Drying of Crude Drugs PDF

4-Drying of crude drug Removal of water or most of it from the fresh living tissues (up to 80%). 4- Careful drying is essential retain physical characters and chemical constituents of Drying drug, and comply the pharmacopoeia of requi...

4-Drying of crude drug Removal of water or most of it from the fresh living tissues (up to 80%). 4- Careful drying is essential retain physical characters and chemical constituents of Drying drug, and comply the pharmacopoeia of requirements for maximum moisture crude contents. drug The duration of drying process varies from (few hour) to (many weeks)  Stops enzymatic action that might change the active constituents. Avoids deterioration upon storage by preventing the growth of microorganisms (bacteria and fungi). Why Drying is necessary? Facilitates grinding into powdered form. Reduces weight and bulk facilitates packing and storage. The most important factors in drying process 1- Temperature 2- Time ❑ To use as low ❑ To carry out the temperature as operation as rapid possible. as possible..  Methods of drying Natural Artificial Drying Drying Sun drying Direct fire Shade drying Heated stove Drying shed chambers Vacuum drying Freeze drying (Lyophilization) Artificial drying has a distinct advantage over air – drying in that it immediately stops enzymatic action Disadvantage of artificial drying by direct fire and heated stoves: ❖Drying should be done carefully to prevent damage or burning. ❖Excessive heat causes gelatinization of starch, as well as, a smoky odor. Stove Drier with removable Sun Drying wire tray or rack.  Drying chambers consist of closed space with several movable trays, arranged to allow the circulation of heated air. It is a controlled process, where its temperature and ventilation can be regulated to be suitable for drying of Drying sheds chambers. different plant organs. Freeze drying (lyophilization): The principle of this process is the removal of the water content of the drug when present in the frozen state under vacuum at which it sublimes into vapor directly without passing through the liquid state. This methods used for thermo labile drugs (hormones, vitamins). Effect of drying; several changes may occur on drying: 1. Size and weight: markedly decreases due to loss of 80-90% of water. 2. Shape and appearance: some drugs shrivel on drying, others have their surface wrinkled or reticulated. The method of drying also affects the appearance of some unorganized drugs aloes, when rapidly heated and cooled, produces homogenous glassy masses but when slowly heated and cooled produces heterogeneous opaque masses 3. Texture: drugs on drying become harder ( roots), brittle (leaves) while those containing starch become horny. 4. Colour: drugs become darker in colour and in certain cases a total change of colour occurs, e.g. poppy, when fresh is scarlet-red, on drying becomes dull- violet, Tea leaves change from green to brown almost black. 5. Odour: Hyoscyamus and Digitalis lose their bad odour on drying. 6. Taste: Fresh Gentian is very bitter becoming pleasant on drying. 7. Constituents: Fresh Vanilla pods contain gluco-vanillin and gluco-vanillic alcohol, on drying, oxidation and hydrolysis of both glycosides occurred to set free vanillin.  Effect of drying on crude drugs 1- Size & weight 2- Shape &appearance Decrease of weight Wrinkled or reticulated (80 – 90%). e.g. black pepper 4- Color Tea (green) 3- Texture black or red. harder (roots), vanilla (yellow) brittle (leaves), dark brown 6- Taste 7- Constituents 5- Odor Bitter e.g. vanilla pleasant taste Vanilla pods Fragrant odor.  Precautions for Drying Different Plant Organs 1-Leaves dried quickly fresh green color & prevent decomposition of active 2-Flowers dried rapidly, constituents e.g. Digitalis leaves low temp. in shade, to retain the color Rapidly Vacuum oven 3-Fruits & seeds: on trays, in sun or 60oC shade 4-Barks, large roots & rhizomes dried in sun , sliced to Senna pods Linseed facilitate drying  5. Packing of the crude drugs Packing provides : Protection Why Packing???? less space during storage and shipment.  Packing of the crude drugs 1-Leaves and herbs: Baled into compact mass. 2-Volatile oil: Enameled cans. Methods 3- Gum resin and extracts: in of packing barrels Cape aloe: in wooden boxes Turkish opium: packed in sub- cylinderical cakes 6- Storage of crude drugs The last and most important stage in handling of crude drugs. Drugs may deteriorate if they are stored under uncontrolled condition. Few drugs are not affected on storage. The quality of some drugs is improved on storage such as Frangula and Cascara barks.  Mentha Aromatic drugs(containing volatile oil) usually lose their aroma. What changes Drugs containing fixed may occur on oil may be rancid. storage? Linseed Digitalis leaves may lose their activity.. Digitalis pharmacopoeias instructions for storage of crude drugs : - 1. In well closed containers. 2. Protected from light, moisture and dust. 3. At low temperature. 4. Protected from insect infestation.  Factors affecting deterioration of crude drugs 1- Moisture A- Physicochemical 2- Light factors 3- Temperature 4- Air 1- Bacteria and fungi B- Biological factors 2- Insects 3- Rodents  A- Physicochemical factors Bad effect of moisture : 1-Hydrolysis of active constituents by enzymes. 2-The growth of bacteria and fungi 3-It increases the weight of the drug thus 1- Moisture decreases the % of active constituents. How to over come? 1-Temporary stabilization using dehydrating agent such as quick lime or calcium chloride 2- Complete stabilization: by exposing fresh drugs to alcohol vapour or by immersing it in boiling alcohol. A- Physicochemical factors ( Cont.) Affect delicate drugs having color: 1-Rose petals are red brown 2-Digitalis leaves lose its activity more rapidly in sun light 2 – Light How to over come? Drugs should be stored in the dark or by the use of opaque or amber-colored glass containers.  A- Physicochemical factors ( Cont.) High temperature up to about 45°C activates the enzymes causing decomposition of active constituents. 3.Temperature Volatile oil containing drugs are directly affected by temperature as Chamomile, Clove and Ginger. ❑Oxygen of air lower the quality of the product. 4. Air ❑Powdered drugs are more liable to oxidative effects than entire drugs as diffusion of oxygen is more faster.  B- Biological factors Bacteria and fungi Insects Fungi attack drugs rich in -render drugs nutritive substances unsuitable They change physical for preparation Rodents: properties of drug (e.g. color of standard and texture). extracts.  How to Destroy Insects before Storage Exposing drug to temp. 60 – 65 oC. I. Heat treatment Treatment kills insects eggs. This method is not suitable if heating affect the active constituents of the drug. Uses of volatile insecticides in closed areas such as carbon disulphide or T-gas (a mixture of 90% II. Fumigation Ethylene oxide and 10% carbon dioxide). Repeat fumigation at intervals will kill insect eggs.  Drug is dipped in freshly slacked lime or sprinkled with quick lime. Block the respiratory system of insects and III. Liming larvae. Used for few drugs e.g. Ginger and Nutmeg. Subjecting drug to refrigerator, as adult IV. Freezing insects, larvae and eggs are sometimes killed at very low temperature.  Rodents:  They cause spoilage of crude drug during storage if the drugs are store in paper, cloth, or wooden containers.  The rodents attack can be prevented by storing in glass, plastic or metal containers.  Rodenticides (e.g. alpha- naphthylthiourea, A.N.T.U.) may be used to eliminate rates and mice. Adulteration of natural product ◼ In general adulteration occurs when the drug is scarce, or when it is expensive.  Sophistication (true adulteration) Substitution Addition of worthless heavy materials Adulteration The presence of adventitious materials within Admixture the drug Deterioration Inferiority or spoilage  1- Sophistication Addition of an inferior material to the original drug with intension. powder ginger Capsicum Ginger Flour curcuma (to restore the color)  2- Substitution An entirely different article used or sold in place of the original drug. Substitution of Substitution of Substitution of inferior superfacially commercial varieties exhausted drugs similar drugs Senna Dog Clove Clove stalk and mother Senna clove exhausted drug 3.Admixture; is the addition of one article to another through accident or ignorance. It may occur during faulty collection as collection in improper time or at improper stage of maturity. 4.Inferiority; meaning any drugs not conforming to standards. In such cases, certain synthetic articles are added to fortify the drug, as addition Citral to lemon oil. 5.Deterioration or spoilage; is impairment of the quality of a drug by destruction of a valuable constituents by extraction, moisture, heat, fungi, insects or other means.  6-Addition of worthless heavy materials ◼ large stone, sand, lime stone to increase weight of the drug e.g. Liqurice 7-Presence of adventitious matter ◼ Naturally occurring with the drug e.g. excessive stem with Stramonium.  Evaluation of drugs ✓ Evaluation of a drug means its identification and determination of its quality and purity. ✓ For each official drug there are limits for its quality and purity listed in its monograph (the part of the pharmacopœia describing the drug).  The identity of a drug can be established by: Collecting it from a plant that is positively identified. Comparing it with a reserved sample (herbarium) that is previously identified. Comparing the unknown drug with a published description of authentic drug sample. The quality of the drug refers to its content of active constituents such as : carbohydrates glycosides alkaloids A high grade of quality in a drug is obtained by collecting it 1. From the correct natural source. 2. At the proper time. 3. At the proper stage of growth. 4. By using the proper manner. 5. By good preparation of the collected drug using proper cleaning and drying processes. 6. By the proper protection of it and of its samples against insect, fungi, dirt and moisture. For the evaluation of drugs we use a number of methods 1-Organoleptic methods The term organoleptic evaluation refers to the sensory evaluation. 2-Microscopic methods Evaluation of drugs (cont.) 3- Chemical methods It includes different chemical tests & chemical assays. 4-Biologic methods  Complete the following: 1.Flora means …………. 2.Papaver somniferum means …………………... 3.Source of the medicinal plants may be ……… and  Complete the following: 4. Official drug means ……… 5. Triticum sativa means ……… 6. Source of the medicinal plants may be ………., …….. and ……….  MCQS with comment ◼ 1. Rhubarb as laxative must be collected in a. Spring b. Autumn c. Sommer d. Winter Comment……………………………….. 2. Colchicum corms not collected in a. Spring b. Autumn c. Sommer d. Winter Comment………………………………..  MCQS with comment 3. Ginger prepared by a. Cleaning b. Garbling c. Bleaching d. Curing Comment………………………………..