Pharmaceutical Powders and Mixtures Quiz

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Questions and Answers

What unit is used to express bulk density?

g/cm³

kg/L

g/mL (correct)

mg/mL

What does an increased difference between bulk and tapped density indicate?

Higher flowability

Decreased particle size

Greater inter-particulate interactions (correct)

Lower compressibility index

Which factor does NOT affect powder flowability?

Density

Surface texture

Environmental temperature (correct)

Particle shape

How is the angle of repose defined?

Angle when the upper body begins to slide Signup and view all the answers

What impact does particle size have in pharmaceuticals?

Direct correlation with efficacy Signup and view all the answers

What is assessed through the compressibility index and Hausner ratio?

Inter-particulate interactions Signup and view all the answers

In particle size analysis, why might a size range be sufficient?

Various sizes may have similar properties Signup and view all the answers

What does an increased tapped density indicate in a powder?

Greater settling and compactness Signup and view all the answers

What is primarily affected by the differences in particle sizes of components in a formulation?

Segregation Signup and view all the answers

Which type of mixture requires continuous energy input to maintain dispersion?

Negative mixtures Signup and view all the answers

How does particle shape influence segregation during mixing?

Spherical particles segregate more than irregular-shaped ones. Signup and view all the answers

What is the main goal of effective powder mixing?

To ensure formulation uniformity Signup and view all the answers

Which of the following best describes a neutral mixture?

Components have no tendency to mix unless worked on. Signup and view all the answers

What is a key factor that can minimize segregation during mixing processes?

Using ingredients with similar shapes Signup and view all the answers

What can be assessed to ensure homogeneity in final products?

Quality control measures Signup and view all the answers

Which of the following describes a positive mixture?

Components mix spontaneously and irreversibly. Signup and view all the answers

What is the maximum volume for an intradermal injection?

0.2 ml Signup and view all the answers

Which method is commonly used for sealing glass ampoules?

Tip sealing method Signup and view all the answers

What is a requirement for parenteral preparations?

Must be sterile Signup and view all the answers

What is the primary route of administration for intravenous injections?

Directly into the vein Signup and view all the answers

Which parameter is NOT essential for parenteral preparations?

Colorless Signup and view all the answers

In which scenario would an intra-arterial injection be used?

Delivering emergency medication Signup and view all the answers

What is the typical volume range for an intramuscular injection?

2 - 5 ml Signup and view all the answers

Which of the following is NOT a common container type for injectable formulations?

Pouches Signup and view all the answers

What does the true volume (Vt) of a powdered solid represent?

The volume of solid particles excluding all void spaces Signup and view all the answers

Bulk density is defined as the ratio of which two components?

Mass to volume including inter-particulate void volume Signup and view all the answers

How is porosity calculated?

Porosity = (Volume of Voids / Total Volume) x 100 Signup and view all the answers

What method of force application is primarily responsible for causing particle disintegration by two rigid forces?

Compression Signup and view all the answers

What is the effect of tapping on the volume of a powdered sample?

It reduces the void spaces and increases packing density Signup and view all the answers

Which of the following methods is NOT typically used for volume measurement of powders?

Optical microscopy Signup and view all the answers

Which milling technique is most suitable for producing very fine particles without generating heat?

Jet Milling Signup and view all the answers

What type of voids does the granular volume (Vg) include?

Both types of intra-particulate voids and inter-particulate voids Signup and view all the answers

Which factor does NOT affect the milling process?

Particle velocity Signup and view all the answers

What is the main purpose of cryogenic milling?

To make materials brittle for fine powders Signup and view all the answers

Which statement correctly describes void volume?

Void volume is calculated as Bulk Volume - True Volume Signup and view all the answers

What is a characteristic of a helium pycnometer?

It relies on pressure changes in a sealed system of helium gas Signup and view all the answers

Which of the following is NOT a use of eye drops?

Correcting vision Signup and view all the answers

How much fluid can a human eye that does not blink accommodate at most?

30 μL Signup and view all the answers

When preparing eye drops, what is the typical volume of a single drop?

50 μL Signup and view all the answers

Which milling technique is primarily suited for larger quantity reductions?

Hammer Milling Signup and view all the answers

What is the primary purpose of adding a binder like 95% ethanol during the granulation process?

To form a wet mass of the proper consistency Signup and view all the answers

What is the suggested drying temperature for granules to prevent degradation of the active pharmaceutical ingredient?

54°C Signup and view all the answers

Which of the following ratios is correct for preparing citric acid, tartaric acid, and sodium bicarbonate?

1:2:3.44 Signup and view all the answers

What is a key impact of the drying process on pharmaceutical products?

Improves shelf life Signup and view all the answers

Which method is NOT typically used for moisture content determination in pharmaceutical formulations?

Gas chromatography Signup and view all the answers

What is a consequence of improper drying in the preparation of pharmaceutical granules?

Increased adverse effects Signup and view all the answers

Which of the following is a common method to analyze moisture content?

Thermogravimetric Analysis Signup and view all the answers

What is the main objective of drying in pharmaceutical manufacturing?

To remove liquid solvents Signup and view all the answers

Signup and view all the answers

Study Notes

Powder Flow and Density

Powdered solids are heterogeneous mixtures of particles with various sizes and shapes, dispersed with air spaces.
Mass-to-volume relationships in powders are complex due to the presence of open intra-particulate voids, closed intra-particulate voids, and inter-particulate voids.
True volume (Vt) excludes all spaces and is determined using helium pycnometry.
Granular volume (Vg) includes all intra-particulate voids.
Bulk volume (Vb) is the total volume occupied by the entire powder mass.
Tapped volume (Vtapped) is the volume after mechanical tapping or compression, which reduces void spaces and increases packing density.
Void volume is the space between particles in the bulk powder (Bulk Volume - True Volume).
Porosity is the percentage of space within a material (Volume of Voids / Total Volume) x 100.

Volume Measurement Techniques

X-ray diffraction method
Helium pycnometer (measures volume using a non-adsorbing gas like helium in a sealed system).
Specific gravity bottle method (usually for granules, using nonsolvent liquids or mercury).
Cylinder method (for measuring volume).

Determination of Density

Bulk density is the ratio of mass to the volume, including inter-particulate voids volume of an untapped powder sample.
It depends on the particles' density and arrangement in the powder bed.
Tapped density is the increased bulk density achieved after mechanically tapping a container containing the powder sample.

Applications

Analyzing bulk and tapped densities provides insights into compressibility index and Hausner ratio.
It helps understand powder flowability and compressibility.

Powder Flowability

Flowability is a powder's ability to flow.
It influences pharmaceutical processes like mixing, transferring, and compression.
Poor flowability can lead to problems during these processes.

Compressibility Index and Hausner Ratio

These are measures of a product's settling ability and the importance of inter-particulate interactions.
In a free-flowing powder, these interactions are less significant, and bulk and tapped densities are closer.
Poorly flowing materials show greater inter-particulate interactions and a larger difference between bulk and tapped densities.
Formulas for Compressibility Index and Hausner Ratio are provided.
Tables relate Hausner ratio to flow character and compressibility index.

Factors Affecting Powder Flow

Particle size
Particle shape
Particle density
Porosity
Surface texture

Angle of Repose

Angle of Repose is the angle between the horizontal and the plane of contact between two bodies when the upper body is just about to slide over the lower body (angle of friction).
Values of angle of repose provide information about flow properties.

Particle Size Analysis

Particle size is a critical process in the pharmaceutical industry, influencing drug properties like efficacy, stability, dissolution rate, bioavailability, formulation design, and drug release.
Particle size can be determined by sieving using predefined mesh sizes.
Equivalent sphere diameter is a concept in particle size analysis, describing irregularly shaped particles as perfect spheres based on a specific measured property.
Methods like Feret's diameter and Martin's diameter help characterize particle size for irregularly shaped particles.

Particle Size Analysis Techniques

Laser Diffraction (LD): measures particle size distribution (0.01 μm to several mm) based on light scattering.
Dynamic Light Scattering (DLS): best for submicron particles (nanometer range), measuring Brownian motion in a liquid medium.
Microscopy (optical and electron): used for larger (>1 μm) and nano-sized particles, providing morphological information.
Sieving: a traditional method for particles larger than 75 μm, involving passing particles through sieves with decreasing mesh sizes.

PDI (Polydispersity Index)

PDI is a dimensionless value quantifying the uniformity or heterogeneity of particle sizes in a sample.
Low PDI indicates a narrow size distribution (monodisperse system).
High PDI indicates a broad size distribution (polydisperse system).
Calculated from cumulant analysis of the correlation function, providing information about particle size variability.
A table provides PDI scale values and their corresponding flow characteristics.

Procedure for Particle Size Analysis

Weigh a specified amount of powder (e.g., 50g) using analytical equipment.
Utilize a machine to vibrate the sample through the varying mesh sizes in the sieve.
Weigh the material retained in each sieve to determine the percentage distribution.

Formulation of Parenteral Products

Parenteral administration means administering medications into tissues or circulatory systems through injection.
Types of parenteral preparations include solutions, suspensions, emulsions, powders, and gels.
Routes of parenteral administration are Intravenous (IV), Intramuscular (IM), Subcutaneous (SC), Intradermal (ID), Intraspinal (IS), Intra arterial (IA).
Requirements for parenteral preparations include sterility, purity, a lack of pyrogens, stability, and isotonicity.
Containers and closures include ampoules, vials, syringes, cartridges, bottles, and bags.
Ampoule sealing techniques include tip sealing and pull sealing.

Mixing and Homogenization

Mixing combines two or more components so particles are positioned as closely as possible.
Homogenization aims to create a uniform mixture and is less common.
Mixing, in powders, is a chance process, and perfect mixing is frequently impossible.

Segregation

Segregation is the opposite of mixing; components may separate.
Factors affecting segregation include particle size, shape, density, and flow characteristics.

Factors Affecting Particle Size Reduction

Material properties (Hardness, Moisture Content, Elasticity, Heat Sensitivity).
Milling Technique (Ball milling vs Hammer milling).
Milling Parameters (Speed and Rotation, Temperature, Milling Time, Feed Rate).
Volatile or unstable materials require specialized milling techniques (e.g., cryogenic milling) to prevent degradation.

Procedure for Particle Size Reduction

Weigh a specified amount of coarse substance and grind it with a mill for different time durations.
Use a sieve to separate the resultant finer particles from the coarse portions.
Weigh the finer substance to establish a relationship with milling time.

Preparation of Eye Drops

Eye drops are topical applications for treating eye surface or intraocular conditions.
Typical conditions include bacterial, fungal, viral infections, allergic or infectious conjunctivitis, inflammation, elevated intraocular pressure, and glaucoma, and dry eye.
Excessive volume considerations are vital; a typical drop has much of its volume lost.
Eye drops need sterility, preservation, isotonicity, buffering, viscosity, ocular bioavailability, and suitable packaging.

Effervescent Granules

Effervescent granules release carbon dioxide when dissolved in water due to chemical reactions between acid and base.
They contain at least one acid and one base (e.g., citric and tartaric acid with sodium bicarbonate).
This mixing results in a fizzy effervescent effect.
Granules, instead of fine powders, are preferable to slow the reactions down to prevent overflow.
Wet and dry methods are used for preparation.

Drying

Drying removes solvents (e.g., water) to create a dry solid product.
Crucial in maintaining stability and quality for various pharmaceutical formulations.
Drying methods consider factors such as moisture content and material sensitivity.
Various techniques exist (e.g., fluidized bed, spray, freeze, vacuum drying) to adjust parameters like time, temperature, and scale.

Moisture Content Determination

Methods include loss on drying, Karl Fischer titration, infrared moisture analysis, thermogravimetric analysis, dielectric moisture meters, microwave drying, and distillation.
Different moisture content (bound vs free) aspects are considered.
Equilibrium moisture content (EMC) is the moisture level a material reaches in balance with its surrounding environment.

Procedure for Measuring Moisture Content

Weigh a sample (e.g., MCC or lactose) and wet it with water.
Dry the sample in an oven at varying time points.
Weigh the sample repeatedly to determine the loss on drying and moisture content.
Plot a graph of moisture content against time.

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Description

Test your knowledge on fundamental concepts related to bulk density, particle size, and powder flowability in pharmaceuticals. This quiz covers key terms like the compressibility index, Hausner ratio, and factors affecting powder mixtures. Enhance your understanding of materials utilized in pharmaceutical formulations.