Excipients Flashcards
What are excipients?
Excipients control behaviour of dosage form
What are the ideal properties of an excipient?
- Stable & Reproducible
- No unintended interaction with drug
- Pharmacaologically inert
- Give desired function
- Cost effective
Pharma grade - Comply with BP, PhEur or USP-NF
What are the roles of excipients?
• Aid in the processing of the drug delivery system during its
manufacture
• Protect, support, or enhance stability, bioavailability, or
patient acceptability,
• Assist in product identification, and enhance any attribute of
the overall safety
• Assist in the effectiveness and/or delivery of the drug in use
• Assist in maintaining the integrity of the drug product during
storage
What are some adverse effects of excipients?
- Glucose and Sucrose: Obesity and tooth decay if taken orally
- Benzyl Alcohol: A gasping syndrome in neonates
- Ethanol: CNS effects
- Polyoxyl castor oils: Severe anaphylactoid reactions
Describe Diluents or bulking agent excipients
• added to make adequate sized tablet, handling
• Lactose (α-lactose monohydrate) –
• pleasant taste
• good solubility/dissolution
• low hygroscopicity
• Inert
• Spray dried lactose – used for direct compression (DC)
• Microcrystalline cellulose also good for DC
• Mannitol for chewable tablets
Describe lubricant excipients used in tablets?
• Prevent powder/metal adherence – ensure smooth ejection
from die
• Enhance flow properties
• Magnesium stearate (up to 1 % w/w), hydrophobic
• Prolong disintegration time, reduce drug dissolution, reduce
tablet strength
• Sodium stearyl fumarate – hydrophilic
Describe Binding agent excipients used in tablets?
• Adhesives to bind particles together during granulation
• Either added as dry powder during dry granulation or as a
solution for wet granulation
• Starch
• Polyvinylpyrrolidone (PVP)
Describe Glidant excipients used in tablets?
• Improve flow of powders or granules
• Reduce interparticulate friction – smooth surface irregularities
• Colloidal silica
Describe the disintegrating agents excipients used in tablets?
• Cause tablet to disintegrate – increases surface area
• Swell in contact with water – burst open tablet e.g. starch, croscarmellose sodium (known as a ‘superdisintegrant’)
• Some work by capillary action, drawing liquid up through pores which
disrupts bonds between particles e.g. pregelatinised starch
• Lyophilised tablets disintegrate with 5 s (orodispersible tablets), mainly
sucrose
Describe the coating excipients used in tablets
• Film or sugar coat
• Enteric coatings e.g. cellulose acetate phthallate, or polymers (Eudragits)
• Polymers for M/R release e.g. HPMC (hydroxypropylmethyl cellulose),
xanthan gum
Describe the water excipient use in liquid preparations
• Most widely used – physiologically non-toxic and compatible
• Good at dissolving ingredients
• BUT – supports microbiological growth and care with drugs
prone to hydrolysis
Describe the water excipient use in liquid preparations
• Most widely used – physiologically non-toxic and compatible
• Good at dissolving ingredients
• BUT – supports microbiological growth and care with drugs
prone to hydrolysis
Describe the water miscible co-solvents excipients used for liquid preparations
• Enhance solubility, taste and stability
• Propylene glycol, glycerol, ethano
Describe the buffer excipients used for liquid preparations
• Control pH to enable physiological compatibility, microbial
and chemical stability and solubility (or insolubility if taste is
an issue)
Describe the antimicrobial agent excipients used for liquid preparations
• Preservatives – prevent growth of opportunistic microbes
(from excipients or externally introduced)
Describe the anti-oxidant excipients used for liquid preparations
• Control oxidation of drug, preservative, other excipients
• Concentration decreases with time since they oxidise first
Describe the wetting agent excipients used for liquid preparations
• Decrease interfacial tension
• Surface active agents (e.g. Cetrimide, SLS), hydrophilic colloids
(e.g cellulose derivatives, tragacanth – also act as suspending
agents)
Describe the antifoaming agent excipients used for liquid preparations
• Simeticone
Describe the thickening agent excipients used for liquid preparations
• Stabilise suspensions – give high viscosity, often thixotropic
• methylcellulose
Describe the sweetening agent excipient used for liquid preparations
• Natural – sucrose
• Artificial – saccharin
Describe the flavouring agent excipient used for liquid preparations
• Natural – peppermint
• Artificial – butterscotch
Describe the humectant excipients used for liquid preparations
• Hygroscopic excipients for external preparations (suspensions,
emulsions) e.g. glycerol, PEGs
• Reduce evaporation of water/aqueous vehicle – prevents
drying after application and during product life
Describe Dyes and flavouring agent excipient used for tablet excipients
- dyed for identification
