Capsules Flashcards
What are capsules
Solid dosage forms composed of gelatin and designed to contain a drug containing formulation
2 types of capsule
Hard - 2 pieces
Soft - one piece
Advantages of capsules
Avoids manufacture operations for tablets such as granulation and drying
Can be for adults to increase oral bioavailability of poorly soluble therapeutic agents - liquid filled
Convents for liquids to be orally administered - actuate dosing
Disadvantages of capsule
Specials manufacturing equipment
Potential stability problems of liquid fills
Problems with homogeneity of full weight
Why hard
For a materials that cannot be as easily formulated as tablets due to:
- change polymorphic form on compression
- degrade on compression
- water sensitive and not easily dry granulated
Capsule design
2 piece capsules
Shorter part is the cap and fit over the open end of the longer body
Have locking grooves and dimples to close
Capsule sealing
HCG sealing for liquid or semi-solid filling
2 methods:
- gelatine ban sealing
- hydroalcoholic solvent seal
Capsule size
8 sizes
000 (largest) - 5
Weigh capacity of each size varies according to combination of drugs and their densities
Composition of HGC
Contains following:
- gelatine
- colourants
- wetting agents
- preservatives
Gelatin
Natural
Prepare by hydrolysis of collagen
2 types:
A- derived from acid hydrolysis of collagen
B - derived from alkali hydrolysis of collagen
Why gelatin
Used for >100yr
• Safety: it is nontoxic, widely used in foodstuffs and acceptable for use worldwide.
• Solubility: it is readily soluble in biological fluids at body temperature.
• Film forming properties: it is capable of producing strong flexible films
• Ease of processing
Quality of gelatine
Grade is defined by bloom strength which is defined as weight g required to depress a plunger to a defined depth within an aged gelatine gel at 10 degrees
higher the bloom the more rigid
Hard capsule = bloom of 200-250
Soft capsule = boom of 150
Colourants
Give distinct appearance
Can be water soluble dyes or water insoluble pigments
Wetting agents
Ensure the luracted metal moulds are uniformly covered when dipped in gelatine solutions
Help water penetration to facilitate dissolution
Preservatives
Added formally in process t prevent morbidly contamination
HGC contain a lot of moisture singly bonded to the gelatin
HGC manufacturing dip coating
Involves metal moulds at room temperature being dipped into hot gelatine solution which gels to form a film. Its friend, cut and removed from mould and 2 part joined together
Capsule shel thickness is controlled by….
Gelatin viscosity
Types of material for filling
Dry solids - powders, granules
Semisolids
Liquids - non aqueous
Excipients
• Diluents: increase the bulk of the working mass.
• Lubricants: reduces powder to metal adhesion.
• Glidants: improve powder flow.
• Wetting agents: improve water penetration.
• Disintegrants: produce disruption of powder mass.
• Stabilizers: improve product stability.
Drugs that aren’t recomended to be formulated into HGC
Potent
Low therapeutic index
Ideal properties of diluents
• Good flow: obtainable using free flowing diluents and glidants.
• No adhesion: obtainable using lubricants.
• Cohesion: important for plug formation, using compressible diluents.
Powder filling of HGC
Same operation: open - fill - close
Dependant and independant dosing
Dependent ; depends on the capsule’s body size, the dose is achieved by complete filling of capsule body.
Independent; controlled by the filling machine, fill is compressed into ‘plug’ at low compression forces
Bench scale
Used in hospitals for small batched
The halves are separated and powder spread to fill the capsule body. Body is locked. Powder is placed onto surface of body plate and spread to fill bodies. Cap plate in positioned over body and cap uses are rejoined.
