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What is the title form designated by the USP for a prepared suspension that requires reconstitution at the time of dispensing?
What is the title form designated by the USP for a prepared suspension that requires reconstitution at the time of dispensing?
Why are suspensions preferred over solid forms of the same drug for certain patients?
Why are suspensions preferred over solid forms of the same drug for certain patients?
What is a disadvantage of certain drugs in solution form that is overcome when administered as undissolved particles of an oral suspension?
What is a disadvantage of certain drugs in solution form that is overcome when administered as undissolved particles of an oral suspension?
Why are insoluble forms of drugs used in suspensions?
Why are insoluble forms of drugs used in suspensions?
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What is the primary consideration in selecting flavorants for an oral suspension?
What is the primary consideration in selecting flavorants for an oral suspension?
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What is the typical diameter of particles in a pharmaceutical suspension?
What is the typical diameter of particles in a pharmaceutical suspension?
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What is a characteristic of most oral suspensions?
What is a characteristic of most oral suspensions?
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What is the main difference between a colloid and a coarse dispersion?
What is the main difference between a colloid and a coarse dispersion?
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Why are some drugs supplied as dry powder mixtures for reconstitution?
Why are some drugs supplied as dry powder mixtures for reconstitution?
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Why are oral suspensions preferred for certain patient populations?
Why are oral suspensions preferred for certain patient populations?
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What is the result of using erythromycin estolate in an oral suspension?
What is the result of using erythromycin estolate in an oral suspension?
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What is the purpose of suspending and dispersing agents in dry powder mixtures?
What is the purpose of suspending and dispersing agents in dry powder mixtures?
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What is the typical appearance of a pharmaceutical suspension?
What is the typical appearance of a pharmaceutical suspension?
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What is a pharmaceutical suspension?
What is a pharmaceutical suspension?
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What is the typical vehicle used for reconstitution of dry powder mixtures?
What is the typical vehicle used for reconstitution of dry powder mixtures?
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What is the term used to describe the dispersion of a solid material in a liquid?
What is the term used to describe the dispersion of a solid material in a liquid?
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What is the proportionality constant in Newton's equation for the flow of a liquid?
What is the proportionality constant in Newton's equation for the flow of a liquid?
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What is the characteristic of non-Newtonian liquids?
What is the characteristic of non-Newtonian liquids?
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What is the behavior of a substance in plastic flow below the yield value?
What is the behavior of a substance in plastic flow below the yield value?
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What is the significance of the yield value in plastic flow?
What is the significance of the yield value in plastic flow?
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What is the characteristic of pseudo-plastic flow?
What is the characteristic of pseudo-plastic flow?
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What is an example of a liquid that exhibits pseudo-plastic flow?
What is an example of a liquid that exhibits pseudo-plastic flow?
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What happens to the volume of a dilatant liquid when shear stress is applied?
What happens to the volume of a dilatant liquid when shear stress is applied?
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What is the relationship between shear stress and shear rate in dilatant flow?
What is the relationship between shear stress and shear rate in dilatant flow?
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What is the minimum percentage of solids required in a suspension to observe dilatant flow?
What is the minimum percentage of solids required in a suspension to observe dilatant flow?
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What is thixotropy?
What is thixotropy?
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What is the primary function of a suspending agent?
What is the primary function of a suspending agent?
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Why is it important to consider the acid environment of the stomach when selecting a suspending agent for oral preparations?
Why is it important to consider the acid environment of the stomach when selecting a suspending agent for oral preparations?
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What is a characteristic of a good suspension?
What is a characteristic of a good suspension?
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Which of the following is an example of a natural suspending agent?
Which of the following is an example of a natural suspending agent?
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What is the purpose of a suspending agent forming a film around particles?
What is the purpose of a suspending agent forming a film around particles?
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What is a consideration that applies to suspensions in terms of stability?
What is a consideration that applies to suspensions in terms of stability?
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What is the primary concern for the chemical stability of a drug?
What is the primary concern for the chemical stability of a drug?
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How is the effect of temperature on the chemical stability of a drug established?
How is the effect of temperature on the chemical stability of a drug established?
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What is the ideal outcome for sedimentation in suspension formulations?
What is the ideal outcome for sedimentation in suspension formulations?
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How should the patient or care taker re-disperse the sediment in a suspension formulation?
How should the patient or care taker re-disperse the sediment in a suspension formulation?
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What is the purpose of assessing the particle size distribution and drug content of representative samples?
What is the purpose of assessing the particle size distribution and drug content of representative samples?
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Why are specifications set for the maximum permitted levels of specified degradation products?
Why are specifications set for the maximum permitted levels of specified degradation products?
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What is the limitation of visual assessment of sediment redispersion on shaking?
What is the limitation of visual assessment of sediment redispersion on shaking?
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What should be consistent across depth and over time in a suspension formulation?
What should be consistent across depth and over time in a suspension formulation?
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Study Notes
Pharmaceutical Suspensions
- A pharmaceutical suspension is a coarse dispersion of insoluble particles (> 1 µm in diameter) in a liquid medium, usually aqueous.
- The solid material (usually the drug) does not dissolve in the vehicle to any appreciable extent but remains as solid particles distributed throughout the vehicle.
- Pharmaceutical suspensions fall across the borderline between colloidal and coarse dispersions, with solid particles generally in the range of 0.1 to 10 µm.
Reasons for Suspensions
- Certain drugs are chemically unstable in solution but stable when suspended.
- Suspensions ensure chemical stability while permitting liquid therapy.
- The liquid form is preferred to the solid form for ease of swallowing and flexibility in administration of a range of doses.
- Suspensions overcome the disadvantage of a disagreeable taste of certain drugs.
Features Desired in a Pharmaceutical Suspension
- Newton's equation for the flow of a liquid: S = ηD (shear stress is directly proportional to shear rate)
- Non-Newtonian flow: emulsions, suspensions, and semisolids have complex rheological behavior and do not obey Newton's law of flow.
- Types of non-Newtonian flow: plastic flow, pseudo-plastic flow, and dilatant flow.
Suspending Agents
- Suspending agents are substances that prevent agglomeration of finely divided insoluble materials and impart viscosity to the dispersion media.
- Suspending agents form a film around particles and decrease interparticle attraction.
- A good suspension should have well-developed thixotropy.
Classification of Suspending Agents
- Natural: animal origin (gelatin), plant origin (acacia, tragacanth, starch, seaweed), and mineral sources (bentonite, kaoline).
- Semi-synthetic: substituted cellulos (hydroxyethyl cellulose, sodium carboxymethylcellulose, methylcellulose, microcrystalline cellulose).
- Synthetic: synthetic polymers (carboxypolymethylene, polyvinyl alcohol, polyvinyl pyrrolidone iodine complex).
Suspension Stability
- Chemical stability: the drug must remain chemically stable over the intended shelf-life of the product.
- Physical stability: sedimentation should be kept to a minimum, and easy redispersion of the sediment is necessary.
- Redispersion pattern should be established, testing at suitable time intervals and under various storage conditions.
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Description
This quiz covers the basics of pharmaceutical suspensions, including their definition, characteristics, and composition. Learn about the properties of suspensions and how they differ from other liquid systems.
