Solid Oral Dosage Forms 3 Flashcards
Why do we use a tablet coating?
Protect API from light and moisture
Mask flavour of bitter API
Mask colour variation of raw materials
Improve patient compliance by producing products with good appearance
Aid product identification
Aid high-speed packaging
Coatings can add functional characteristics to release
Types of coating
Film coating- most used process
Sugar coating- traditional method, widely used in confectionary industry
Press coating- minor method, increasing interest as used to manufacture complex release forms
Tablets for coating
Tablets produced to coating called the core
Robust enough to survive extra handling involved in coating process
Strong cores made, especially for film coating, using excipients producing tough compact e.g. microcrystalline cellulose adds plastic component to formulation
Film coating
Application of thin polymer film to tablet surface, film must be strong enough to withstand mechanical handling
Film coating solution consists of film forming polymer, plasticizer, colorants and solvents
Polymers- non-release modifying, release modifying
Comparison of film and sugar coating
Film coating: c. 2% weight gain, formulation: polymer, plasticizer and colorants, short process, identity marks on tablet surface can be seen through coating
Sugar coating: c. 50% weight gain, formulation: sugar, colorants and others, long process, need to print to identify
Capsule shell composition
Soft (one piece): gelatin, colorants, water, plasticizer
Hard (two piece): gelatin, hypromellose, colorants, water
Capsule identification
Colour- use combinations of approved soluble dyes and insoluble pigments
Printing- use approved pigments and lake form of dyes dispersed in organic solutions of shellac (an edible polymer)
Information- company names and logos, identity code, product name, amount of API etc.
Gelatin capsule filling
What can be filled- powders, granules, pellets, semisolids, liquids (non-aqueous solutions and suspensions)
What cannot be filled- gelatin reactors (formaldehyde), free moisture, large doses, high bulk volume
Hypromellose capsules- do not react with formaldehyde
Capsule filling: powders
Lab scale: manual devices, separate cap from body, powder filled into body with spatula
Industrial scale: dependent- use capsule body to measure dose of powders, fill uniformity requires complete filling
Independent- use separate device to measure powder to produce a plug, capsule body can be part filled
Formulation: influence of API dose
Low dose (<25mg): most of tablet or capsule formulation will be the excipient, challenge content uniformity High dose (>250mg): most of tablet or capsule will be the API, challenge, compactibility and fluidity API solubility important for both, governs selection of excipient
Disintegration in vivo
In vivo, signal from radio transmitter in pH meter, inside capsule or attached with string
Capsule filled with sodium bicarbonate
Formulation for release
Capsule disintegration
The rate controlling step is formulation of contents
Active ingredient is the most important component- formulator can modify API by changing particle size
Particle size- change by processing, granulation
Effect of contents on release
Magnesium stearate is hydrophobic, in excess prevents wetting of powder fill and slows down shell rupture
Soft gelatin capsules manufacture and properties
Shell made and sealed in one operation
Sealed at 37c
Capsule wall composition- gelatin, plasticiser (glycerin), moisture content 7-9%, wall c. 400 micrometres thick
Soft capsule formulation
Single liquids, mixtures of miscible liquids, API dissolved or suspended in a liquid vehicle
Difference from hard capsules, shell composition changed according to properties of fill
