Inorganic Pharmaceutical Chemistry: Protectives, Adsorbents, and Cathartics PDF

University of Babylon College of Pharmacy Department of Pharmaceutical Chemistry Inorganic Pharmaceutical Chemistry: Protectives, Adsorbents and Cathartics Yousef Sabah Ali M.Sc. Pharmaceutical Chemistry [email protected]  By the end of this session, you will be...

University of Babylon College of Pharmacy Department of Pharmaceutical Chemistry Inorganic Pharmaceutical Chemistry: Protectives, Adsorbents and Cathartics Yousef Sabah Ali M.Sc. Pharmaceutical Chemistry [email protected]  By the end of this session, you will be able to: Define and explain the role of protectives and adsorbents. Learning Describe the mechanism of adsorption and differentiate Outcomes between physical and chemical adsorption. Explain the action of saline cathartics. Assess the risks and benefits of using laxatives and cathartics. Diarrhea is a symptom and not a disease! Results when some factor impairs digestion and/or absorption, thereby increasing the bulk of the intestinal tract. Acute diarrhea can be caused by bacterial toxins, chemical poisons, drugs, allergy, and disease. Chronic diarrhea can result from gastrointestinal surgery, carcinomas, chronic inflammatory conditions, and various absorptive defects. Diarrhea Diarrhea is a serious condition, particularly for very young or elderly patients. The loss of fluids and electrolytes can quickly lead to dehydration and electrolyte imbalances. It is currently believed that some of the bacterial toxins stimulate the flow of electrolytes into the intestines, thereby increasing the intestinal osmotic load. Diarrhea Most products for the treatment of diarrhea will consist: Adsorbent-protective. Antispasmodic Possibly an antibacterial agent. Adsorption Adsorption is a process by which a substance (the adsorbate) adheres to the surface of another substance (the adsorbent). Physical Adsorption: This occurs due to Van der Waals forces, which are weak, non- specific forces. Chemical Adsorption: Involves the formation of stronger chemical bonds. What are the Factors affecting Adsorption? Bismuth-Containing Products These compounds provide a dual action, adsorbing toxins and bacteria while forming a protective barrier in the intestines. Intestinal hydrogen sulfide acts upon the bismuth salts to form bismuth sulfide; hence, the black stools. 2Bi3+ + 3H2​S → Bi2​S3 (black precipitate) + 6H+ Bismuth Subnitrate [Bi(OH)2NO3]4·BiO(OH) White, slightly hygroscopic powder which gives an acid reaction using blue litmus paper. Bismuth subnitrate has a well-recognized incompatibility with tragacanth, in which tragacanth precipitates as a hard mass in the presence of the salt. This difficulty may be overcome by the protective action of sodium biphosphate or trisodium phosphate. Milk of Bismuth Milk of Bismuth contains bismuth hydroxide and bismuth sub carbonate in suspension in water. NH₂CO₂NH₄·NH₄HCO₃ + NH₄OH ⇌ 2(NH₄)₂CO₃ It is made by converting bismuth subnitrate to bismuth nitrate [Bi(NO₃)₃] by the addition of nitric 3(NH₄)₂CO₃ + 2Bi(NO₃)₃ → Bi₂(CO₃)₃ ↓ + 6NH₄NO₃ acid. 2Bi₂(CO₃)₃ + H₂O → [(BiO)₂CO₃]₂·H₂O + 4CO₂ ↑ Then, by treatment with ammonium carbonate and ammonia solution, bismuth nitrate is Bi(NO₃)₃ + 3NH₄OH → Bi(OH)₃ ↓ + 3NH₄NO₃ converted to bismuth hydroxide and sub carbonate. Activated Clays and Other Adsorbents Kaolin is a native hydrated aluminum silicate, powdered and freed from gritty particles. Kaolin is used as an adsorbent. Kaolin-containing products have been reported to interfere materially with the intestinal absorption of lincomycin. Activated charcoal has been used as an adsorbent in the treatment of diarrhea. It is now a recommended antidote in certain types of poisoning. It works primarily through physical adsorption. Saline Cathartics Constipation is the infrequent or difficult evacuation of feces. It may be due to a person resisting the natural urge to defecate. Constipation can also be caused by intestinal atony (lack of muscle tension), intestinal spasm, emotions, drugs, and diet. Saline cathartics (purgatives) are agents that quicken and increase evacuation from the bowels. Saline Cathartics Laxatives should only be used for short- term therapy because of the so-called "laxative habit.“ They are used to: ease defecation in patients with painful hemorrhoids or other rectal disorders. avoid potentially hazardous rises in blood pressure. relieve acute constipation. remove solid material from the intestinal tract.  The stimulant laxatives act by local irritation on the intestinal tract. The bulk-forming laxatives are made from cellulose and other nondigestible polysaccharides. They swell when wet, with Types of the increased bulk stimulating peristalsis. Laxatives The emollient laxatives act either as lubricants or as stool softeners. The saline cathartics act by increasing the osmotic load of the gastrointestinal tract. Official Saline Cathartics Sodium Biphosphate occurs as colorless crystals or as a white, crystalline powder. When saline cathartics, like sodium biphosphate (NaH₂PO₄) dissolve in water, they dissociate into their respective ions: NaH2PO4 → Na+ + H2PO4− H₂PO₄⁻ + H₂O ⇌ H₃O⁺ + HPO₄²⁻ Official Saline Cathartics Sodium Phosphate occurs as a colorless or white granular salt which effervesces in warm, dry air. Na2​HPO4​ → 2Na+ + HPO42−​ Dried Sodium Phosphate is a nearly anhydrous white powder which readily absorbs moisture. Effervescent Sodium Phosphate is a mixture of sodium bicarbonate, tartaric acid, and citric acid. Sodium tartrate is also a saline cathartic, and sodium citrate provides a lemon-like flavor which, along with the carbonation provided by the carbon dioxide, masks the saline taste. NaH2​PO4​ + NaHCO3​ → Na2​HPO4​ + CO2​ + H2​O Summary Role of Protectives and Adsorbents: These agents are primarily used to treat mild diarrhea by adsorbing toxins, bacteria, and viruses, and providing a protective coating to the intestinal mucosa. Key compounds include activated charcoal, bismuth salts, and kaolin. Mechanism of Adsorption: Adsorption involves the adherence of toxins or bacteria to the surface of an adsorbent. This can be through physical adsorption (Van der Waals forces) or chemical adsorption (stronger bonds). The efficiency depends on factors like surface area, polarity, and pH. Saline Cathartics: These agents, such as sodium biphosphate, increase the osmotic load in the gastrointestinal tract, stimulating peristalsis and relieving constipation. They should be used cautiously to avoid dependency and electrolyte imbalances Minute Paper Question What is the most important concept you learned today about protectives and adsorbents?