Podcast
Questions and Answers
What are the two main methods for drying crude drugs?
What are the two main methods for drying crude drugs?
Natural drying and artificial drying
What is the primary objective of drying crude drugs?
What is the primary objective of drying crude drugs?
What is the critical threshold level in drying?
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.
Sun drying is preferable for all types of drugs.
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Which of the following is an advantage of artificial drying over natural drying?
Which of the following is an advantage of artificial drying over natural drying?
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Which of the following is NOT a method of applying artificial heat for drying drugs?
Which of the following is NOT a method of applying artificial heat for drying drugs?
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Drying tunnels are primarily used for drying small quantities of drugs.
Drying tunnels are primarily used for drying small quantities of drugs.
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Which drying method is considered an extreme form of vacuum drying and uses very low temperatures and high vacuum?
Which drying method is considered an extreme form of vacuum drying and uses very low temperatures and high vacuum?
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Chemical drying is a suitable method for drying large quantities of drugs.
Chemical drying is a suitable method for drying large quantities of drugs.
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What is the difference between an 'absolutely dried drug' and an 'air-dry drug'?
What is the difference between an 'absolutely dried drug' and an 'air-dry drug'?
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What primary change occurs to the size and weight of drugs during drying?
What primary change occurs to the size and weight of drugs during drying?
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The color of all drugs becomes darker during drying.
The color of all drugs becomes darker during drying.
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How does drying affect the odor of certain drugs?
How does drying affect the odor of certain drugs?
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What is the main change that occurs in fresh vanilla pods upon drying?
What is the main change that occurs in fresh vanilla pods upon drying?
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Why is it important to control the drying process accordingly, based on the required or objectionable changes in the drug?
Why is it important to control the drying process accordingly, based on the required or objectionable changes in the drug?
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What are the two main purposes of packing crude drugs?
What are the two main purposes of packing crude drugs?
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Which of the following is NOT a common shipping and storage container for crude drugs?
Which of the following is NOT a common shipping and storage container for crude drugs?
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Drugs that are easily affected by moisture are generally packed in airtight containers.
Drugs that are easily affected by moisture are generally packed in airtight containers.
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The effect of packing can never alter the appearance of a drug.
The effect of packing can never alter the appearance of a drug.
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What is one way that packing can provide an indication of the geographical origin of a drug?
What is one way that packing can provide an indication of the geographical origin of a drug?
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The packing of drugs is solely for aesthetic purposes.
The packing of drugs is solely for aesthetic purposes.
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Rain is the only source of sweet water.
Rain is the only source of sweet water.
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What percentage of the cytoplasm does water constitute?
What percentage of the cytoplasm does water constitute?
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What are the three temperatures that affect plant growth rates?
What are the three temperatures that affect plant growth rates?
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What is the term used to describe the response of plants to the relative length of day and night?
What is the term used to describe the response of plants to the relative length of day and night?
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What are the three broad photoperiodic classes of plants with respect to their flowering behavior?
What are the three broad photoperiodic classes of plants with respect to their flowering behavior?
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The amount of water that remains in the soil after excess water has drained away is called the ______.
The amount of water that remains in the soil after excess water has drained away is called the ______.
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Which of these is NOT a macro-element?
Which of these is NOT a macro-element?
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Nitrogen deficiency in plants leads to a condition called chlorosis, resulting in a yellow-colored plant.
Nitrogen deficiency in plants leads to a condition called chlorosis, resulting in a yellow-colored plant.
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Which plant hormone acts by antagonizing GA?
Which plant hormone acts by antagonizing GA?
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The qualitative and quantitative composition of medicinal plants can change during the growing season.
The qualitative and quantitative composition of medicinal plants can change during the growing season.
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When is the ideal time to collect leaves for medicinal purposes?
When is the ideal time to collect leaves for medicinal purposes?
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Which of these plant parts is typically collected in the autumn or winter?
Which of these plant parts is typically collected in the autumn or winter?
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Rhubarb collected in the winter contains no anthraquinones.
Rhubarb collected in the winter contains no anthraquinones.
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Which of these is NOT a general rule for collecting drugs?
Which of these is NOT a general rule for collecting drugs?
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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)
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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.