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Questions and Answers
What is one primary purpose of formulating suspensions for parenteral administration?
What is one primary purpose of formulating suspensions for parenteral administration?
- To increase the solubility of the drug
- To prolong the action of the drug (correct)
- To enhance the drug's absorption rate
- To create a more palatable form of the drug
Which vehicle is advantageous for prolonging the activity of parenteral suspensions?
Which vehicle is advantageous for prolonging the activity of parenteral suspensions?
- Fixed oils such as arachis oil (correct)
- Alcohol-based vehicles
- Glycerin-based vehicles
- Aqueous vehicle
What is a significant factor in controlling the duration of activity in parenteral suspensions?
What is a significant factor in controlling the duration of activity in parenteral suspensions?
- The color of the suspension
- pH level of the suspension
- Varying particle size (correct)
- Temperature of storage
Which of the following is NOT a characteristic of small particles in suspensions?
Which of the following is NOT a characteristic of small particles in suspensions?
Which of these features is important for the selection of particle sizes in suspensions?
Which of these features is important for the selection of particle sizes in suspensions?
What role do polymorphic forms of a drug play in suspensions?
What role do polymorphic forms of a drug play in suspensions?
What is the purpose of optimizing the particle size in aerosol suspensions?
What is the purpose of optimizing the particle size in aerosol suspensions?
Which ingredient is included in Betolvex® for enhancing Vitamin B12 preparations?
Which ingredient is included in Betolvex® for enhancing Vitamin B12 preparations?
What characteristic defines flocculated systems in the context of suspension formulation?
What characteristic defines flocculated systems in the context of suspension formulation?
Which component is primarily responsible for increasing viscosity in a deflocculated suspension?
Which component is primarily responsible for increasing viscosity in a deflocculated suspension?
What is the ideal outcome of formulating suspensions for optimum physical stability?
What is the ideal outcome of formulating suspensions for optimum physical stability?
What initial step is necessary for preparing a suspension from a powder?
What initial step is necessary for preparing a suspension from a powder?
What potential issue arises from the fast sedimentation rate in flocculated systems?
What potential issue arises from the fast sedimentation rate in flocculated systems?
Which combination is suggested for optimum physical stability in suspensions?
Which combination is suggested for optimum physical stability in suspensions?
What is the purpose of using a flocculating agent in suspension formulation?
What is the purpose of using a flocculating agent in suspension formulation?
In the context of suspension formulation, what challenge is posed by air-adsorbed layers on particles?
In the context of suspension formulation, what challenge is posed by air-adsorbed layers on particles?
What is the primary use of Bentonite?
What is the primary use of Bentonite?
Which of the following can be used both internally and externally?
Which of the following can be used both internally and externally?
What property do Laponites exhibit compared to natural products?
What property do Laponites exhibit compared to natural products?
What is the role of buffers in formulation additives?
What is the role of buffers in formulation additives?
Which of the following is NOT a function of density modifiers?
Which of the following is NOT a function of density modifiers?
What role does Tween 80 serve in the Metronidazole Oral Suspension formulation?
What role does Tween 80 serve in the Metronidazole Oral Suspension formulation?
Which ingredient is commonly used to prevent formulations from drying out after application to the skin?
Which ingredient is commonly used to prevent formulations from drying out after application to the skin?
Which of the following corresponds to the role of Methyl paraben in the suspension?
Which of the following corresponds to the role of Methyl paraben in the suspension?
What is the primary purpose of preservatives in formulations?
What is the primary purpose of preservatives in formulations?
Which of the following sweetening agents is considered a synthetic sweetener that may affect flocculation?
Which of the following sweetening agents is considered a synthetic sweetener that may affect flocculation?
According to Stokes' Law, which factor does NOT influence the velocity of sedimentation?
According to Stokes' Law, which factor does NOT influence the velocity of sedimentation?
The sedimentation volume, F, is defined as which of the following?
The sedimentation volume, F, is defined as which of the following?
Which ingredient in the formulation primarily acts as a thickening agent?
Which ingredient in the formulation primarily acts as a thickening agent?
Which factor is inversely proportional to the velocity of sedimentation?
Which factor is inversely proportional to the velocity of sedimentation?
Which ingredient in the Metronidazole Oral Suspension contributes to sweetness?
Which ingredient in the Metronidazole Oral Suspension contributes to sweetness?
Which of the following tests would be used to assess the physical stability of a suspension?
Which of the following tests would be used to assess the physical stability of a suspension?
What happens if excessive electrolyte is added to a system containing bismuth subnitrate suspension?
What happens if excessive electrolyte is added to a system containing bismuth subnitrate suspension?
Which of the following is a potential consequence of using high concentrations of polymeric flocculating agents?
Which of the following is a potential consequence of using high concentrations of polymeric flocculating agents?
What is the primary role of suspending agents in a suspension?
What is the primary role of suspending agents in a suspension?
Why is tragacanth considered a better thickening agent than acacia gum?
Why is tragacanth considered a better thickening agent than acacia gum?
Which polysaccharide is cited as a commonly used suspending agent?
Which polysaccharide is cited as a commonly used suspending agent?
What is the effect of avoiding excessive blending during the manufacture of flocculating agents?
What is the effect of avoiding excessive blending during the manufacture of flocculating agents?
What characteristic of hydrated silicates affects their use in formulations?
What characteristic of hydrated silicates affects their use in formulations?
What can result from the swelling of bentonite in a formulation?
What can result from the swelling of bentonite in a formulation?
What effect does average particle size have on the viscosity of a suspension?
What effect does average particle size have on the viscosity of a suspension?
Which measurement technique is suitable for ensuring that individual particles are assessed in a suspension?
Which measurement technique is suitable for ensuring that individual particles are assessed in a suspension?
What type of behavior do flocculated systems exhibit under shear stress?
What type of behavior do flocculated systems exhibit under shear stress?
What happens to the viscosity of a flocculated suspension when shear stress is applied slowly?
What happens to the viscosity of a flocculated suspension when shear stress is applied slowly?
What is the likely impact of temperature cycling on a suspension?
What is the likely impact of temperature cycling on a suspension?
What behavior do deflocculated systems demonstrate?
What behavior do deflocculated systems demonstrate?
How does the shape of the particles influence the viscosity of suspensions?
How does the shape of the particles influence the viscosity of suspensions?
What is thixotropy in the context of suspensions?
What is thixotropy in the context of suspensions?
Flashcards
Wetting agent
Wetting agent
A wetting agent that helps solubilize ingredients by encapsulating them within micelles.
Polymer
Polymer
A large molecule that can interact with other ingredients to help stabilize the suspension.
Suspended solids
Suspended solids
These can bind to preservatives, making them less effective.
Sedimentation volume (F)
Sedimentation volume (F)
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Degree of flocculation (β)
Degree of flocculation (β)
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Rheological assessment
Rheological assessment
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Temperature cycling
Temperature cycling
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Particle size assessment
Particle size assessment
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Depot suspension
Depot suspension
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Controlled-release suspension
Controlled-release suspension
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Vehicle selection for injectable suspensions
Vehicle selection for injectable suspensions
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Long-acting suspension
Long-acting suspension
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Selection of particle size for suspensions
Selection of particle size for suspensions
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Control of particle size distribution
Control of particle size distribution
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Polymorphism in drug formulations
Polymorphism in drug formulations
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Stable Polymorphic Form
Stable Polymorphic Form
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Deflocculated suspension
Deflocculated suspension
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Flocculated suspension
Flocculated suspension
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Charge reversal in suspensions
Charge reversal in suspensions
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Flocculating agents
Flocculating agents
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Polymeric flocculating agents
Polymeric flocculating agents
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Viscosity modifiers (suspending agents)
Viscosity modifiers (suspending agents)
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Polysaccharides as suspending agents
Polysaccharides as suspending agents
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Bentonite
Bentonite
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Hydrated Silicates
Hydrated Silicates
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Veegum
Veegum
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Laponites
Laponites
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Carbopol
Carbopol
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Buffers
Buffers
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Density Modifiers
Density Modifiers
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Preservatives
Preservatives
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Suspending agent
Suspending agent
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Sedimentation of suspensions
Sedimentation of suspensions
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Optimum physical stability of a suspension
Optimum physical stability of a suspension
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Formulation of a suspension
Formulation of a suspension
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Particle Size and Viscosity
Particle Size and Viscosity
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Zeta Potential and Viscosity
Zeta Potential and Viscosity
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Particle Shape and Viscosity
Particle Shape and Viscosity
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Viscosity of Flocculated vs. Deflocculated
Viscosity of Flocculated vs. Deflocculated
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Thixotropy
Thixotropy
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Yield Value
Yield Value
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Study Notes
Pharmaceutical Suspensions
- Pharmaceutical suspensions are liquid preparations where solid particles are dispersed in a liquid phase.
- Suspensions are used when a drug is poorly soluble or difficult to swallow as a solid dosage form.
- Suspensions need to be prepared to remain homogeneous after shaking and while removing the required dose.
- The sediment produced on storage should be easily resuspended using moderate agitation.
- The viscosity needs to be suitable, not too high to make the suspension difficult to remove from the container, or too low so it doesn't remain homogenous.
- Suspended particles' size should be uniform.
- Suspensions must resist microbial contamination.
- Different types of suspensions exist;
- Aqueous suspensions (dispersion medium is water)
- Oily suspensions (dispersion medium is oil)
- Ready-to-use suspensions (for stable drugs)
- Reconstituted powder suspensions (for non-stable drugs)
- Flocculated suspensions
- Deflocculated suspensions
- Oral, Parenteral, Topical, or Ocular eye drops (based on intended use)
Liquid Dosage Forms
- Solutions are homogeneous mixtures made by dissolving one or more solutes in a solvent.
- Emulsions are dispersion systems that contain two immiscible liquids.
- Suspensions are dispersions containing solid particles in a liquid.
Coarse Suspensions
- Coarse suspensions are systems where the solid particles are larger than colloidal size (1µm).
- The dispersion medium in the system could be aqueous or oily liquid.
- Solid particles are typically insoluble.
Intended Learning Outcomes
- Understand the physical and chemical principles affecting suspensions' formulation and performance.
- Independently formulate pharmaceutical suspensions.
- Evaluate information from various sources specific to pharmaceutical suspensions.
Reasons for Preparing Suspensions
- Difficulty swallowing solid dosage forms (if drug is insoluble).
- Drugs with poor solubility.
- Bad taste drugs (suspensions can masks tastes that are undesirable).
- Drugs that degrade in the presence of water (suspensions can provide a more stable dosage form).
Preformulation of Suspensions
- Selecting suitable particle size.
- Controlling particle size and distribution to avoid changes that alter the drug.
- Ensuring small particle sizes (less than 5μm), to prevent gritty texture/irritation from injections or instillation into eyes and to prevent clogging of needles.
- Using appropriate particle size ranges to control drug release rate and bioavailability.
- Selecting stable polymorphic forms to avoid changes in solubility or precipitation.
- Preventing crystal growth during manufacture and storage.
- Controlling crystal growth by careful manufacturing processes and storage conditions. This ensures that the particle size of the suspended drug is maintained.
Formulation of Suspensions
- Deflocculated systems use agents to reduce particle-particle attraction, leading to evenly distributed particles and minimal settling.
- Flocculated systems use agents that create small aggregates of particles, which lead to settling but can be easily redissolved/resuspended, improving ease of dispensing.
- Selection of appropriate wetting agents, which assists drug dispersal.
- Adjusting solvents to improve wetting and dispersal.
- Selecting hydrophilic colloids to coat solid particles to improve wetting.
- Using appropriate flocculation and suspending agents for ideal stability and redispersion.
- Using substances like buffers, density modifiers, flavors, colors, perfumes, humectants, and preservatives, adding desired properties.
Stability Testing of Suspensions
- The testing ensures particles remain uniformly distributed.
- Sedimentation parameters: assessing the volume of the sediment, its rate, and the degree of flocculation.
- Rheological assessments (using a Brookfield viscometer) are used to evaluate viscosity at various stages of storage, giving the change in the structure/stability of the products with time.
- Temperature cycling tests help maintain stability under varying temperatures and conditions, by causing variations that can occur in the suspension during use.
- Particle size assessment to analyze potential crystal growth/particle size changes.
Preparation of Suspensions on Large Scale
- Suitable equipment should be used for particle size reduction.
- Concentrated dispersions with suspending agents should be prepared on large scale, to ensure that agglomerates are fully broken up in a homogenizer.
- Precautions should be taken to prevent the structure of suspending agents from being destroyed.
- Wetting the drug to be suspended using the wetting agent.
- Dissolving other ingredients in a portion of the vehicle.
- Homogenization to make a homogeneous final suspension.
Rheology of Suspensions
- Ideal suspensions display high viscosity at low shear rates during storage and low viscosity at higher shear rates during shaking.
- Flocculated systems exhibit time-dependent properties like thixotropy (reversible viscosity change).
- Deflocculated suspensions display Newtonian behavior (constant viscosity regardless of shear rate), though highly concentrated systems might show dilatancy (increased viscosity at higher stress levels).
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Description
This quiz explores the fundamentals of pharmaceutical suspensions, including their preparation, types, and characteristics. Learn about the significance of viscosity, particle size, and microbial resistance in creating effective suspensions for drug administration.
