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What is a primary reason for utilizing suspensions in drug formulations?
What is a primary reason for utilizing suspensions in drug formulations?
Which feature is essential for a pharmaceutical suspension to be considered effective?
Which feature is essential for a pharmaceutical suspension to be considered effective?
What characteristic is required regarding the settling of particles in a suspension?
What characteristic is required regarding the settling of particles in a suspension?
Why might a clinician choose a liquid suspension over a solid dosage form?
Why might a clinician choose a liquid suspension over a solid dosage form?
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What is one disadvantage that is often associated with drug solutions, which suspensions can overcome?
What is one disadvantage that is often associated with drug solutions, which suspensions can overcome?
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What type of suspension is particularly useful for medications administered through injection?
What type of suspension is particularly useful for medications administered through injection?
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Which of the following is NOT a type of suspension mentioned for route of administration?
Which of the following is NOT a type of suspension mentioned for route of administration?
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What must happen to the particle size of the suspensoid over time in a well-formulated suspension?
What must happen to the particle size of the suspensoid over time in a well-formulated suspension?
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What is the primary reason manufacturers prefer dry powders for oral suspension?
What is the primary reason manufacturers prefer dry powders for oral suspension?
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Which of the following is NOT typically included in a dry powder for oral suspension preparation?
Which of the following is NOT typically included in a dry powder for oral suspension preparation?
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What must be used for reconstitution of dry powders meant for oral suspension?
What must be used for reconstitution of dry powders meant for oral suspension?
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Which of the following combinations includes Amoxicillin as one of its components?
Which of the following combinations includes Amoxicillin as one of its components?
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What type of agent is xanthan gum when used in dry powder preparations?
What type of agent is xanthan gum when used in dry powder preparations?
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What is the role of stabilizing agents like citric acid in dry powder formulations?
What is the role of stabilizing agents like citric acid in dry powder formulations?
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Which component is commonly added to dry powders for oral suspension to manage flavor?
Which component is commonly added to dry powders for oral suspension to manage flavor?
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Which antibiotic is officially recognized for oral suspension preparations?
Which antibiotic is officially recognized for oral suspension preparations?
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What is the role of wetting agents in the preparation of suspensions?
What is the role of wetting agents in the preparation of suspensions?
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Why should preservatives be omitted from formulations intended for neonates?
Why should preservatives be omitted from formulations intended for neonates?
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What happens to the rate of descent of particles in a suspension when the density of the medium is increased?
What happens to the rate of descent of particles in a suspension when the density of the medium is increased?
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Which method is generally employed for reducing particle size to under 10 um for certain pharmaceutical suspensions?
Which method is generally employed for reducing particle size to under 10 um for certain pharmaceutical suspensions?
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What is a key consideration when formulating an extemporaneous suspension?
What is a key consideration when formulating an extemporaneous suspension?
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What characteristic of flocculated particles contributes to their stability in a suspension?
What characteristic of flocculated particles contributes to their stability in a suspension?
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What potential adverse effect can result from excessive use of aluminum hydroxide in antacid preparations?
What potential adverse effect can result from excessive use of aluminum hydroxide in antacid preparations?
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Why is it not advisable to over-reduce the particle size in a pharmaceutical suspension?
Why is it not advisable to over-reduce the particle size in a pharmaceutical suspension?
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What must pharmacists consider regarding the stability of compounded suspensions?
What must pharmacists consider regarding the stability of compounded suspensions?
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In the preparation of suspensions, what is the purpose of using a colloid mill?
In the preparation of suspensions, what is the purpose of using a colloid mill?
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What is the typical diameter range for particles in good pharmaceutical suspensions?
What is the typical diameter range for particles in good pharmaceutical suspensions?
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Which component commonly provides viscosity and sweetness in oral suspensions?
Which component commonly provides viscosity and sweetness in oral suspensions?
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Which of the following agents is NOT commonly used as a suspending agent in dispersion mediums?
Which of the following agents is NOT commonly used as a suspending agent in dispersion mediums?
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What type of containers are recommended for packaging suspensions?
What type of containers are recommended for packaging suspensions?
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In what way can electrolytes contribute to the physical stability of suspensions?
In what way can electrolytes contribute to the physical stability of suspensions?
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Which antacid component is associated with the potential to cause diarrhea?
Which antacid component is associated with the potential to cause diarrhea?
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What does Stokes' law primarily describe regarding suspended particles?
What does Stokes' law primarily describe regarding suspended particles?
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How can increasing the viscosity of the dispersion medium affect the suspension?
How can increasing the viscosity of the dispersion medium affect the suspension?
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What is a crucial precaution when administering tablet-induced suspensions for neonates?
What is a crucial precaution when administering tablet-induced suspensions for neonates?
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Which characteristic is typical of flocculated particles in suspensions compared to unflocculated particles?
Which characteristic is typical of flocculated particles in suspensions compared to unflocculated particles?
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In the preparation of suspensions, what occurs after the powder is wetted?
In the preparation of suspensions, what occurs after the powder is wetted?
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In formulating pediatric suspensions, what method is typically used for dosing?
In formulating pediatric suspensions, what method is typically used for dosing?
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What is a critical concern when selecting a suspending agent for pharmaceutical suspensions?
What is a critical concern when selecting a suspending agent for pharmaceutical suspensions?
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What should be included in the formulation of suspensions to prevent contamination?
What should be included in the formulation of suspensions to prevent contamination?
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During the preparation of an oral suspension of a drug, which flocculating agent is most likely to be used?
During the preparation of an oral suspension of a drug, which flocculating agent is most likely to be used?
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What is the potential issue with using a suspending agent in excessive quantities?
What is the potential issue with using a suspending agent in excessive quantities?
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When administering antacids, what important factor must pharmacists counsel patients about?
When administering antacids, what important factor must pharmacists counsel patients about?
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What behavior is exhibited by a suspension that employs flocculated particles?
What behavior is exhibited by a suspension that employs flocculated particles?
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Study Notes
Suspensions: Definition and Types
- Suspensions are preparations where finely divided drug particles (the suspensoid) are uniformly dispersed in a liquid vehicle.
- Some are ready-to-use, while others are dry powders for reconstitution in a liquid.
- Types include oral, topical, parenteral (injectable), rectal, otic, ophthalmic, and pulmonary/aerosol suspensions.
- Typically, these preparations are powders containing the drug, suspending/dispersing agents, and a vehicle (often purified water).
Reasons for Using Suspensions
- Chemical Stability: Some drugs are unstable in solution but stable in suspended form.
- Patient Preference: Liquids are often preferred for ease of administration (and dosing flexibility) over solids.
- Palatability: Undissolved particles can mask unpleasant tastes of certain drugs. For example, the use of insoluble salts for drugs that taste badly in solution.
- Taste masking: Use of insoluble forms reduces the potential for taste masking issues.
Desired Features of Suspensions
- Slow Sedimentation: Particles should settle slowly and redisperse easily upon shaking.
- Constant Particle Size: Particle size should remain consistent over time.
- Easy Pouring: The suspension should pour smoothly.
Sedimentation Rate and Stokes' Equation
- Stokes' Law describes various factors affecting suspension settling rates:
- Particle diameter (larger particles settle faster)
- Particle density (greater density means faster settling)
- Density of the medium (aeration is required to ensure proper uniform distribution of the suspended particles in the vehicle).
- Viscosity of the medium (higher viscosity slows settling)
- To enhance stability, the factors (density, diameter and viscosity) can be adjusted. Higher viscosities are undesirable (pourable and easy to redisperse).
- Adjustments are generally made to the dispersed phase rather than the dispersion medium. This mainly involves particle size and size uniformity.
- The suspension should not tend to form a solid cake.
Physical Features of the Dispersed Phase
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Ideal particle size range for most pharmaceutical suspensions is 1-50 μm.
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Particle reduction methods: dry milling, micropulverization, fluid energy grinding (jet milling/micronizing), and spray-drying.
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Fine particles, while promoting slow, uniform settling, reduce the stability of the suspension. Fine particles cake more easily leading to compaction and creating a resistent aggregate.
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Avoiding cake formation is paramount by promoting flocculates (loosely aggregated particles).
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Flocculated particles prevent compaction during settling.
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Methods for flocculation include the use of clays(e.g, bentonite magma) or changes in pH to promote the formation of a floc structure.
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Electrolytes can also help to induce formation of a floc of the dispersed phase.
Dispersion Medium
- Suspending agents are added to the dispersion medium to provide structure.
- Examples include carboxymethylcellulose, methylcellulose, microcrystalline cellulose, polyvinyl pyrrolidone (Povidone), xanthan gum, and bentonite.
- Suspending agents should not interact negatively with the drug (inactivation or binding leading to inactivity)
- Viscosity should not be too high to cause difficulties in suspension of solid and dispersion/homogenization and in pouring
Preparation of Suspensions
- Understanding the dispersed phase and dispersion medium characteristics is critical.
- Wetting agents (like alcohol, glycerin, propylene glycol) are added if the drug doesn't readily mix with the medium.
- The mixture is thoroughly blended and the suspension is brought to the desired final volume.
- Colloid mills or blenders are used to ensure uniformity.
- Preservatives are often added to prevent contamination.
Extemporaneous Compounding of Suspensions
- Sometimes, drugs are not readily available in liquid form, necessitating extemporaneous compounding.
- Capsule contents or crushed tablets are combined with a vehicle in a mortar to create a paste.
- This paste is diluted to the correct volume.
- Safety concerns for neonates are important and should considered. Preservatives, colorants, flavorings, and alcohol should potentially be omitted.
- Stability issues are minimized by storing in airtight, light-resistant containers in the refrigerator.
Packaging and Storage of Suspensions
- Wide-mouth containers are preferred for easy shaking and pouring.
- Suspensions should be stored in tight containers protected from freezing, excessive heat, and light.
- Shaking before each use is critical for uniform drug distribution (and proper dosage).
Antacid Oral Suspensions
- Antacids counteract excess stomach acid (e.g., peptic ulcers).
- Mainly composed of water-insoluble substances (e.g., aluminum hydroxide, calcium carbonate, magnesium hydroxide).
- Sodium bicarbonate can cause sodium overload or systemic alkalosis.
- Careful consideration of potential adverse effects is important for the patient.
- Antacids may interact with other medications (e.g., tetracycline)
Antibacterial Oral Suspensions
- Consist of antibiotics (e.g., amoxicillin, erythromycin, cephalosporins) or sulfonamides (e.g., sulfamethoxazole).
- Many antibiotics aren't stable in solution, thus the dry powder forms are marketed (easy to reconstitute).
Dry Powders for Oral Suspension
- Dry powder and granular mixtures are commonly used for oral administration.
- These often contain the drug, flavorings, colorings, sweeteners, stabilizing agents, suspending and preserving agents.
- Accurate purified water volume measurements are important.
- Example of commercially available oral suspension: Amoxicillin or Ampicillin. May be combined with other substances (e.g. Augmentin).
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Description
This quiz explores the definition and various types of drug suspensions, including oral, topical, and injectable forms. Understand the reasons behind using suspensions, such as chemical stability and patient preference. Test your knowledge on the benefits and characteristics of these pharmaceutical preparations.
