Pharmacognosy I Lecture 3: Drug Preparation
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Questions and Answers

What are the two main methods for drying crude drugs?

Natural drying and artificial drying

What is the primary objective of drying crude drugs?

  • To enhance their color.
  • To aid their preservation. (correct)
  • To make them more palatable.
  • To increase their weight.
  • What is the critical threshold level in drying?

    The moisture content below which the drug is considered safe from spoilage by molds and bacteria.

    Sun drying is preferable for all types of drugs.

    <p>False</p> Signup and view all the answers

    Which of the following is an advantage of artificial drying over natural drying?

    <p>Artificial drying is more controllable and can be done at a specific temperature.</p> Signup and view all the answers

    Which of the following is NOT a method of applying artificial heat for drying drugs?

    <p>Refrigeration</p> Signup and view all the answers

    Drying tunnels are primarily used for drying small quantities of drugs.

    <p>False</p> Signup and view all the answers

    Which drying method is considered an extreme form of vacuum drying and uses very low temperatures and high vacuum?

    <p>Freeze drying</p> Signup and view all the answers

    Chemical drying is a suitable method for drying large quantities of drugs.

    <p>False</p> Signup and view all the answers

    What is the difference between an 'absolutely dried drug' and an 'air-dry drug'?

    <p>An absolutely dried drug is completely free from water. An 'Air-dry drug' has absorbed some moisture from the air.</p> Signup and view all the answers

    What primary change occurs to the size and weight of drugs during drying?

    <p>Contraction</p> Signup and view all the answers

    The color of all drugs becomes darker during drying.

    <p>False</p> Signup and view all the answers

    How does drying affect the odor of certain drugs?

    <p>Drying can either enhance or eliminate the odor of drugs depending on the drug's constituents.</p> Signup and view all the answers

    What is the main change that occurs in fresh vanilla pods upon drying?

    <p>Hydrolysis and oxidation occur, producing vanillin.</p> Signup and view all the answers

    Why is it important to control the drying process accordingly, based on the required or objectionable changes in the drug?

    <p>Controlling the drying process ensures the drug's quality and effectiveness by either promoting or preventing specific chemical changes during drying.</p> Signup and view all the answers

    What are the two main purposes of packing crude drugs?

    <p>Packing protects drugs from damage and provides economy of space.</p> Signup and view all the answers

    Which of the following is NOT a common shipping and storage container for crude drugs?

    <p>Glass jars</p> Signup and view all the answers

    Drugs that are easily affected by moisture are generally packed in airtight containers.

    <p>True</p> Signup and view all the answers

    The effect of packing can never alter the appearance of a drug.

    <p>False</p> Signup and view all the answers

    What is one way that packing can provide an indication of the geographical origin of a drug?

    <p>The specific method of packing, or the unique markings left on the drug by the packing process, can reveal the origin.</p> Signup and view all the answers

    The packing of drugs is solely for aesthetic purposes.

    <p>False</p> Signup and view all the answers

    Rain is the only source of sweet water.

    <p>True</p> Signup and view all the answers

    What percentage of the cytoplasm does water constitute?

    <p>90%</p> Signup and view all the answers

    What are the three temperatures that affect plant growth rates?

    <p>Minimum, optimum, and maximum</p> Signup and view all the answers

    What is the term used to describe the response of plants to the relative length of day and night?

    <p>Photoperiodism</p> Signup and view all the answers

    What are the three broad photoperiodic classes of plants with respect to their flowering behavior?

    <p>Short day plants, long day plants, and day neutral plants</p> Signup and view all the answers

    The amount of water that remains in the soil after excess water has drained away is called the ______.

    <p>absolute water capacity</p> Signup and view all the answers

    Which of these is NOT a macro-element?

    <p>Iron</p> Signup and view all the answers

    Nitrogen deficiency in plants leads to a condition called chlorosis, resulting in a yellow-colored plant.

    <p>True</p> Signup and view all the answers

    Which plant hormone acts by antagonizing GA?

    <p>Abscisic acid</p> Signup and view all the answers

    The qualitative and quantitative composition of medicinal plants can change during the growing season.

    <p>True</p> Signup and view all the answers

    When is the ideal time to collect leaves for medicinal purposes?

    <p>When the flowers are just beginning to expand</p> Signup and view all the answers

    Which of these plant parts is typically collected in the autumn or winter?

    <p>Storage tissues such as roots, rhizomes, and bulbs</p> Signup and view all the answers

    Rhubarb collected in the winter contains no anthraquinones.

    <p>True</p> Signup and view all the answers

    Which of these is NOT a general rule for collecting drugs?

    <p>Flowers should be collected in full expansion.</p> Signup and view all the answers

    Study Notes

    Introduction to Drug Preparation

    • Lecture 3 of Pharmacognosy I (PHCG 111) for first-year pharmacy students
    • Presented by Dr. Rafik Mounir Nassif

    Preparation of Crude Drugs

    • Cleaning: Underground plant parts are cleaned to remove soil by brushing or washing
    • Garbelling: Extraneous matter, like sand or other plant parts, is removed and the remaining material is graded
    • Bleaching: Some drugs, like white beeswax, are bleached to achieve their desired color

    Drying of Crude Drugs

    • Fresh plant parts can be used immediately after collection, or dried for later use
    • Objectives of Drying:
      • Preserve the drug
      • Inactivate enzymes to prevent decomposition of active constituents
      • Prevent microbial growth (bacteria and fungi)
      • Facilitate powdering (comminution) of the drug
      • Reduce size and weight for easier storage and transport
    • Essential drying factors: proper temperature/humidity regulation is crucial

    Drying Methods

    • Natural Drying:

      • Shade Drying: Used to maintain natural color as well as preserve sensitive active constituents, used on more delicate plants
      • Sun Drying: Used on plants less sensitive to direct sunlight
    • Artificial Drying:

      • Physical Method: Using elevated temperature, decreased pressure (vacuum), or electromagnetic radiation (infrared/microwave ovens)
      • Chemical Method: Using desiccants (e.g., anhydrous CaCl2, concentrated H2SO4, or silica gel)
    • Advantages of artificial drying:

      • Stops enzymatic action immediately
      • Rapid drying, preserving active ingredients
      • Retains the drug's color

    Artificial Drying Methods - Details

    • Direct fire: Drugs are placed on a wire mesh over burning coals or wood. Excessive heat can gelatinize starch or create undesirable odors
    • Heated stones/Stoves: Stones or stoves are used, heated materials, in place of wire. Care is required to prevent damage like scorching
    • Drying sheds or chambers: These have thermostats and thermometers that control the temperature to avoid issues with variable weather
    • Drying tunnels: Used for bulk drying and uses fans and on wheels
    • Drying ovens: Small, electrically heated cabinets maintain specific temperatures and can utilize vacuums
    • Pneumatic high-speed drying: High heat and a vacuum used for a very short time to avoid damage, commonly used for delicate compounds like Digitalis

    Freeze Drying (Lyophilization)

    • A specialized vacuum drying technique used for highly sensitive compounds
    • Involves freezing the drug and then subjecting it to a high vacuum to cause sublimation of the ice
    • Used to preserve biological fluids, enzymes, hormones, and extracts (insulin)

    Chemical Drying

    • Drugs are placed in a closed container (desiccator) over a desiccant (e.g., anhydrous CaCl2, concentrated H2SO4, or silica gel) to absorb moisture
    • Used for small amounts of drugs, or when storing pure natural products

    Changes in Drugs During Drying

    • Size and weight: The drug loses water, resulting in a decrease in size and weight (80-90% in loss)
    • Shape and appearance: Many drugs will shrivel, shrink, or develop wrinkles/reticulated textures
    • Color: Color changes are common, with some becoming darker and others changing color completely. Examples include tea leaves changing from green to dark brown and vanilla changing from yellow to dark brown
    • Odor: Some drugs change their odors during drying, either becoming less objectionable, or taking on new odors. Examples include orris root changing from disagreeable to pleasant and vanilla pods gaining a fragrant, pleasant odor.
    • Taste: Changes in taste during drying commonly occur. Example: Gentian is very bitter fresh and becomes pleasant on drying
    • Constituents: Changes to active ingredients are possible. Examples include fresh vanilla undergoing hydrolysis and oxidation to produce vanillin and alteration of alkaloids in some plants depending on the time of year and time of day

    Packing of Drugs

    • Methods for packing: Loose or under pressure
    • Packing preserves drugs and maximizes space usage
    • Commonly used containers: Wooden, paper boxes, and barrels
    • Moisture-sensitive drugs (e.g., Digitalis, Ergot) are stored in moisture-proof containers
    • Effect of packaging on appearance: Indian Senna example shows hydraulic pressure and transverse markings
    • Packing often indicates the source (geographic location -e.g. Aloes, Opium)

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    Description

    This quiz covers Lecture 3 of Pharmacognosy I (PHCG 111) for first-year pharmacy students, presented by Dr. Rafik Mounir Nassif. It explores the preparation and drying of crude drugs, including cleaning methods and objectives of drying. Test your knowledge on these essential pharmacognosy concepts.

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