Lecture 4 Pharmacognosy I PHCG 111 PDF

For First year Pharmacy Students By  D- PRESERVATION AND PROTECTION OF CRUDE DRUGS: FACTORS AFFECTING DETERIORATION OF CRUDE DRUGS: A- PHYSIOCHEMICAL FACTORS 1. Moisture Moisture activate enzymes, hydrolysis active constituents and decrease its percent, increase bulk of the...

For First year Pharmacy Students By  D- PRESERVATION AND PROTECTION OF CRUDE DRUGS: FACTORS AFFECTING DETERIORATION OF CRUDE DRUGS: A- PHYSIOCHEMICAL FACTORS 1. Moisture Moisture activate enzymes, hydrolysis active constituents and decrease its percent, increase bulk of the drug and help growth of micro-organisms on the drugs. ▪ Humidity: amount of moisture present in the atmosphere ▪ Humidity 100% = atmosphere is completely saturated ▪ Humidity 50% = atmosphere is half saturated ▪ Humidity greater than 75% make stored materials ex. Digitalis absorb moisture until deleterious amounts are present. ▪ Drugs stored in usual containers (sacks-wooden cases-cardboard boxes-paper bags) reabsorb 10-12% moisture (air-dry drug) ▪ Permissible moisture content reported in pharmacopoeias ▪ Air-dried drugs are liable to insect attack ▪ Drugs showing mould or worminess should be rejected ❑Process of Stabilization: inhibition of enzymatic action and retains drug without alteration in shape and constituent. Temporary: [for a certain period - partial stabilization] by placing containers over dehydrating agent as quick lime (absolute dry condition) or by natural drying. Complete: destruction of enzyme permanently by exposure of fresh drug to alcohol vapor or dipping in alcohol. 2. Light ▪ It affects stored drugs in different ways 1. It destroys sensitive active constituents e.g Digitalis. 2. Affect colored drugs e.g. santonin (santonica) turns black and rhubarb (yellow) turns red. ▪ Drugs affected by light should be stored in dark places or using opaque or amber-coloured glass 3- Temperature ▪ Enzymes act rapidly by raising temperature to 45 ⁰C. High temperature evaporates volatile constituents leading to rapid deterioration of the drug e.g. chamomile. 4- Air (Oxygen of the air) ▪ It brings about oxidation of active constituents. E.g. Rancidity of fixed oils and Resinification of volatile oils. ▪ General rule for the preservation of drugs from the physico-chemical factors it should be stored in moisture-proof, air-tight, light proof containers at low temperature.  B- Biological factors ▪ These include living organisms 1. Bacteria and fungi 2. Moulds, mites and worms. 3. Insects 4. Rodent ❑ CONTROL OF INFESTATION: 1. Heat treatment: ▪ Exposing the drug to a temperature of 60 to 65°C is often effective and kill insects and eggs. ▪ Not suitable for drugs contain thermolabile or volatile oil (V.O.) constituents. 2. Fumigation: ▪ It is suitable for large quantities. ▪ Drugs are subjected to a poisonous gas and should be carefully applied e.g. Carbon bisulfide and Cyanide gas ▪ Carbon tetrachloride satisfactory with advantage being non-flammable ▪ T-gas commonly used (90% ethylene oxide + 10% CO2) ▪ 60CO radiation in large doses kills mites and their eggs ▪ Stored drugs should be routinely fumigated every 3 or 4 month 3-Liming: ▪ Drugs covered by coat of lime to protect them from insect e.g. Ginger and Nutmeg. 4. Low temperature storage ▪ Preferred to fumigants and liming. ▪ Adult insects, pupae, larvae and eggs sometimes are killed by extremely low temperatures. Exposure to sub-freezing temperature of -10 to -15 oC for 12 to 18 hours sometimes will destroy even eggs. ▪ Exposure to alternate periods of low and high temperature frequently is more effective for killing insects than a prolonged period of low temperature exposure. Rodents: ▪ Attack drugs in paper, cloth or wooden containers. ▪ Presence of filth of rodents, their hairs or excreta causes rejection of drugs. ▪ Packing in metal, plastic or glass containers prevent this attack. ▪ Rodent hairs and excreta often can be detected macroscopically ▪ The presence of rodent urine on drugs can be detected by ultraviolet radiation. This test is not infallible, however, since a number of drugs fluoresce ▪ Using rodenticides as A.N.T.U.(Alpha Naphthyl Thio Urea)  VII- ADULTERATION OF DRUGS AND DETECTION OF ADULTERANTS ▪ In general, adulteration occurs when a drug is scarce or when the price of a drug is normally high, though there may be no scarcity. ▪ The adulterant must be both cheap and available. 1. Sophistication or True adulteration: ‫غش‬ The addition of an inferior material to any article with intends to defraud ‫احتيال‬. Examples: ▪ Addition of wheat flour to Powdered Ginger, with enough Capsicum to restore the pungency and enough Curcuma to maintain the color. ▪ Paraffin wax colored yellow has been added to beeswax. ▪ Artificial invert sugar has been added to Honey. ▪ Pieces of string dipped in red ink have been added to Saffron. 2. Substitution: ‫استبدال و احالل‬ An entirely different article used or sold in place of the one required or asked for. ‫عمد‬ ‫و‬ ‫احتيال‬ ▪ A complete substitution, even though intentional and fraudulent, is not sophistication, as none of the true article is present. ▪ Substitution may occur in different ways: i. Substitution of inferior commercial varieties e.g. Arabian Senna and Dog Senna have been used to adulterate Senna. ii. Substitution of exhausted drugs e.g. cloves and Umbelliferous fruits. iii. Substitution of superficially similar but cheaper natural substances, usually having no relation to genuine drugs, e.g. leaves of Phytolacca and Scopalia for Belladonna; Leaves of Xanthium for Stramonium and of Dandelion for Henbane 3. Admixture: ‫اختالط‬ The addition of one article to another through accident, ignorance or carelessness. ▪ If the addition has been done intentionally to defraud, it is Sophistication. ▪ Admixture may occur through faulty collection, as collecting the drug not at the proper time, e.g. collecting Colchicum corm in early autumn ▪ Collection at the last stage of development e.g. umbelliferous fruits, when are fully mature and ripe ▪ Collection of other parts of the same plant e.g. stems, stalks, aerial parts with leaf drugs ▪ Collection from other plants by mistake or ignorance of collectors, e.g. Argel instead of Senna leaves. 4- Deterioration: ‫تدهور‬ Impairment of the quality of the drug by the abstraction or destruction of valuable constituents by distillation, extraction, aging, moisture, heat or other means. ▪ Whole cloves by distillation ▪ Coffee which lost caffeine through over-roasting. 5. Spoilage: ‫تلف‬ A form of deterioration in which the quality or value or usefulness of an article is impaired or destroyed by the action of bacteria or fungi to render the article unfit for human consumption. 6. Inferiority: ‫ردئ‬ It is any substandard condition for any cause. ▪ The dried ripe seeds of Nux vomica, containing less than 1.15% strychnine would be inferior or substandard drug. 7. Addition of worthless heavy materials: ▪ A large mass of stone has been found in the center of Licorice bales. ▪ Lead shots have occurred in pieces of opium. ▪ Mineral or vegetable oils, glycerin or ammonium nitrate are added to Saffron. ▪ Uniformity of quality is promoted by the use of standards. ▪ There are Three pharmacognostical standards 1. Structural standards 2. Analytical standards 3. Physical constants ▪ The identity is established by comparison with authentic samples