Excipients

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Questions and Answers

What is one of the main functions of buffers in liquid preparations?

To provide a sweet taste to the formulation

To enhance the solubility of pigments

To increase the viscosity of the solution

To control pH for physiological compatibility (correct)

Which of the following is primarily used as a wetting agent in liquid preparations?

Propylene glycol

Sucrose

Cetrimide (correct)

Ethanol

What property makes glycerol useful as a humectant in liquid preparations?

It enhances flavor and sweetness

It increases drug solubility

It reduces evaporation of water from products (correct)

It acts as a stabilizer for emulsions

Which polymer is commonly used for sustained or controlled release formulations?

HPMC (hydroxypropylmethyl cellulose) Signup and view all the answers

What is the primary role of preservatives in liquid preparations?

To prevent growth of opportunistic microbes Signup and view all the answers

What is a potential consequence of using glucose or sucrose as excipients?

Obesity and tooth decay Signup and view all the answers

Which excipient is known to prevent powder adherence and ensures smooth tablet ejection from the die?

Magnesium stearate Signup and view all the answers

What is the main function of a disintegrating agent in tablet formulation?

To cause tablet disintegration and increase surface area Signup and view all the answers

Which of the following excipients is considered a 'superdisintegrant'?

Pregelatinised starch Signup and view all the answers

What characteristic should an ideal diluent have when used in tablet formulation?

Pleasant taste and good solubility Signup and view all the answers

What is the primary role of binding agents in tablet formulation?

To bind particles together during granulation Signup and view all the answers

Which of the following is a common lubricant that is hydrophobic and can prolong tablet disintegration time?

Magnesium stearate Signup and view all the answers

Which excipient is primarily used as a coating to enhance the stability and appearance of tablets?

Enteric coatings Signup and view all the answers

What is the primary function of excipients in drug formulations?

Facilitate manufacturing and improve stability Signup and view all the answers

Which property is NOT ideal for excipients in pharmaceutical formulations?

Pharmacologically active Signup and view all the answers

What could happen if a poorly chosen excipient is used in a formulation?

Cause an increase in serum concentration beyond the toxic threshold Signup and view all the answers

Which regulatory standards must pharmaceutical-grade excipients comply with?

BP, PhEur, or USP-NF and GMP Signup and view all the answers

What role do excipients play in maintaining the integrity of drug products during storage?

They can stabilize the chemical structure of the drug Signup and view all the answers

Which example illustrates the potential adverse effects of excipients on drug therapy?

The use of lactose instead of calcium sulfate in phenytoin capsules Signup and view all the answers

Why is it important for excipients to be pharmacologically inert?

To prevent unintended interactions that could affect drug performance Signup and view all the answers

The use of diethylene glycol instead of glycerin in a cough syrup formulation led to which outcome?

Nephrotoxicity and hepatotoxicity Signup and view all the answers

Study Notes

MPharm Programme - Excipients

Excipients are minor components of dosage forms, not therapeutically active, but crucial for various purposes.
They influence dosage form behavior, impacting bioavailability.
Examples include tablets, affecting manufacturing, administration and identification processes.
Excipients promote consistent drug release and bioavailability.
They also improve drug stability and protect against degradation.

Excipient - Ideal Properties

Stable and reproducible properties are essential.
No unintended interactions with the drug should occur.
They should be pharmacologically inert.
The excipient should provide the desired function for the dosage form.
Cost-effectiveness is a key factor.
Pharma-grade excipients adhere to standards like BP, PhEur, or USP-NF (US pharmacopoeia) and manufactured under GMP (Good Manufacturing Practices).

Excipients - Role

Excipients aid the processing of drug delivery systems during manufacture.
They protect, support, or enhance stability, bioavailability, and patient acceptability.
They assist in product identification and enhance the overall safety of the drug.
They aid in the effectiveness and delivery of the active drug substance.
They maintain the integrity of the drug product during storage.

Excipients - Safety

In the 1960s, switching from calcium sulfate to lactose in phenytoin capsules led to a 4.5-fold increase in serum phenytoin concentration, exceeding the narrow therapeutic index.
Calcium sulfate forms a matrix, prolonging drug release, while lactose provides immediate release.
Diethylene glycol, used instead of glycerin in a Panama cough syrup in 2007, proved nephrotoxic and hepatotoxic.

Excipients - Adverse Effects

Glucose and sucrose can lead to obesity and tooth decay.
Benzyl alcohol can cause gasping syndrome in neonates.
Ethanol can have central nervous system (CNS) effects.
Aspartame contains phenylalanine, potentially harmful to phenylketonuria (PKU) patients.
Polyoxyl castor oils can cause severe anaphylaxis.
Propylene glycol affects the CNS, especially in neonates and children under 4.
Colourants like tartrazine can cause hypersensitivity and behavioral disturbances.

Tablet Compression/Compaction

Tablet compression is a multi-step process.
The hopper shoe moves granules into the die, where they are compressed into a tablet.
The upper and lower punches move repeatedly throughout the compression and ejection cycle.

Tablet Excipients - Diluents or Bulking Agents

Diluents/bulking agents are added to create adequately sized tablets and aid handling.
Examples include lactose (α-lactose monohydrate) for its pleasant taste, good solubility and low hygroscopicity.
Spray-dried lactose and microcrystalline cellulose are suitable for direct compression.
Mannitol is used for chewable tablets.

Tablet Excipients - Lubricants

Lubricants prevent powder/metal adherence during ejection.
Magnesium stearate (hydrophobic) enhances flow properties and prolongs disintegration time.
Reducing drug dissolution and tablet strength are other considerations.
Sodium stearyl fumarate (hydrophilic) is another option.

Tablet Excipients - Binding Agents

Binding agents (adhesives) join particles during granulation, both dry and wet.
Starch and polyvinylpyrrolidone (PVP) are examples.

Tablet Excipients - Glidants

Glidants improve powder/granule flow.
They reduce interparticulate friction for smoother flow.
Colloidal silica is a common example.

Tablet Excipients - Disintegrating Agents

Disintegrating agents increase tablet surface area upon contact with water.
Starch, croscarmellose sodium (superdisintegrant), and pregelatinised starch are examples.
Lyophilised tablets disintegrate within 5 seconds.

Tablet Excipients - Dyes and Flavouring Agents

Dyes and flavourings enhance tablet properties beyond their primary role.
Coatings like sugar coats, film, enteric coatings (e.g., cellulose acetate phthalate, polymers like Eudragits), and polymers for modified release (M/R) are significant roles of additional excipients.

Excipients for Liquid Preparations - Water

Water is a physiologically non-toxic and compatible ingredient.
Suitable for dissolving ingredients.
Supports microbial growth and should be used cautiously with drugs.
Water tends to break down easily, thus, must be controlled.

Excipients for Liquid Preparations - Water Miscible Co-Solvents

Enhance solubility, taste, and stability.
Propylene glycol, glycerol, and ethanol are water-miscible co-solvents.

Excipients for Liquid Preparations - Buffers

Buffers control pH for maintaining compatibility, microbial stability, and solubility.

Excipients for Liquid Preparations - Antimicrobial Agents

Preservatives prevent the growth of opportunistic microbes.
Excipients or externally added preservatives should be carefully considered.

Excipients for Liquid Preparations - Antioxidants

Antioxidants control drug and excipient oxidation, preserving concentration.
The concentration decreases due to oxidation over time.

Excipients for Liquid Preparations - Wetting Agents

Decrease interfacial tension, enhancing mixing of liquid and solid phases.
Surface-active agents like cetrimide, sorbitan monooleate, and hydrophilic colloids like cellulose derivatives and tragacanth are used.

Excipients for Liquid Preparations - Antifoaming Agents

Chemicals that inhibit or reduce foam development (like Simeticone).

Excipients for Liquid Preparations - Thickening Agents

Stabilizing suspensions; increase viscosity; often thixotropic (e.g., methylcellulose).

Excipients for Liquid Preparations - Sweetening Agents

Natural (e.g., sucrose) or artificial sweeteners (e.g., saccharin)

Excipients for Liquid Preparations - Flavouring Agents

Natural (like peppermint) or artificial (like butterscotch) flavours.

Excipients for Liquid Preparations - Humectants

Humectants (e.g., glycerol and polyethylene glycols (PEGs)) prevent drying out of liquid preparations after application.

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Description

This quiz covers the essential aspects of excipients in pharmaceuticals, including their roles, ideal properties, and significance in dosage forms. Understand how excipients influence drug behavior, bioavailability, and stability. Gain insights into the standards and manufacturing practices for excipients.