOH is needed to neutralize the solution.

66. Assay- complexometry Substance dissolved in HCl by warming in water bath to this excess amount of EDTA is added. The solution is then neutralised with NaOH using methyl red as indicator.[ The color change from red to yellow.] To this solution hexamine is added as buffer and xylenol orange as an indicator. Titrate it against lead nitrate.

67. Preparation of Potassium citrate

68. Mixing of hot solution of citric acid and potassium bi carbonate then the solution is filtered off and then evaporated to dryness. A fine powder is obtained by trituration in a warm water. Cooling saline taste Hygroscopic Mechanism of action The body tissue easily oxidises the potassium citrate and liberate CO2 and water and equivalent amount of potassium bi carbonate which function as an alkalinizing agent.

69. uses Osmotic diuretic Diaphoretic action Systemic alkalinizing agent Slight laxative action A nticoagulant

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