Presentation on theme: “Poison and Antidote.”— Presentation transcript:
1 Poison and Antidote
2 Overdose of a potent drug.Poison :- poisons are substances that cause disturbances in organisms Antidote :- Antidotes may be defined as those substances which react specifically with an They act either by Neutralising Poison Toxic effect Pharmaceutically Antagonistic action Chemically Converting to non-toxic or less toxic forms (e.g., chelates, acids, insoluble derivatives). Ingested poison Toxic substance Overdose of a potent drug.
3 Antidotes on the basis of their mechanism of action as follows:Physiological antidotes. They act by producing the effect opposite to that of poison, or to counteract the effect of poison physiologically. Chemical antidotes. They act usually by combining with the poison and thus changes its nature and poison cannot act any more. Mechanical antidotes. They usually act by preventing the absorption of poisons in the body or expelling out the poison by emesis or elimination through urine.
4 Common poisoning occursHeavy metals as the environment is getting richer in heavy metals, or metallic contamination of food and water. Many times the metals get leached from eating utensils and cookwares can give rise to inadvertent poisoning. The poisoning can also occur because of the insecticides or pesticides. The poisoning can occur because of excessive use of drugs (drug over doses). Heavy metal and cyanide poisoning and the use of antidotes in these poisoning.
5 HEAVY METALS AND THEIR ANTAGONISTSThe common heavy metals responsible for poisoning are the salts of arsenic, lead, mercury, iron and cadmium. Heavy metal poisoning occurs because of overdose intake or because of their imcomplete metabolism in the body. Depending upon the content and type of heavy metal the toxic effects can be seen treatment will given. The initial treatment in heavy metal poisoning is to administer activated charcoal for adsorbing heavy metal or poison. It is followed by administrating compounds which are able to produce emesis.
6 Activated Charcoal Preparation. Commercially, it is obtained as a residue during destructive distillation of various organic matters or from burning of organic materials in a special manner. The coarse material is crushed and powdered. Properties. It is a fine black, odourless, tasteless powder having smooth touch and free from gritty particles. It is almost insoluble in usual solvents. The fine powder provides more surface area for adsorbent properties.
7 Action and Uses. It is a general type of adsorbent use in poisoning. Adsorbs heavy metals and also adsorbs drugs such as hypnotics, sedatives, alkaloids etc. and also gases like carbon monoxide, carbon dioxide, nitrous oxide etc. It is normally employed in the ratio of 5 : 1 or 10 :1 (charcoal to poison). It is administered in the form of tablets. It also finds use in diarrhoea to adsorb toxins.
8 CYANIDE POISONING Cyanide poisoning normally takes place accidently or when cyanide poison is taken intentionally to commit suicide. Cyanide ion combines with ferric ion of cytochrome oxidase, an enzyme which is responsible for electron transfer reactions. This causes stoppage of cellular respiration and metabolic reaction. Antidotes in cyanide poisoning:- Sodium nitrite and Sodium thiosulphate. Both are used in conjunction with each other.
9 First of all an intravenous infusion of sodium nitrite injection is given. This is then followed by sodium thiosulphate infusion intravenously. The sodium nitrite is able to convert haemoglobin to methaemoglobin, which binds cyanide ions. Thus cyanide poisoning of cytochrome oxidase gets prevented, which is the main toxic action of cyanides. However, the cyanide-methaemoglobin complex slowly gets dissociated. The sodium thiosulphate converts this immediately to non-toxic thiocyanate, which gets excreted by the kidney.
10 2Na2CO3 + 4NO + O2 4NaNO2 + 2CO2↑ Sodium nitrite, USPNaNO Mol. wt Preparation :- This is manufactured by passing of nitrogen oxide gas (NO) obtained during the catalytic oxidation of ammonia and oxygen in sodium carbonate solution. The solution is concentrated to crystallize out the product. 2Na2CO3 + 4NO + O NaNO2 + 2CO2↑ Properties. Sodium nitrite occurs in the form of white grannular powder or as a white crystal having a saline taste. It is water soluble, sparingly soluble in alcohol, when exposed to air it deliquescesand gets slowly oxidised to sodium nitrate. It is easily decomposed by the acidification with dilute sulphuric acid. Chemically it acts as reducing agent and gets oxidised in acidic medium.
11 Uses :- It is mainly used as antidote in cyanide and has a hypotensive effect. It has relaxant action on smooth muscles used as a vasodilator. It prevents rusting of surgical instruments by immersing them in a dilute solution and it is also used as food preservative.
12 2NaHSO3 + Na2CO3 2Na2SO3 + H2O + CO2↑Sodium Thiosulphate Na2S2O3.5H2O Preparation:- It is obtained from soda ash, sulphur dioxide and sulphur. Sodium carbonate [Soda ash] is Dissolved in hot water and then passed sulphur dioxide. The resulting solution of bisulphite liquor is treated with a further quantity of soda ash which is then made to heat with sulphur. The solution is then concentrated, allowed to settle and is crystallized. Na2CO3 + H2O + 2SO2 2NaHSO3 + CO2↑ 2NaHSO3 + Na2CO3 2Na2SO3 + H2O + CO2↑ Na2SO3 + S Na2S2O3
13 Properties :- It is colourless crystals or as a coarse crystalline powder or as transparent, monoclinic prismatic crystals. It is odourless and is having an alkaline taste. It melts at 500 C, while decomposes on being heated at 100°C It effloresces in dry air and deliquesces moist air. It is soluble in water (0.5 part) but insoluble in alcohol.
14 Assay 0.1 N Iodine 1 gm Sodium thiosulphate + 20 ml WaterStarch as Indicator Each ml of 0.1 N iodine is equivalent to g of sodium thiosulphate.
15 Sodium Thiosulphate Na2S2O3.5H2O 284.2 Assay:-It is assayed by titration with standard iodine solution with starch as indicator. About its 0.8g accurately weighed is made to dissolve in about 30 ml of water in a conical flask. This is titrated with 0.1 N (standard) iodine solution added from a burette. Towards the end-point, 3 ml of starch solution is added as indicator. The approach of endpoint can be recognised, by the yellow colour of iodine, which gets discharged by shaking for a few seconds. Each ml of 0.1 N iodine is equivalent to g of sodium thiosulphate.
16 Uses :- Sodium thiosulphate has been included in Pharmacopoeia as an antidote for cyanide poisoning. For this purpose a 10% w/v solution is used intravenously although a 2.98% w/v solution is isotonic. It reacts with the cyanide ion to form relatively harmless thiocyanate. Sodium thiosulphate is also a very important reducing agent Used as a standard titrant in iodimetric analysis. Storage. It should be stored in tightly closed containers.
17 Astringents
18 Astringent (to bind fast)Definition- Astringent is a drug that reacts chemically with cellular proteins producing coagulation which is accompanied with shrinkage of body tissues.
19 CHARACTERISTICS • Affect only the superficial layer. Reduce cellular permeability. • Make the surface mechanically stronger, decrease exudation. • Protect from external irritation. • Possess local styptic and local antiseptic action. • May interfere with the function of pain receptors. The pain relieving action is mild.
20 TYPES OF ASTRINGENTS Vegetable astringents – tannic acid, gallic acid Metallic astringents – • Aluminium salts – alum, aluminium chloride, aluminium acetate • Zinc salts – zinc chloride, zinc sulfate • Ferric chloride • Strontium chloride • Silver nitrate and copper sulfate Others – very cold water, alcohol
21 THERAPEUTIC USES OF ASTRINGENTS• Externally applied astringents, which cause mild coagulation of skin proteins, dry, harden, and protect the skin. • Cleaning the face and preventing acne breakouts. • Stopping bleeding. Haemorrhoids [ piles ]. Relief from minor skin irritations like superficial cuts, allergies, insect bites, or fungal infections such as athlete’s foot – Aluminium acetate and calamine lotion. • Other uses of astringents – in bleeding piles and as antiperspirant/deodorant
22 Zinc Sulphate ZnO + H2SO4 + 6 H2O → ZnSO4•7H2O ZnSO4 161.47Preparation:- Zinc sulfate is produced by treating virtually any zinc-containing material (metal, minerals, oxides) with sulfuric acid. The reaction of the metal with aqueous sulfuric acid: Zn + H2SO4 + 7 H2O → ZnSO4•7H2O + H2 Pharmaceutical-grade zinc sulfate is produced by treating high-purity zinc oxide with sulfuric acid: ZnO + H2SO4 + 6 H2O → ZnSO4•7H2O The solution is then concentrated, allowed to settle and is crystallized.
23 Properties When heated above 680 °C, zinc sulfate decomposes into sulfur dioxide gas and zinc oxide fume Appearance white powder Odor odorless Density 3.54 g/cm3 (anhydrous) g/cm3 (hexahydrate) Melting point 680 °C (1,256 °F; 953 K) decomposes (anhydrous) 100 °C (heptahydrate) 70 °C, decomposes (hexahydrate) Boiling point 740 °C (1,360 °F; 1,010 K) (anhydrous) 280 °C, decomposes (heptahydrate) Solubility in water 57.7 g/100 mL, anhydrous (20 °C) (In aqueous solutions with a pH < 5) Solubility Alcohol
24 Uses It is used together with oral rehydration therapy (ORT) and an astringent. Zinc sulfate is an inorganic compound and dietary supplement. As a supplement it is used to treat zinc deficiency The main application is as a coagulant in the production of rayon. It is also a precursor to the pigment lithopone. It is also used as an electrolyte for zinc electroplating, as a mordant in dyeing, and as a preservative for skins and leather.
25 Potassium alum K2SO4 + Al2(SO4)3 KAl(SO4)2 KAl(SO4)2 474.38Preparation:- Potassium alum industrially prepare by adding potassium sulfate to a concentrated solution of aluminium sulfate. K2SO4 + Al2(SO4) KAl(SO4)2
26 Properties Appearance white small crystals Odor watery metallic Density 1.725 g/cm3 Melting point 92 to 95 °C (198 to 203 °F; 365 to 368 K) Boiling point 200 °C (392 °F; 473 K) Solubility in water 14.00 g/100 mL (20 °C) g/100 mL (50 °C) Solubility insoluble in acetone
27 Uses Potassium alum is used in medicine mainly as an astringent (or styptic) and antiseptic. Potassium alum was also used topically to remove pimples and acne. It has been used to stop bleeding in cases of hemorrhagic cystitis. It is used in some countries as a cure for hyperhidrosis. use in some antiperspirants and deodorants, acting by inhibiting the growth of the bacteria responsible for body odor. Potassium alum was the major adjuvant used to increase the efficacy of vaccines Potassium alum is used as a fire retardant Potassium alum is used in leather tanning