Pharmaceutical Powder Flowability Quiz

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Questions and Answers

Which factor does NOT influence powder flowability?

Environmental humidity (correct)

Particle’s size & distribution

Particle shape & texture

Flow activators

What is the role of flow activators in improving powder flowability?

Altering the particle shape

Decreasing particle size

Increasing the rate of flow (correct)

Changing particle color

Which property of powder is affected by both shape and texture?

Flowability (correct)

Temperature resistance

Color consistency

Chemical composition

Which of these is a factor associated with surface forces in powders?

Interparticle adhesion Signup and view all the answers

Which option best describes the impact of particle size on flowability?

Size distribution affects flow characteristics Signup and view all the answers

What is one of the intended uses of a medicated powder?

For oral administration Signup and view all the answers

Which of the following describes a type of pharmaceutical preparation?

Medicated powder Signup and view all the answers

Which of these is NOT a method of administration for medicated powders?

Intravenous injection Signup and view all the answers

What is a key advantage of wet granulation?

It results in higher quality granules. Signup and view all the answers

What type of medicated powder is intended for topical use?

Topical powder Signup and view all the answers

Which of the following correctly states the two main uses of medicated powders?

Oral and topical Signup and view all the answers

Which of the following materials can be utilized in wet granulation?

A wide variety of materials. Signup and view all the answers

What is a benefit of achieving good content uniformity in granulation?

It ensures consistent performance of the final product. Signup and view all the answers

What role does a solvent play in the wet granulation process?

It facilitates the mixing of ingredients. Signup and view all the answers

How does the quality of granules produced by wet granulation compare to other methods?

It generally produces higher quality granules. Signup and view all the answers

What does Powder Flowability refer to?

The ease with which the powder flows under specified conditions Signup and view all the answers

Which of the following factors affects the flow of powder?

Superficial adhesiveness Signup and view all the answers

Which of these is NOT a factor that affects powder flow?

Temperature stability Signup and view all the answers

If a powder has high superficial adhesiveness, how is its flowability likely to be affected?

It will be inconsistent and difficult Signup and view all the answers

What can be inferred about powders with excellent flowability?

They may have low superficial adhesiveness Signup and view all the answers

What is the primary purpose of applying pharmaceutical calculations in compounding and dispensing?

To ensure accurate dosing and stability of the products Signup and view all the answers

Which metric is essential when conducting stability calculations for pharmaceuticals?

The environmental conditions for storage Signup and view all the answers

What should be considered when determining the storage conditions for molded solid dosage forms?

The formulation ingredients and their stability Signup and view all the answers

Why is it important to understand the principles of stability in relation to pharmaceutical products?

To prolong the effectiveness of the medication Signup and view all the answers

When compounding solid dosage forms, what is a key consideration regarding the final product?

The weight of the individual doses Signup and view all the answers

What is a primary disadvantage of wet granulation?

It demands a large number of equipment. Signup and view all the answers

Which of the following is NOT a disadvantage associated with wet granulation?

Requires no additional processing time. Signup and view all the answers

Which statement correctly reflects an aspect of wet granulation?

It is time-consuming and expensive. Signup and view all the answers

What aspect of wet granulation primarily contributes to its high operational costs?

The large number of equipment required. Signup and view all the answers

Which of the following is most likely a reason for the time-consuming nature of wet granulation?

It often involves several complex procedures. Signup and view all the answers

Study Notes

Introduction to Solid Dosage Forms

Pharmaceutics III covers solid dosage forms.
The course is taught by Dr. Reem Ragaey.
The university is Ahram Canadian University.

Course Vision

Leadership in the pharmaceutical field on a national level with international recognition for excellence.
The vision aims to be a leader in the pharmaceutical field domestically and excel internationally.

Course Mission

The Pharmacy Faculty at Ahram Canadian University aims to provide an up-to-date learning environment using advanced programs.
Graduates will be equipped with professional ethics and job market competencies.
The faculty supports community engagement and encourages scientific research.
The mission is to produce graduates with professional ethics and competencies for the job market. They strive for effective community participation and scientific research.

Course Assessment

Lectures: 2 hours/week + 1 hour/week lab.
Work: 5 marks
Midterm exam: 10 marks
Practical exam: 25 marks
Final written exam: 50 marks
Oral: 10 marks
Total: 100 marks

Learning Outcomes

Recognize properties: Identify various properties of solid dosage forms (e.g., powders, granules, tablets, capsules, and suppositories).
Comprehend kinetics: Understand reaction order kinetics and apply pharmaceutical knowledge to design and prepare different solid dosage forms.
Integrate knowledge: Use pharmaceutical knowledge to formulate safe and effective dosage forms.
Validate drug products: Apply reaction order kinetics to determine product shelf life.
Compounding, dispensing and storage: Apply pharmaceutical calculations for compounding, dispensing, and storage of solid dosage forms.
Stability calculations: Predict optimal storage conditions for different pharmaceutical products.

Classification of Dosage Forms

Liquid Dosage Forms: Solutions, suspensions, emulsions.
Solid Dosage Forms: Powders, granules, tablets, capsules.
Semisolid Dosage Forms: Ointments, creams, gels, pastes.
Molded Solid Dosage Forms: Suppositories, pessaries.
Sterile Dosage Forms: Parenterals (injections), ophthalmic, radiopharmaceuticals.

Powders: Definition and Uses

Powders are solid dosage forms made of mixtures of dry, finely divided drugs or chemicals.
Particle size ranges from 0.1 micron to 1000 micron (0.1 μm to 1 mm).
Powders can be used in:
- Fabricating solid dosage forms (tablets, capsules)
- Dissolving or suspending in solvents/liquid vehicles to make liquid dosage forms
- Incorporating into semisolid bases (ointments, creams)

Micrometrics

Micrometrics is the science of small particles with defined shapes and dimensions.
The unit for particle size is the micrometer (µm)
Characterized by:
- Particle size and analysis (methods, distribution)
- Particle shape
- Surface area
- Porosity
- Densities
- Powder flow and compressibility

Particle Size: Effects and Analysis

Dissolution rate: Smaller particle size leads to faster dissolution rate.
Suspendability: Fine particles (0.5-10 µm) improve suspension uniformity in liquid vehicles.
Uniform distribution: Ensures consistent dose-to-dose content within a powder mixture/solid dosage form.
Penetrability: Fine particles (1-5 µm) are suitable for deep respiratory tract deposition.
Lack of grittiness: Smooth, fine particles (50-100 µm) prevent grittiness in dermal, ophthalmic, and other topical preparations.
Particle size analysis: USP uses descriptive terms like very coarse, coarse, moderate, fine, and very fine.

Particle Size Analysis: Methods

Sieving: Particles pass through a series of progressively smaller sieves to determine the proportion retained on each.
Microscopy: Particles are sized using calibrated grids or measuring devices (0.2 µm to 100 µm).
Transmission Electron Microscopy (TEM): Used for submicron particles to study internal structures.
Scanning Electron Microscopy (SEM): Used for submicron particles to study surface details.
Sedimentation rate: Measured by terminal settling velocity of particles through a liquid medium (0.8-300 µm). Calculated using Stoke's law which considers particle radius, density, and medium viscosity.
Counter Coulter: Particles are sized and counted using an electronic method. The suspension is made to flow through a capillary tube between two electrodes and the voltage is measured.
Light scattering/diffraction: Measures particle size by observing light reduction as a dispersed particle passes through the sensing zone. (0.2-500 µm range).
Laser scattering/holography: A pulsed laser is fired through an aerosolized sample; its three-dimensional image is captured and the particles are sized individually.

Powder Flowability

Powder flowability is the ease with which the powder flows under a specified set of conditions.
Factors affecting flow:
- Superficial adhesiveness
- Particle shape (spherical vs. irregular)
- Particle surface characteristics (smooth vs. wrinkled)
- Electrostatic charges
- Hygroscopicity (moisture content)
Disadvantages of bad flow, advantages of good flow

How to Improve Powder Flowability

Alter particle size and distribution (coarse preferred for reduced cohesiveness)
Alter particle shape (spherical > irregular shape)
Alter particle surface forces (smooth surfaces improve flowability)
Use flow enhancers

Flow Enhancers/Glidants

Flow enhancers improve powder flowability by reducing inter-particle friction.
Commonly used glidants include talc, magnesium stearate, starch, and silica gel.

Flow Properties of Powders

Tests to evaluate powder flowability include:
- Angle of repose
- Hausner ratio
- Carr's compressibility index

Angle of Repose

The angle of repose is the angle between the surface on which the powder is piled and the surface of the cone of the pile.
Calculation using the height and diameter of the cone.
Can easily be determined by allowing a powder to flow through a funnel and fall freely onto a surface.
Different ranges for angle of repose correlate to different flow properties.

Mass-Volume Relationships:

True volume (VT): The actual space occupied by the particles.
Bulk volume (VB): The volume of a powder sample including inter-particulate void space.
Tapped volume (V tapped): The volume after tapping.
Tapping compresses the powder, reducing the volume. This relates to the Hausner ratio.

Hausner Ratio and Carr's Index

Hausner ratio measures the degree of compressibility of a powder.
It is calculated by dividing the bulk volume by the tapped volume.
A high ratio (>1.25) indicates poor flow ability.
Similar to Hausner ratio, Carr's index measures compressibility.

Particle Size Reduction (Comminution of Drugs)

It involves reducing the particle size of a solid substance.
Objective:
- Facilitate crude drug extraction.
- Increase drug dissolution rates.
- Aid in the formulation process.
- Enhance absorption.
Advantages:
- Improved mixing
- Increased surface area, wettability, and dissolution rate
- Faster absorption of drugs
- Improved physical stability of dosage forms

Techniques for Particle Size Reduction (On Small and Large Scales)

Small Scale: Trituration, pulverization, levigation
Large Scale: Hammer mills, pulverizers

Mixing (Blending) of Powders

Blending combines two or more substances to create a uniform powder mixture.
Typical techniques used include:
- Spatulation, trituration, sifting, and tumbling

Methods of Mixing Powder (Small Scale)

Spatulation: Blending small amounts of powders using a spatula over a surface. It isn't suitable for large quantities or potent substances.
Trituration: Used for both mixing and comminution. A glass mortar works especially well for mixing where the need to reduce the size isn't important.
- The geometric method is used when mixing a small amount of a potent substance with a larger amount of a different substance. Quantities of diluent are added in equal parts to the powder. The method ensures the potent drug is evenly dispersed.
Sifting: Passing powders through sieves (sifters) to separate particles by size
Large scale techniques include tumbling in a variety of containers

Sachets

Sachets are a way to dispense single doses of powders.
They are single-dose packages, usually from laminated paper or metal foil.
Ideal for single-dose dispensing of powders reconstituted with liquids or soft foods.

Medicated Powders

Powders are mixtures of dry, finely divided drugs suited for internal or external use.
They can be in bulk, or individually dose packs.
Types of powders used include bulk, divided, dusting, dental cleansing, and those for reconstitution or injection.

Classification of Powders

Bulk Powders (e.g., antacids, laxatives)
Divided Powders (e.g., oral, dusting, dental cleansing, injections, reconstitution)

Bulk Powders

Packing: Mixed ingredients are packed in a wide-mouthed container.
Constituents: Typically non-potent/non-toxic/high dose medicaments.
Forms of distribution:
- Used in dry form
- Dissolved in water
- Used for reconstitution
Examples: Dusting powders, dentifrices (toothpastes), douche powders.

Powders Used in Dry Form (e.g., Dusting Powders)

Homogeneous mixture: Finely divided particles are essential to enhance spreading and effectiveness, minimizing irritation
Free flowing: powders should flow freely and stick to the surface.
Dilution: Active ingredients are diluted with materials with good flow, e.g., talc, maize starch.
Uses: Therapeutic and prophylactic applications; lubrication and drying.
Examples: Canesten Powder (antifungal) and talc powder.

Dental Cleansing Powders (Dentifrices)

Components:
- Soap/detergent
- Mild abrasives (e.g., calcium carbonate, sodium bicarbonate, sodium chloride)
- Anticariogenic agents
- Sweeteners/flavoring agents

Powders to Be Dissolved or Reconstituted in Water

Used for administering high doses of antacids or laxatives.
The correct amount of the powder is dissolved in water before consumption.

Powders Requiring Reconstitution (e.g., Oral Antibiotics)

Stability issues: Some medications are unstable in solution.
Dry form: For stability, medications are packaged in a dry form (powder or granules).
Reconstitution: A specified amount of water is added to the medication before administration.
Short shelf life: Patients must be informed of the short shelf life (usually 1-2 weeks) of reconstituted medications.

Powders for Injection

Unstable solutions: Medications unstable in solution are presented as sterile powders for immediate reconstitution in an ampoule.
Sterile diluent: Sterile water or other appropriate diluents may be added for desired drug concentration.
Immediate use: Injections are prepared/used immediately.

Problems Encountered in Powder Formulation

Hygroscopic/Deliquescent powders: These substances absorb moisture. Packing procedures must avoid moisture to maintain integrity and safety.
Effervescent powders: These interactions create solutions or gases, that may be unsafe if exposed to moisture. Packing should protect against moisture.
Efflorescent powders: When exposed to air, some crystalline substances lose water and can result in a change in consistency. The powders should be packaged to prevent this change.

Divided Powders

Packaged into single-dose units
May have a unique preparation.
Often used in paper packets or sealed plastic bags.

Granules

Form of concentrated medication
Powder particles that clumped together into agglomerates.
Irregular, but can be formed in spherical shapes.
Usually 2mm to 4mm diameter

Methods of Granulation

Wet Granulation: A widely used method. A binder is added to the powder to create a wet mass.
- Suitable for materials not affected by heat or moisture
- Binder examples include PVP solution, paste (starch in hot water).
- Solvent needs to be volatile and nontoxic.
Dry Granulation: Creates granules by applying pressure without moisture.
- Effective for heat and moisture sensitive materials.

Effervescent Granules

Granules of a drug combined with dry mixtures of citric acid, tartaric acid, and sodium bicarbonate that create a gas (carbon dioxide) when added to water.
The effervescence can be therapeutic or just a means to create an enjoyable delivery method (the carbonated solution can mask unpleasant tastes).
Requires special packaging to prevent moisture exposure (generally double-wrapped).

Advantages and Disadvantages of Granules

Advantages: Stability to moisture, better flow properties/uniform dosing, easier to compact.
Disadvantages: May not mask unpleasant tastes, can be bulky to carry in large amounts. Individual packaging is generally recommended.

Advantages of Powdered Dosage Forms

Chemical stability: Solid preparations are more stable than liquids, with a longer shelf life, especially for antibiotics.
Convenience: Suitable for drugs requiring high doses.
Patient suitability: Allows administration to patients with difficulty swallowing conventional dosage forms (like tablets).
Rapid therapeutic effect: Smaller particles mean faster dissolution, faster uptake.

Disadvantages of Powdered Dosage Forms

Unstable substances: Susceptible to moisture/humidity or volatility.
Inaccurate Dosage: Individual packaging of doses may help to avoid issues with different measuring instruments/tools used by patients to get correct doses.
Bulkier to transport: Can be bulkier to carry than tablets or capsules.
Unpleasant taste: Some active ingredients cannot be masked effectively in powder form.
Irritation: When using a powder for topical application, improper size or surface characteristics of the powder can lead to irritation.

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Description

Test your knowledge on powder flowability and its significance in pharmaceutical science. This quiz covers various factors affecting flowability, roles of flow activators, and methods of administration for medicated powders. Perfect for students and professionals in the field of pharmacy and formulation science.