40 Questions
Why are granules preferred over powders in making solutions?
Granules are more easily wetted by a solvent
Why is ampicillin usually prepared as granules?
Ampicillin is unstable in aqueous solution
What do granules contain in addition to the medicinal agent?
Colorants and flavorants
What feature of granules results in content uniformity?
Particle-size uniformity
What is one disadvantage of bulk powders?
The ingredients may segregate due to particle size differences
Why are powder mixtures usually granulated if they are intended to be compressed into tablets?
To improve compressibility
What is one advantage of granules over powders?
They eliminate or control dust
What characteristic makes granules more stable physically and chemically than powders?
Smaller surface area
What is the typical particle size range of micronized medication used in products for the treatment of asthma and bronchial disorders?
1 to 6 μm
What purpose do inert propellants and pharmaceutical diluents serve in the products used for the treatment of asthma and bronchial disorders?
Aid flow properties and metering uniformity, protect the powder from humidity
How are nasal powders intended to be administered into the nasal cavity?
Inhalation by means of a suitable device
How is a hard gelatin capsule presented when used with a nasal delivery device for nasal powders?
Placed in the body of the nasal delivery device and broken upon assembly
What is the recommended ratio of citric acid to tartaric acid in a good effervescent blend?
1:2
Which method is used to prepare effervescent granules when using only citric acid as the acid component?
Wet method
What happens to the effervescent powder mixture during the heating process?
It forms granules easily
Why should the mixing of powders be performed in an environment of low humidity?
To prevent premature chemical reaction
What is the recommended ratio of citric acid to tartaric acid in a good effervescent blend?
3:2
Which method is used to prepare effervescent granules when using the fusion method?
Heating the powder mixture in an oven
What is the role of water in the fusion method of preparing effervescent granules?
It acts as a binding agent for the powder mixture
What characteristic of granules makes them more stable physically and chemically than powders?
Their resistance to moisture absorption
What is the primary factor determining the selection of the type of paper for powder papers?
Moisture resistance of the paper
What is the most popular commercially available size for powder papers?
2.75 × 3.75 in.
Why are small cellophane or plastic envelopes used to enclose individual doses of powder instead of folding individual powder papers?
For uniform packaging
What type of paper should be used if the powder contains hygroscopic or deliquescent materials?
Waxed paper
What is the main difference between a powder and a granule?
Granules consist of aggregated powder particles, while powders are composed of finely divided particles
What is the typical diameter of granules used as a dosage form?
2-4 mm
Why are granules preferred over powders in making solutions?
Granules are less prone to caking and dust formation compared to powders
Why do granules have an advantage over powders in terms of content uniformity?
Granules have a more uniform particle size distribution compared to powders
Why are effervescent salts usually presented as granules or coarse powders rather than small powder particles?
To decrease the rate of solution and prevent violent and uncontrollable effervescence
What is the purpose of using a combination of citric and tartaric acids rather than either acid alone in effervescent salts?
To avoid certain difficulties in the effervescence process
Why are fines, which are powder that has not agglomerated into granules, separated, collected, and reprocessed in the production of tablets?
To improve the overall quality and uniformity of the tablets
What characteristic makes granules more stable physically and chemically than powders?
Decrease the rate of solution and prevent violent and uncontrollable effervescence
What is the primary difference between oral powders and granules?
Powders are composed of loose, dry particles, while granules are compacted particles.
What is the purpose of using dry powder inhalers (DPIs) for administering medicated powders?
To aerosolize and deliver an accurately metered amount of micronized particles of medication.
Why are effervescent salts usually presented as granules or coarse powders rather than small powder particles?
To reduce the risk of caking and produce a more elegant product.
Powder papers are typically commercially available in sizes like 2.75 × 3.75 in., 3 × 4.5 in., 3.75 × 5 in., and 4.5 × 6 in.
True
Waxed paper should be used for powders containing hygroscopic or deliquescent materials.
True
Today, compounded powder papers are frequently used on an outpatient, community practice basis.
False
Glassine paper is a waterproof, glazed, and transparent paper with limited moisture resistance.
False
Pharmacists may use cellophane or plastic envelopes to enclose individual doses instead of folding individual powder papers to achieve non-uniform packaging.
False
Study Notes
Advantages of Powders
- Powders enable primary care providers to easily alter the quantity of medication for each dose.
- Powders aid in clinical studies of drug preparations because the dose can be readily adjusted.
- Doses can be individually weighed and placed in powder papers, envelopes, or small vials/bottles.
Use of Powders
- Infants and young children who cannot swallow tablets or capsules can accept powders mixed with a formula or sprinkled in food.
- Powders provide a rapid onset of action because they are readily dispersed, have a large surface area, and usually require only dissolution, not disintegration, before absorption.
- Drugs that are too bulky to be prepared as a capsule or tablet may be suitable for a powder dosage form.
Micromeritics
- Micromeritics is the science of small particles, studying characteristics such as particle size, size distribution, shape, angle of repose, porosity, and true volume.
- Angle of repose is a technique for estimating the flow properties of a powder, which can be determined by allowing a powder to flow through a funnel and fall freely onto a surface.
Comminution of Drugs
- Comminution of drugs involves reducing the size of chemical substances by grinding with a mortar and pestle (trituration) or using mills and pulverizers on a large scale.
- Manual methods include trituration, levigation, and pulverization by intervention.
Trituration
- Trituration is the process of reducing particle size by rubbing in a mortar and pestle, resulting in a significant increase in the specific surface area of the substance.
Levigation
- Levigation is commonly used in small-scale preparation of ointments and suspensions to reduce the particle size and grittiness of added powders.
- A paste is formed by combining the powder and a small amount of liquid (the levigating agent) in which the powder is insoluble.
Pulverization by Intervention
- This method includes reduction of particle size with the aid of a second agent, which can be readily removed from the pulverized product.
Mixing Powders
- Powders can be mixed by trituration, sifting, tumbling, or using motorized blenders or mixers.
- Sifting results in a light, fluffy product, but is not suitable for incorporating potent drugs into a diluent powder.
- Tumbling is a thorough but time-consuming process, widely employed in industry.
Inhalation Powders
- Micronized medications are prepared in the range of 1 to 6 μm in diameter for inhalation deep into the lungs.
- Inhalation powders are administered in a metered-valve container, powder blowers, or insufflators.
Nasal Powders
- Nasal powders are medicated powders intended for inhalation into the nasal cavity using a suitable device.
- Delivery devices have been developed to enhance convenience and ensure uniform dose delivery.
This quiz covers the characteristics and uses of powders and granules in pharmacy, focusing on their differences in caking, hardening, wetting by solvents, and preparation of solutions. It also discusses an example of a pharmaceutical product prepared as granules and reconstituted prior to dispensing.
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