Solid Excipients Flashcards
(24 cards)
Functions of excipients in tablet processing
Help manufacturing, control dissolution, taste masking, improves appearance and protect API for degeneration
Filler/dilutant Function
Reducing tablet size to make it suitable for handling. Quantity of fillers depends on quantity of API
Ideal Properties of Fillers
Chemically inert, non-hygroscopic, biocompatible (non-toxic), favourable biopharmaceuticals (efficient processing), favourable material properties, patient acceptable and cheap
Types of Fillers
Carbohydrates, sugar molecules or inorganic salts. Eg lactose
Lactose as a Filler
Most common. Relatively inert, non-hygroscopic, pleasant taste and good compatibility
Mannitol/Sorbitol as a Filler
Chewable tablets/losengez. Cooling effect. Produces laxative effect
Disintegrant Function
Tablet breaks down into smaller fragments onto exposure of water
Mechanisms of disintegrant function
Hydrophobic interactions allow holes (water absorption), sorption of water (swelling, starch), increase osmotic pressure (rupturing tablet, mannitol) and effervescent gas production (due to interaction with water, citric acid and bicarbonate salt)
Binders Functions
Ensures dosage form has adequate mechanical strength. Facilitate bonding mechanisms and deform well
Different methods of adding binder
Wet granulation: dry binder mixed in before process begins or wet binder added to solution during process. Dry Granulation: Dry powder mixed in before granulation or tablet compression
Differences between wet and dry binder
Wet: solution form (used only in wet granulation). Dry: powder (used in wet/dry granulation and before tablet compressing)
Dry Binder Outline
crosprovidone and microcrystalline cellulose
Microcrystalline Cellulose Outline
Multipurpose excipient (binder, disintegrant and Filler). Hydrolysed cellulose that has been sprayed dry (aglomerulus of crystal fibres). contains both amorphous and crystalline regions
Glidant Functions
Improve powder flowability, by reducing friction between individual particles (no cohesion). Added before compaction at low concs (minimum amount to coat. Don’t want to weigh down)
Glidant Example
Colloidal Silica
Lubricant Function
Reduces friction tablet experiences ensuring physical stability and safe release. Eg redduce friction between tablet and dye prevents fragmentation. Used in low concs as may interfere with bonding mechanisms
Lubricant Mechanisms of Action
Fluid lubrication (full layer of liquid between surfaces) and Boundary lubrication (fine solid particles form thin layer separating surfaces).
Fluid Lubricant Example
Liquid paraffin
Boundary Lubricant Example
Mg Stearate. Disadvantages low shear resistance, interferes with compaction bonding mechanisms and disintegration and dissolution inference
Anti-adherents Function
Reduce friction caused by dampness between equipment and machine.
Anti-adherents Examples
Multipurpose. Eg mg sterate, cellulose
Sorbent Function
Removes residual moisture, reducing adherence. Eg microcrystalline cellulose and silica
Flavoring Function
Masks taste. Eg lactose and glucose
Colourant Def
Alters tablet appearance
